Lithostratigraphy, age and distribution of Eocene volcanic sequences on eastern King George Island, South Shetland Islands, Antarctica

Smellie, John L.; Hunt, Richard J.; McIntosh, William C.; Esser, Richard

doi:10.1017/s0954102021000213

Cited by 12 publications

(18 citation statements)

References 25 publications

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“…While the Eocene and Oligocene rocks appear in several small outcrops in west-centre King George Island (Smellie et al, 2021a), here we show the two main exposures, which are located in Admiralty Bay and Polonez Cove (Figure 13). We have used the lithostratigraphy presented by Smellie et al (2021a), who revised the conflictive models presented by former contributions (e.g., Barton, 1965;Birkenmajer, 1981;Birkenmajer, 1982;Birkenmajer et al, 1985;Birkenmajer and Zastawniak, 1989;Smellie et al, 1984;Kraus, 2005;Panczyket al, 2009; Admiralty Bay is located in the east of King George Island (Figure 13) and its exposures are dominated by the Hennequin Formation and more recent clastic and lavas rocks. While the Hennequin Formation is constrained by basaltic andesites, andesite lavas and amygdaloidal breccias, with minor presence of rhyolites (Smellie et al, 1984), Smellie et al (2021a) suggested that these rocks, along with other Eocene strata, extensively crop out in eastern King George Island.…”

Section: Admiralty Bay and Polonez Cove Areasmentioning

confidence: 58%

“…Additionally, while there is a plethora of local-scale geological maps, these are mostly located near research stations and unfortunately often introduce new geological units as opposed to attempting regional correlation. The most comprehensive geological map of the South Shetland archipelago was presented in the work of Smellie et al (1984), and now after almost four decades, significant new information is available (e.g., Bastias et al, 2019;Smellie et al, 2021a;Smellie et al, 2021b;Chen et al, 2021), which we gather and present herein.…”

Section: Introductionmentioning

confidence: 95%

“…This has resulted in a complex stratigraphy that has been supported mainly by poorly constrained K-Ar geochronology (e.g., Leat and Riley, 2021). The exposures in King George Island are dominated by Cenozoic volcanic and sedimentary strata (e.g., Birkenmajer and Zastawniak, 1989;Dutra and Batten, 2000;Poole et al, 2001;Fontes and Dutra, 2010;Warny et al, 2019b;Smellie et al, 2021a;Smellie et al, 2021b;Chen et al, 2021). These exposures (particularly those in northeast King George Island) are relevant because they provide a record of Antarctica's glacial history, and have been used to suggest episodes of late Cenozoic glaciation (e.g., Warny et al, 2019a;Smellie et al, 2021a;Smellie et al, 2021b).…”

Section: King George and Nelson Islandsmentioning

confidence: 99%

“…The exposures in King George Island are dominated by Cenozoic volcanic and sedimentary strata (e.g., Birkenmajer and Zastawniak, 1989;Dutra and Batten, 2000;Poole et al, 2001;Fontes and Dutra, 2010;Warny et al, 2019b;Smellie et al, 2021a;Smellie et al, 2021b;Chen et al, 2021). These exposures (particularly those in northeast King George Island) are relevant because they provide a record of Antarctica's glacial history, and have been used to suggest episodes of late Cenozoic glaciation (e.g., Warny et al, 2019a;Smellie et al, 2021a;Smellie et al, 2021b). Additionally, the presence of Late Cretaceous rocks has been indicated based on analyses of taphoflora, which are preserved in Fildes Peninsula on King George Island and Rip Point on Nelson Island (Birkenmajer, 1981;Smellie et al, 1984;Li et al, 1989;Cao, 1994;Shen, 1994;Dutra & Batten, 2000).…”

Section: King George and Nelson Islandsmentioning

confidence: 99%

“…Later, approaching the Eocene/Oligocene boundary, northward propagation of the Antarctic icesheet and marine transgression occurred (Baker, 2007;Davies et al, 2012), which led to glacial, glaciomarine and marine sedimentation (Troedson and Riding, 2002;Troedson and Smellie, 2002). This was followed by a period of glaciations and interglacials that are recorded at the northwestern end of the archipelago on King George Island (e.g., Birkenmajer et al, 1985;Birkenmajer, 2001;Troedson and Smellie, 2002;Whittle et al, 2014;Smellie et al, 2021a;Smellie et al, 2021b). These paleoenvironmental events are related to globally significant climate events (e.g., Kennett, 1977;Zachos et al, 2001;De Conto & Pollard, 2003), and the South Shetland Islands are one of the few regions in Antarctica where these processes are preserved in the geological record.…”

Section: Introductionmentioning

confidence: 99%

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The South Shetland Islands, Antarctica: Lithostratigraphy and geological map

et al. 2023

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Over the last few decades, numerous geological studies have been carried out in the South Shetland Islands, which have greatly contributed to a better understanding of its geological evolution. However, few attempts have been conducted to correlate the geological units throughout this archipelago. We present herein a review of the literature available in the South Shetland Islands, which we use to propose a lithostratigraphical correlation that constitutes a coherent stratigraphy for the main Mesozoic and Cenozoic rocks of the South Shetland Islands along with a new geological map. The lithostratigraphical correlation shows that the geological and environmental evolution comprises three main stages: 1) deep marine sedimentation from ∼164 to 140 Ma, 2) subaerial volcanism and sedimentation with a proliferation of plants and fauna from ∼140 to 35 Ma and 3) glacial and interglacial deposits from ∼35 Ma. The lithostratigraphical correlation also shows a broad geographical trend of decreasing age of volcanism from southwest to northeast, which has been previously suggested. However, this spatial age trend is disrupted by the presence of Eocene magmatism in Livingston Island, located in the centre of the archipelago. We suggest that the migration of volcanism occurred from the Late Cretaceous until the early Eocene. Subsequently, enhanced magmatic activity took place from the mid-Eocene until the Miocene, which we associate with processes related with the waning of subduction. Constraining the protolith age of the metamorphic complex of Smith Island remains challenging, yet holds key implications for the tectonic and accretionary evolution of the Antarctic Peninsula. The rocks recording the glaciation of this sector of Antarctica are well exposed in the northern South Shetland Islands and hold critical information for understanding the timings and processes that lead to the greenhouse to icehouse transition at the end of the Eocene. Finally, contemporaneous rocks to the breakup of Antarctic Peninsula from Patagonia that led to the opening of the Drake Passage and the development of the Scotia Sea are exposed in the centre and north of the South Shetland archipelago. Better constraints on the age and tectonic settings on these units may lead to further understanding the paleobiogeographical evolution of the region, which may have played an important role for speciation as a land bridge between South America and Antarctica. The dataset containing the geological map and associated information is shared as a shapefile or KML file.

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