The geology of King George Island, South Shetland Islands: uniting local geological maps and stratigraphical columns

2021 ◽  
Author(s):  
Bastian Lopez ◽  
Joaquin Bastias ◽  
Daniela Matus ◽  
Ricardo Jaña ◽  
Marcelo Leppe
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
King George Island ◽  
The South ◽  
Moby Dick ◽  
Shetland Islands ◽  
Ice Cap ◽  
The North ◽  
South Shetlands ◽  
Geological Map

<p>King George Island is the largest one of the South Shetland Islands group distributed parallel to and separated by the Bransfield Strait of the northern tip of Antarctic Peninsula. The archipelago of the South Shetlands is mainly composed of the products of the active margin developed as a result of the subduction of the Phoenix Plate beneath the continental crust of the Antarctic Peninsula (e.g. Barker, 1982; Bastias et al., 2019). The lithologies are largely dominated by Mesozoic and Cenozoic sedimentary and volcanic successions that are cut by a few hypabyssal plutons. While some authors have suggested a southwest to northeast trend along the archipelago from older to younger magmatic activity (e.g. Haase et al., 2012), others have indicated that some of the magmatic events may have been recorded along the entire archipelago (e.g. Valanginian arc rocks; Bastias et al., 2019). Regardless, King George Island hosts an exceptional stratigraphical record of the Cenozoic period. Moreover, this island is mostly covered by an ice cap at the present day, which is commonly terminated with ice cliffs around much of the island. The southern edge of the island host Mesozoic and Paleogene successions, these rocks are dominated by volcanic and volcaniclastic units. The rocks in King George Island are generally young to the east and to the north ends. Cape Melville, the southeast extreme of the island, hosts the youngest sedimentary rocks known on the island: the Moby Dick Group (Birkenmajer, 1985).</p><p>While several authors have presented local studies in the King George Island over the last three decades, an integrated assessment of the outcropping units in the entire island remains unexplored. A new geological map for King George Island will allow to update the current understanding of the stratigraphy of the South Shetland Islands, which will help to support not only the geological studies but also those focused on the environmental and paleontological record.</p><p>Barker, 1982. Journal of the Geological Society 19, 787-801. (DOI: 10.1144/gsjgs.139.6.0787)</p><p>Bastias et al. (2019). International Geology Review 62 (11), 1467-1484. (DOI: 10.1080/00206814.2019.1655669)</p><p>Birkenmajer (1985). Bulletin Polish Academic Earth Sciences 33:15-23.</p><p>Haase et al. (2012). Contributions to Mineralogy and Petrology 163, 1103-1119. (DOI: 10.1007/s00410-012-0719-7).</p>

Geotectonic evolution of the Bransfield Basin, Antarctic Peninsula: insights from analogue models

2008 ◽  
Vol 20 (2) ◽  
pp. 185-196 ◽  
Author(s):  
M.A. Solari ◽  
F. Hervé ◽  
J. Martinod ◽  
J.P. Le Roux ◽  
L.E. Ramírez ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
The West ◽  
Shetland Islands ◽  
Scotia Ridge ◽  
The North ◽  
Analogue Models ◽  
Bransfield Basin ◽  
The Phoenix

AbstractThe Bransfield Strait, located between the South Shetland Islands and the north-western end of the Antarctic Peninsula, is a back-arc basin transitional between rifting and spreading. We compiled a geomorphological structural map of the Bransfield Basin combining published data and the interpretation of bathymetric images. Several analogue experiments reproducing the interaction between the Scotia, Antarctic, and Phoenix plates were carried out. The fault configuration observed in the geomorphological structural map was well reproduced by one of these analogue models. The results suggest the establishment of a transpressional regime to the west of the southern segment of the Shackleton Fracture Zone and a transtensional regime to the south-west of the South Scotia Ridge by at least c. 7 Ma. A probable mechanism for the opening of the Bransfield Basin requires two processes: 1) Significant transtensional effects in the Bransfield Basin caused by the configuration and drift vector of the Scotia Plate after the activity of the West Scotia Ridge ceased at c. 7 Ma. 2) Roll-back of the Phoenix Plate under the South Shetland Islands after cessation of spreading activity of the Phoenix Ridge at 3.3 ± 0.2 Ma, causing the north-westward migration of the South Shetland Trench.

