Marie Byrd Land

Late Holocene Deglaciafion of Marie Byrd Land, West Antarctica Science, 299, 99—102. 

Wilch Tl, McIntosh WC, Dunbar NW (1999) Late Quaternary volcanic activity in Marie Byrd Land Potential Ar-40/Ar-39-dated time horizons in West Antarctic ice and marine cores. Geol Soc Am Bull 111 1563-1580... 

Mountains of East Antarctica, in the Ellsworth Mountains of West Antarctica, and in the extinct volcanoes of Marie Byrd Land. In addition, small mountain ranges project through the East Antarctic ice sheet in Queen (or Dronning) Maud Land, in Enderby Land, in Mac. Robertson Land, and in a few places in Wilkes Land (e.g., Gaussberg, Section 1.3.3). 

The volcanoes of Antarctica occur not only in the Transantarctic Mountains and on the islands off the coast of Victoria Land, but also in Marie Byrd Land of West Antarctica, on the Antarctic Peninsula and on its off-shore islands, on the South Sandwich Islands, in East Antarctica, and on the islands of the Southern Oceans. All of these volcanoes were described in a book edited by LeMasurier and Thomson (1990). The descriptions of the volcanoes include photographs, maps, chemical analyses of the rocks, and interpretations of these analyses. Even the Gaussberg on the coast of East Antarctica (Section 1.3.3) is included in this compilation of Antarctic volcanoes. The book also... 

The volcanoes in the Transantarctic Mountains and in Marie Byrd Land of West Antarctica erupted lava flows and pyroclastic ash that was deposited on the surface of the ice sheets. The ash was subsequently buried by snow and was thereby incorporated into the ice. The resulting ash layers now serve a useful purpose in the study of the ice sheets because they are unique event horizons whose age can be determined by isotopic methods (e.g., Folco et al. 2007). In addition, these horizons have preserved a record of the deformation of the ice sheets that is revealed by mapping their outcrop patterns on the bare-ice surfaces in the ablation zones. The chemical composition of the ash has been used to identify the volcanoes from which certain ash layers were erupted, while the sulfate concentration and the acidity (pH) of the ice above an ash layer provide clues to the amount of sulfuric acid that was injected into the stratosphere (Palais 1985). The volcanic dust and sulfuric acid in the stratosphere can cause temporary cooling of the global climate as demonstrated by the eruptions of Krakatau (Indonesia) in 1883, Mount St. Helens (Washington) in 1980, El Chichon (Mexico) in 1982, and Mount Pinatubo (Philippines) in 1992 (Holland and Petersen 1995 Thompson and Mosley-Thompson 1981 Kyle et al. 1981 Self etal. 1981). 

American scientists and support personnel who are scheduled to work in the Transantarctic Mountains or on the polar plateau of East Antarctica, in Marie Byrd Land in West Antarctica, and at South Pole Station will, in most cases, depart from Christchurch, New Zealand, and fly to McMurdo Station which is located at the tip of the Hut Point Peninsula on Ross Island in Fig. 2.8 (Section 1.2). This site was originally selected in 1955 by Admiral George J. Dufek as a logistics base for Operation Deep Freeze in preparation for research to be carried out by American scientists during the IGY (1957-1958). The site was chosen because it is located in a broad basin adjacent to a deep harbor where supply ships can unload cargo either onto a floating ice dock or directly to the shore. These favorable conditions also caused Robert Scott in 1901 to select this site for his winter-over base where he set up his Discovery Hut in Fig. 2.9 which still contains some of the equipment and supplies that he and his men left behind (Section 1.4.1). 

Long WE (1959) Preliminary report of the geology of the central range of the Horlick Mountains, Antarctica. Ohio State Univ Res Found Rept 825-2, Part 7 1-23 Long WE (1961) Byrd Station and Marie Byrd Land traverse, 1958/59. Ohio State Univ Res Found Rept 825-2, Part 11 1-296... 

