K040 : The Sedimentology and Trace Fossils of Devonian Strata at Table Mountain
Antarctica New Zealand December 1993 - January 1994
LOGISTICS REPORT TO THE NEW ZEALAND ANTARCTIC PROGRAM
THE SEDIMENTOLOGY AND TRACE FOSSILS OF DEVONIAN STRATA AT TABLE MOUNTAIN (EVENT K040)
The origin of the 1000 m thick sequence of the Devonian quartzose sandstones of the lower Beacon Supergroup, South Victoria Land, Antarctica has generated considerable debate. The controversy centres on the presence of varied and abundant trace fossils, especially Skolithos, frequently used by some geologists to interpret marine paleoenvironments. However, the trace fossils are considered by others to be consistent with nonmarine deposition. Most previous studies have been conducted on a regional scale and insufficient data has been collected to establish sedimentary processes and the depositional environment with confidence.
This study was designed to examine the lowermost Beacon Super group (lower Taylor Group) in detail, collecting data from a relatively limited area and stratigraphic interval. Excellent 3-dimensional exposures at Table Mountain are ideal for lateral profiling techniques, which take into account lateral as well as vertical facies changes in order to provide a refined depositional model. Improved understanding of the depositional system will contribute not only to resolving the trace fossils problem, but also to southern Victoria Land paleogeographic and tectonic reconstructions.
- To reconstruct the depositional environment of the lower Taylor Group
- To determine the habitats in which the trace fossils were made.
- Further investigate the enigmatic Pivot Member (Arena Sandstone).
The only problem in the palnning aspect of the expedition was the failure for Event K040 to obtain, for what ever reason, the 1993/94 NZAP field event directive. This was discovered during the event briefing at Scott Base, but did not cause any any trouble.
There were a few situations during the expedition that could not have been anticipated (see Cargo and Field Transportation sections). Flexibility in the operations in Antarctica made our tasks easier and greatly assisted in the fulfilment of our objectives.
Wizevich and Thornley attended Tekapo and thoroughly enjoyed and benefited from the experience. Woolfe could not attend because of committments in Australia, but he could have benefited from receiving copies of the Antarctic Operations Manual, the Antarctic Field Manual, and the Antarctic First Aid Manual.
The overall approach used at Tekapo (i.e., teaching and building confidence by lecturing and then a 'hands on' session, and finally a simulated Antarctic experience during the overnight), was effective. Including the Antarctic veterans was extremely helpful in the learning process (as well as an opportunity to meet interesting people and learn about their studies), but at times (especially during the preliminary basic lectures) many appeared to be bored. Perhaps restructuring the Tekapo schedule such that the veterans can come after the basic lectures (over the weekend, which might mollify some complaints that the training interrupted work) may alleviate the boredom and still provide valuable resources for Antarctic neophytes.
Because of unforeseen circumstances, it was deemed necessary by the Event Leader that collected geologic specimen (rock samples) should be immediately returned to New Zealand so that analyses could begin without delay. A request was made to the SENZREP, who informed the Base Manager and 50 kg were allocated for the flight back to Christchurch. Luckily, Air New Zealand was just as accommodating and the samples made it to Wellington without a problem.
|Dr. Michael C. Wizevich:
Victoria University of Wellington
|Dr. Kenneth J. Woolfe:
James Cook University,
|Mr. Stephen Thornley:
Victoria University of Wellington
Preparations for the Field
Very smooth transition. With a little bit of luck, a dose of experience, and heaps of help from the Base staff, we were able to put in at our field site about 68 hours after landing in Antarctica. This included overnight field training, and was a full day ahead of schedule.
Helicopter support was the only field transport required for our expedition. Unfortunate circumstances led to additional support other than our basic allocation for put in and pull out. The party was transported to Table Mountain on one flight, although the helicopter was carrying a near full load. After a week in the field, Woolfe developed a medical complication and had to be evacuated from the field. Woolfe was eventually transported to New Zealand and was not be able to return. This left us without our most experienced Antarctic person, and seriously jeopardised our capacity to achieve the scientific objectives. A second medical evacuation (Thornley) nearly caused cancellation of the expedition. Fortunately, Thornley was returned the same day after being examined by the medical personnel at McMurdo Base. Dom McCarthy (Base Engineer) was sent up to assist Wizevich in Thornley's absence. The swiftness in which both evacuations (and one return) was achieved was impressive.
