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An S4 meter which continuously records velocity, temperature and salinity, will be deployed on the sea floor in Granite Harbour for 2 months to determine the velocity of currents responsible for carrying mud off the Antarctic landmass. A continuously recording tide gauge will be installed on nearby Cape Roberts so that tidally generated currents can be recognised.
New digital recording equipment for the Erebus seismic net from the New Mexico Institute of Mining and Technology will be linked with TV and infrasonic surveillance equipment previously established for monitoring eruptions of the volcano. This will improve the accuracy and reliability for timing and location of the eruptions.
This is the first of a 3 year programme to monitor the climate, hydrology and sediment transport. The valley is typical of many in the region. The study will help understand the effect on climatic change on glaciers, streams and lakes and sediment transport.
This begins a 3 year programme to determine the geography of the Ross Sea region during Beacon times 400 to 140 Million years ago. The study continues and builds on earlier work at VUW on these sedimentary strata, and will allow inferences to be made about changes in crustal structure and climate during this period.
A current meter mooring with eight small (400 cm2) sediment traps was deployed in 702 m of water near the snout of the McKay Glacier for 53 days between 15 November 1988 and 6 January 1989. The current velocities 1 m above sea floor average between 6.9 and 4.3 cm/s with intermittent speeds up to 10 cm/s. These speeds are considered capable of resuspending fine sediment to form a near bottom nephloid layer, and this is confirmed by much higher sediment fluxes below 520 m. The dominant flow direction at this site is towards the glacier tongue (240° – 270°T) but "daily" swings occur towards the south which are most likely related to the diurnal tidal cycle.
Tidal data were recorded continuously for fifty days (19 November – 8 January) from Cape Roberts, the first continuous tide record from the Antarctic continent in the Ross Sea sector. The Cape Roberts tide gauge is designed to record throughout the year and thus should provide data to establish a mean sea level bench mark as well as record relative sea level change over a longer period.
The purpose of this project is to investigate mud-carrying bottom currents in Granite Harbor. Such currents have been suggested as the explanation for the deposits of mud flooring the deeper parts of McMurdo Sound and the basins/harbors along the southern Victoria Land Coast, (Barrett et al. 1983, Kelly 1986, Macpherson 1987). There is no single obvious source or depositional process for the mud deposits although Anderson et al. (1984) suggested impinging geostrophic currents and subglacial meltwater as potential sources.
In the Granite Harbor sedimentary system there is good circumstantial evidence of mud transport in a sea floor nephloid layer Macpherson (1986), Dunbar et al. (1985), Dunbar & Leventer (1987). Macpherson (1987), suggests these currents might be density driven from under the glacier tongue.
This season's program was designed to check on bottom currents originating from beneath the Mackay Glacier Tongue in Granite Harbor. A single current meter/sediment trap mooring was to be set for about 2 months (November – January) at the snout of the Mackay Glacier Tongue. During the 1987–88 season a 14 hour deployment at this site recorded low velocity (<10 cm/s) flows which exhibit progressive changes in direction and duration that appear to be related to the diurnal tide cycle. A tide gauge was also to be established at Cape Roberts initially to record the tide cycle during the period of the current meter deployment and if successful remain to continue recording during the following year.
A north-south bathymetry profile was measured across the north-eastern tip of the glacier tongue to determine the deepest part of the channel striking east from under the glacier tongue. Eight 250 mm diameter holes were drilled through 3 m thick second year sea ice and a 28 kHz echosounder transducer lowered through the holes to record water depth.
The InterOcean S4 current meter was then set one metre off the bottom in about 702 m of water to check the mooring design and that the instrument was functioning correctly. Two days later on 15 November the current meter was recovered, checked, reprogrammed and redeployed on a mooring with 8 small (400 cm2) sediment traps (Figure 1).
The fast ice on the eastern side of Cape Roberts forms a well developed ice foot each season with the tide crack between 8–12 m from the exposed rock on shore. Several sites were checked and the ice foot drilled to determine water depth profiles beneath the ice foot. We intended to install the tide gauge vibrating wire pressure transducer through the ice foot within a 2" galvanised pipe that would be bolted and possibly cemented to the shore rock face. Unfortunately a suitable site for cementing was not available and we had to be satisfied with terrier bolting 10 m of pipe to rock face (Figure 2). A 3 m deep hole was cut into the ice foot with a chain saw to install the transducer pipe, finally using a drill to break through to clear water below.
The data recording system consists of a Campbell CR10 data logger, 135 Ahr (C20) lead acid battery and 22W (GL125-M25) solar panel mounted on a tripod frame located about 10 m from the surface end of the transducer pipe. A tide gauge bench mark has been established by the NZARP surveyors and the height of this will be progressively refined as more tidal data is recorded.
We had also hoped to determine the tidal time lag between Cape Roberts and inner Granite Harbor by establishing a temporary tide station at Cuff Cape 22 km away. Unfortunately because of time constraints this was carried out during the neap part of the tide cycle (17–21 November), and the results have poor resolution.
This phase of our program was carried out using surface transport (ASV and trailer) on the sea ice. We were not subject to the poor flying weather this season and consequently the program went smoothly. The extent of fast sea ice along the Victoria Land Coast was much less this season than for the last 8 years but still suitable for safe surface travel to Granite Harbor from Scott Base. In Granite Harbor second year sea ice was present west of a line between First View Point to Cape Archer and this made travelling slower and more difficult than usual.
The mooring was recovered during the evening of 6 January after flying by helo' to Granite Harbor from Scott Base. The mooring's sea ice anchor had melted about 30 cm into the sea ice and was partly refrozen. Melting of the sea ice around the site was less than expected and was probably due to a cloudier than normal summer in this area. Recovery of the mooring went smoothly once the subice line had been caught through a newly drilled 30 cm ice hole adjacent to the mooring line.
The Cape Roberts tide gauge was checked the following day after the helo move from the mooring site to Cape Roberts. The previous 50 days data was downloaded using a Zenith lap top computer at the tide gauge site. The data logger was then returned to the Cape Roberts hut where new power supply protection was installed and a new recording program downloaded into the logger. The following 36 hours were spent periodically levelling the sea surface to recalibrate the reinstalled logger. A swell surge with a range of up to 8 cm was measured with the ice edge still about 3 km to the east.
The tide gauge has now been programmed to record through the winter months to November 1989. The instrumentation is rated to −55°C and should theoretically continue to operate during the winter. However, we are less confident that the transducer pipe will remain it the ice foot floats off. By 9 January the bottom part of the pipe was still frozen solidly into the base of the ice and there was little evidence of basal ice melting around the pipe. We had expected basal melting would occur, thereby freeing the pipe before icefoot breakout. The life of the lead acid battery power supply is also of some concern during the winter months even though theoretically it should not freeze if it remains sufficiently charged during the winter.
Fifty three days of continuously recorded data (15 November – 7 January), was recovered from S4 current meter at the Mackay Glacier Tongue site. Current velocities are low as expected with 10 day averages between 6.9 and 4.3 cm/s and intermittent speeds slightly in excess of 10 cm/s. The dominant flow direction is towards the glacier tongue (240°-270° true) with "daily" swings towards the south that appear to correlate with the main diurnal tide cycle.
At Cape Roberts 50 days of continuous tide data (19 November – 8 January) was recovered giving 48 days of data common between tide gauge and current meter. The tide data shows a dominant diurnal cycle with a maximum measured range of 1.192 m. Neap tides occur approximately every 14 days and are semidiurnal for about two days.
More detailed comparison between the tide record and current meter data is yet to be done but a preliminary comparison suggests a correlation between spring/neap tide cycles and current velocity/direction. However this correlation is out of step by about 2–3 days which is greater than expected and suggests a more complex coupling of tide and circulation within Granite Harbor than first thought.
The eight sediment trap samples showed a much greater "apparent flux" in the bottom four traps below 520 m than in the upper four traps. This result is similar to previous trap data from the inner basin in Granite Harbor and supports the contention that fine-grained sediment is resuspended from near the sea floor in this basin. The current velocities measured this season are certainly capable of maintaining this sediment in suspension. The trap samples will be analysed for opal content and organic carbon by Dr R. Dunbar at Rice University as part of our cooperative program.
The results of this year's program will be analysed during 1989 and written up jointly with R. Dunbar (Rice University) in this year.
Part of our program submitted for the 1989/90 season is to repeat this study at a site towards the mouth of Granite Harbor away from the influence of the Mackay Glacier. Measurement of bottom current velocities and water column sediment flux will help us to quantify the sediment contribution flowing into the inner basin of Granite Harbour from the Ross Sea. This seasons results have proven the value of collecting data with automatically recording instruments in the Antarctic. We intend to continue recording tidal data at Cape Roberts. The ability of the tide gauge to record data throughout the year is still to be proven but we anticipate that some refurbishing and modification of the tide gauge will be necessary next season to achieve the goals of measuring long term tidal change from the continent in this area of the Ross Sea.
