Depositional facies and radiocarbon ages of a drill core from the Mekong River lowland near Phnom Penh, Cambodia: Evidence for tidal sedimentation at the time of Holocene maximum flooding
The depositional facies and radiocarbon ages of a long Holocene sediment core (KS) from Cambodia are reported here to clarify the sedimentary environments of the Mekong River delta system at the time of Holocene maximum flooding by the sea. The 30.7-m-long KS core, from the upper Mekong River lowlan...
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Published in | Journal of Asian earth sciences Vol. 29; no. 5; pp. 585 - 592 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.03.2007
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Subjects | |
Online Access | Get full text |
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Summary: | The depositional facies and radiocarbon ages of a long Holocene sediment core (KS) from Cambodia are reported here to clarify the sedimentary environments of the Mekong River delta system at the time of Holocene maximum flooding by the sea. The 30.7-m-long KS core, from the upper Mekong River lowland about 20
km southeast of Phnom Penh, penetrated five depositional facies, A to E in ascending order. Facies A is cross-laminated fluvial sand. Facies B is laminated, very fine sand with mud drapes. Facies C to E are salt marsh, flood-plain and natural-levee deposits, characterized by a succession of peat, organic clay, and reddish-brown silt. Facies B dates to 9.0–7.5
ka and is interpreted as aggradational tidal deposits, 16.5
m thick, deposited during a rapid rise of sea level; these deposits became overlain by an accumulation of salt marsh and flood-plain deposits during the subsequent period of slowly rising and then falling sea level. The maximum flooding surface lies in the Facies B interval. The presence of tidal deposits implies that the core site, about 230
km inland from the present river mouth, was near the shoreline and experienced strong tidal influences during the early Holocene. |
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ISSN: | 1367-9120 1878-5786 |
DOI: | 10.1016/j.jseaes.2006.03.009 |