Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula
The LeMay Group of Alexander Island, Antarctic Peninsula, is a Mesozoic accretionary prism that was constructed during subduction of Pacific and proto-Pacific oceanic crust. In central Alexander Island, several distinct lithologic associations can be identified, including two interpreted as underpla...
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ftnerc:oai:nora.nerc.ac.uk:519087 2023-05-15T13:15:16+02:00 Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula Tranter, T.H. 1992 http://nora.nerc.ac.uk/id/eprint/519087/ https://doi.org/10.1016/0895-9811(92)90013-O unknown Elsevier Tranter, T.H. 1992 Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula. Journal of South American Earth Sciences, 6 (1-2). 1-20. https://doi.org/10.1016/0895-9811(92)90013-O <https://doi.org/10.1016/0895-9811(92)90013-O> Publication - Article PeerReviewed 1992 ftnerc https://doi.org/10.1016/0895-9811(92)90013-O 2023-02-04T19:46:02Z The LeMay Group of Alexander Island, Antarctic Peninsula, is a Mesozoic accretionary prism that was constructed during subduction of Pacific and proto-Pacific oceanic crust. In central Alexander Island, several distinct lithologic associations can be identified, including two interpreted as underplated units: (i) a sandstone-mudstone association, consisting of thin- to medium-bedded non-channelled turbidite deposits, representing probable trench fill, and (ii) a basalt-chert association, representing oceanic crustal rocks, and its siliceous sedimentary cover. These two units are complexly deformed by dominantly westward-(oceanward-) directed thrusting. Structural relief introduced by later faulting reveals a wide range of structural styles and metamorphic grades representing different levels within the progressively deforming underplated units. Deformation ranges from thrust-related stratal disruption of poorly-lithified clastic sediment, achieved by independent particulate flow and cataclasis, through solution-dominated processes in clastic and siliceous rocks, to the development of pervasive cleavage fabrics at green-schist and transitional blueschist facies, with local crystal-plastic deformation. Later deformation (crenulation fabrics and isolated zones of folding) is of uncertain origin but probably resulted from further accretionary adjustments within the underplated units. The deepest levels may have been partially exhumed by syn-accretionary backthrusting or by transpression within a strike-parallel zone related to oblique convergence. Microstructural evidence reveals the importance of fluids in controlling deformation. Fluids were introduced with the underthrusting sediment and/or were generated during diageneis and metamorphism. In particular, evidence for locally elevated pore-fluid pressures is consistent with the rapid tectonic burial of a lithologically heterogeneous sequence and its subsequent evolution in a semi-closed system, with only limited fluid escape. Such microstructural criteria may be ... Article in Journal/Newspaper Alexander Island Antarc* Antarctic Antarctic Peninsula Natural Environment Research Council: NERC Open Research Archive Antarctic Antarctic Peninsula Pacific Alexander Island ENVELOPE(-69.895,-69.895,-71.287,-71.287) Journal of South American Earth Sciences 6 1-2 1 20 |
institution |
Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
unknown |
description |
The LeMay Group of Alexander Island, Antarctic Peninsula, is a Mesozoic accretionary prism that was constructed during subduction of Pacific and proto-Pacific oceanic crust. In central Alexander Island, several distinct lithologic associations can be identified, including two interpreted as underplated units: (i) a sandstone-mudstone association, consisting of thin- to medium-bedded non-channelled turbidite deposits, representing probable trench fill, and (ii) a basalt-chert association, representing oceanic crustal rocks, and its siliceous sedimentary cover. These two units are complexly deformed by dominantly westward-(oceanward-) directed thrusting. Structural relief introduced by later faulting reveals a wide range of structural styles and metamorphic grades representing different levels within the progressively deforming underplated units. Deformation ranges from thrust-related stratal disruption of poorly-lithified clastic sediment, achieved by independent particulate flow and cataclasis, through solution-dominated processes in clastic and siliceous rocks, to the development of pervasive cleavage fabrics at green-schist and transitional blueschist facies, with local crystal-plastic deformation. Later deformation (crenulation fabrics and isolated zones of folding) is of uncertain origin but probably resulted from further accretionary adjustments within the underplated units. The deepest levels may have been partially exhumed by syn-accretionary backthrusting or by transpression within a strike-parallel zone related to oblique convergence. Microstructural evidence reveals the importance of fluids in controlling deformation. Fluids were introduced with the underthrusting sediment and/or were generated during diageneis and metamorphism. In particular, evidence for locally elevated pore-fluid pressures is consistent with the rapid tectonic burial of a lithologically heterogeneous sequence and its subsequent evolution in a semi-closed system, with only limited fluid escape. Such microstructural criteria may be ... |
format |
Article in Journal/Newspaper |
author |
Tranter, T.H. |
spellingShingle |
Tranter, T.H. Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
author_facet |
Tranter, T.H. |
author_sort |
Tranter, T.H. |
title |
Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
title_short |
Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
title_full |
Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
title_fullStr |
Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
title_full_unstemmed |
Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula |
title_sort |
underplating of an accretionary prism: an example from the lemay group of central alexander island, antarctic peninsula |
publisher |
Elsevier |
publishDate |
1992 |
url |
http://nora.nerc.ac.uk/id/eprint/519087/ https://doi.org/10.1016/0895-9811(92)90013-O |
long_lat |
ENVELOPE(-69.895,-69.895,-71.287,-71.287) |
geographic |
Antarctic Antarctic Peninsula Pacific Alexander Island |
geographic_facet |
Antarctic Antarctic Peninsula Pacific Alexander Island |
genre |
Alexander Island Antarc* Antarctic Antarctic Peninsula |
genre_facet |
Alexander Island Antarc* Antarctic Antarctic Peninsula |
op_relation |
Tranter, T.H. 1992 Underplating of an accretionary prism: An example from the LeMay group of central Alexander Island, Antarctic Peninsula. Journal of South American Earth Sciences, 6 (1-2). 1-20. https://doi.org/10.1016/0895-9811(92)90013-O <https://doi.org/10.1016/0895-9811(92)90013-O> |
op_doi |
https://doi.org/10.1016/0895-9811(92)90013-O |
container_title |
Journal of South American Earth Sciences |
container_volume |
6 |
container_issue |
1-2 |
container_start_page |
1 |
op_container_end_page |
20 |
_version_ |
1766267765162770432 |