This season's program went very smoothly and we thank the staff of Antarctic Division and all the staff at Scott Base for efficiently implementing our field program. We are especially grateful to John Alexander (Scott Base Operations Manager) the Scott base mechanics, Store Personnel, Garth Varcoe and his group who moved some of our equipment to Cape Roberts early in the season.
NZARP Surveyors, Garth Falloon and Pat Sole, provided invaluable survey assistance and helped establish the Cape Roberts tide gauge.
The VUW Mechanical Workshop maintained and built new equipment for this program which included the tide gauge frame and mooring recovery equipment. Eric Broughton (VUW RSES) and Peter Issacs (NZ Meteorological Office), helped with the development and programming of the tide gauge and NZ Oceanographic Institute (DSIR) maintained the S4 current meter.
Digital recording of Erebus seismic activity began on 25.11.88, using a PC-computer-based system in parallel with the Japanese analog tape recorder. Activity was very low. Daily earthquake counts ranged from zero to c20, and few of these were explosion earthquakes. Equipment on the volcano was mostly OK, but no picture was present on the TV transmission.
The heated plastic-coated window fitted to the camera housing last season was obscured by volcanic sublimates, and the camera had a serious intermittent fault which necessitated its return to Philips NZ Ltd, but Dr Phil Kyle of S-081 loaned his NTSC colour camera, which was installed on 9 December, and recorded at Scott Base until 30 December. The lava lake was so inactive that no incandescence was recorded, and only a few explosions were seen to eject bombs. After our repaired camera was reinstalled on 30 December, its superior infrared sensitivity revealed convecting hot lava not seen in the colour transmissions.
By 8 February, when the last recordings were dispatched from Scott Base, 177 digital earthquake recordings on floppy disk, and 16 explosions with ejected bombs had been recorded. Those processed so far, confirm that the foci obtained using stacked seismograms of explosion earthquakes, and a velocity of 4 km/s in the volcano, are much shallower and nearer to the lava lake, and have smaller RMS errors (0.02 s) than those obtained from individual explosion earthquakes using the old 2.1 km/s velocity (0.33+/−0.14 s).
Recording of the Windless Bight Infrasonic Array recommenced on 27.11.88 after a gap since late August 1988, due to tapes going astray in the Scott Base Store. Both field and lab equipment were still operating well, but the RTG Hut at Windless Bight was visited for safety checks, and to raise the antenna, and adjust the power supply. The off-line analysis computer was shifted to Victoria University, and the accumulated tapes since 1987 are being searched for signals from Erebus, and other volcanic eruptions world wide.
Erebus is a unique volcano in its high latitude location within a tectonic plate, and its persistently active lava lake of phonolitic composition. In an aseismic region, more than 100 volcanic earthquakes have been recorded in a day. The larger (M=c1) accompany the 3.6 +/−2.7 strombolian eruptions observed per day during summer expeditions. The largest observed eruption (17/9/74) had air wave energy 1.6x10E9 joule, and seismic magnitude M=2.4.
Video recordings of the eruptions, begun in December 1986, show that they occur too early to be triggered by earthquakes at depths up to 4 km, as previously hypothesised, and are probably the source of the earthquakes, and at shallow depth. It was also found that similar explosions have similar seismic waveforms, as in earthquake families, and that when these are stacked to improve the quality of the seismic onsets, the apparent velocity is 4.0 km/s, which is much higher than that previously determined by minimising the time residuals during focal determination. The probable consequence is that the previously determined distribution of explosion earthquakes in a column down to 4 km depth is in error. The digital seismic recordings begun this season, allow the data
The infrasonic recordings of Erebus explosions have always had a controlling influence on the interpretation of the seismic data, and in 1984, the recordings from the Windless Bight Infrasonic Array were complete enough to describe the explosions and calculate the quantity and rate of gas release during the enhanced activity of Erebus. As well, the Windless Bight Array has recorded large eruptions from all over the world.
Disappointingly WBA became no-man's-land from 1985 to 1988, and although it is now agreed to be part of IMEEMS, approval to operate it past the end of 1989 has not been forthcoming. A tragedy I think!
We installed our new digital seismograph, consisting of a Compaq 286 Deskpro computer with a 40 Mbyte hard disk, and 1.66 Mbyte of RAM, in the Science Lab beside the existing Sony and San-ei recorders. It is fitted with a Data Translation DT 2821 A/D board with 16 inputs sampled 100 times/s, and was programmed by Dr W.H.K. Lee of USGS, Menlo Park, CA. Although it displays the seismograms continuously on the computer screen, it only records when it is triggered by a large enough earthquake, or by serious electrical interference (such as the D-region Radar). These events are stored and later edited to remove false triggerings, and transferred to floppy disks. This data can be displayed on another computer one channel at a time, filtered, and the onset times picked for focal location using program Hypo71.PC. A full range of seismic programs for IBM PC computers has been provided by Dr W.H.K. Lee.
Static electricity was a serious hazard to the computer, and was possibly the reason that only Howard Nicholson's printer would work with our computer. Our printer was OK with his computer. To prevent further trouble, we earthed the computer table, and zapped ourselves on it before touching the computer. Misinterpretation of some teething problems with the program resulted in the hard disk becoming non-accessible, and we were grateful to Mr Bill Schmidt of the McMurdo Communications Message Centre for help in retrieving it.
Skilton, MacKay, and Dibble flew to Fang acclimatization camp on 30 Nov., but cloud prevented the helicopter returning with Grizzly G2, and it was left at Cape Royds until 2 December. Gentle 17 brought it up, but had trouble releasing the hook, and could not lift us to the hut. Attempts to drive up with 2 people on the toboggan (as laid down by the Operations Manager) were unsuccessful, but when S-081 arrived, we obtained permission for Bill McIntosh to drive up alone.
Continuing cloud deprived us of US Skidoos, and G2 was used to move both parties to the hut on 4 December. The TV camera, infrasonic microphones, and long period horizontal seismograph all needed servicing this season. The plastic coated heated window fitted to the camera box last season had become opaque, and was replaced by an acrylic window.
The camera had an intermittent fault, and had to be sent to Philips in Auckland for repair. Phil Kyle also had a TV system on the volcano to monitor crater activity at the Erebus Hut, but when he discovered his transmitter was unusable, we agreed to connect his NTSC colour camera to our transmitter, and it was recorded at Scott Base. We are sharing this data. Our camera was returned
New infrasonic pressure sensors of type SCX05 DN were installed at E1 and CON in place of the low sensitivity LX0503A types installed last season, and the long period horizontal seismometer was readjusted. Ice buildup in the rock recess around it appears to delevel it. 10-19 December: Re-activating the Windless Bight Infrasonic Array.
The array had been idle since August 1988 because the new tapes had been mislaid, and the off-line analysis computer had faults in the monitor and printer. The Array (Fig. 1) consists of 7 condenser type microphones arranged in two quadrilateral arrays - one large (RTG,ERE,TER,ROS) and one small (RTG.5,6,7), with one microphone common to each. Each microphone has an acoustic filter consisting of a 91 m long pipe with holes spaced along it, for the purpose of reducing wind noise. The pipes, RTG hut, and telemetry antenna are being progressively buried in snow, increasing the low pass filter effect, and threatening the RF signal level. Preamplifiers, VCO modulators and RF transmitters are powered by a radio-thermoelectric generator (RTG) in the hut at the common microphone, ensuring continuous operation. Initially of 40 W capacity, the RTG has decayed exponentially to c11 W, but the loading resistor intended to soak up the surplus power had not been removed.
At Scott Base, the analog signals are filtered to give bandwidths of 1 to 10 s for the small array, and 7 to 70 s for the large array, and digitised, 4 times per second for the small array and once a second for the large array, and after on-line processing in blocks of 128 s, are recorded on 800 BPI tapes lasting 5 days each. I was able to get the off-line computer to scan these tapes by exchanging components between two faulty unused consoles, but there was no serviceable serial input printer. This was my first success in reading the tapes since my 1984 visit to University of Alaska (attempts always stopped at the question "do you have the source code"), and so I requested and received permission to shift the off-line computer to Wellington.
The RTG hut was visited on 14 December by R. Dibble, K. MacKay, H. Nicholson, T. Exley, T Eason, M Van der Sluy, and Bill Schmit. The loading resistor was removed, restoring the 11.5 V supply to 12.0 V, and the RF outputs were measured, being within 65 to 250 mW on all 7 channels.
Currents to all microphones were 19-20 mA, and all were transmitting carrier tone. Apart from being untidy, and buried in snow, the hut and equipment were in excellent order. McMurdo had already checked the RTG itself.
