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Taphonomic controls on the distribution of palynomorphs in tidally influenced coastal deltaic settings

Robert A. Gastaldo
Taphonomic controls on the distribution of palynomorphs in tidally influenced coastal deltaic settings (in Special issue commemorating the 20th anniversary meeting of the International workshop on Plant taphonomy, Carole T. Gee (editor) and Lutz Kunzmann (editor))
Palaios (November 2012) 27 (11): 798-810

Abstract

Palynomorph concentrations for water-column and sediment-water interface samples are presented for two coastal deltaic systems influenced by the range of tidal regimes to assess whether any taphonomic bias exists in pollen assemblages. The localities are the microtidally influenced Mobile-Tensaw River Delta, Alabama, United States, and the meso- to macrotidally influenced Rajang River Delta, Sarawak, East Malaysia. Mobile-Tensaw Delta data represent collections over a 13-month period; Rajang River Delta data represent sampling during the 1992 dry season. Results are reported for: (1) pollen concentration in suspended sediment loads and bottom sediments of distributary channels, and (2) selected spore-and-pollen frequencies in channels influenced by meso- and macrotidal processes. An increase in pollen concentration/liter occurs in all delta distributaries at water-column depth, and a positive relationship exists between pollen concentration and suspension load. Concentrations at the sediment-water interface are highest in tidally influenced areas where Heterogenous Aggregate Organic Matter (OM) clasts (floccules) dominate palynofacies assemblages, and statistically significant for Mobile-Tensaw lower delta plain sites. Hence, microtidal influence at the interface between fresh and brackish waters affects palynomorph concentration in bottom sediment and may be a function of flocculation induced by salinity flux. In contrast, concentrations are highest in bottom sediments of Rajang River distributaries where little active sediment transport occurs and tidal range is highest, and is due to several factors including a high proportion of Heterogenous Aggregate OM clasts. Additionally, the magnitude of tidal displacement impacts palynomorph distribution in the Rajang Delta, with mangrove pollen found in alluvial plain samples, a distance of approximately 120 km from distributary mouth bars. Understanding the sedimentological conditions under which coastal deltaic pollen assemblages are preserved is critical before these can be used for paleoecological reconstruction.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 27
Serial Issue: 11
Title: Taphonomic controls on the distribution of palynomorphs in tidally influenced coastal deltaic settings
Title: Special issue commemorating the 20th anniversary meeting of the International workshop on Plant taphonomy
Author(s): Gastaldo, Robert A.
Author(s): Gee, Carole T.editor
Author(s): Kunzmann, Lutzeditor
Affiliation: Colby College, Department of Geology, Waterville, ME, United States
Affiliation: University of Bonn, Division of Paleontology, Bonn, Germany
Pages: 798-810
Published: 201211
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
Meeting name: 20th international workshop on Plant taphonomy
Meeting location: Dresden, DEU, Germany
Meeting date: 20110325March 25-27, 2011
References: 75
Accession Number: 2013-011017
Categories: Paleobotany
Document Type: Serial Conference document
Bibliographic Level: Analytic
Annotation: NSF grants EAR-9111842, EAR 9625992, and EAR-9104945
Illustration Description: illus. incl. sketch maps
N02°00'00" - N02°45'00", E111°00'00" - E112°00'00"
N30°40'00" - N31°15'00", W88°00'00" - W87°49'60"
Secondary Affiliation: Senckenberg Natural History Collections Dresden, DEU, Germany
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 201308
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