The Bellingshausen-Palmer meeting

Polar Record ◽  
2015 ◽  
Vol 51 (6) ◽  
pp. 644-654 ◽  
Author(s):  
Rip Bulkeley
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Contentious Issue ◽  
Balanced Assessment ◽  
Absolute Certainty ◽  
South Shetlands ◽  
The Antarctic

ABSTRACTThe celebrated meeting between Captain Bellingshausen of the Imperial Russian Navy and the American sealing skipper Nathaniel Brown Palmer, off the South Shetland Islands in February 1821, has often been described by following just one or other of the two men's divergent and in some respects irreconcilable accounts. The most contentious issue is whether or not Palmer told Bellingshausen about the existence of a body of land to the south of the South Shetlands, known today as the Antarctic Peninsula. This note attempts to reach a balanced assessment of the matter by examining evidence from both sides, including several previously unconsidered items. It concludes that, although the truth will never be known with absolute certainty, the basic American account is more plausible, by the narrowest of narrow margins, than the Russian.

scholarly journals Southern elephant seal movements and Antarctic sea ice

2000 ◽  
Vol 12 (1) ◽  
pp. 3-15 ◽  
Author(s):  
H. Bornemann ◽  
M. Kreyscher ◽  
S. Ramdohr ◽  
T. Martin ◽  
A. Carlini ◽  
...  
Keyword(s):  
Sea Ice ◽  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
Mirounga Leonina ◽  
King George Island ◽  
The South ◽  
Elephant Seals ◽  
Shetland Islands ◽  
Pack Ice ◽  
The Antarctic

Weaned pups and post-moult female elephant seals (Mirounga leonina) were fitted with satellite transmitters at King George Island (South Shetland Islands) between December 1996 and February 1997. Of the nine adult females tracked for more than two months, three stayed in a localized area between the South Shetland Islands and the South Orkney Islands. The other six females travelled south-west along the coast of the Antarctic Peninsula up to the Bellingshausen Sea. Two of them then moved north-east and hauled out on South Georgia in October. One female was last located north of the South Shetland Islands in March 1998. In total, eight females were again sighted on King George Island and six of the transmitters removed. The tracks of the weaners contrasted with those of the adults. In January, five juveniles left King George Island for the Pacific sector spending about four weeks in the open sea west of the De Gerlache Seamounts. Three of them returned to the tip of the Antarctic Peninsula in June, of which one was last located on the Patagonian Shelf in November 1997. The juveniles avoided sea ice while the adults did not. The latter displayed behavioural differences in using the pack ice habitat during winter. Some females adjusted their movement patterns to the pulsating sea ice fringe in distant foraging areas while others ranged in closed pack ice of up to 100%. The feeding grounds of adult female elephant seals are more closely associated with the pack ice zone than previously assumed. The significance of the midwater fish Pleuragramma antarcticum as a potential food resource is discussed.

Chapter 3.1a Antarctic Peninsula and South Shetland Islands: volcanology

2021 ◽  
pp. M55-2018-52
Author(s):  
Philip T. Leat ◽  
Teal R. Riley
Keyword(s):  
Antarctic Peninsula ◽  
Continental Margin ◽  
Volcanic Rocks ◽  
South Shetland Islands ◽  
West Antarctica ◽  
The South ◽  
Shetland Islands ◽  
The North ◽  
Climate Cooling ◽  
Tectonic Features

AbstractThe voluminous continental margin volcanic arc of the Antarctic Peninsula is one of the major tectonic features of West Antarctica. It extends from the Trinity Peninsula and the South Shetland Islands in the north to Alexander Island and Palmer Land in the south, a distance of c. 1300 km, and was related to east-directed subduction beneath the continental margin. Thicknesses of exposed volcanic rocks are up to c. 1.5 km, and the terrain is highly dissected by erosion and heavily glacierized. The arc was active from Late Jurassic or Early Cretaceous times until the Early Miocene, a period of climate cooling from subtropical to glacial. The migration of the volcanic axis was towards the trench over time along most of the length of the arc. Early volcanism was commonly submarine but most of the volcanism was subaerial. Basaltic–andesitic stratocones and large silicic composite volcanoes with calderas can be identified. Other rock associations include volcaniclastic fans, distal tuff accumulations, coastal wetlands and glacio-marine eruptions.Other groups of volcanic rocks of Jurassic age in Alexander Island comprise accreted oceanic basalts within an accretionary complex and volcanic rocks erupted within a rift basin along the continental margin that apparently predate subduction.