The recorded tapes are being processed in two ways, using the programs provided by University of Alaska. SCAN and AZSCAN search the on-line analysis results recorded on the tapes, and print out times, amplitudes, spectral peak frequency, and arrival direction and velocity when the cross correlation coefficient exceeds a chosen level. These programs run very fast, but it is only the best correlated signal in any 128 second block which is returned. Brief eruption signals from Erebus are ignored unless very large. The other option is to reprocess the original digital waveforms, using BEMSCN, DATPLT, SPCTRM, and others. Of these, BEMSCN was specially modified for me by Mr B. Mckibben of the University of Alaska, to find the cross correlation coefficient of signals with Erebus azimuth and infrasonic velocity, and also the ratio of peak to RMS amplitude in each two minute block. Computer time was 9 s per block, Erebus is a frequent source of wind eddie signals, but only explosions give a high peak to RMS ratio.
Also in this period, a major effort was made to reduce the number of false triggers of the digital seismograph by the D- region radar. The frequent short duration high power radar pulses have a wide bandwidth, and the large horizontal loop antenna practically above the Science Lab induces strong signals in everything. Steps to reduce their effect included: (i) running the entire IMEEMS installation off one power point (because neighbouring points had separate long cables from the fuse box); (ii) running the computer from an isolating transformer and power filter; (iii) having a single common earth point at the power point for all chassis, racks, and table frames; (iv) coiling
Prof Kaminuma and Kevin MacKay made chart records of all earthquakes well recorded on the Sony data-tape recorded, and printouts of the digitally recorded earthquakes. The latter were also archived onto floppy disk, at a normal rate of 5 per disk. This will allow 1500 earthquakes to be recorded on our 300 disks during the year. They also made continuous video tapes of Erebus TV, and recycled the tapes with no useful information, and made both PAL and NTSC copies of all the eruptions recorded for distribution to collaborators.
Earthquake families were recognised by cross correlation of different earthquakes recorded on the same channel, using programs written by M. Iguchi, and after stacking to improve waveform clarity, the onset times of the stack were used to locate the family focus. These times, when used with the new 4 km/s model, give an epicentre 120 m from the lava lake, and depth 340 m below it, with an RMS time residual of 0.02 s. Using the old 2.1 km/s model, and the onset times of each of the 8 separate explosions in the best family, the epicentres were a mean distance of 2170 m +/−2470 m from the lava lake, and depth 6.2 +/− 4.4 km below it. The mean RMS residual was 0.33 +/−0.14 second.
Thus the new higher velocity model results in foci for explosion earthquakes which are shallower and nearer the lava lake than for the old velocity model. However, it is the stacking which produces the improvement in error statistics, not the change in velocity.
The work will be presented at the conference on Continental Magmatism at Santa Fe this year. Papers on IMEEMS published in 1988 are as follows:
Dibble, R.R., 1988: Infrasonic recordings of strombolian eruptions of Erebus, Antarctica, March-December 1984, covering the jump in activity on 13 September 1984. Proceedings in Volcanology, Vol.1, Elsevier, J.H. Latter (Ed).
Dibble, R.R., Barrett, S.I.D., Kaminuma, K., Miura, S., Kienle, J., Rowe, C.A., Kyle, P.R., McIntosh, W.C., 1988: Time comparisons between video and seismic signals from explosions in the lava lake of Erebus volcano, Antarctica. Bull. Disaster Res. Inst., Kyoto Univ., 38 (3):49-63.
Kaminuma, K., Dibble, R.R., 1988: An eruption process of Mount Erebus, Antarctica. Proceedings of the Kagoshima International Conference on Volcanoes, 1988: 66-70.
Kaminuma, K., Dibble, R.R., 1988: Geophysical studies on Mount Erebus, Antarctica. Proceedings of the Kagoshima International Conference on Volcanoes, 1988: 242-245.
Shibuya, K., Baba, M., Dibble, R.R., Kyle, K., 1988: Classification of volcanic earthquakes at Mount Erebus, Antarctica. Proceedings in Volcanology, Vol.1, Elsevier.
It is anticipated that sufficient digital earthquake recordings will be available by the end of 1990 to define enough earthquake families to establish an approximately correct velocity structure, and focal distribution within the volcano. The NSF owned telemetry seismographs on the volcano may need major renovation by that time also, but grant applications for this have not been approved since 1984. Consequently, the present leader plans to remove the VUW equipment from Erebus, for probable re-deployment on Taranaki volcano, which is showing signs of reawakening. Also, his compulsory retirement on 13 June 1991, will impede further work in Antarctica.
However, I see volcanic seismology as near the end of the pioneering phase, in which researchers settled for minimum equipment to obtain the skeleton of the situation. Already the earthquake seismologists are using arrays of 100 to 500 geophones to study earth structures far simpler than a volcano. The ease and reliability with which Erebus has been instrumented may attract more ambitious researchers. Until then, the activity of Erebus is important and unique enough to warrant a minimum monitoring program, by one or two telemetry seismometer/ microphone stations and a two channel San-ei long term ink-chart recorder. I would recommend Truncated Cones for the telemetry site, because it has very good signal/noise characteristics, and is easy to reach by motor-toboggan from the lower hut on Erebus. If the present equipment there could be acquired from NSF, maintenance costs would be minimal.
Historically, Victoria University has refused to support monitoring programs on volcanoes, handing the equipment at both Ruapehu and White Island volcanoes over to DSIR when the work reached that stage. They may do the same at Erebus, but I consider that the TV surveillance equipment is too precarious for long term monitoring, and that a 16 channel digital seismograph would be wasted on only two channels. I would be happy to consult and cooperate with anyone about this. NIPR and/or NSF may be interested.
The infrared thermometry work which was part of IMEEMS in 1986/7 and 87/8, but omitted in 1988/9 due to the NIPR application to RDRC going astray, should be continued to help assess the total heat output of the volcano, using satellite infrared data (by The Open University), and plume observations from TV and COSPEC measurements of SO2 flux (by the New Mexico Institute of Mining and Technology).
Problems of International cooperation surfaced this season when an application to RDRC for NIPR participation in IMEEMS went astray in the mail. An attempt to have the application approved in reduced form at a later date was unsuccessful, and it was fortuitous that one of the approved VUWAE members resigned to emigrate, and enabled Prof K. Kaminuma to be approved as his replacement, and invited to Scott Base by Hugh Logan. Official invitations are a special feature of Japanese society.
I thank everyone concerned for this solution, which also satisfied DPP, and put us on a friendly footing once more.
Special thanks are due to Hugh Logan for oiling the diplomatic wheels; David Crerar for getting the RTG checked by McMurdo; John Alexander for the smooth field operations, Phil Robins for making G2 available for familiarisation; John Skilton for curing the oil leaks in G2; Terry Eason for extending the WBA antenna masts, Howard Nicholson for lending his printer; Bill Schmit for retrieving our hard disk; Phil Kyle for lending his colour camera; Bill McIntosh for installing it, and helping diagnose the faults in ours; Philips Industries for fixing ours in time, and Neilya Dunbar for reinstalling it.
This project involves a three year hydrological, glaciological, and sediment transport monitoring programme in the Miers Valley.
Information required to study and quantify the energy and mass balances of the glacier-river-lake system will be collected.
The data will permit:
During the 1988-89 season three automated hydrometric sites were installed together with climate monitoring equipment. All the equipment and software was fully tested and functioned well during December and January. Quarter hourly data values of fourteen different variables at 3 sites were recorded. Networks of ablation poles were installed on the Miers and Adams glaciers and a considerable amount of survey control was established. The sedimentary facies of the valley were mapped and the aeolian sediment transport processes monitored.
An initial examination of the hydrologic and climatic data indicates that:
The sediment samples are currently being analysed and this must be completed before any definitive comments can be made. However, it would appear that the average, "long term", sedimentation rates are slow but that periods with extremely high rates occur periodically to produce a disjoint stratigraphy.
The principal aims of the 1988-89 programme were therefore to:
While much of the proposed work for the 1988-89 season was of a preliminary nature the achievements were significant.
Three hydrometric sites were installed within the Miers Valley. A 120° "V" notch weir was established on the Adams Stream approximately 150 m downstream from the glacier front and a 60° "flume" was installed on the Miers, also approximately 150 m downstream from the snout. The third site, a 120° "V" notch weir, was installed on the lower Miers, approximately 300 m below the lake outlet. The two upper valley sites had backup Foxboro recorders installed as well as Geokon transducers linked to Campbell CR10 dataloggers to record stage height. The lower site was only monitored by a Geokon transducer and datalogger.
The weirs were installed in trenches approximately 7 m long (depending on the site characteristics), 400 mm deep, and a minimum of 300 mm wide. The upstream faces of the weirs were lined with PVC sheeting and backfilled with sand to prevent leakage. The wing-walls were extended with sand bagging, PVC sheeting, and hessian as required by the nature of the specific site. Leakage at all sites was less than 0.1% and it is believed that after the present winter, that is once the sites have refrozen, leakage will have stopped completely.
