Late Cenozoic glacier-volcano interaction on James Ross Island and adjacent areas, Antarctic Peninsula region

Abstract

Hambrey, M.J., Smellie, John L., Nelson, Anna E., Johnson, Joanne S., (2008) Late Cenozoic glacier-volcano interaction on James Ross Island and adjacent areas, GeoAntarctic Peninsula region, Geological Society of America Bulletin 120 (5-6), 709-731The northern Antarctic Peninsula region has undergone ~10 m.y. of eruptive activity by basaltic volcanoes, mainly in subglacial settings. Spectacular exposures of lava-fed deltas, capped by basalt flows and commonly underlain by glacigenic sediments on top of a Cretaceous sedimentary ?basement,? characterize James Ross, Vega, and other islands and promontories in the region. Neogene strata are collectively known as the James Ross Island Volcanic Group and record a cryptic history of glaciation, with the timing of events determinable by argon-isotope dating. Focusing especially on the glacigenic sediments themselves, and their relationships with overlying or bounding volcanic rocks, we define facies associations related to (1) eruptions beneath thick ice (>200 m) that produced lava-fed deltas resting on, and intermingling with, diamictite; and (2) eruptions under marine conditions that typically culminated in the development of several tuff-cone successions, some on top of presumably relict glacially striated surfaces. A combination of provenance studies on clasts in the glacigenic sediments, some of which are derived from the Antarctic Peninsula, and geochronology, leads to the conclusion that an Antarctic Peninsula Ice Sheet extended over James Ross and Vega Islands at about the time that the main volcanic edifi ces began to grow, i.e., prior to ca. 6.2 Ma at least. Much of the subsequent development of the succession is attributed to the interaction between the growing volcanoes and local ice caps. Full resolution of glacial-interglacial events in this region promises to inform the debate about the stability of the most climatically sensitive part of the Antarctic Ice Sheet during the Neogene Period.Peer reviewe

Progressive Cenozoic cooling and the demise of Antarctica’s last refugium

“…These sediments are interpreted to represent a current-influenced deposit with abundant iceberg-rafted material from distant sources. These results are consistent with those from a well-dated ( 87 Sr∕ 86 Sr and 40 Ar∕ 39 Ar) succession of interbedded volcanic and glacial deposits on James Ross Island that has yielded a record of glacial-interglacial oscillations since approximately 6.2 Ma (27)(28)(29).…”

“…Strata of late Miocene age were not sampled as part of the SHALDRIL project; however, late Miocene glacial deposits do occur on Seymour Island (23) and on James Ross Island (27)(28)(29). The extent of these glaciations has remained uncertain, but seismic records from the continental shelves on the western and eastern sides of the AP imaged glacial unconformities that are interpreted to be of late Miocene age (6,30,31).…”

“…The last remnant of vegetation on Antarctica existed in the peninsula region; a tundra landscape persisted until at least 12.8 Ma and was extinguished no later than 5.3 Ma. The late Miocene was not sampled, but is known to have been a time of growth and expansion of the Antarctic Peninsula Ice Sheet (5,6,23,(27)(28)(29)(30)(31) (Fig. 4).…”

Fossil proxies of near-shore sea surface temperatures and seasonality from the late Neogene Antarctic shelf

“…Some 10 million years of late Neogene and Quaternary history is recorded in the JRIVG Smellie et al 2008;Hambrey et al 2008;Smellie et al 2009 Table 2). Sr/ Sr chronology has also been used on calcitic bivalve shells collected from diamicts (Table 2).…”

“Bottomsets” of the lava−fed delta of James Ross Island Volcanic Group, Ulu Peninsula, James Ross Island, Antarctica

“…Several hundred meters thick succession of basaltic hyaloclastite breccias, alkali basalt lavas, and tuffs of the James Ross Island Volcanic Group (Late Miocene−Ho− locene) rest unconformably on the Cretaceous strata (Nelson 1975;Smellie 1999;Skilling 2002;Smellie et al 2008Smellie et al , 2013Hambrey et al 2008;Košler et al 2009). The James Ross Island Volcanic Group (JRIVG) is a large (c. 6000 km 2 ) basaltic volcanic field situated in northern Antarctic Peninsula (Nelson 1975;Smellie 1999;Smellie et al 2008Smellie et al , 2013 dominating by the Mount Haddington stratovolcano.…”