Chapter 5.1a Northern Victoria Land: volcanology

2021 ◽  
pp. M55-2018-60
Author(s):  
John L. Smellie ◽  
Sergio Rocchi
Keyword(s):  
Thermal Regime ◽  
Middle Miocene ◽  
Ice Sheet ◽  
Volcanic Group ◽  
Prevailing Paradigm ◽  
Shield Volcanoes ◽  
Victoria Land ◽  
Glacial Periods ◽  
Scoria Cones ◽  
Source Of Information

AbstractNeogene volcanism is widespread in northern Victoria Land, and is part of the McMurdo Volcanic Group. It is characterized by multiple coalesced shield volcanoes but includes a few relatively small stratovolcanoes. Two volcanic provinces are defined (Hallett and Melbourne), with nine constituent volcanic fields. Multitudes of tiny monogenetic volcanic centres (mainly scoria cones) are also scattered across the region and are called the Northern Local Suite. The volcanism extends in age between middle Miocene (c. 15 Ma) and present but most is <10 Ma. Two centres may still be active (Mount Melbourne and Mount Rittmann). It is alkaline, varying between basalt (basanite) and trachyte/rhyolite. There are also associated, geographically restricted, alkaline gabbro to granite plutons and dykes (Meander Intrusive Group) with mainly Eocene–Oligocene ages (52–18 Ma). The isotopic compositions of the plutons have been used to infer overall cooling of climate during the Eocene–Oligocene. The volcanic sequences are overwhelmingly glaciovolcanic and are dominated by ‘a‘ā lava-fed deltas, the first to be described anywhere. They have been a major source of information on Mio-Pliocene glacial conditions and were used to establish that the thermal regime during glacial periods was polythermal, thus necessitating a change in the prevailing paradigm for ice-sheet evolution.

scholarly journals Some Aspects of the Cenozoic Glaciation of Southern Victoria Land, Antarctica

1983 ◽  
Vol 29 (102) ◽  
pp. 343-349 ◽  
Author(s):  
Howard Brady ◽  
Barrie McKelvey
Keyword(s):  
Middle Miocene ◽  
Ice Sheet ◽  
Basement Complex ◽  
Antarctic Ice Sheet ◽  
Victoria Land ◽  
Transantarctic Mountains ◽  
East Antarctic Ice Sheet

AbstractPalaeoglacial evidence at three sites in southern Victoria Land has been examined to consider the possible uplift of the Transantarctic Mountains through the East Antarctic ice sheet prior to the Middle Miocene. A Cenozoic tillite at Mount Feather and a striated pavement at Mount Brooke pre-date uplift. Another tillite remnant adjacent to Odell Glacier near Mount Brooke post-dates the uplift and is locally derived. This tillite, together with the Mount Feather tillite, has been previously placed in the Sirius Formation, a term that the authors abandon as it covers tillites of varying ages. Basement complex derived clasts in the Mount Feather tillite. previously reported by these authors, could be inherited from the Jurassic Mawson Formation or the Permian Metschel Tillite but they still provide evidence that the Mount Feather tillite was deposited by a regional glaciation.

scholarly journals Some Aspects of the Cenozoic Glaciation of Southern Victoria Land, Antarctica

1983 ◽  
Vol 29 (102) ◽  
pp. 343-349 ◽  
Author(s):  
Howard Brady ◽  
Barrie McKelvey
Keyword(s):  
Middle Miocene ◽  
Ice Sheet ◽  
Basement Complex ◽  
Antarctic Ice Sheet ◽  
Victoria Land ◽  
Transantarctic Mountains ◽  
East Antarctic Ice Sheet

AbstractPalaeoglacial evidence at three sites in southern Victoria Land has been examined to consider the possible uplift of the Transantarctic Mountains through the East Antarctic ice sheet prior to the Middle Miocene. A Cenozoic tillite at Mount Feather and a striated pavement at Mount Brooke pre-date uplift. Another tillite remnant adjacent to Odell Glacier near Mount Brooke post-dates the uplift and is locally derived. This tillite, together with the Mount Feather tillite, has been previously placed in the Sirius Formation, a term that the authors abandon as it covers tillites of varying ages. Basement complex derived clasts in the Mount Feather tillite. previously reported by these authors, could be inherited from the Jurassic Mawson Formation or the Permian Metschel Tillite but they still provide evidence that the Mount Feather tillite was deposited by a regional glaciation.