At each site special gauging reaches were constructed and over 20 gaugings were undertaken to develop a rating curve (calibration of stage height against discharge) for each weir. These rating curves would appear to be very accurate with little scatter about the best fit line.
In the coming season the transducers will be sealed in anti-freeze and a rubber membrane to prevent freezing and the resultant change in calibration offset. With regular maintenance this, however, was not a major problem last season.
The Water Resources Survey DSIR site in the Garwood valley was also maintained by K046 during the 1988-89 season.
Two fully automated climate stations were established close to the hydrometric sites on the upper Miers and Adams Streams. These sites monitored air temperature, water temperature, humidity, incoming solar radiation, wind direction and speed, and soil temperature. All the sensors worked well, as did the data loggers which collected all the data, and a data record spanning 21/12/88 until 20/1/89 was recovered.
Various pieces of software were written to calibrate the sensors and control the data loggers. All this software appears to have functioned well under the conditions found in the Miers valley.
Three rows of five ablation poles were installed on each of the Miers and Adams glaciers. The poles were placed in holes drilled 1.2 m into the glacier surface and were marked with flags for relocation. The position of each pole was determined from survey control sites adjacent to and above each glacier. Movement of the poles and the ice around them will be monitored in future seasons.
Forty-four benchmarks were established by DOSLI during the period 1980-83 in the Marshall and Miers Valleys (L&S 37/99). Two of these stations were subsequently "doppler" fixed.
Seven of these benchmarks, BMM21-BMM27 were used during the 1988-89 season as a basis for control in the Upper Miers Valley. BMM21 is one of the doppler-fixed stations. BMM21 (Adjusted position) 163° 47′ 15.988′E 78° 05′47.086′S H = 164.080 m asl
All seven DOSLI stations were observed and measured by K046. Five new stations were established to provide a triangulated control over the Upper Miers Valley. All lines to these 12 stations were observed and measured. One MWD lake level station was located and tied-into the above network.
Five new stations were established above and along the south-east side of the Adams Glacier to provide control stations to locate ablation poles on the glacier surface. All lines were observed and measured. Three similar stations were fixed above and along the south edge of the Miers Glacier.
Three stations were set-up to control each of the weir profiles and all lines to these stations were observed and measured. One station was set-up at the western end of Lake Miers to provide a control for levelling the lake surface. This level station was defined by repeated readings from BMM21. One station was set-up to establish the height of Keyhole Saddle. Nine stations were established to provide control for measuring the Adams glacier snout and five similar stations were established for measuring the Miers glacier snout.
Three profile lines were measured and observed through the swales among the moraine ridges and six stations were established to provide control for the lake ice level survey.
All the above stations were marked permanently and "cairned" for easy location. The locations of the stations on the rocky slopes above each glacier were described in detail and indicated by direction markers beside the glaciers.
Twenty-one photogrammetric height and planimetric control marks were established. Suitable features were observed and measured and graphically described to assist aerial photographic identification.
At each of the three weirs, observations and measurements were made to establish stream bed profiles. The observations were made using the SET-4 EDM and a prism mounted on a hand-held range pole. Observations were taken at 50 cm intervals, reducing to 1 m over the near-level flood plane. In all 10 profiles were measured, each involving between 19 and 34 readings.
Three profiles were measured using the conventional automatic level and levelling staff. The ends of the profiles were fixed by observation and measurement from the nearest benchmarks.
Three rows of ablation poles were set into each of the glacier surfaces. Those on the Miers Glacier were fixed by observations from 2 control stations and measured from one. The Adams Glacier poles have been fixed by observations from 3 control stations. Bad weather conditions made distance measurements impossible.
Nine control stations were established for the Adams Glacier and 56 marks, approximately 10 m apart, were set-up on the ice front. All 56 marks were observed from two stations with 18 observed from three stations for better control. At each mark the front of the icefall apron was observed and measured, as was the interface between the ice-fall apron and the vertical glacier front. The top of the glacier face was also observed from two stations. A similar procedure was carried out for the Miers Glacier.
Three lines were surveyed across the western portion of Lake Miers with eleven ice stations and two shore stations being observed and measured. At each lake station the features were measured and described.
Lake levels were measured at the eastern outlet of Lake Miers using the existing MWD control. At the western end of the lake a new levelling station was established and readings taken. Lake Salina was also levelled and profiled.
Assistance to DOSLI A member of K046 assisted K191 to measure and observe a number of benchmarks in the Garwood, Marshall and Miers Valleys to ensure that the necessary adjustments can be made to provide accurate survey and height control for these areas for the first time.
A number of observations were made of the surrounding peaks from the benchmark control in the valley.
"Sketching-up" of the data was attempted in the Miers Valley as the surveys progressed. As yet, accurate plotting has not been undertaken except for a basic triangulation to establish enough control to fix the scale and planimetry of a map produced by photogrammetric plotting. This work provided the base for a geological map of the Miers Valley.
An attempt is also being made to describe and explain the aeolian features found in the upper Miers Valley. A series of "megaripples" originate on the Miers-Adams delta at the western end of Lake Miers and appear in a series of swales delineated by lateral moraines paralleling the north side of the valley.
The "megaripples" or granule/pebble ripples (Sharp, 1963) are low amplitude ripples of relatively long wavelength, having a ripple index of about 20-23, and are asymmetrical in shape. They are chiefly composed of granule to pebble size material and are formed by the impact of saltating sand particles creating surface creep rather than direct movement by the wind (Sharp, 1963). Such ripples have been described before in the Antarctic Dry Valleys (Selby et al 1974; Smith, 1966) and in other parts of the world (Bagnold, 1941; Sharp, 1963; Weir, 1962).
These ripples were mapped and measurements taken of their size (windward and lee slope heights and angles) and extent. Their orientation and the general ground slope on which the features were located were also recorded. Profiles were surveyed across the area in which the features occurred to aid their description and to place them in topographic context.
Samples were taken of the source material; of the material forming the windward and lee slopes of the ripples; the material forming the "armouring" layer at various locations; and the subsurface material.
A number of "tails" formed in the lee of large rocks were also measured for height, slope, and length for study in relation to the size of the obstacle i.e., rock.
In addition, a number of simple aeolian sediment traps were set to sample the sediment being moved by the wind during our time in the valley. Ten traps were positioned about the upper Miers Valley in locations determined by potential sediment supply and wind direction.
The traps were also positioned at various heights above ground level to check for any vertical stratification in particle size and quantity within the air mass. These traps were moved on several occasions to provide as complete information as possible of the summer aeolian sediment transport pattern.
During reconnaissance mapping of the Koetlitz-Blue Glacier region Blank et al (1963) noted glacial sediments of varying ages in the Miers Valley. In a more recent hydrological study, the Water Resources section of the Ministry of Works noted fluvial transport of sediment, and Hendy (1987, 1988) and others have examined lacustrine sediments and evaporite deposits in the valley. It was also assumed that aeolian sediments existed in the valley because wind transport and
Further characterisation of these deposits by laboratory analysis; using grain properties, stable isotope data, and recreating certain environments in the flume; in conjunction with observations of contemporary sediment movement, are expected to provide more detailed knowledge of their mode of deposition and inter-relationships. Aeolian and fluvial sediment traps, designed to measure the full range of moving sediment, were operated within the valley throughout the field study period.
Petrographic studies, and a study of the processes and paleoclimatic history, should link the deposits and allow a reconstruction of the Quaternary history.
An initial examination of the hydrologic and climatic data indicates that:
Work undertaken during the 1988-89 season will be published in the following manner:
The results of the 1988-89 season were expected to be "preliminary" and "preparatory" for the work outlined in the above abstract. In this respect the season yielded significantly more information than hoped for and was therefore a tremendous success. In the coming season it is hoped to:
This data should allow the determination of the energy and mass balances of the Miers Valley as discussed in the original proposal.
The success of the 1988/89 programme reflects the tremendous assistance received from many persons. The University Grants Committee provided the basic expedition funding and the Internal Research Committee of Victoria University funded all the prefabricated weirs and flumes, and the data logging equipment and sensors.
Graeme Hewitt and the staff of the Mechanical Workshop at Victoria University constructed all the weirs, flumes, sediment traps, and instrument mountings within a very short time frame. A tribute to their work is the fact that all the pieces slotted together with the precision of a jigsaw on arrival in the field. The quality of the data collected hung on their craftsmanship which could not be faulted.
Staff at Scott Base, but in particular John Alexander and Phil Robbins, assisted the project in many ways including finding a replacement PC at short notice at a critical time in the project. This was the best field season that I have had on the "Ice" in terms of support from Scott Base and this is a credit to the summer staff hired by Antarctic Division.
