Gugliotta, M, Kurcinka, CE, Dalrymple, RW et al. (2 more authors) (2016) Decoupling seasonal fluctuations in fluvial discharge from the tidal signature in ancient deltaic deposits: an example from the Neuquén Basin, Argentina. Journal of the Geological Society, 173 (1). pp. 94-107. ISSN 0016-7649
Abstract
Fluvial discharge fluctuations are a fundamental characteristic of almost all modern rivers and can produce distinctive deposits that are rarely described from ancient fluvial or mixed-energy successions. Large-scale outcrops from the Middle Jurassic Lajas Formation (Argentina) expose a well-constrained stratigraphic succession of marginal-marine deposits with a strong fluvial influence and well-known tidal indicators. The studied deposits show decimetre-scale interbedding of coarser- and finer-grained facies with mixed fluvial and tidal affinities. The alternation of these two types of beds forms non-cyclic successions that are interpreted to be the result of seasonal variation in river discharge, rather than regular and predictable changes in current velocity caused by tides. Seasonal bedding is present in bar deposits that form within or at the mouth of minor and major channels. Seasonal bedding is not preserved in channel thalweg deposits, where river flood processes were too powerful, or in floodplain, muddy interdistributary-bay, prodelta and transgressive deposits, where the river signal was weak and sporadic. The identification of sedimentary facies characteristic of seasonal river discharge variations is important for accurate interpretation of ancient deltaic process regime.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Editors: |
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Copyright, Publisher and Additional Information: | © 2016 The Author(s). Published by The Geological Society of London. All rights reserved. This is an author produced version of a paper published in Journal of the Geological Society. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | River discharge, seasonality, heterolithic, IHS, tidalite |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Sep 2015 10:09 |
Last Modified: | 28 Oct 2016 05:40 |
Published Version: | http://dx.doi.org/10.1144/jgs2015-030 |
Status: | Published |
Publisher: | Geological Society |
Identification Number: | 10.1144/jgs2015-030 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:88814 |