Van Schmus WR, McKenna LW, Gonzales DA, Fetter AH, Rowell AJ (1997) U-Pb geochronology of parts of the Pensacola, Thiel, and Queen Maud mountains, Antarctica. In Ricci A (ed) The Antarctic Region Evolution and Processes. Terra Antartica, Siena, Italy, pp 187—200 Wade FA (1974) Geological surveys of Marie Byrd Land and the central Queen Maud Range. Antarctic J US 9(5) 241-242... 

Fig. 10.20 Mt. Glossopteris (2,867 m) of the Ohio Range is composed of 1,220 m of flat-lying sedimentary rocks of the Beacon Supergroup. These rocks were first examined in December of 1958 by four American geologists who reached the Ohio Range during the Marie-Byrd Land oversnow-...

In the following year, Dreschhoff and Zeller (1978) reported a similar result from a snow pit in Marie Byrd Land in West Antarctica where they found a peak in the activity profile at a depth of approximately 3.3 m. Subsequently, they tested the snow in a pit near South Pole Station which was more than 10 m deep. The resulting gamma-ray activity profile in Fig. 11.18... 

Even the elevation of the West Antarctic ice sheet exceeds 2,000 m above sea level in the area of the Whitmore Mountains and in parts of Marie Byrd Land (Image from global/global.html> The site is maintained by )... 

During the early part of the Mesozoic Era a subduction zone in Fig. 15.3 stretched from the west coast of South America to the paleo-Pacific coast of East Antarctica. This subduction zone dipped under the Antarctic Peninsula, Thurston Island, Marie Byrd Land, Southern New Zealand, and Tasmania all of which were later moved into the positions they occupy at the present time (Elliot 1991). The subduction of oceanic crust caused the eruption of large amounts of... 

Fig. 15.5 West Antarctica is a mosaic of several crustal fragments that are arranged about the Byrd Subgladal Basin, the bedrock surface of which is below sea level. The crustal fragments include the Ellsworth-Whitmore Block, EiUsworth Land, Thurston Island, the Jones Mountains, and Marie Byrd Land. The Byrd Subglacial Basinis roughly parallel to the Transantarctic Mountains and their extension to the Thiel and Pensacola mountains. The line A-B is the approximate position of the cross section of the subduction zone on the paleo-Pacific coast of Gondwana in Fig. 15.6 (Adapted from Elliot (1974) and LeMasuiier (2008))...

Fig. 15.6 The subduction of a lithospheric plate during the Mesozoic Era caused the eruption of felsic and mafic lavas in the Antarctic Peninsula and in Marie Byrd Land. The crust of Gondwana in the back-arc basin was stretched which caused block-faulting and subsidence of the Byrd Subglacial Basin. Crustal extension of the back-arc basin may also have caused rifts to form in the Ross orogen and in the overlying rocks of...

Antarctica at this time the Antarctic Peninsula, the Ellsworth Mountains, the Whitmore Mounteiins, Thurston Island, Marie Byrd Land, the North and South islemds of New Zealand, and Tasmania (Adapted from Lawver and Scotese (1987))... 

Australia was still attached to East Antarctica and the microcontinents (Antarctic Peninsula, the Ellsworth-Whitmore block, Marie Byrd Land, and New Zealand) continued in their original positions. 

Figure 15.8d At 70 Ma (latest Late Cretaceous) Africa and South America moved north and the gap between them widened. As a result, the Atlantic and Indian oceans were approaching their present areal dimensions. The islands of New Zealand also moved north into the Pacific Ocean, and Australia started to pull away from East Antarctica. The Antarctic Peninsula, the Ellsworth-Whitmore block, and Marie Byrd Land were amalgamated into West Antarctica.