Martin Doyle (Water Resources Survey technician) provided considerable assistance with the installation of the weirs and flumes early in the season. His company was also much appreciated by the event personnel.
Finally, I acknowledge the assistance provided by IBM (NZ) Ltd in loaning an IBM Convertible PC for the duration of the season. When a disk drive in the first machine failed as a result of the sandy environment they sent a replacement at very short notice. Without this equipment the project would not have been able to go ahead.
Exposures of Beacon strata in the Darwin Mountains, Cook Mountains and Britannia Range and in the Convoy Range-Allan Hills area were visited during the 1988-89 Antarctic field season The field program involved measurement of stratigraphic sections, paleocurrent directions, facies interpretation and a systematic study of trace fossil distributions.
Initial findings from the project include:
Devonian strata from southern Victoria Land have been variously interpreted as marine (Vialov 1962, Allen 1962, Gevers et al 1971, Bradshaw 1981, Gevers and Twomey 1982) and non-marine (eg Gunn and Warren 1962. Webb 1963, Barrett and Kohn 1975, Plume 1978, Barrett 1979, Sherwood et al 1989); the debate largely results from the presence of trace fossils that have previously been considered to indicate marine environments in sediments which are strongly indicative of alluvial plain deposition.
The large scale setting of the Beacon Supergroup is also under debate with some authors holding the view that the Beacon was deposited in a foreland basin while others believe that the strata were deposited in a intracratonic basin.
This program is examining both the local and large scale depositional setting of the Beacon in southern Victoria Land. Field work is concentrating on solving problems such as paleoenvironment, paleoslope, basin shape and provenance of the sediment, With computer based modelling being used to examine the regional tectonic setting.
A three man party was put in to the Darwin Glacier near Richardson Hill, by LC-130 aircraft, on November 16. The party travelled by sledge and motor toboggan visiting exposures in the Darwin Mountains, Cook Mountains and in the Britannia Range. The second phase of the expedition was seriously effected by a 17 day aircraft delay on our pull out from the Darwin Glacier. It was hoped that 1:50,000 geological mapping of the northern Convoy Range and Allan Hills would be undertaken and published in conjunction with the NZGS however air photos ordered by Antarctic Division for this work were not forwarded to the field party in time for the work to be undertaken.
Two Grizzly toboggans and three Tamworth sledges were used in the Darwin Mountain phase of the program one Tamworth being reserved to carry fuel while the others carried camp plus general cargo. The duration of camps ranged from three to ten days during which time the party worked locally, using motor toboggans and a sledge for local transport.
The Darwin Glacier area is in places heavily crevassed and areas of blue ice are common, travel was generally slow and accident free. The party was returned to Scott Base on Jan 5 and Henare returned to New Zealand the same day. A two man party was flown to Elkhorn Ridge (Convoy Range) on Jan 7 and worked from a fixed camp for ten days. The party was joined by Peter Barrett on Jan 17 and moved to Allan Hills for six days before returning to Scott Base on Jan 24.
Sections were measured at numerous localities in the Darwin Glacier area, the Devonian sections show the lower half of the Taylor Group (below Hatherton Sandstone) to be of similar 0 thickness in both the Darwin Glacier and Knobhead areas. The upper part of the Taylor Group (Hatherton Sandstone and above) is significantly thinner in the Darwin Glacier area. A number of sections were also measured through the Victoria Group and these will be compared with strata in the central part of the basin following the 1989-90 field season.
The reappearance of abundant pebbles near the top of Junction Sandstone (?Lower Hatherton Sandstone, Haskell et al 1965) is correlated to the appearance of scattered pebbles near the top of Altar Mountain Formation in the Knobhead area. A platform developed at the boundary between Junction and Hatherton Sandstone is littered with well rounded quartz pebbles which are very similar to the quartz pebbles that litter the platform identified at the Attar Mountain Formation Arena Sandstone boundary in the Knobhead area. Field characteristics (including trace fossil assemblage) of the Hatherton Sandstone are very similar to those of the Arena Sandstone and the units are inferred to be equivalent. The discovery of Aztec Siltstone by a party led by Margaret Bradshaw
et al (1965) is incorrect.
The presence of paleosols, desiccation polygons, red beds, small scale channels, intraformational conglomerate, plant fossils and carbonaceous shale in all formations except the Hatherton Sandstone indicates the Taylor Group to be non-marine. The absence of many of these features in the Hatherton Sandstone makes this part of the Taylor Group harder to interpret, but the presence of dominantly unidirectional trough cross bed axes and similarity to the Arena Sandstone and Beacon Heights Orthoquartzite suggests that the Hatherton Sandstone is also non-marine. This interpretation is supported by trace fossil evidence, the trace fossil assemblage in the lower part of Hatherton Sandstone is very similar to assemblage found in the Junction Sandstone which is considered to be fluvial.
Abundant fish plates, scales and spines were found in the Aztec Siltstone near the summit of peak 1960 m, 5 km southeast of Mt Hughes in the Cook Mountains. Preliminary investigation by J.A. Long has indicated an unusual association of sharks and phylloioids. Further work on this association will be conducted in order to determine both paleoenvironmental and biostratigraphic significance.
A systematic study of the relationships between trace fossil distributions and sedimentological controls was conducted in the Darwin Glacier area. Initial results confirm observations made in 1988-89 which indicated that ichnogenera which have formerly been used as marine indicators were in fact occurring in non-marine strata. Skolithos in the Taylor Group is generally closely associated with ephemeral pond deposits and massive green sandstone beds interpreted as overbank deposits.
Diplichnites is restricted to large trough and tabular cross-bed surfaces in the Junction and Hatherton Sandstones. We believe that these tracks were made by terrestrial arthropods walking on exposed bed forms during periods of low flow and consider it unlikely that the tracks could be preserved if they were made in submerged or saturated sand.
Two previously undescribed facies sequences were recorded in the Darwin Tillite in the Hatherton Glacier area. At one locality, a red shale sequence overlies an erosion surface cut in Hatherton Sandstone, abundant sand blebs indicate periodic influxes of sand and up section sand beds become increasingly common and the unit passes upwards into a bluff forming sandstone. The sand beds are up to 40 cm thick and grade from medium to fine sand, load casts occur at the base of beds and ripples are preserved on the top surfaces. The sandstone units are inferred to have been deposited by turbidity flows in a glacio-lacustrine setting. The slumped sandstone unit is truncated by an erosion surface containing glacial striations and is overlain by a green diamictite phase of the Darwin Tillite. The sequence is 150 m thick and records a glacial advance prior to diamictite emplacement.
On the south side of the Hatherton Glacier a similar red shale with thin sandstone beds and blebs occurs above the green diamictite. The interbedded sandstone and shale grades upwards into varved black shale containing scattered (probably ice rafted) pebbles. The unit is directly overlain by the basal Misthound Coal Measures and records glacial retreat following diamictite emplacement.
Section measuring and facies description was conducted with in the Victoria Group at a number of locations in the Darwin and Hatherton Glacier area. Comparison with the Victoria Group in the central part of McMurdo basin will be carried out following the 1989-90 field season.
Exposures of Beacon Heights Orthoquartzite in the Fry Glacier area were examined and found to be similar to exposures at the type section and at knobhead.
The Metschel Tillite does not occur in any of the sections visited in the Towle and Northwind Valleys and the Weller Coal Measures directly overlie the Maya Erosion Surface in this area.
Large slump folds have been described in the Beacon Heights Orthoquartzite from several locations in the Convoy Range (Burgess et al 1981), only one such occurrence was observed on Elkhorn Ridge. About 50 m of Beacon Heights Orthoquartzite is incorporated in a slump fold on the southside of Elkhorn Ridge, however, the presence of a thin sliver of Weller Coal Measures within the slump shows it is not the result of soft sediment deformation. Geometry of adjacent dolerite bodies suggests that the folding is associated with the intrusion of Ferrar Dolerite.
Sections were measured though all the Victoria Group formations exposed at Allan Hills. The section data along with similar data collected in the Darwin Glacier area will be compared with the sequence in the Skelton Neve following field work in 1989-90. Facies descriptions and paleocurrent measurements were collected during section measuring. The ten degree unconformity reported by Ballance (1977) was found to result from the juxtaposition of very large dipping point bars and horizontal channel floor deposits.
Structures resembling hummocky cross-stratification were observed in the upper part of the Weller Coal Measures at Allan Hills. Further work will be required before the significance of the discovery can be fully evaluated. HCS is normally considered a marine indicator its occurrence in an acknowledged alluvial setting (Weller Coal Measures) is likely to be significant.
The results of this field work will be written up as a PhD thesis at VUW, a paper on the correlations with in the Taylor Group has been submitted to NZJGG, a detailed study of the fish fauna from the Cook Mountains is being prepared (with J.A. Long, Hobart) and a paper addressing sedimentological controls on trace fossil distributions is planned.
