C. Alexander Island, Palmer Island, and Ellsworth Land

Rowley, Peter D.; Thomson, John W.; Smellie, John L.; Laudon, T. S.; Prade, K.E. La; LeMasurier, Wesley E.

doi:10.1029/ar048p0256

Cited by 8 publications

(11 citation statements)

References 19 publications

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“…Along with the Pine Island Glacier (PIG) region, the Hudson Mountains, a Neogene volcanic province characterized by three large, extensively eroded stratovolcanoes, is located in the ASE sector of the TIE crustal block (Rowley et al., 1990) (Figure 1). There is evidence of a recent (207 BCE ± 240 years) volcanic eruption in the Hudson Mountains (Corr & Vaughan, 2008).…”

Section: Introductionmentioning

confidence: 99%

Seismicity and Pn Velocity Structure of Central West Antarctica

Lucas

Nyblade

Lloyd³

et al. 2021

Geochem Geophys Geosyst

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We have located 117 previously undetected seismic events mainly occurring between 2015 and 2017 that originated from glacial, tectonic, and volcanic processes in central West Antarctica using data recorded on Polar Earth Observing Network (POLENET/ANET) and UK Antarctic Network (UKANET) seismic stations. The seismic events, with local magnitudes (ML) ranging from 1.1 to 3.5, are predominantly clustered in four geographic regions; the Ellsworth Mountains, Thwaites Glacier, Pine Island Glacier, and Mount Takahe. Eighteen of the events are in the Ellsworth Mountains and can be attributed to a mixture of glacial and tectonic processes. The largest event noted in this study was a mid‐crustal (∼19 km focal depth; ML 3.5) normal mechanism earthquake beneath Thwaites Glacier. We also located 91 glacial events near the grounding zones of Thwaites Glacier and Pine Island Glacier that are predominantly associated with time periods of significant calving activity. Eight events, likely arising from volcano‐tectonic processes, occurred beneath Mount Takahe. Using Pn travel times from the seismic events, we find laterally variable uppermost mantle structure in central West Antarctica. On average, the Ellsworth Mountains are underlain by a faster mantle lid (VPn = ∼8.4 km/s) compared to the Amundsen Sea Embayment region (VPn = ∼8.1 km/s). Within the Amundsen Sea Embayment itself, we find mantle lid velocities ranging from ∼8.05 to 8.18 km/s. Laterally heterogeneous uppermost mantle structure, indicative of variable thermal and rheological structure, likely influences both geothermal heat flux and glacial isostatic adjustment spatial patterns and rates within central West Antarctica.

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Section: Introductionmentioning

confidence: 99%

Seismicity and Pn Velocity Structure of Central West Antarctica

Lucas

Nyblade

Lloyd³

et al. 2021

Geochem Geophys Geosyst

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“…Geological map of the Antarctic Peninsula, showing the distribution of the principal geological units defined in the text (Fleming & Thomson 1979; Thomson & Harris 1979;Thomson 1981; Thomson et al 1982;Storey et al 1986;Rowley et al 1992;Moyes et al 1993;Riley et al 2011a,b). EPLSZ, East Palmer Land Shear Zone; WD, Western Domain; CD, Central Domain; ED, Eastern Domain.…”

mentioning

confidence: 99%

Autochthonous v. accreted terrane development of continental margins: a revised in situ tectonic history of the Antarctic Peninsula

Burton‐Johnson

Riley

2015

JGS

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The allochthonous terrane accretion model previously proposed for the geological development of the Antarctic Peninsula continental margin arc is reviewed in light of recent data and the geology is reinterpreted as having evolved as an in situ continental arc. This is based upon the following factors: (1) the presence of Early Palaeozoic basement and stratigraphic correlation of sequences between the autochthonous and previously proposed allochthonous terranes; (2) isotopic evidence for similar deep crustal structure across the different terranes; (3) ocean island basalt magmas and deep marine sedimentary rocks formed during continental margin extension within the previously proposed accretionary wedge sequence (i.e. not formed against an active oceanic arc); (4) the distribution of magnetic susceptibility measurements and aeromagnetic data locating the palaeo-subduction zone along the west of the Peninsula; (5) a lack of clear palaeomagnetic distinction between the terranes. The following alternative tectonic history is proposed: (1) amalgamation and persistence of Gondwana; (2) subsequent silicic large igneous province magmatism and extension; (3) development and history of Andean subduction until its cessation in the Cenozoic. A number of features in the Antarctic Peninsula correlate with those of other circum-Pacific margins, supporting a global evaluation of allochthonous v. autochthonous margin development to aid our understanding of crustal growth mechanisms.

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“…Previous workers suggested there are three, mostly icecovered, major volcanoes at Teeters Nunatak, Mount Moses and Mount Manthe, which are overlain by smaller parasitic volcanoes (see Rowley et al 1990). Analysed rocks range from tephrite to hawaiite in composition (Rowley et al 1990). Three general lithofacies have been noted: a lower pillow lava and associated hyaloclastite tuff (as much as 60 m thick) observed at Mount Nickens; a middle subhorizontal to et al (1990).…”

Section: Hudson Mountains Volcanic Fieldmentioning

confidence: 83%

Section: Hudson Mountains Volcanic Fieldmentioning

confidence: 89%

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Chapter 5.4a Marie Byrd Land and Ellsworth Land: volcanology

Wilch

McIntosh

Panter

2021

Memoirs

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Nineteen large (2348–4285 m above sea level) central polygenetic alkaline shield-like composite volcanoes and numerous smaller volcanoes in Marie Byrd Land (MBL) and western Ellsworth Land rise above the West Antarctic Ice Sheet (WAIS) and comprise the MBL Volcanic Group (MBLVG). Earliest MBLVG volcanism dates to the latest Eocene (36.6 Ma). Polygenetic volcanism began by the middle Miocene (13.4 Ma) and has continued into the Holocene without major interruptions, producing the central volcanoes with 24 large (2–10 km-diameter) summit calderas and abundant evidence for explosive eruptions in caldera-rim deposits. Rock lithofacies are dominated by basanite and trachyte/phonolite lava and breccia, deposited in both subaerial and ice-contact environments. The chronology of MBLVG volcanism is well constrained by 330 age analyses, including 52 new 40Ar/39Ar ages. A volcanic lithofacies record of glaciation provides evidence of local ice-cap glaciation at 29–27 Ma and of widespread WAIS glaciation by 9 Ma. Late Quaternary glaciovolcanic records document WAIS expansions that correlate to eustatic sea-level lowstands (MIS 16, 4 and 2): the WAIS was +500 m at 609 ka at coastal Mount Murphy, and +400 m at 64.7 ka, +400 m at 21.2 ka and +575 m at 17.5 ka at inland Mount Takahe.

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C. Alexander Island, Palmer Island, and Ellsworth Land

Cited by 8 publications

References 19 publications

Seismicity and Pn Velocity Structure of Central West Antarctica

Seismicity and Pn Velocity Structure of Central West Antarctica

Autochthonous v. accreted terrane development of continental margins: a revised in situ tectonic history of the Antarctic Peninsula

Chapter 5.4a Marie Byrd Land and Ellsworth Land: volcanology

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