Alexandria Digital Research Library

The Holocene History and Facies Architecture of the Nueces Bayhead Delta of the Northwestern Gulf of Mexico

Author:
Rice, Johnathan Aaron
Degree Grantor:
University of California, Santa Barbara. Geological Sciences
Degree Supervisor:
Alexander R. Simms
Place of Publication:
[Santa Barbara, Calif.]
Publisher:
University of California, Santa Barbara
Creation Date:
2015
Issued Date:
2015
Topics:
Sedimentary geology, Geology, and Geomorphology
Keywords:
Holocene
Grain size
Climate
Delta evolution
Facies architecture
Nueces Bayhead Delta
Genres:
Dissertations, Academic and Online resources
Dissertation:
M.S.--University of California, Santa Barbara, 2015
Description:

The economic importance of coastlines highlights the need to understand how coasts evolve in response to changing climate. Prior work suggests that many of the estuaries in the northwestern Gulf of Mexico underwent large changes at 2.6, 4.8, and 8.2 ka. Twenty-eight vibracores, eight Geoprobe cores, twenty-eight radiocarbon ages, and twenty-five kilometers of seismic profiles were used to determine the response of the Nueces Bay-head Delta to the 2.6 ka and 4.8 ka events. Within the cores we identified nine sedimentary facies representing five distinct deltaic environments. Within the 25 kilometers of seismic data, we identified five seismic facies that correspond to the deltaic environments identified within the sediment cores.

Fifteen sand lobes interpreted to be buried mouth-bar deposits identified in the seismic profiles and cores were used to track changes in the location of the seaward edge of the delta through the middle to late Holocene. Following progradation of the delta at 7.5 ka, the delta underwent two backstepping events in which the delta front transgressed up to 20 km at 4.8 ka and 2.6 ka. Following these two backstepping events the delta prograded up to 20 km seaward of the deltas maximum landward location. During delta progradation from 4.8-3.2 ka delivering 8.3x103 m3/yr of sand was delivered to the delta. During delta backstepping from 3.2-2.6 ka 6.5x103 m3/yr of sand was delivered to the delta. During the last phase of delta progradation from 2.6 ka-present delivering 6.6x103 m3/yr of sand was delivered to the delta. The decrease in the volume of sand delivered to the delta during the backstepping event at a time when the rate of sea-level rise as sea-level rise was decreasing and regional records of climate show drying suggests that the backstepping events were likely driven by climate changes.

Physical Description:
1 online resource (64 pages)
Format:
Text
Collection(s):
UCSB electronic theses and dissertations
ARK:
ark:/48907/f3cz36n0
ISBN:
9781339472270
Catalog System Number:
990046180100203776
Rights:
Inc.icon only.dark In Copyright
Copyright Holder:
Johnathan Rice
File Description
Access: Public access
Rice_ucsb_0035N_12850.pdf pdf (Portable Document Format)