Victoria Group sediments in the Skelton Neve region will be examined in 1989-90 and this work should permit correlation of all units to be made throughout the McMurdo Basin. The nature of the
The 17 day delay experienced during our pull out from the Darwin Glacier have been shortened considerably if:
The planned 1:50,000 scale geological mapping of the Convoy Range and Allan Hills could not be undertaken due to the non-arrival of the required air photos. This is of concern because the photos were ordered from USGS some months before hand and arrived in Christchurch on or before Dec 1st. However they did not arrive in Antarctica until after our last camp move which was on Jan 17. It is of serious concern that our co-operative project with NZGS was unsuccessful due to the slowness of mail between Christchurch and Antarctica, every effort should be made to upgrade the system before next season.
This season's program was designed to test if density driven bottom currents originate from beneath the Mackay Glacier Tongue in Granite Harbor. A single current meter/sediment trap mooring would be set for about two months (November – January) at the snout of the Mackay Glacier Tongue. Last season (1987-88) a 14 hour deployment at this site recorded low velocity (<10 cm/s) flows which exhibit progressive changes in direction and duration that appear to be related to the diurnal tide cycle. A tide gauge will also be established at Cape Roberts initially to record the tide cycle during the period of the current meter deployment and if successful remain to continue recording during the following year.
Tom Perrett arrived four days before Pyne at Scott Base and during this time had completed his survival course and prepared about half of the field equipment required. Some cargo including fuel had already been transported to Cape Roberts in mid October. Vehicles were not available until the day after Pyne arrived on 4 November.
Preparations for this event were handled promptly and efficiently by the OIC and his staff at Scott Base and we were able to depart for the field 3 days after Pyne's arrival. Equipment was stored at Cape Roberts for the return part of the field work in January 1989.
The January part of our field work was also handled efficiently from Scott Base enabling our event to fly to Granite Harbor the day after arrival at Scott Base.
Event K042 was allocated a "half track" all seasons vehicle (ASV)#21. This vehicle performed very well with no major problems or breakdowns. It is a relatively light vehicle and we were careful not to overload it although we carried a maximum load in the newly built box sledge most of the time. The new box sledge is a very useful compliment to the ASV although the tray is high and slopes towards the front when attached to the ASV draw bar. This is particularly annoying when lifting some of our very heavy equipment into it, e.g. winch (550 lb).
Analysis of the above vehicle log shows that fuel consumption should be calculated at about 13l per 10 km. The radiator overflow system did not seem to work correctly and coolant leaked out of the overflow tank although there was little loss from the radiator itself. The dip stick in the hydraulic tank is also unmarked so it is difficult to establish the correct level in this tank.
The ASV does not perform well in very soft snow (e.g. snow drifts) and we spent several hours digging out on one occasion.
This operation went smoothly and was efficiently programmed from Scott Base. The helo was not able to lift both our internal load and the sling load from Cape Roberts so an extra 20 minute shuttle was required.
The quality and serviceability of NZARP field equipment is improved each year, although sometimes changes seem to slow. The following comments and suggestions are intended to help plan for the future.
VHF hand held radios with high gain aerials were used most of the time by K042. We mounted a high gain aerial on the Cape Roberts hut working the Mt. Newall repeater to Scott Base while this hut was in use. In January while at the Mackay Glacier Tongue we tried to use the repeater on the flank of Mt. Erebus with a VHF high gain. Communication was established with Scott Base but it was intermittent, especially when receiving Scott Base. This may be due to the low power output of this repeater. HF communication was also used on occasion while in Granite Harbor, but this was also erratic and certainly less convenient.
The Cape Roberts hut was used as a base for work in Granite Harbour. The hut was adequate for our programme this season but could be improved if future work in this area justifies the improvements. Cape Roberts is a small skua nesting area and any larger establishment will have to take this into consideration.
Future buildings could be sited on the higher north side of the flat area because this lower area becomes wet with ponds during high summer.
The present hut should have new kitchen utensils provided because many of the old utensils were from an older kitchen box and are now unserviceable.
Several empty drums with unknown contents should be moved from C. Roberts when the next transport opportunity arises.
This season's program went very smoothly and we thank the staff of Antarctic Division and all the staff at Scott Base for efficiently implementing our field program. We are especially grateful to John Alexander (Scott Base Operations Manager) the Scott Base mechanics, Store Personnel, Garth Varcoe and his group who moved some of our equipment to Cape Roberts early in the season.
NZARP Surveyors Garth Falloon and Pat Sole provided invaluable survey assistance and helped establish the Cape Roberts tide gauge.
The VUW Mechanical Workshop maintained and built new equipment for this program which included the tide gauge frame and mooring recovery equipment. Eric Broughton (VUW RSES) and Peter Issacs (NZ Meteorological Office), helped with the development and programming of the tide gauge and NZ Oceanographic Institute (DSIR) maintained the S4 current meter.
The aim of the IMEEMS project is to understand the mechanism of the strombolian eruptions of Erebus Volcano. The present methods are telemetry recordings at Scott Base of seismic, infrasonic, and video data from the volcano, over as great a part of the year as possible, supplemented by short term measurements of volcanic gas output, infrared thermometry of the liquid lava lake, and petrology of the lava being erupted, made during expeditions to the volcano by an international group of cooperating scientists from USA, Japan, and France.
This has been carried out at three levels: Event proposals to RDRC; discussions within the VUW Antarctic Research Centre; communications between foreign scientists. The International communications are distributed through the year, and concern the expeditions, distribution of data, presentation of results at conferences, joint publications, direction of future work, and the willingness and ability of each National group to do it. The VUWAE discussions are concerned with finance and grant applications, selection of student research assistants, and the preparation of yearly reports.
The RDRC proposals are the earliest formal plans, but on a continuing project such as IMEEMS are strongly guided by the thinking of the International group on Erebus. If everyone did their own thing without concern for the others, the International group would fall apart. It is mutual friendship which holds it together.
This is the reason I am concerned by the lack of a visible RDRC policy on cooperative International Research. The cooperation cannot be turned on and off like a tap.
Cargo movements were as follows:
For IMEEMS, field preparations always begin with servicing the recording equipment at S.B., because the field telemetry equipment cannot be serviced reliably if signals cannot be recorded. This work was done by Ray Dibble, with assistance from Howard Nicholson, and so Kevin MacKay prepared the food boxes and checked the field equipment, with help and guidance from John Skilton.
Kevin attended the full survival course, but Ray rode Grizzly G2 out to join the course for the snow/ice craft practise, and to run-in, test, and familiarise the grizzly. It performed OK, but a few days later, the gearbox was out of oil, and after refilling, a fast run to the ski field and back into the garage was made to find the leak and prove the maximum power. Unfortunately, this test was both misunderstood and unsuccessful.
This was very good, and the willing help and cooperation from everyone was much appreciated.
The put-in was by helicopter Gentle 17, which also brought up the Grizzly next day from Royds, where it had been left over night. Although the Grizzly left Scott Base in a horizontal position, it arrived at Fang camp hanging vertically, and oil and battery acid had leaked on to the front cowl.
Grizzly G2 proved incapable of ascending Erebus with two on board, as required by the Field Manager, but it carried all our equipment, and much of S-081′s equipment up from Fang to the lower Erebus Hut, and together with the Yamahas stored at the hut, transported us to the telemetry equipment sites around the plateau. The gearbox continued leaking oil rapidly, until John Skilton discovered that a bolt had been left out and another not tightened after its last overhaul. It must be said that G2 was only able to do the work required because it was nursed along by Bill McIntosh of S-081. It seemed to lose and regain power in a cyclic way, and was nowhere near as good as in 1987/88.
Return to Scott Base was by helo from the lower hut for Ray, and from Fang for Kevin and John with the Grizzly.
The trip to the RTG Hut at the Windless Bight Infrasonic Array was made in the Haglund, after plans to use the Hovercraft became impossible for operational reasons.
No unusual conditions were encountered. The snow was clean and hard, giving rise to predictions from Survival School members who had climbed Erebus before our put-in, that the Grizzly would have poor traction. In fact, traction was good along the flagged routes.
The weather was good from 18 November to 19 December except for a snow storm on Erebus from 6 to 7 December, and a ground fog on 17 December at Scott Base. The latter delayed a second trip to the RTG Hut to complete the raising of the telemetry antenna above the snow.
The use of Polar tents at Fang, and Dome tents at the lower Erebus hut again proved ideal. Normally the Polar tents would remain erected at Fang until the Grizzly was taken from there to Scott Base by helicopter. On this occasion, the S-081 camp at Fang provided security, and our Polar tents were back loaded during resupply flights. Purging the generator proved a problem. Running it out of fuel and inverting it proved insufficient. Finally it was flushed with DFA. Clear instructions are needed.