Holocene isostatic uplift of the South Shetland Islands, Antarctic Peninsula, modelled from raised beaches

2010 ◽  
Vol 29 (15-16) ◽  
pp. 1880-1893 ◽  
Author(s):  
P.T. Fretwell ◽  
D.A. Hodgson ◽  
E.P. Watcham ◽  
M.J. Bentley ◽  
S.J. Roberts
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Isostatic Uplift ◽  
Raised Beaches

scholarly journals Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy

2004 ◽  
Vol 16 (3) ◽  
pp. 339-344 ◽  
Author(s):  
BRENDA L. HALL ◽  
ETHAN R. PERRY
Keyword(s):  
Antarctic Peninsula ◽  
Ocean Circulation ◽  
Late Holocene ◽  
Warming Trend ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Livingston Island ◽  
The Antarctic ◽  
Glacial Advance

Raised beach ridges on Livingston Island of the South Shetland Islands display variations in both quantity and source of ice rafted detritus (IRD) received over time. Whereas the modern beach exhibits little IRD, all of which is of local origin, the next highest beach (∼250 14C yr BP) has large amounts, some of which comes from as far away as the Antarctic Peninsula. Significant quantities of IRD also were deposited ∼1750 14C yr BP. Both time periods coincide with generally cooler regional conditions and, at least in the case of the ∼250 yr old beach, local glacial advance. We suggest that the increases in ice rafting may reflect periods of greater glacial activity, altered ocean circulation, and/or greater iceberg preservation during the late Holocene. Limited IRD and lack of far-travelled erratics on the modern beach are both consistent with the ongoing warming trend in the Antarctic Peninsula region.

scholarly journals Climate sensitivity of the ice cap of King George Island, South Shetland Islands, Antarctica

1996 ◽  
Vol 23 ◽  
pp. 154-159 ◽  
Author(s):  
Wouter H. Knap ◽  
Johannes Oerlemans ◽  
Martin Cabée
Keyword(s):  
Climate Change ◽  
South Shetland Islands ◽  
Balance Model ◽  
King George Island ◽  
Shetland Islands ◽  
Ice Volume ◽  
Ice Cap ◽  
Current State ◽  
Highly Sensitive ◽  
Business As Usual

A two-dimensional vertically integrated ice-flow model has been used to simulate the current state of the ice cap of King George Island, South Shetland Islands, Antarctica, as well as the sensitivity of this state to climate change. The model was forced by an energy-balance model that generates the specific mass balance from climatological input data of two research stations. It proved difficult to simulate-satisfactorily the entire geometry of the present-day ice cap. Nevertheless, it was possible to simulate a steady-state ice cap whose volume and areal extent approximate the (estimated) current situation. Several experiments have indicated that this state is highly sensitive to climate change. The model predicts that cooling by 1 K will increase the ice volume by 10% and warming by 1 K will decrease it by 36%. A 10% change in precipitation will alter the ice volume by less than 8%. Application of the IPCC-90 Business-as-Usual scenario leads to a 55% reduction in the ice volume by the year AD 2100, compared to the present-day situation. The response of the ice cap to warming is therefore totally different from the response of the main Antarctic ice sheet which is believed to gain mass by increasing temperatures.

scholarly journals Kinematics and segmentation of the South Shetland Islands-Bransfield basin system, northern Antarctic Peninsula

2008 ◽  
Vol 9 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Frederick W. Taylor ◽  
Michael G. Bevis ◽  
Ian W. D. Dalziel ◽  
Robert Smalley ◽  
Cliff Frohlich ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands ◽  
Bransfield Basin ◽  
Basin System
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