REPORT FROM THE FIRST WEEK OF CRUISE LMG02-9 OF THE ARSV LAURENCE M GOULD TO THE SOUTH SHETLAND ISLANDS AND ANTARCTIC PENINSULA

23-30 November 2002
By Dr. Frederick W. Taylor, Chief Scientist
Cruise LMG02-9

Antarctic Research Support Vessel (ARSV) Laurence M. Gould Cruise LMG02-9 is conducted in support of US NSF-sponsored projects IO-194-E of Dr. Brenda Hall, University of Maine-Orono and GO-080-0 of Dr. Fred Taylor and Dr. Ian Dalziel, University of Texas-Austin. The science party also volunteered to conduct water sampling in the Drake Passage on behalf of Dr. Michael Bender and Dr. Matthew Reuer of Princeton University. As part of its customary mission, the ship carries cargo and passengers bound for Palmer Station and will carry some cargo and passengers from Palmer Station back to Punta Arenas, Chile. Dr. Hall's primary objectives involve mapping and dating moraines and paleo-shorelines that provide information about the history of glaciation, relative sea-level changes, and isostatic response of sites to changes in ice mass and sea level. Taylor's project involves re-visiting Global Positioning System (GPS) reference marks that he and colleagues established and first measured in December 1997 and re-measured in December 1998. The purpose of the GPS work is to determine velocities for major and minor tectonic plates in the region and as well as plate boundary deformation. The Hall and Taylor projects are both interested in vertical crustal motions and may benefit mutually from each other's results.

The ship departed Punta Arenas at 16:00 on 23 November and had an uneventful crossing of the Drake Passage to Smith Island. (Note: I will use ship's time (same as Punta Arenas and Palmer Station) except for rare occasions when I may refer to GMT). The first science conducted was water sampling and other measurements of oceanographic parameters crossing the Drake Passage.

Water Sampling (Dr. Cliff Frohlich)
Prior to the cruise, Dr. Michael Bender and Dr. Matt Reuer of Princeton University requested that we take water samples at 49 sites in the Drake Passage and within Antarctic waters; for this he provided 98 evacuated sample bottles. At each site we took two water samples and recorded position as well as salinity and sea surface temperature (SST) from the ship's underway thermosalinograph (TSG) system. Several individuals are required for the sampling because it is an around-the-clock effort; on the Chile-Antarctica leg the sampling crew included myself, Krishnavikas Gudipati, Emily Lindsey, and Leonardo Cantoni. Our sampling efforts will complement Reuer's own program when he joins the Nathanial B. Palmer for cruise NBP02-09. At this time we have successfully collected samples at 23 sites. There was initially some difficulty because the Gould's TSG system did not function, and no replacement hardware was available on board.
As a temporary fix the ship's electronics tech, Joel Lenorovitz rigged up a thermocouple to measure temperature as the water stream reached the wet lab. And, the ship has an AUTOSAL system and appropriate standard samples so that it is possible to measure salinity from samples directly. Moreover Cantoni has used an AUTOSAL system previously. Thus we took water samples in spite of the absence of information from the TSG.
Fortunately, the Lenorovitz and Cantoni were able to repair the TSG system midway through the Drake Passage. The apparent problem was that an O-ring seal had deteriorated, and water had compromised some of the signal wires. Thus, for the remainder of the cruise we will measure both temperature and salinity in two waysfrom the TSG system, and from the thermocouple and AUTOSAL. In all our sampling efforts we have had exemplary cooperation from the both the RPS people and passengers. Because of the unforeseen problem with the TSG, it would not have been possible to collect samples without the persistent repair efforts of the ET, and without Cantoni's willingness and experience with the AUTOSAL system. My only recommendation for future cruises is that the TSG system should be checked out thoroughly prior to sailing, and that spare TSG hardware should always be kept on board."

GPS Measurements
We arrived at Smith Island (site CJAM) at about 03:00 on 27 November with conditions suitable for Zodiac operations and landed on Smith Island at about 04:30. An hour of digging was required to remove snow and ice from the reference mark, but we encountered no other difficulty. Dr. Brenda Hall also came ashore and scouted the exposed terrain for useful geological data. By about 08:00 we regained the ship and immediately departed for Low Island.

The area of the GPS site at Low Island (CWAL) consists of a broad hummocky terrain with areas of exposed, glacially striated bedrock and numerous scattered erratics. All of this is of potentially great interest to Dr. Hall. She and John Evans set up camp for an extended stay while the GPS set up a station. The GPS team returned to the ship and immediately set sail at about 17:30 for Spring Point on the Antarctic Peninsula. We arrived at Spring Point at 08:30 on 28 November to nice weather and barely a breath of wind. We motored ashore to find our GPS site (SPPT) buried beneath more snow than in previous years, but in less than 30 minutes we found the GPS mark and removed the snow. By 12:30 the shore party reboarded the Gould. The Gould transited the Neumayer Channel and visited Hugo Island during late morning of 29 November where RPSC staff attended to an automated weather station. We then continued on to Smith Island where we recovered the CJAM GPS receiver and its data during the morning of 30 November. By mid-afternoon we had also recovered the GPS equipment from the CWAL site at Low Island as well as John Evans and Brenda Hall. The Gould then departed for Palmer Station, arriving there at about 08:30 on 1 December.

Glaciology and Relative Sea Level Studies (Dr. Brenda Hall)
After a smooth crossing of the Drake Passage, I-194 commenced scientific operations on Nov. 27. Brenda Hall and John Evans went ashore on Cape James (Smith Island). The purpose of this shore visit was to do glacial geologic reconnaissance in the vicinity of Fred Taylor's GPS station. The ice-free area was limited and very steep. A quick survey showed that glacial features, such as striations and erratics, were lacking. Nor were there any raised beaches, although there did seem to be a raised marine platform at about 15-20 m elevation, the site of an extensive chinstrap penguin rookery.
Later that same day, Hall and Evans went ashore on Cape Wallace, Low Island. There, they set up camp in preparation for a couple days of fieldwork. They were assisted by the ship's marine staff, as well as by numerous volunteers from the Palmer Station-bound passengers. At Low Island, the purpose was to locate moraines and other glacial features, as well as raised beach ridges. We were very successful in locating such features. However, snow cover (in places exceeding 90%) greatly hampered this work. Adverse weather (strong winds, snow, and fog) also affected our work. The site may warrant further work in the future, because there is a well-preserved set of beaches extending to elevations much higher than generally found. We took samples for exposure-age dating, but, given the poor working conditions, we were unable to make a detailed search for radiocarbon-datable material within the beaches.

Summary
Cruise LMG02-9 has gotten off to an excellent start. The weather has been kind, but in addition we are yet again fortunate to have a perfect performance by Captain Robert Verret and his men, MPC Skip Owens and Special Projects Coordinator John Evans, MT's Toby Koffman and Jamee Johnson, Joel Lenorovitz, our passengers to Palmer, and the GPS support team. Of special note is the aid of our Argentine guest, Leonardo Cantoni, who is a great pleasure to have aboard, in addition to the fact that he has been very helpful in repairing some of the seawater monitoring equipment.