The Tait VHF radio provided good comms everywhere except at Fang Glacier, and the Compac radio filled that gap adequately, in contrast with the Codan 8332 which had failed in previous years. The solar panel was again excellent. The only problem was loose and missing screws holding the top panels on the Taits. This caused intermittent operation of one radio, and a replacement was sent up. The radio skeds were very good, and the operators very helpful.
The Science Lab is a very good facility, and I am very grateful for the generous space provided, but it could be improved. Lighting was very poor, even after I had replaced all the blown bulbs. More protection against electrostatic damage to computer-type equipment caused by charged-up technicians, should be provided in the form of conductive floor and table mats (Senior Technician Nick Millar says the failure rate of computers at Scott Base is near 100%). There is not enough basic test equipment for more than one major problem at a time. The convenience of closely spaced power plugs on walls, floor and ceiling is compromised by the long individual feed wires to each plug, and the spike voltages induced in them by the D-region Radar. The technicians are frustrated by delays in buying minor tools and stock, and need authority to purchase it directly. Even so, it is the best facility on Ross Island, and I greatly appreciate the expert assistance of Howard Nicholson in maintaining and operating my new computer-based equipment installed in the Lab.
Both huts on Erebus are in good order, and equipped with adequate heating, cooking, and eating equipment, fuel and food. There are no tents or sleeping bags, except in the survival boxes outside. The lower hut (Jamesway) was extended this year by S-081 to provide an instrumental observing room with a large window, facing the crater.
No disposal areas are available on Erebus, and all waste is returned to Scott Base/McMurdo by helicopter.
The 1984 eruption obliterated the Lava Lake, and the Active Vent, and new lava pools called (from NE to SW) the Main Vent, the Potato, and the Penny have formed. The Black Hole occupies the approximate site of Verner's Fumarole, which also disappeared in 1984.
A fine example of International cooperation and friendship was provided by Dr P.R. Kyle, in connecting his colour video camera to our TV transmitter, while ours was away for repairs, and by reinstalling ours when it returned after we had left the mountain.
This project aims to undertake a three year hydrological, glaciological, and sediment transport monitoring programme in the Miers Valley. Information required to study and quantify the energy and mass balance of the glacier-river-lake system will be collected.
The data will permit:
The principal aims of the 1988-89 programme were therefore to:
Preparations for the field went remarkably smoothly with the event personnel arriving at Scott Base on the scheduled date. All event cargo had already arrived, or arrived on the same flight as the event personnel. All the requested field gear was available at Scott Base except for the Pionjar hammer which had already gone into the field with K161. Some time was spent in organising its availability for our event.
The only real problems experienced were the restrictions on weight for our initial helo flight to the Miers valley because of the scheduling of only one flight. Considerable effort was required to weigh every item of equipment and to assign priorities. Because of this weight restriction even the food was reduced to only five days supplies. This would have led to significant problems had
The transport of our bulky items and fuel to Cape Chocolate saved considerably on helo support although problems were experienced in arranging for this gear to be brought up to Lake Miers. In hindsight the cargo train to Cape Chocolate was under-utilised and the bulk of our fuel (kerosene), food boxes, and the camp for the Garwood should have also been shifted to this staging point. The extra weight would have been negligible to the cargo train but was significant for helo support.
The support of all the Scott Base staff, particularly John Alexander, the field storeman, and mechanic, ensured we were ready to depart for the field on the scheduled date.
This event was largely self sufficient except for helicopter support. As indicated above, and listed in the Event Diary to follow, considerable frustrations and delays were experienced as a result of helicopter operations, particularly at the start of the 1988-89 season. When helos were flying, and actually arrived, they usually carried out all the tasks required although one could not say that they were efficient. The problems we experienced were not a result of Scott Base planning which was always efficient and in fact ensured a much higher level of support than we anticipated. Replacement of the PC and various other items from Scott Base was such that minimal delays were experienced and the project in no way suffered from poor planning.
I don't believe that helo operations last season were any better or worse than in the past. I do, however, strongly believe that New Zealand operators (civilian or military) are considerably more efficient, and indeed better, than VXE6. The sooner the New Zealand Antarctic programme is supported by New Zealand operators the better.
With increasing concerns over costs of science in the Antarctic we must look at improving the efficiency of the operations and I believe the simplest way of achieving this is by having our own helo support even given the added costs.
All the field equipment functioned well except for the Sorrel boots with the "plastic" soles issued to one of the party. These soles were not up to Dry Valley conditions and soon split causing leaks and consequently wet feet. While this was largely a question of comfort, considerable risks are also inherent in having wet feet in the Antarctic. When these boots were replaced, the new pair started leaking after only 3 days use.
One of the polar tents issued to our event was smaller (by about 0.5 m in each dimension) than the usual. This led to cramped living conditions for two of the party which, while not critical since we had the use of the Miers Hut for activities other than sleeping, would have led to severe problems had we been a "sledging" event.
Food was excellent with plenty of variety. The major difficulties are now the bulk, given all the "freshies", and keeping frozen supplies from thawing.
We dug a large pit into the permafrost beside the hut to act as a fridge and this worked well for most of the season. For the coming season I would recommend four sheets of ply to line the walls and stop the hole collapsing as it thaws out. I would also recommend a 1 m square sheet of polystyrene to act as a lid and stop melting later in the season.
The crampons tended to loose screws during the season and replacements were required from Scott Base. I would suggest that "Locktite" is available at Scott Base so that after adjustment the
While I arranged to have the 40 mm ice auger sharpened before heading "south" I soon discovered that there is a technique for using it is glacier ice. It would be worthwhile informing others that to make reasonable progress (to drill a 1.2 m hole in 7 mins) a hole should be formed with a pinch bar first and then this reamed with the auger. The angle of the auger flights, and hardness of ice, are such that without the "pilot" hole little progress is possible with the auger alone.
During the season we used a Codan SSB set for communications with Scott Base and two Tait VHF radios for communications within the valley when working away from camp. In general communications were good, particularly with Scott Base and at no time were communications missed because of "technology" failure.
The Taits were of limited use because of the "shape" of the Miers. In many situations "Line of sight" communications were not possible and since no repeater was available this restricted the use of the Taits. It was possible to listen to Scott Base, and even transmit from certain sites, but this was not generally practical.
It is suggested that if parties are to be working in the Miers, Dromedary areas again a repeater should be set up on either Black Island or Brown Peninsula. From either of these sites good communications using VHF could be provided throughout the Miers Valley, from the Miers to Scott Base, and to a field camp in the Garwood. Such a repeater location would greatly extend the practical range of the VHF sets, improve safety when working in the field, and provide complementary coverage to the Mt Newall site.
The Coms operators this season provided an excellent service and an efficient link to Scott Base.
The Miers refuge hut was found to be in good condition on our arrival and certainly made our stay considerably more comfortable than having to rely solely on tentage. The hut was used mainly as a laboratory for operating the PC although it was also used for cooking, eating, and recreation. Only two problems were experienced. One was that the hut is poorly vented and when cooking this led to severe condensation problems. The other was that following snow falls the joints between the various panels "leaked" badly. All joints were subsequently sealed with "RTV Sealastic" and this solved the problem.
The provision of a field toilet made life considerably more comfortable, particularly on windy days and reduces the risk of polluting Lake Miers. This toilet was "wired down" on top of a moraine ridge approximately 100 m from the hut. It is as far as possible from the streams in the area and is therefore unlikely to cause pollution of Lake Miers.
A considerable amount of food has accumulated in the Miers hut over the past few seasons. While this provides a good backup in an emergency, much of it is now "too" old to be of use. Some of this was returned to Scott Base as "rubbish" and further material will be returned in the coming season.
The Miers refuge box, which is on a high moraine mound 100 m from the hut, was still sealed and was therefore not checked and no inventory was carried out.
All garbage from the expedition was sorted into "Burnable" and "Non Burnable" bags and back-loaded to Scott Base. Smoke canisters found through the valley were recovered and included in our non-burnable rubbish. Several depots of rubbish (obviously old campsites) were located in the valley. Where possible this rubbish (mainly rusty tins) was collected and returned to Scott Base. Further sites will be tidied during the 1989-90 season.
Human waste from the field toilet was double bagged and returned to Scott Base for further disposal.
The objectives of the 1988-89 field program were to study exposures of the Beacon Supergroup near the present day northern and southern boundaries of McMurdo Basin. It was also planned to conduct 1:50,000 scale geological mapping in the northern Convoy Range and at Allan Hills for the NZGS. The program was planned on the basis of a three man sledging party operating in the Darwin Glacier area and the Convoy Range and a four man party at Allan Hills.
