Subsurface reflections of prograded paleoscarps in Avis Island, North Andaman, India
IR@NISCAIR: CSIR-NISCAIR, New Delhi - ONLINE PERIODICALS REPOSITORY (NOPR)
View Archive Info| Field | Value | |
| Title |
Subsurface reflections of prograded paleoscarps in Avis Island, North Andaman, India
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| Creator |
Vijaya Lakshmi, C.S.
Trivedi, Deshraj Srinivasan, P. Murthy, S.G.N. Nair, Rajesh R |
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| Subject |
Ground Penetrating Radar
Heavy minerals Magnetic susceptibility Paleoscarps Avis Island Extreme wave events |
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| Description |
331-337
Prominent subsurface reflections from two GPR transect marked four lithological anomalies below Avis Island coral reefs. These scarps dip 5-10° towards sea and they consist of sands with more than 30-40% heavy mineral concentrations that produce distinct subsurface reflections that make possible to locate the buried erosional scarps. Heavy minerals are considered as the indicators of erosion as well as a proxy for sediment transport of extreme wave events. Heavy minerals including magnetite have higher magnetic susceptibility values: L1a:°644.6;°L1b:°556.8, L2a: 584.2 and L2b: 612×10<sup>-5</sup>°SI units to the background magnetic susceptibility of 5-10×10<sup>-5</sup>°SI units for quartz-rich sands suggest severe reworking process during an extreme wave event. The two profiles (L1 and L2) with four paleoscarps: L1a at a distance of 10 m from the shore, L2a approximately 15 m from the shore, L2b around 30 m from the shore and L1b nearly 35 m from the shore and the corresponding age of the dated coral above the paleoscarps increases towards land exhibiting progradation sequence. These subsurface reflections of paleoscarps were found at a depth of 1–1.5 m below the ground surface beneath the reported age of coral reefs suggesting that these coral reefs and the paleoscarps are found due to the same event. |
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| Date |
2011-07-19T04:43:45Z
2011-07-19T04:43:45Z 2011-06 |
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| Type |
Article
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| Identifier |
0975-1033 (Online); 0379-5136 (Print)
http://hdl.handle.net/123456789/12422 |
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| Language |
en_US
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| Rights |
<img src='http://nopr.niscair.res.in/image/cc-license-sml.png'> <a href='http://creativecommons.org/licenses/by-nc-nd/2.5/in' target='_blank'>CC Attribution-Noncommercial-No Derivative Works 2.5 India</a>
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| Publisher |
NISCAIR-CSIR, India
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| Source |
IJMS Vol.40(3) [June 2011]
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