Because of the loss of Woolfe, we were not able to traverse glaciers and thus not capable to visit remote sites for geologic sampling. We requested the SENZREP for additional helicopter time in order to visit the locations. The additional time was granted and an experienced guide (Grant Avery, geophysics technician) was sent to accompany us. Unfortunately, our attempts were thwarted by bad weather (winds over 40 knots) and we could not complete our sampling. Furthermore, with the weather rapidly deteriorating, there was no time to load all of the camp into the helicopter. Left behind was approximately 700 lbs of equipment, including 70 lbs of rock samples that were intended to accompany the party back to New Zealand. Because the sampling was considered critical to accomplishing an event objective and because of the samples left at Table Mountain, the SENZREP and Operations Manager granted another attempt (i.e., additional helicopter time to revisit Table Mountain) before our scheduled departure to New Zealand. During the aborted attempt at sampling the Platform Spur site, it was determined that the only method to attain samples was to lower down on a rope over the edge of a near-vertical cliff face. Bruce Jenks (Field Supply Officer), experienced in rock climbing, was added to the party. On the return to Table Mountain, Thornley, Avery, and Jenks were dropped off at Platform Spur to sample on the face of the steep cliff. Wizevich was then transported up to Sickle Ridge. The helicopter pilot resolved that the locality to be sampled was ∼10,000 ft (map read <9500 ft, see discussion in Event Map section) and dropped Wizevich and a crewman (the helicopter needed to refuel at Marble Point) at ∼9,000. After sampling was completed, Wizevich was flown around Table Mountain in order to photograph the rock outcrops. Upon completion of the task, the remaining equipment at the camp was loaded. The party members at Platform Spur were picked up and we returned to Scott Base (via Marble Point for fuel).
|4 Dec||Wizevich and Woolfe flew to Christchurch and were met (−5 PM) at NZAP clothing shed by Thornley, who arrived the previous evening.|
|5 Dec||Departed Christchurch ∼12 PM arrived in Antarctica ∼6 PM.|
|6 Dec||Wizevich and Thornley attended survival school, overnight on ice. Woolfe drew and prepared field gear and provisions. Woolfe joined party at 10 pm for overnight stay, and to assist in next day's training.|
|7 Dec||Field training, including 'shakedown' of field equipment, and practice as a team. Evening event briefing. Visited Discovery Hut - a very worthwhile experience.|
|8 Dec||Helicopter arrived at Scott Base ∼12:30 PM, arrived and put in at Table Mountain about 2 PM. Because of snow, wind and limited visibility, the proposed camp site could not be reached. Set up camp. Weather deteriorated in late afternoon.|
|9 Dec||Reconnaissance of geology and local terrain. Walked to eastern peak (Navajo Butte) on Table Mountain, across saddle to 'Table Mountain' (western peak) and down northern slope of Table Mountain before returning to camp. In evening walked to edge of Bindshadler Glacier to look for best route for crossing of glacier next day.|
|10 Dec||Traversed Bindshadler Glacier to Platform Spur. Route was flagged for future treks to Spur and to Sickle Ridge. Examined geology. Weather deteriorated; returned to camp across glacier at slightly higher elevation than flag route and encounter numerous 1-2 m wide crevasses on west side. Walked across lower Sphinx Valley and Navajo Butte to camp.|
|11 Dec||More snow on ground from previous night. Further reconnaissance of Navajo Butte, Table Mount, Sphinx Valley and Centurion, a peak between The Handle (northern end of Sickle Ridge) and Sphinx Valley.|
|12||Dec Began measuring stratigraphic section on southern end of Table Mountain (west summit), on Columnar Valley side. Woolfe returned to camp with painful cheek area.|
|13 Dec||Additional snow makes it difficult to examine gentle sloped outcrops. At same Table Mountain location, studied section higher up stratigraphically, where the rock faces are near vertical and thus not covered with snow. Woolfe remained in camp.|
|14 Dec||Continued measuring stratigraphic section on upper part of Table Mountain (west summit). Woolfe remained in camp.|
|15 Dec||Reviewed work to date with Woolfe, who returned to camp at noon. Continued measuring section on upper part of west summit. Weather deteriorated (−20 knot wind) in afternoon. Finished early.page 5|