Gillespie and Woolfe spent one week on base prior to the arrival of Henare, this time was largely spent repacking food boxes and readying sledges for glacier travel. Considerable time was spent removing food items from cardboard packing, returning unwanted food items to the store, collecting deep field essentials such as flour and incorporating extras and freshies into the standard boxes. We found the toboggan G7 was loosing gear box oil and two members of the party had to return early from the shake down trip on the Aurora Glacier to pick up more oil. This problem was eventually fixed by the placement of a small baffle beneath the breather in the filler cap, the enthusiasm and determination of the mechanics to ensure the problem was fixed in time for our scheduled put-in was outstanding.
Replacing the standard snow craft survival course with a shake down trip of reasonable length was very worth while, although for first time visitors the second day of the standard course is worth doing in addition to the shake down trip.
Three tamworth sledges and two motor toboggans were used extensively in the Darwin Glacier area. Both toboggans performed well, the following minor problems arose;
The thrown track on G7 was undoubtably the most serious incident and resulted from excessive sideways force being applied while attempting to turn the sledge train around in a crevassed sastrugi field. Wind shields were useless when travelling with a strong following wind, trap fumes on calm days and are inconvenient on the second toboggan when using a personnel line from lead toboggan to last sledge. Wind shields were not used after part way through out first camp move, they are difficult to carry when unattached to the toboggan and we recommend that future deep field parties are not issued with them. The Tamworths suffered minor damage including a broken slat on T4 resulting from the collapse of a drum cradle, broken handle bar fixings on T5 and T6 and minor runner delamination on T4 and T5.
The sledges performed exceptionally well, spreading the load over three sledges meant that no sledge was over loaded and this combined with slow travel ensured minimum strain on the sledges. This meant that we took longer on some routes than previous parties but the time was more than made up by not having to carry out major sledge repairs. When travelling all units of the train were linked, by 17 mm rope and a separate 10 mm rope was used as a personnel line. For all but the steepest slopes instep crampons were worn in preference to twelve point crampons, to reduce crampon damage to both sledges and toboggans.
The provision of a sledging guide would be useful to first time sledging parties, included in this should be different train configurations and methods for moving both laden and unladen aircraft pallets.
The total distance travelled was about 800 km, for which we used 310 litres of Mogas. At times fuel consumption was much higher than this figure indicates, consumptions of up to 1.5 km per litre were recorded when towing heavy loads up snow covered slopes.
Travel on the Darwin Glacier was generally good, although crevasses occur on a roll which runs across the glacier about 4 km east of Richardson Hill. Extensive areas of heavily crevassed hummocky blue ice occur off the northern ends of Haskell and Coloseum Ridges and travel through these areas is difficult. The crevasse field off Colosseum Ridge extends northwards for about 4 km.
A route on to the edge of the plateau exists close in to the western side of Haskell Ridge, further west however sastrugi and crevasse fields are encountered.
Entry into the Hatherton Glacier is easy only where the ice fall is divided into a number of platforms, this point is clearly shown on the 1:250,000 map and once found only a few crevasses need be crossed. Travel up this route is not recommended if towing sledges.
The Hatherton Glacier provides easy down hill travel, it is mostly blue ice and generally free from crevasses except for the first 5 km below the ice fall, which is partly snow covered and lightly crevassed. Care must be taken not to get on the wrong side of the medial moraines because crossing them is all but impossible in many places. Several steep rolls occur close to Mt Ash, travel down these is hazardous and travel up would be very difficult.
Extensive crevasses occur north and northwest of Junction Spur and smaller crevasses persist for about 9 km down glacier. The best crossing point between the Hatherton and Touchdown Glaciers is at 158°00′ East because the area to the east is also crevassed.
Travel between Roadend and Mulgrew Nunataks is good with easy gradients, a crevasse field extends off the south-western tip of Mulgrew Nunatak but can be avoided by passing as close to the Nunatak as possible (avoiding the wind scoop).
Access to the Tentacle Ridge-Mt Hughes area is best gained from the valley north-eastward of Tentacle Ridge. Travel into the embayment is on blue ice, there are few crevasses but the route is moderately steep. Access to the south-western side of Tentacle Ridge appears difficult and camp sites are exposed to strong catabatic winds.
Although no sledging was conducted in the Convoy Range, the Fry Glacier area has only limited crevassing and blue ice and could easily be sledged. Sledging routes are summarised in figure 3.
The put-in site on the Darwin Glacier, just north of Richardson Hill proved to be unsuitable due to moderate crevassing. There appear to be no suitable landing sites in this area.
The only ideal landing site found was the pull out site which is close to that used by the Darwin Project in 1978-79. It is about 5 km west of the southern tip of Roadend Nunatak (79° 51′S 158° 10′E), a 3000 m strip was marked out by two rows of flags 500 m apart, the strip was orientated along the length of the glacier and provided good approach and escape routes.
Airdrops of mail and food were made into the Darwin Glacier and six 12 gallon drums containing mogas and DFA were dropped into the Fry Glacier. All the airdrops were successful and no breakages occurred, the Darwin drops made use of aircraft returning from regular pole flights and as such were economical on aircraft hours.
The Fry Glacier drop (fuel) and landing site recce used considerably more LC-130 hour than was expected due to four missions which had to be abandoned because of weather and mechanical problems.
Only 14.5 of our allocated 22 helo hours were used, due mainly to the decision not to use motor toboggans and sledges in the Convoy Range-Allan Hills area.
Detailed notes on field equipment have been submitted separately (G. Gillespie, End of Season Report) and are held by Antarctic Division. In general the quality and quantity of field equipment was excellent and it was good to see that many of the suggestions made last year have been implemented. The following suggestions and observations are made: The weights stated in the field manual for toboggans and sledges are up to 20% too light in some cases. The purple Olympus Tent was difficult to see when pitched on rock and the sewn in ground sheet rather unsubstantial. Both these problems could be fixed by the inclusion of a standard yellow ground sheet, this could be used as added protection to the floor of the tent when pitched on rock and as a high visibility object in the event of a SAR or similar operation.
Frozen food is difficult to keep frozen in the standard red food boxes while camped on rock or hard ice where they can not be buried. The provision of white boxes (with red stripe if required) should be considered.
Much time was spent repacking food boxes, maybe field parties should be given the option of pack your own or prepacked boxes. For long stay or deep field parties total repacking is often necessary to reduce bulk and to remove unwanted items while including others and little time is saved by having prepacked boxes in such cases.
The provision of a steering compass, such as a marine hand held navigation compass that could be used for both steering and position fixing would be useful. A handle bar mount for Tamworth sledges should also be provided. The new yogurt was great.
Two Tait hand helds were used to maintain communications between the field party on days when the party split up to work on separate outcrops. These radios worked well and were invaluable when steering the sledge train by compass.
HF communications varied and at times it was not possible to raise any station but generally communications were good. The awkward nature of the box on the Codan meant that the less powerful Compak 8 was used in preference while sledging (see G. Gillespie End of Season report for suggested improvements).
All burnable material (excluding plastics) were incinerated in the field and the non-burnable material was returned to Scott Base. In the Darwin Mountains human wastes were disposed of in crevasses, human wastes from the Convoy Range and Allan Hills were returned to Scott Base.
Five 12 gallon drums of two stroke mix (2% oil, 1% isopropyl alcohol) and one 12 gallon drum of DFA were air dropped into the Fry Glacier and later lifted to Cape Roberts. The drums are in as new condition, unopened and clearly labelled, they will not be required at this location by the event in 1989-90 and should be made available to events operating in the Cape Roberts area.
Abstract
Glutathione S-transferase activity was found in liver homogenates from Antarctic fish species Dissostichus mawsoni and Pagothenia borchgrevinki. Activities measured with 1-chloro-2, 4-dinitrobenzene were 11.2 μmol min−1 mg−1 and 16.7 μmol min−1 mg−1 respectively. Little or no activity was detected with p-nitrobenzyl chloride or 3,4-dichloro-1-nitrobenzene. Glutathione was found in the livers of Antarctic fish in millimolar quantities.
The partial purification of glutathione S-transferases from D. mawsoni is described.
The effects of temperature and pH on the spontaneous and enzyme catalysed reaction are described. The spontaneous reaction rate being characterized by the activation parameters (A=26.33±0.7, ΔH# = 50.71±1.67 KJ mol−1) and the sulphdryl proton ionization parameters (ΔH=31.4±2.5 KJ mol1−1, ΔS = 72±8 J mol−1 K−1).
The effects of pH on the glutathione S-transferase from G. mellonella are examined. The reduction in catalytic action at high pH being due to ionizations associated with flutothione binding (pKa 8.6±0.2, 9.2±0.2).
The effects of temperature are discussed in both thermodynamic terms and in the ability to enhance the spontaneous reaction. Isoenzymes from rat, G. mellonella and D. mawsoni are characterized. Rate enhancement factors were within a ten fold range, suggesting antarctic fish have an effective detoxication system.