Significance of active growth faulting on marsh accretion processes in the lower Pearl River, Louisiana

Kevin M. Yeager, Charlotte A. Brunner, Mark A. Kulp, Dane Fischer, Rusty A. Feagin, Kimberly J. Schindler, Jeremiah Prouhet, Gopal Bera

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Neotectonic processes influence marsh accretion in the lower Pearl River valley. Active growth faults are suggested by groupings of ponded river channel sections, transverse and linear river channel sections, and down- and across-valley contrasts in channel sinuosity. Seismic profiles identified several likely, fault-induced structural anomalies, two of which parallel the axes of surface distributary networks. Lithostratigraphy and biostratigraphy of six cores from across a suspected fault in the West Middle River, combined with 14C-based age control, yielded evidence of vertical offsets, indicating that this river section is on the plane of a growth fault. These data were used to estimate fault slip rates over two time intervals, 1.2mm/y over the last 1300yr, and 0.2mmyr -1 over the last 3700yr, and delineated a sinusoidal pattern of deformation moving distally from the fault, which we interpret as resulting from fault-propagation folding. Higher rates of sediment accumulation (of the order of cmyr -1 from 210Pb xs and 137Cs activity data) on the down-thrown side are consistent with sedimentary response to increased accommodation space, and mass-based sediment accumulation rates (gcm -2yr -1) exhibit a pattern inverse of that shown by fault-driven sinusoidal deformation. We contend that near-surface growth faults are critically important to driving accretion rates and marsh response to sea-level rise.

Original languageEnglish
Pages (from-to)127-143
Number of pages17
JournalGeomorphology
Volume153-154
DOIs
StatePublished - Jun 1 2012

Bibliographical note

Funding Information:
The research presented herein was funded in its entirety by the Coastal Restoration and Enhancement through Science and Technology (CREST) program, which was established in 2001 as an alliance of academic institutions in southern Louisiana and Mississippi. Primary funding for CREST has been provided by the U.S. National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS). The research sponsor had no role in the study design, collection, analysis or interpretation of data; nor did they have any role in the composition of the final report or decision to submit any part of the research for publication in the peer-reviewed literature.

Keywords

  • Foraminifera
  • Growth fault
  • Lithostratigraphy
  • Marsh
  • Radionuclides
  • Sediment

ASJC Scopus subject areas

  • Earth-Surface Processes

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