|16 Dec||High winds (up to 30 knots); remained in tent for day. Much snow removed from outcrops.|
|17 Dec||Woolfe returned to Scott Base for medical reasons. Returned to lower part of Table Mountain section.|
|18 Dec||Snowed heavily during previous PM and continued lightly throughout day. Most of the outcrops are again covered in snow. Started section along vertical cliffs on northern side of Navajo Butte.|
|19 Dec||Returned to northern side of Navajo Butte and finished measuring available (vertical) section. Began measuring new section on (upper) south side of Navajo Butte. Light snow fell all day.|
|20 Dec||Returned to southern side of Navajo Butte and continued measuring section. Light snow fell throughout day.|
|21 Dec||Returned to south side of Navajo Butte and finished measuring section. Light snow fell all day. Woolfe left Antarctica for Christchurch.|
|22 Dec||Walked along SE Navajo Butte, noting areas for future work, through Sphinx Valley to Centurion. Measured short section. Snowed all day.|
|23 Dec||Returned to Table Mountain (west summit) and continued measuring stratigraphic section on upper part of steep (subvertical) exposure .|
|24 Dec||Visited by Santa; requested wind to blow snow from outcrops. Began measuring lower part of section on north side of Navajo Butte. In late PM, winds increase to 20-25 knots. We believe in Father Christmas!|
|25 Dec||Inspected lower Table Mountain section; still had considerable snow. Returned to northern side of Navajo Butte and continued measuring section. Strong winds (probably <30 knots) during PM.|
|26 Dec||Winds continued in AM, but diminished in early PM. Returned to northern Navajo Butte; work went slow in moderate wind and cold.|
|27 Dec||Returned to lower Table Mountain section. Outcrop visibility vastly improved. Continued measuring stratigraphic section.|
|28 Dec||Returned to lower Table Mountain and continued measuring section.|
|29 Dec||Returned to north side of Navajo Butte and in PM returned to south side of Table Mountain section. Continued measuring sections.|
|30 Dec||Thornley evacuated to Scott Base for medical exam, returned same day. D. McCarthy joined party while Thornley was away. Strong wind (20 knots) in AM, got stronger (∼40 knots) in PM. Remained in tent for day.|
|31 Dec||Continued to measure section on north side of Navajo Butte.page 6|
|1 Jan||Same as previous day.|
|2 Jan||Spent AM finishing section on north side of Navajo Butte. In PM returned to Table Mountain (west summit) to also finish section.|
|3 Jan||Started to measure section on (lower) south side of Navajo Butte.|
|4 Jan||Detailed reconnaissance of SE side of Navajo Butte. Examined New Mountain Sandstone in Sphinx Valley area, recorded paleocurrents and observations of trace fossils and sedimentary structures. Determined outcrop in Sphinx Valley was not sufficient for detailed study.|
|5 Jan||Finished measuring stratigraphic section on south side of Navajo Butte. Started measuring series of smaller sections on SE side of Navajo Butte.|
|6 Jan||Finished measuring series of sections on SE side of Navajo Butte.|
|7 Jan||Measured section on SW side of Navajo Butte. At 10 AM, 12 and 2 PM hiked to top of outcrop (Mt Newell repeater is N of Table Mountain) to communicate with Scott Base regarding visit by Distinguished Visitors (DVs). Visit delayed (until following day) by bad weather at Base.|
|8 Jan||Visit from DVs (scientists in influential positions) enjoyed by all. Requested from SENZREP additional helicopter time at pull out, in order to sample rocks at Platform Spur and Sickle Ridge. Started and finished measuring a section between Navajo Butte and west summit.|
|9 Jan||Traversed SE side of Navajo Butte and traced beds between series of sections measured earlier. Recorded additional paleocurrents and observations of trace fossils and sedimentary structures in Sphinx Valley. Climbed up Centurion, sampling sandstones for petrographic analyses, and then up The Handle for samples of Ferrar Dolerite. Hiked along ridge towards NE terminus, dropped down to Columnar Valley. Crossed Valley to base of Table Mountain, sampled lower stratigraphic units and inspected lower New Mountain Sandstone for future study.|
|10 Jan||Finished up loose ends on several sections in the Navajo Butte area.|
|11 Jan||Climbed down to Columnar Valley to finish remainder (lower 30 m) of stratigraphic section at Table Mountain.|
