Sedimentological and palaentological examination of the Devonian Horlick formation in the Ohio Range of the Horlick Mountains
15 sections of the Horlick formation were measured in detail along the Ohio escarpment from Discovery Ridge to Lackey Ridge. The Ohio Range contains the only well exposed record of unequivocally marine Devonian sediments in Antarctica, and is a unique and rarely visited locality. Three sections were studied on Discovery Ridge where the main lithofacies were established. One section was studied on ... the second spur west of Discovery Ridge, five sections were studied on Lackey Ridge at the extreme western end of the escarpment and four on Darling Ridge. To complete the coverage, two sections were measured on Schulthess Buttress, one on the western spur and the other on the eastern spur. Seven lithofacies were described and the inter-relationship between each was studied in detail. Fossils that had not been recorded before were collected and the relationships of these fossils to each other and to the sediment in when they were enclosed was examined. The fossils include large bivalves, brachiopods, trilobites, gastropods, monoplacophorans, crinoidal detritus, fish bones and plates and tentaculitids. Psilophyte plant fossils were also discovered. Detailed palaeontological collections were made. The exposed base of the Horlick Formation allowed a unique chance to study a near-shore assemblage of sediments derived from a granitic landmass. Shale samples were collected for palaeomagnetic work. The Buckeye Formation is one of the thicker sequences of Permian glacial sediments in the Transantarctic Mountains and formed some spectacular outcrops. Three small slumped horizons were measured. A three-directional foliation in the sandstones at the top of the formation was measured and photographed. Animal trails were noted and several lithologies sampled. A horizon rich in Glossopteris leaves and non-marine Permian bivalves, the latter recorded for the first time in Antarctica, were collected from the the highest coal measure beds on Mt. Glossopteris.
(Click for Interactive Map)
The values provided in temporal and spatial coverage are approximate only.
Taken from the 2008-2009 Progress Report:
Variations to work plan or objectives:
Project AAS 3025 was varied from the original plan to drill an ice core at Aurora Basin. For operational reasons, we could not access our original GC41 drilling site on Aurora Basin. The topography at the site was ... considered too rough to land an aircraft. Further reconnaissance in the area failed to find a suitable landing site. Consequently, a modification to the project (AAS 3025) was submitted and approved to retrieve an ice core from Law Dome, Totten Glacier and/or Mill Island. Our revised aims were:
(i) To collect an intermediate depth ice core at W10k to at least 110m (~200 years).
(ii) To collect shallow cores (10-15m) at either or both Totten Glacier and Mill Island.
(iii) If possible, to collect ice samples for AAS project 3064 at DSS on Law Dome.
Law Dome was accessed by traverse from Casey and three ice cores were collected (127m Hans Tausen ice core at W10k; a 10m PICO ice core at DSS and W10k sites). Totten Glacier and Mill Island were accessed using C212 aircraft and three ice cores were collected (17m PICO ice core at Mill Island; 17m and 15m PICO ice cores at Totten Glacier). Samples were also taken for AAS project 3064.
Table 1 summarises the location, depth and approximate age of each ice core collected.
Summary of achievements against revised aims:
(i) Our aim was to drill at least 110m on Law Dome at a site 10 km (W10k) to the west of our deep ice core site (Dome Summit South DSS). We drilled to 127m (in 5 drilling days) and we had no major problems with the drill and the core quality was excellent. This will provide a 250 year record from a site with intermediate accumulation on Law Dome. This will compliment our records from DSS and W19k. At a minimum we needed to drill to around 200 years before present to a volcanic layer from the Tambora eruption (1815). This will give us accurate dating and accurate mean snow accumulation rate to compare with DSS and WS19k. We intend to send this ice to Joe McConnell's lab for analysis (consistent with existing project 3025) and compliment with our in-house analysis of trace chemistry and stable isotopes.
This project also provided a unique opportunity to test, and train with, the Danish Hans Tausen (HT) ice core drill and training our staff with ice core drilling, particularly our new staff (Andrew Moy and Tessa Vance) and students (Joel Pedro) and looking at succession. It was highly valuable having Vin Morgan in the team and he was a good drilling mentor. As a stepping stone for Aurora Basin ice core drilling, we achieved a lot including, staff training, camp experience, grooming a skiway, flight landing operations, weather observations and air ground support.
(ii) A great effort from the Casey logistics coordinators, station leader and expeditioners, and in particular Skytraders ensured success achieving more than we originally aimed. Two ice cores were recovered from the Totten Glacier - upper (15m) and lower (17m) Totten (Table 1). These will be used to look at accumulation changes over the past decade to investigate why the Totten is thinning. These results will feed into models, and will provide valuable information to the ICECAP project on why the Totten is thinning. A shallow ice core (17m) was also collected from Mill Island which will be a valuable pilot study towards drilling a deeper record at this site in 2009/10 (AAS project 1236). At all sites, deeper cores were recovered than we hoped for, which gives us a longer and therefore better record to work with. All assistance for this work was greatly appreciated.
(iii) An opportunity to collect ice cores and snow pit samples for AAS project 3064 was taken (Table 1). All samples required for this project were collected at the required site (DSS) and according to the work plan listed in AAS 3064.
Table 1 Details of ice cores drilled in season 2008/2009 in the Casey region:
Site Drill date Depth (m) ~age elevation (m) lat long AAS
DSS 0809 W10k 18/12/2008 127.00 250 1242 66o 46'10.56"S 112o 34'47.76"E 3025/757
DSS 0809 pW10k 14/12/2008 1.83 3 1242 66o 46'10.56"S 112o 34'47.76"E 3025/757
DSS 0809 p2W10k 16/12/2008 9.75 13 1242 66o 46'10.56"S 112o 34'47.76"E 3025/757
DSS 0809 29/12/2008 10.43 6 1263 66o 49'60.00"S 112o 49'60.00"E 3025/757
DSS 0809 P1 29/12/2008 5.67 4 1263 66o 49'60.00"S 112o 49'60.00"E 3064
DSS 0809 P2 29/12/2008 5.79 4 1263 66o 49'60.00"S 112o 49'60.00"E 3064
DSS 0809 P3 29/12/2008 5.90 4 1263 66o 49'60.00"S 112o 49'60.00"E 3064
DSS 0809 pit 29/12/2008 0.75 0.4 1309 66o 43'46.56"S 112o 50'5.28"E 3064
DSS 0809 pit pico 29/12/2008 1.02 0.5 1309 66o 43'46.56"S 112o 50'5.28"E 3064
Totten Glacier 1 1/01/2009 17.45 10 89 66o 59'49.90"S 116o 0'11.50"E 3025/757
Totten Glacier 2 30/01/2009 15.33 9 528 67o 26'31.62"S 113o 32'27.66"E 3025/757
Mill Island 22/01/2009 16.69 15 338 65o 33'25.02"S 100o 33'26.46"E 3025/757
The core collected this season will be analysed and reported against AAS 757
Difficulties affecting project:
Ice core drilling at Aurora Basin (site GC41) was not achieved, however ice cores were recovered from Law Dome (site W10k, 127m; site DSS 10m), Mill Island (site MI 17m) and Totten Glacier (site TOT1 17m; TOT2 15m). Details given in Table 1.
These data are not yet publicly available.
Data Set Progress
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