Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica

Siliciclastic rocks of the upper Byrd Group in the Transantarctic Mountains record rapid denudation and molasse deposition during Ross orogenesis along the early Paleozoic convergent margin of Gondwana. These rocks, which stratigraphically overlie Lower Cambrian Byrd carbonate deposits, are dominate...

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Main Authors: Goodge, John W, Myrow, Paul M, Phillips, David, Fanning, Christopher, Williams, Ian
Other Authors: Bernet, M., Spiegel C.
Format: Book Part
Language:unknown
Published: Geological Society of America Inc 2015
Subjects:
Online Access:http://hdl.handle.net/1885/87248
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spelling ftanucanberra:oai:digitalcollections.anu.edu.au:1885/87248 2023-05-15T13:56:14+02:00 Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica Goodge, John W Myrow, Paul M Phillips, David Fanning, Christopher Williams, Ian Bernet, M. Spiegel C. 2015-12-13T23:09:58Z http://hdl.handle.net/1885/87248 unknown Geological Society of America Inc Detrital thermochronology - Provenance analysis, exhumation, and landscape evolution of mountain belts 1st Edition 0813723787 http://hdl.handle.net/1885/87248 Book chapter 2015 ftanucanberra 2015-12-21T23:56:25Z Siliciclastic rocks of the upper Byrd Group in the Transantarctic Mountains record rapid denudation and molasse deposition during Ross orogenesis along the early Paleozoic convergent margin of Gondwana. These rocks, which stratigraphically overlie Lower Cambrian Byrd carbonate deposits, are dominated by fresh detritus from proximal igneous and metamorphic sources within the Ross Orogen. Biostratigraphic evidence indicates that deposition of the siliciclastic succession is late Botomian or younger (<515 Ma). The largest modes of U-Pb and 40Ar/39Ar ages from detrital zircons and muscovites respectively in the siliciclastic molasse are Early to Middle Cambrian, but based on ages from crosscutting igneous bodies and neoblastic metamorphic phases, deposition of individual molasse units continued until ∼490-485 Ma (earliest Ordovician). The entire episode of interrelated tectonic, denudational, sedimentary, deformational, and magmatic events is restricted to a time interval of 7-25 m.y. in the late Early Cambrian to earliest Ordovician, within the resolution of these stratigraphic and geochronologic data. Stratigraphic relationships suggest that the detrital zircon and muscovite in the sediments came from the same source terrain, consistent with large volumes of molasse having been shed into forearc and/or marginal basins at this time, primarily due to erosion of igneous rocks and metamorphic basement of the early Ross magmatic arc. Rapid erosion and unroofing in the axial Ross Orogen is consistent with a sharp carbonate-to-clastic stratigraphic transition observed in the upper Byrd Group, reflecting an outpouring of alluvial fan and fluvial-marine clastic detritus. The short time lag between tectonism and sedimentary response is similar to that determined for the corresponding section of the RossDelamerian orogen in South Australia and other continental-margin arc systems, such as in the Mesozoic Peninsular Ranges of California. Mineral cooling ages from metamorphic basement adjacent to the orogen yield a syn- to late-orogenic cooling rate of ∼10 °C/m.y., which, combined with a known metamorphic geotherm, indicates a denudation rate of ∼0.5 mm/yr. Such denudation rates are comparable to those in recent convergent or collision orogens and suggest that crustal thickening associated with both magmatic intrusion and structural shortening was balanced by near-synchronous erosional exhumation. Book Part Antarc* Antarctica Australian National University: ANU Digital Collections Byrd Transantarctic Mountains
institution Open Polar
collection Australian National University: ANU Digital Collections
op_collection_id ftanucanberra
language unknown
description Siliciclastic rocks of the upper Byrd Group in the Transantarctic Mountains record rapid denudation and molasse deposition during Ross orogenesis along the early Paleozoic convergent margin of Gondwana. These rocks, which stratigraphically overlie Lower Cambrian Byrd carbonate deposits, are dominated by fresh detritus from proximal igneous and metamorphic sources within the Ross Orogen. Biostratigraphic evidence indicates that deposition of the siliciclastic succession is late Botomian or younger (<515 Ma). The largest modes of U-Pb and 40Ar/39Ar ages from detrital zircons and muscovites respectively in the siliciclastic molasse are Early to Middle Cambrian, but based on ages from crosscutting igneous bodies and neoblastic metamorphic phases, deposition of individual molasse units continued until ∼490-485 Ma (earliest Ordovician). The entire episode of interrelated tectonic, denudational, sedimentary, deformational, and magmatic events is restricted to a time interval of 7-25 m.y. in the late Early Cambrian to earliest Ordovician, within the resolution of these stratigraphic and geochronologic data. Stratigraphic relationships suggest that the detrital zircon and muscovite in the sediments came from the same source terrain, consistent with large volumes of molasse having been shed into forearc and/or marginal basins at this time, primarily due to erosion of igneous rocks and metamorphic basement of the early Ross magmatic arc. Rapid erosion and unroofing in the axial Ross Orogen is consistent with a sharp carbonate-to-clastic stratigraphic transition observed in the upper Byrd Group, reflecting an outpouring of alluvial fan and fluvial-marine clastic detritus. The short time lag between tectonism and sedimentary response is similar to that determined for the corresponding section of the RossDelamerian orogen in South Australia and other continental-margin arc systems, such as in the Mesozoic Peninsular Ranges of California. Mineral cooling ages from metamorphic basement adjacent to the orogen yield a syn- to late-orogenic cooling rate of ∼10 °C/m.y., which, combined with a known metamorphic geotherm, indicates a denudation rate of ∼0.5 mm/yr. Such denudation rates are comparable to those in recent convergent or collision orogens and suggest that crustal thickening associated with both magmatic intrusion and structural shortening was balanced by near-synchronous erosional exhumation.
author2 Bernet, M.
Spiegel C.
format Book Part
author Goodge, John W
Myrow, Paul M
Phillips, David
Fanning, Christopher
Williams, Ian
spellingShingle Goodge, John W
Myrow, Paul M
Phillips, David
Fanning, Christopher
Williams, Ian
Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
author_facet Goodge, John W
Myrow, Paul M
Phillips, David
Fanning, Christopher
Williams, Ian
author_sort Goodge, John W
title Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
title_short Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
title_full Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
title_fullStr Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
title_full_unstemmed Siliciclastic record of rapid denudation in response to convergent-margin orogenesis, Ross Orogen, Antarctica
title_sort siliciclastic record of rapid denudation in response to convergent-margin orogenesis, ross orogen, antarctica
publisher Geological Society of America Inc
publishDate 2015
url http://hdl.handle.net/1885/87248
geographic Byrd
Transantarctic Mountains
geographic_facet Byrd
Transantarctic Mountains
genre Antarc*
Antarctica
genre_facet Antarc*
Antarctica
op_relation Detrital thermochronology - Provenance analysis, exhumation, and landscape evolution of mountain belts
1st Edition
0813723787
http://hdl.handle.net/1885/87248
_version_ 1766263601249648640