|12 Jan||Traversed NE side of Table Mountain to examine lower units of the Taylor Group. Recorded paleocurrents and observations of trace fossils and sedimentary structures; collected samples for petrographic study.|
|13 Jan||Spent day re-examining the stratigraphic sections that we have studied. Collected samples of concretions for Woolfe to study.|
|14 Jan||Winds in AM about 15-20 knots. G. Avery put in to help collect flags (placed 10-12-93) on Bindshadler Glacier, and sample rocks on Platform Spur and Sickle Ridge. Party traversed glacier as weather deteriorated page 7 (wind >40 knots). Helicopter picked up party on Spur. Studied Spur from air, decided sample site could not be reached without ropes. Sickle Ridge covered in clouds, no attempt to reach. Weather deteriorated further, pilot decides to retrieve some of camp gear and head back to Scott Base. Met with SENZREP and Operations Officer and decided to retry sampling and to retrieve equipment on Monday. Showered.|
|15 Jan||Formally requested additional helicopter time.|
|16 Jan||Played American football and beat the Yanks at their own game!|
|17 Jan||Helicopter moved Thornley, Avery and B. Jenks (rock climbing expert) to Platform Spur to sample. Wizevich flown to Sickle Ridge to sample. Wizevich returned to Table Mountain; photographed outcrops and retrieved camp. Picked up party at Spur and returned to Scott Base.|
|18 Jan||Wizevich and Thornley returned to Christchurch.|
Figure 1 is a detailed sketch map of the Table Mountain area, showing the camp site and the locations visited by helicopter (Platform Spur and Sickle Ridge). Other areas mentioned in the diary are also indicated.
During our expedition, we noted in two instances that the measured altitude was approximately 500 feet (150 m) higher than what was printed on our maps. Upon landing at Table Mountain, we measured the altitude using an altimeter set at Scott Base. Our reading of 2338 m was significantly different than the 2183 m on the 1:50,000 USGS-DOSLI topographic map (1993, Cathedral Rocks sheet) and radically different from the 1800-1900 m on the topographic base of the geologic map (Geology of the Knobhead Area, Woolfe et al., 1989). In addition, during helicopter transport to a sampling locality to Sickle Ridge the helicopter altimeter read ∼10,000 ft, whereas the map (Woolfe et al., 1989) indicated 2800-3000 m (∼9000-9500 ft). This particular error was costly in terms of helicopter time because the pilot refused to land on top of the ridge and the field party was dropped at the next lowest site (∼9,000 ft) and it was necessary to climb (this took time) up the 1,000 ft to the sampling site while the helicopter waited. The pilot was following regulations that require oxygen for the crew at altitudes above 10,000 ft. Oxygen was not brought on the mission, because it was believed the site was ∼9,000 ft.
A labelling error was spotted on the 1:50,000 USGS -DOSLI topographic map (1993, Cathedral Rocks sheet). 'Navajo Butte' was placed at a feature marked 2183 m elevation (actually, the location of our camp!), approximately 1 km northeast of its correct location (feature marked 2263 m).
A detailed weather log using the instruments supplied by Scott Base was kept in a "Met book" and relayed at each sked (9 AM and 9 PM daily) to Scott Base.page 8
Generally, the weather at Table Mountain was good. Recorded temperatures ranged from a high of −11°C to a low of −23°C. Winds were recorded in an excess of 40 knots on a few occasions, but only 4 of the 38 field days were deemed severe enough to remain in the tent (perhaps two more should also have been designated as such). During the first half of the field season, significant snow (up to 10 cm) of recent snow covered the rock outcrops and hindered work greatly. Fortunately, on Christmas and Boxing days (Dec. 25-26) high winds blew, and were sufficient to remove most of the snow. Most fortunately, a stable high pressure system settled over the Table Mountain area for about 10 days. The resultant brilliant weather allowed the party the opportunity to collect data, unencumbered by the weather.
On the day of the pull out, high winds (in excess of 40 knots) and impending deteriorating weather forced a cancellation (later rescheduled) of helicopter movements to sampling sites and necessitated leaving about half of our camp equipment (and rock samples) at Table Mountain.