Ocean. During the latest Cretaceous, at 70 Ma (d), Australia separated from East Antarctica, Marie Byrd Land merged into West Anteirctica, and New Zealand moved north into the Pacific Ocean. By the middle Miocene at 15 Ma, Antarctica as we know it had emerged from Gondwana (Adapted from Lawver et al. (1991))... 

Antarctica increases stepwise from about 20 to 40 km in West Antarctica, to 40-50km under the Transantarctic Mountains (TAM), and to more than 60 km under the Gamburtsev Mountains (GM). The principal exceptions in West Antarctica are the Ellsworth-Whitmore Mountains (EWM) and Marie Byrd Land (MBL) where the thickness of the crust rises to more than 40 km. The crustal thickness under the Transantarctic Mountains rises abruptly from 35 to about 45 km which suggests that this boundary is a fault zone or crustal suture. 

These authors also assumed that in pre-Jurassic time Marie Byrd Land in Fig. 15.12 was located adjacent to northern Victoria Land and was later moved to its present position in West Antarctica by strike-slip motion along the Transantarctic rift. Schmidt and Rowley (1986) attributed the movement along the Transantarctic rift system to seafloor spreading between Queen Maud Land and Africa in Fig. 15.8a. In other words, the Transantarctic rift system may be a Late Jurassic transform fault of the Weddell-African rift. 

Fig. 15.12 According to a proposal by Schmidt and Rowley (1986), the Antarctic plate was split by a rift that developed during the Jurassic Period. This rift caused the eruption of basalt flows and the intrusion of dolerite sills of the Ferrar Group in the Transantarctic Mountains along the raised margin of the rift valley. Marie Byrd Land, which was originally located adjacent to northern Victoria Land, moved to its present position in West Antttfctica by right-lateral motion along the Transantarctic rift system tmd the EUsworth Mountain block was rotated clockwise out of alignment with the Transantarctic Mountains at about the same time. These displacements of blocks of continental crust were caused by transform faults that developed in the spreading ridge that separated Africa from Queen Maud Land of East Antarctica (Adapted from Fig. 1 of Schmidt and Rowley (1986))...

The former association of Marie Byrd Land (MBL) with northern Victoria Land (NVL) was tested by isotopic age determinations of the Swanson Formation in the Ford Ranges located east of Edward Vn Peninsula in MBL (Adams 1986 Adams et al. 1995). The Swanson Formation consists of folded metasedimen-tary rocks that were intruded by granitoids of Late Devonian age and by leucogranites of Jurassic to Cretaceous age. These plutons are surrounded by contact metamorphic aureoles of biotile homfels that are 100-500 m wide. The pre-Devonian deformation of the Swanson Formation was accompanied by low-grade regional metamorphism of the rocks. 

The apparent failure of the correlation of the Swanson Formation in Marie Byrd Land and the Robertson Bay Group does not necessarily invalidate the hypothesis that Marie Byrd Land moved from a location near northern Victoria Land to its present position in West Antarctica. The paleomagnetic data of Schamberger and Scharon (1972) as well as the evidence for strike-slip motion along the Transantarctic rift postulated by Robinson and Splettstoesser (1986) and by Schmidt and Rowley (1986) virtually require that Marie Byrd Land moved to its present position in West Antarctica in the course of the Late Jurassic to Early Cretaceous break-up of Gondwana. 

Table 15.1 Whole-rock Rb-Sr dates of slates from the Swanson Formation in the Ford Ranges of Marie Byrd Land (Adams 1986)...

The Transantarctic Mountains are now widely regarded as the unusually high margin of the West Antarctic rift system (Behrendt and Cooper 1991). The Cenozoic alkali-rich volcanic rocks that were erupted along this rift occur not only along the Transantarctic Mountains but also characterize the surface geology of Marie Byrd Land and of Ellsworth Land (LeMasurier and Thomson 1990 LeMasurier 2006). 

