Supercritical-flow structures on a Late Carboniferous delta front: Sedimentologic and paleoclimatic significance
Supercritical-flow structures on a Late Carboniferous delta front: Sedimentologic and paleoclimatic significance
Deposits of fluvial systems in highly seasonal tropical climates possess unique architectural and facies characters owing to a flood-prone regime alternating with lengthy periods of ineffective discharge. Distally linked deltaic successions should also feature distinctive attributes, with great potential to preserve the stratigraphic evidence of exceptional discharge events. We describe Late Carboniferous delta-front, valley-confined sandstones from the Pennine Basin (UK), originally deposited at paleoequatorial latitudes during final assembly of the Pangean megacontinent and characterized by giant sedimentary structures with repetitively sigmoidal geometry. Facies traits indicate geologically instantaneous deposition of a large sediment volume from a density current at sustained supercritical-flow conditions, leading to aggradation of cyclic steps, recently identified bedforms developing in high-energy flows and of which this is the first complete outcrop example. The lack of unconformable erosional surfaces and absence of different associated facies point to a single aggradational event during which the structures attained dimensions comparable to those indicated by seismic data sets from which they are remotely detected on modern seafloors. Cyclic-step formation in a deltaic setting suggests that Pangean megamonsoons could have triggered hydrologic events capable of imprinting sedimentologic signatures on shallow-marine deposits.
731-734
Ventra, Dario
75362ccc-9b38-4ddd-bfb7-2aac352e6ab0
Cartigny, Matthieu J.B.
d252d7b1-16c6-47b1-bf86-8087070934ce
Bijkerk, Jochem F.
981ccc23-aa47-45d6-83d9-9557a438f212
Acikalin, Sanem
c5f9c767-b9d1-4aa6-b678-1296f8a65570
August 2015
Ventra, Dario
75362ccc-9b38-4ddd-bfb7-2aac352e6ab0
Cartigny, Matthieu J.B.
d252d7b1-16c6-47b1-bf86-8087070934ce
Bijkerk, Jochem F.
981ccc23-aa47-45d6-83d9-9557a438f212
Acikalin, Sanem
c5f9c767-b9d1-4aa6-b678-1296f8a65570
Ventra, Dario, Cartigny, Matthieu J.B., Bijkerk, Jochem F. and Acikalin, Sanem
(2015)
Supercritical-flow structures on a Late Carboniferous delta front: Sedimentologic and paleoclimatic significance.
Geology, 43 (8), .
(doi:10.1130/G36708.1).
Abstract
Deposits of fluvial systems in highly seasonal tropical climates possess unique architectural and facies characters owing to a flood-prone regime alternating with lengthy periods of ineffective discharge. Distally linked deltaic successions should also feature distinctive attributes, with great potential to preserve the stratigraphic evidence of exceptional discharge events. We describe Late Carboniferous delta-front, valley-confined sandstones from the Pennine Basin (UK), originally deposited at paleoequatorial latitudes during final assembly of the Pangean megacontinent and characterized by giant sedimentary structures with repetitively sigmoidal geometry. Facies traits indicate geologically instantaneous deposition of a large sediment volume from a density current at sustained supercritical-flow conditions, leading to aggradation of cyclic steps, recently identified bedforms developing in high-energy flows and of which this is the first complete outcrop example. The lack of unconformable erosional surfaces and absence of different associated facies point to a single aggradational event during which the structures attained dimensions comparable to those indicated by seismic data sets from which they are remotely detected on modern seafloors. Cyclic-step formation in a deltaic setting suggests that Pangean megamonsoons could have triggered hydrologic events capable of imprinting sedimentologic signatures on shallow-marine deposits.
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Published date: August 2015
Organisations:
Marine Geoscience
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Local EPrints ID: 380516
URI: http://eprints.soton.ac.uk/id/eprint/380516
ISSN: 0091-7613
PURE UUID: 4ee4f2d2-40fe-4eb0-ab10-9d185ba5e980
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Date deposited: 17 Aug 2015 10:48
Last modified: 14 Mar 2024 21:01
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Author:
Dario Ventra
Author:
Matthieu J.B. Cartigny
Author:
Jochem F. Bijkerk
Author:
Sanem Acikalin
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