Degree of rock surface weathering on fjell summits in northern Finland: implications for the thermal regime of the last ice sheet

Boreas ◽  
2008 ◽  
Vol 25 (1) ◽  
pp. 1-7
Author(s):  
DANNY McCARROLL ◽  
JYRKI AUTIO ◽  
OLAVI HEIKKINEN ◽  
LEO KOUTANIEMI
Keyword(s):  
Thermal Regime ◽  
Ice Sheet ◽  
Rock Surface

On the thickness of the Antarctic ice, and its relations to that of the glacial epoch

2021 ◽  
pp. 1-8
Author(s):  
James CROLL ◽  
David SUGDEN
Keyword(s):  
Thermal Regime ◽  
Freezing Point ◽  
Ice Sheet ◽  
Heat Sources ◽  
Mean Velocity ◽  
Point Estimates ◽  
Glacial Epoch ◽  
Antarctic Continent ◽  
Global Sea Level ◽  
The Antarctic

ABSTRACT At a time when nobody has yet landed on the Antarctic continent (1879), this presentation and accompanying paper predicts the morphology, dynamics and thermal regime of the Antarctic ice sheet. Mathematical modelling of the ice sheet is based on the assumptions that the thickness of tabular icebergs reflects the average thickness of the ice at the margin and that the surface gradients are comparable to those of reconstructed former ice sheets in the Northern Hemisphere. The modelling shows that (a) ice is thickest near the centre at the South Pole and thins towards the margin; (b) the thickness at the pole is independent of the amount of snowfall at that place; and (c) the mean velocity at the margin, assuming a mean annual snowfall of two inches per year, is 400–500 feet per year. The thermal regime of the ice sheet is influenced by three heat sources – namely, the bed, the internal friction of ice flow and the atmosphere. The latter is the most significant and, since ice has a downwards as well as horizontal motion, this carries cold ice down into the ice sheet. Since the temperature at which ice melts is lowered by pressure at a rate of 0.0137 °F for every atmosphere of pressure (something known since 1784), much of the ice sheet and its base must be below the freezing point. Estimates of the thickness of ice at the centre depend closely on the surface gradients assumed and range between 3 and 24 miles. Such uncertainty is of concern since both the volume and gravitational attraction of the ice mass have an effect on global sea level. In order to improve our estimate of the volume of ice, we will have to wait 76 years for John Glen to develop a realistic flow law for ice.

Multiple cosmogenic nuclides document the stability of the East Antarctic Ice Sheet in northern Victoria Land since the Late Miocene (5–7 Ma)

2012 ◽  
Vol 57 ◽  
pp. 85-94 ◽  
Author(s):  
Luigia Di Nicola ◽  
Carlo Baroni ◽  
Stefan Strasky ◽  
Maria Cristina Salvatore ◽  
Christian Schlüchter ◽  
...  
Keyword(s):  
Late Miocene ◽  
Ice Sheet ◽  
Cosmogenic Nuclides ◽  
Antarctic Ice Sheet ◽  
Victoria Land ◽  
The Stability ◽  
East Antarctic Ice Sheet

