Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula

Lower Cretaceous conglomeratic strata exposed on southern Sobral Peninsula were deposited on a deep-marine apron in the back-arc Larsen Basin close to its faulted boundary with the Antarctic Peninsula magmatic arc. The succession is dominated by amalgamated beds of clast-supported conglomerate, whic...

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Published in:Sedimentology
Main Authors: Hathway, B., Kelley, S.P.
Format: Article in Journal/Newspaper
Language:unknown
Published: International Association of Sedimentologists 2001
Subjects:
Online Access:http://nora.nerc.ac.uk/id/eprint/20574/
https://doi.org/10.1046/j.1365-3091.2000.00307.x
id ftnerc:oai:nora.nerc.ac.uk:20574
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spelling ftnerc:oai:nora.nerc.ac.uk:20574 2023-05-15T13:45:12+02:00 Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula Hathway, B. Kelley, S.P. 2001 http://nora.nerc.ac.uk/id/eprint/20574/ https://doi.org/10.1046/j.1365-3091.2000.00307.x unknown International Association of Sedimentologists Hathway, B.; Kelley, S.P. 2001 Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula. Sedimentology, 47 (2). 451-470. https://doi.org/10.1046/j.1365-3091.2000.00307.x <https://doi.org/10.1046/j.1365-3091.2000.00307.x> Publication - Article PeerReviewed 2001 ftnerc https://doi.org/10.1046/j.1365-3091.2000.00307.x 2023-02-04T19:33:00Z Lower Cretaceous conglomeratic strata exposed on southern Sobral Peninsula were deposited on a deep-marine apron in the back-arc Larsen Basin close to its faulted boundary with the Antarctic Peninsula magmatic arc. The succession is dominated by amalgamated beds of clast-supported conglomerate, which, together with minor intercalated sandstones, consist of varied, but largely basaltic to andesitic, volcanic material and clasts derived from the Palaeozoic–Triassic (meta)sedimentary basement of the arc. Most of the volcanic clasts are thought to have been derived from lithified volcanic successions or older synvolcanic deposits, rather than from sites of coeval eruption. These mixed-provenance strata enclose a number of intervals, consisting mainly of inverse–normally graded conglomerate and graded–stratified pebbly sandstone, in which the sand fraction is dominated by crystals and vitric grains considered to have been redeposited in the immediate aftermath of explosive silicic arc volcanism. Like syneruption deposits on non-marine volcaniclastic aprons, these intervals are more sand-prone than the enclosing strata and appear to show evidence of unusually rapid aggradation. Plagioclase from one such interval has yielded 40Ar/39Ar ages concordant at ≈121 Ma, similar to those obtained from the non-marine Cerro Negro Formation, deposited within the magmatic arc. It is suggested that the two successions can be viewed as counterparts, both recording a history of mainly basaltic to andesitic volcanism, punctuated by relatively infrequent, explosive silicic eruptions. Whereas the Cerro Negro Formation consists mainly of syneruption deposits, most of the volcaniclastic material delivered to the eruption-distal, deep-marine apron appears to have been derived by normal degradation processes. Only rare silicic eruptions were capable of supplying pyroclastic material rapidly enough and in sufficient quantities to produce compositionally distinct syneruption intervals. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Antarctic Peninsula Sobral ENVELOPE(-40.650,-40.650,-81.083,-81.083) Cerro Negro ENVELOPE(-61.002,-61.002,-62.655,-62.655) Larsen Basin ENVELOPE(-60.000,-60.000,-68.000,-68.000) Sobral peninsula ENVELOPE(-59.682,-59.682,-64.490,-64.490) Sedimentology 47 2 451 470
institution Open Polar
collection Natural Environment Research Council: NERC Open Research Archive
op_collection_id ftnerc
language unknown
description Lower Cretaceous conglomeratic strata exposed on southern Sobral Peninsula were deposited on a deep-marine apron in the back-arc Larsen Basin close to its faulted boundary with the Antarctic Peninsula magmatic arc. The succession is dominated by amalgamated beds of clast-supported conglomerate, which, together with minor intercalated sandstones, consist of varied, but largely basaltic to andesitic, volcanic material and clasts derived from the Palaeozoic–Triassic (meta)sedimentary basement of the arc. Most of the volcanic clasts are thought to have been derived from lithified volcanic successions or older synvolcanic deposits, rather than from sites of coeval eruption. These mixed-provenance strata enclose a number of intervals, consisting mainly of inverse–normally graded conglomerate and graded–stratified pebbly sandstone, in which the sand fraction is dominated by crystals and vitric grains considered to have been redeposited in the immediate aftermath of explosive silicic arc volcanism. Like syneruption deposits on non-marine volcaniclastic aprons, these intervals are more sand-prone than the enclosing strata and appear to show evidence of unusually rapid aggradation. Plagioclase from one such interval has yielded 40Ar/39Ar ages concordant at ≈121 Ma, similar to those obtained from the non-marine Cerro Negro Formation, deposited within the magmatic arc. It is suggested that the two successions can be viewed as counterparts, both recording a history of mainly basaltic to andesitic volcanism, punctuated by relatively infrequent, explosive silicic eruptions. Whereas the Cerro Negro Formation consists mainly of syneruption deposits, most of the volcaniclastic material delivered to the eruption-distal, deep-marine apron appears to have been derived by normal degradation processes. Only rare silicic eruptions were capable of supplying pyroclastic material rapidly enough and in sufficient quantities to produce compositionally distinct syneruption intervals.
format Article in Journal/Newspaper
author Hathway, B.
Kelley, S.P.
spellingShingle Hathway, B.
Kelley, S.P.
Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
author_facet Hathway, B.
Kelley, S.P.
author_sort Hathway, B.
title Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
title_short Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
title_full Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
title_fullStr Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
title_full_unstemmed Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula
title_sort sedimentary record of explosive silicic volcanism in a cretaceous deep-marine conglomerate succession, northern antarctic peninsula
publisher International Association of Sedimentologists
publishDate 2001
url http://nora.nerc.ac.uk/id/eprint/20574/
https://doi.org/10.1046/j.1365-3091.2000.00307.x
long_lat ENVELOPE(-40.650,-40.650,-81.083,-81.083)
ENVELOPE(-61.002,-61.002,-62.655,-62.655)
ENVELOPE(-60.000,-60.000,-68.000,-68.000)
ENVELOPE(-59.682,-59.682,-64.490,-64.490)
geographic Antarctic
The Antarctic
Antarctic Peninsula
Sobral
Cerro Negro
Larsen Basin
Sobral peninsula
geographic_facet Antarctic
The Antarctic
Antarctic Peninsula
Sobral
Cerro Negro
Larsen Basin
Sobral peninsula
genre Antarc*
Antarctic
Antarctic Peninsula
genre_facet Antarc*
Antarctic
Antarctic Peninsula
op_relation Hathway, B.; Kelley, S.P. 2001 Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula. Sedimentology, 47 (2). 451-470. https://doi.org/10.1046/j.1365-3091.2000.00307.x <https://doi.org/10.1046/j.1365-3091.2000.00307.x>
op_doi https://doi.org/10.1046/j.1365-3091.2000.00307.x
container_title Sedimentology
container_volume 47
container_issue 2
container_start_page 451
op_container_end_page 470
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