Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach
The last glacial maximum, ca. 21,000 years ago, caused a fall in eustatic sea level of ca. 120 m below present. The low-gradient, shallow Sunda Shelf, Southeast Asia was subaerially exposed during this sea-level lowstand and experienced rising sea level thereafter. Sea level rose to a +1.3--5 m high...
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East Carolina University
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fteastcaroluni:oai:TheScholarship.intra.ecu.edu:10342/7017 2023-05-15T18:00:49+02:00 Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach Twarog, Michael R. Leorri, Eduardo Soriano Culver, Stephen J. Geological Sciences 2019-01-08T21:12:37Z application/pdf http://hdl.handle.net/10342/7017 en eng East Carolina University http://hdl.handle.net/10342/7017 sunda shelf paleoenvironmental reconstruction depositional environments Paleoecology--South China Sea--Holocene Sedimentation and deposition--Research--South China Sea Global environmental change Foraminifera--South China Sea Sea level--South China Sea Master's Thesis text 2019 fteastcaroluni 2022-07-11T11:42:01Z The last glacial maximum, ca. 21,000 years ago, caused a fall in eustatic sea level of ca. 120 m below present. The low-gradient, shallow Sunda Shelf, Southeast Asia was subaerially exposed during this sea-level lowstand and experienced rising sea level thereafter. Sea level rose to a +1.3--5 m highstand ca. 6,500 cal yr BP, and then fell to modern sea level. The objective of this research is to characterize environmental change on the Sunda Shelf in response to the post-glacial rising eustatic sea level. To address this objective, six gravity cores were collected along a transect crossing the paleo-Chao Phraya incised river valley complex between peninsular Malaysia and southern Vietnam. Thirteen AMS radiocarbon samples, 130 bulk sediment magnetic susceptibility samples (BMS), 66 X-ray fluorescence spectrometry (XRF) samples, and 54 samples for the analysis of foraminiferal assemblages were used to characterize change in the depositional environments of the cored sediments. BMS, XRF, and foraminiferal analysis distinguish two main units. Unit 1 is found in the lower part of the cores and typically contains more terrestrial material than sediments further up-core as shown by higher BMS values, higher % Ti, % Al, % Fe, and lower indicators of marine influence, for example, lower % Ca, % planktonic foraminifera, and percentages of deeper water benthic foraminifera such as Heterolepa dutemplei. Unit 2 is characterized by a significant increase in % Ca, % Heterolepa dutemplei and % planktonic foraminifera ca. 6,500 cal yr BP. Unit 1 is consistent with shallower water depths and is part of a transgressive systems tract (TST, ca. 1 m thick) that terminates ca. 6,500 cal yr BP. Unit 2 represents the overlying highstand systems tract (HST, ca. 1 m thick) and is characterized by an increase in % planktonics, % Ca, and shifts in benthic foraminiferal assemblages, indicating deeper water conditions than the sediments below. This shift from a TST to a HST ca. 6500 cal yr BP is consistent with the Sunda Shelf sea-level ... Master Thesis Planktonic foraminifera East Carolina University: The ScholarShip at ECU Sunda ENVELOPE(-6.982,-6.982,62.205,62.205) |
institution |
Open Polar |
collection |
East Carolina University: The ScholarShip at ECU |
op_collection_id |
fteastcaroluni |
language |
English |
topic |
sunda shelf paleoenvironmental reconstruction depositional environments Paleoecology--South China Sea--Holocene Sedimentation and deposition--Research--South China Sea Global environmental change Foraminifera--South China Sea Sea level--South China Sea |
spellingShingle |
sunda shelf paleoenvironmental reconstruction depositional environments Paleoecology--South China Sea--Holocene Sedimentation and deposition--Research--South China Sea Global environmental change Foraminifera--South China Sea Sea level--South China Sea Twarog, Michael R. Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
topic_facet |
sunda shelf paleoenvironmental reconstruction depositional environments Paleoecology--South China Sea--Holocene Sedimentation and deposition--Research--South China Sea Global environmental change Foraminifera--South China Sea Sea level--South China Sea |
description |
The last glacial maximum, ca. 21,000 years ago, caused a fall in eustatic sea level of ca. 120 m below present. The low-gradient, shallow Sunda Shelf, Southeast Asia was subaerially exposed during this sea-level lowstand and experienced rising sea level thereafter. Sea level rose to a +1.3--5 m highstand ca. 6,500 cal yr BP, and then fell to modern sea level. The objective of this research is to characterize environmental change on the Sunda Shelf in response to the post-glacial rising eustatic sea level. To address this objective, six gravity cores were collected along a transect crossing the paleo-Chao Phraya incised river valley complex between peninsular Malaysia and southern Vietnam. Thirteen AMS radiocarbon samples, 130 bulk sediment magnetic susceptibility samples (BMS), 66 X-ray fluorescence spectrometry (XRF) samples, and 54 samples for the analysis of foraminiferal assemblages were used to characterize change in the depositional environments of the cored sediments. BMS, XRF, and foraminiferal analysis distinguish two main units. Unit 1 is found in the lower part of the cores and typically contains more terrestrial material than sediments further up-core as shown by higher BMS values, higher % Ti, % Al, % Fe, and lower indicators of marine influence, for example, lower % Ca, % planktonic foraminifera, and percentages of deeper water benthic foraminifera such as Heterolepa dutemplei. Unit 2 is characterized by a significant increase in % Ca, % Heterolepa dutemplei and % planktonic foraminifera ca. 6,500 cal yr BP. Unit 1 is consistent with shallower water depths and is part of a transgressive systems tract (TST, ca. 1 m thick) that terminates ca. 6,500 cal yr BP. Unit 2 represents the overlying highstand systems tract (HST, ca. 1 m thick) and is characterized by an increase in % planktonics, % Ca, and shifts in benthic foraminiferal assemblages, indicating deeper water conditions than the sediments below. This shift from a TST to a HST ca. 6500 cal yr BP is consistent with the Sunda Shelf sea-level ... |
author2 |
Leorri, Eduardo Soriano Culver, Stephen J. Geological Sciences |
format |
Master Thesis |
author |
Twarog, Michael R. |
author_facet |
Twarog, Michael R. |
author_sort |
Twarog, Michael R. |
title |
Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
title_short |
Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
title_full |
Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
title_fullStr |
Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
title_full_unstemmed |
Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf, Southwest South China Sea, using a Multidisciplinary Approach |
title_sort |
holocene paleoenvironmental reconstruction of depositional environments on the sunda shelf, southwest south china sea, using a multidisciplinary approach |
publisher |
East Carolina University |
publishDate |
2019 |
url |
http://hdl.handle.net/10342/7017 |
long_lat |
ENVELOPE(-6.982,-6.982,62.205,62.205) |
geographic |
Sunda |
geographic_facet |
Sunda |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
http://hdl.handle.net/10342/7017 |
_version_ |
1766170062608138240 |