scholarly journals Morphology and late Cenozoic (<5 Ma) glacial history of the area between David and Mawson Glaciers, Victoria Land, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 55-60
Author(s):  
Anja L.L.M. Verbers ◽  
Volkmar Damm
Keyword(s):  
Ice Sheet ◽  
Field Work ◽  
Topographic Map ◽  
Glacial History ◽  
Ice Surface ◽  
Victoria Land ◽  
Radio Echo Sounding ◽  
History Of ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Glacio-geological field work and radar ice-thickness sounding were carried out in the area between David and Mawson Glaciers. A subglacial topographic map has been compiled from radio-echo-sounding data. The northern part of this map shows that the trench of David Glacier reaches a depth of more than 1000 m below sea level. The area south of David Glacier comprises a landscape of nunatak clusters dissected by glaciated valleys with ice thicknesses as much as 800 m. Subglacial cirques occur at the outer margins of the nunatak clusters. A model for the regional glacial history is proposed. It starts with a major deglaciation in the Pliocene, which results in marine transgression in basins west of the Transantarctic Mountains. During the late Pliocene, the ice advanced towards the northeast, depositing a thin layer of (Sirius Group) till containing reworked mid-Pliocene marine diatoms. Due to accelerated mountain uplift, the ice cut iIlto the pre-Pliocene peneplain, eroding broad valleys. A period of ice-sheet retreat followed to expose a landscape of large nunataks separated by wide valleys. During this period, local cirque glaciation occurred. When the ice sheet advanced again, another phase of uplift forced the glaciers to cut deeper into the valleys. Probably since the Last Glacial Maximum the ice surface has lowered by about 100 m.

scholarly journals Herpetological phylogeographic analyses support a Miocene focal point of Himalayan uplift and biological diversification

2020 ◽  
Author(s):  
Wei Xu ◽  
Wen-Jie Dong ◽  
Ting-Ting Fu ◽  
Wei Gao ◽  
Chen-Qi Lu ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Focal Point ◽  
Himalayan Region ◽  
The World ◽  
Early Paleocene ◽  
The Rich ◽  
Source Of Information ◽  
The Himalaya ◽  
Exact Timing

Abstract The Himalaya are among the youngest and highest mountains in the world, but the exact timing of their uplift and origins of their biodiversity are still in debate. The Himalayan region is a relatively small area but with exceptional diversity and endemism. One common hypothesis to explain the rich montane diversity is uplift-driven diversification–that orogeny creates conditions favoring rapid in situ speciation of resident lineages. We test this hypothesis in the Himalayan region using amphibians and reptiles, two environmental sensitive vertebrate groups. In addition, analysis of diversification of the herpetofauna provides an independent source of information to test competing geological hypotheses of Himalayan orogenesis. We conclude that the origins of the Himalayan herpetofauna date to the early Paleocene, but that diversification of most groups was concentrated in the Miocene. There was an increase in both rates and modes of diversification during the early to middle Miocene, together with regional interchange (dispersal) between the Himalaya and adjacent regions. Our analyses support a recently proposed stepwise geological model of Himalayan uplift beginning in the Paleocene, with a subsequent rapid increase of uplifting during the Miocene, finally give rise to the intensification of the modern South Asia Monsoon.

scholarly journals The East Antarctic Ice Sheet: The Problem of Palaeoglaciological Reconstruction (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 344 ◽  
Author(s):  
V.I. Bardin
Keyword(s):  
Ice Sheet ◽  
East Antarctica ◽  
Regional Studies ◽  
Glacial Deposits ◽  
Antarctic Ice Sheet ◽  
Space And Time ◽  
Victoria Land ◽  
East Antarctic Ice Sheet ◽  
Comprehensive Studies

Palaeoglaciological studies, including glaciogeomorphological observations and comprehensive studies of the composition of glacial deposits, undertaken by scientists of a number of countries, enable the major stages in the evolution of glaciation of some regions of East Antarctica to be outlined. In this report, palaeoglaciological reconstructions for certain key territories: Queen Maud Land, Mac. Robertson Land, and Victoria Land are considered. The completeness and reliability of such reconstructions are also discussed. The region of Prince Charles Mountains (Mac. Robertson Land) turned out to be one of the most significant for palaeoglaciology. In this region, the author has discovered and studied glacial deposits of at least six age stages, their formation having taken place during approximately 20 Ma. An attempt is made to compare the results of regional studies and to present the evolution of the development of the whole East Antarctic ice sheet in space and time. Different examples of palaeoglaciological reconstructions of the ice sheet of East Antarctica are presented, the possibilities of different approaches are evaluated practically, and schematic maps of the change in glaciation of East Antarctic regions at different evolutional stages, compiled by the author, are presented for discussion.

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