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Depositional Analysis of a Holocene Carbonate Strand Plain Using High Resolution GPR, Sediment Analysis, and C-14 Dating

Understanding modern carbonate depositional systems gives valuable insights into the interpretation of ancient carbonate systems. Ancient carbonate strand plains have the potential to act as productive hydrocarbon reservoirs because of their relatively high porosity. Unfortunately, they are difficult to identify in the rock record because of the lack of work done on modern analogues. San Salvador Island in the Bahamas hosts a well-exposed and easily accessible Holocene strand plain, ideal as a modern analogue. Sandy Hook, located on the southeast part of the island, consists of approximately 35 ridge-swale features that show signs of four distinct zones of deposition. In this study, 20 sediment samples were collected from one meter in depth, and throughout each zone. The sediment analysis reveals remarkably consistent grain-size distributions across the four zones. Carbon-14 ages were taken from the sediment samples. They revealed ages decreasing from 2617 ± 188 YBP to modern moving seaward through zone 4. The ages reveal depositional rates of 0.08 to 0.29 meters of accretion per year. Four pseudo-3D GPR surveys were acquired in Zones B, C, and D, and a 2D GPR survey was acquired that spanned the three zones. The pseudo-3D surveys revealed consistent reflectors through the width of the survey indicating that the 2D surveys represent more than the single line. The 2D survey reveals semi-parallel seaward-dipping reflectors (representing fair-weather deposits) that are truncated by sigmoidal seaward-dipping reflectors (high-energy storm deposits). Indicating that Sandy Hook was built through both fair-weather deposits and high-energy storm events.

Identiferoai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-8751
Date01 December 2019
CreatorsMarkert, Kaleb Robert
PublisherBYU ScholarsArchive
Source SetsBrigham Young University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations
Rightshttp://lib.byu.edu/about/copyright/

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