Fig. 15.16 The Transantarctic Mountains form part of the margin of the West Antarctic Rift which swings west near the southern tip of the Ross Ice Shelf and extends from there across West Antarctica toward the Bellingshausen Sea. The opposite margin of the West Antarctic Rift is located along the southern edge of Marie Byrd Land. Both margins of the West Antarctic Rift contain volcanoes of Cenozoic age which have erupted...

Adams CJ (1986) Geochronological studies of the Swanson Formation of Marie Byrd Land, West Antarctica, and correlation with northern Victoria Land, East Antarctica, and South Island, New Zealand. New Zealand J Geol Geophys 29 354—358... 

Adams CJ, Seward D, Weaver SD (1995) Geochronology of Cretaceous granites and metasedimentary basement on Edward VII Peninsula (Ross maigin), Marie Byrd Land, West Antarctica. Antarctic Sci 7 265-277... 

LeMasurier WE (2006) What supports the Marie Byrd Land dome An evaluation of potential uplift mechanisms in a continental rift system. In Fiitterer DK, Damaske D, Kleinschmidt G, Miller H, Tessensohn F (eds) Antarctica Contributions to global earth science. Springer, Heidelberg, Germany, pp 299-302... 

LeMasurier WE, Rex DC (1989) Evolution of linear volcanic ranges in Marie Byrd Land, West Antarctica. J Geophys Res 94(B6) 7223-7236... 

Wade FA (1969) Geology of Marie Byrd Land. In Craddock C (ed) Geologic map of Antarctica. Folio 12, Sheet 18. American Geographical Society, New York... 

Wilson TJ (1995) Cenozoic transtension along the Transantarctic - West Antarctic Rift boundary, southern Victoria Land, Antarctica. Tectonics 14 531-545 Winberry JP, Anandakrishnan S (2004) Crustal structure of the West Antarctic rift system and Marie Byrd Land hotspot. Geology 32(ll) 977-980... 

Fig. 16.4 The silica and total-alkali concentrations of Cenozoic lavas of the McMurdo Volcanics in the Erebus volcanic province range widely and are classifiable as basanite (Bn), tephrite (Tp), phonotephrite (Ftp), tephriphonolite (Tpp), phonolite (P), and benmoreite (Bm). All of the Cenozoic lavas in the diagram are alkali-rich and undersaturated with respect to silica. The alkali-rich Cenozoic lavas are associated with the West Antarctic rift system and occur not only in the Transantarctic Mountains but also in Marie Byrd Land and Ellsworth Land in West Antarctica (Data from Goldich et al. (1975) and Stuckless et al. (1981))...

Is Marie Byrd Land breaking away from the mainland of Antarctica by the widening of the West Antarctic rift system ... 

We cannot yet answer any of these questions except to assert in agreement with Kyle and Cole (1974) that the volcanic activity is a consequence of deep-seated tectonic processes which have caused patterns of crustal fractures that control the positions of the volcanoes in the Erebus volcanic province and elsewhere in Victoria Land, as well as in Marie Byrd Land (e.g., the Executive Committee Range). 

Given the variation in the speed and direction of the wind on Ross Island, the particles in the Erebus plume are dispersed widely such that their surface concentration is below detection. Deposits of volcanic ash that do occur in the East Antarctic ice sheet as well as locally on the surface of valley glaciers and ice caps formed during volcanic eruptions not only of Mt. Erebus but also of the other volcanoes and vents in the Transantarctic Mountains of Victoria Land and in Marie Byrd Land of West Antarctica (Keys et al. 1977 Palais et al. 1982,1983a, b Palais and Legrand 1985 Palais et al. 1989 Radke 1982 Kyle et al. 1982b). 

All of these islands are Cenozoic volcanoes that erupted silica undersaturated and alkali-rich volcanic rocks that superficially resemble the volcanic rocks of the West Antarctica rift valley along the coast of Victoria Land and in Marie Byrd Land of West Antarctica. The existence of these volcanoes in the oceans close to Antarctica raises a question about... 

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