Accident, Incidents or Hazards
Two medical evacuations were necessary during the expedition at Table Mountain. The first, Woolfe returned to Scott Base, then returned to New Zealand was caused by an infection in the upper jaw area. Although dentally related, a potential problem was not recognised in the mandatory dental examination. The second evacuation was required when Thornley reported to the Scott Base medical technician a green discolouration of a friction blister on his foot, and gangrene was suspected. After inspection of the foot by medical staff at McMurdo, Thornley returned to Table Mountain on the same day he was evacuated. The blister was caused by improper fitting Sorell boots, however, they were the largest size available.
In general, the clothing and equipment issued by NZAP was of sufficient quality and performed admirably. We had problems finding the right boots for work. Neither plastic (too cold when standing still and too rigid for climbing rocks), Sorells (too flexible for climbing and crampons, and do not breathe well-sweat inside), and mukluk (poor support of ankles, and not durable) boots are ideal for our type of work. Our work requires climbing of rocks and ice, standing in one place (examining rocks) for extended periods of time. Unfortunately we can not suggest an alternative. Perhaps either a warmer plastic boot or a more supportive and durable mukluk type boot would be better. We did experience some troubles with the Primus stoves, which often do not burn cleanly and kerosene spillage is a sad fact of life. Are gas (e.g., propane) cartridge stoves a possible alternative? Waste Management Officer Thornley reports that plastic bags supplied for buckets are at least twice as large as bucket. Either smaller bags or larger buckets would be more efficient.
The food box contained plenty of food, however, many of the items were not utilised, primarily because of personal preferences of the party members. Perhaps it would be best if some input could be made by party members for their page 9 own food boxes. Simple substitutions such as pasta for mashed potatoes or peanut butter for salami would have made a difference.
K040 was issued with both VHF and compak HF radios. The HF radio was emplaced, tested, and remained in standby for duration of stay at Table Mountain, but was not utilised because of the ease of use of the VHF radio. Communications via the Mt. Newall repeater were always adequate and the high gain antenna was not required. On several instances, the battery appeared to become flat prematurely and our signal would weaken such that Scott Base could not receive our broadcasts, necessitating a changing of batteries. It became apparent that one of the batteries failed to hold a full-capacity charge. However, we were able to get enough use from the faulty battery to allow sufficient recharge time for the good battery. Nevertheless, an extended period of cloudy, sun-less weather may have required use of the VHF radio as a backup. Solar panels worked well, but were often difficult to keep in an efficient orientation in the ice and snow. Perhaps a wire frame or backrest with small spikes in the base (to keep the panel from slipping, especially in moderate winds) would be a worthwhile, low-cost, and lightweight component that can be easily added to the panels.
The Comms operators provided excellent service and an efficient link to Scott Base. Their friendly and helpful manner made the radio skeds much looked forward to occasions. News about other events, Scott Base happenings, electronic mail from New Zealand, and a casual chat were much appreciated by all event members. Weather forecasts were not supplied and would have generally have been of little help as frequently the weather was localised.
Details of field movements (i.e., helicopters) were given in advance, but updates on the arrival time were often not available. This was certainly not a fault of the Scott Base Comms operators, but due to the lack of communication from the helicopters. In several instances we were surprised by the sudden arrival of a helicopter. In other instances we had difficulty communicating directly with the helicopters and had to use Scott Base as an intermediary. On the return to Table Mountain on 17 Jan, one member of the party was in the helicopter when communications were attempted, and it was clear that the field party could not hear the helicopter broadcasts for whatever reason, but were well received by the air crew. Both the lack of warning and the difficult direct communication wasted valuable helicopter time.
See attached sheets.
We saw no trace of earlier camps on Table Mountain, but did find (and return to Scott Base) a smoke grenade on the NE corner of the mountain.
Management of Science in the Ross Dependency
Our type of expedition probably requires less amount of forward planning and logistical support than most Antarctic projects and thus NZAP was able to easily cater to all our needs. In the unfortunate circumstances of our two medical evacuations, Scott Base personnel were able to coordinate and execute the pull outs in an efficient and impressive manner. Furthermore, the flexibility of the program, which allowed us to return to Table Mountain to collect samples and photograph the outcrops, allowed us to achieve important scientific objectives.page 11
Figure 1. Location map for event K040. Camp marked with 'x' and areas sampled on 17 January 1994, at Sickle Ridge and Platform Spur marked with arrows.