Understanding the Transport Mechanism of Paleo-deposits in the Sonoran Desert with Grain Size Distribution and Shape Analysis

서지정보

· 발행기관 : 한국지리학회
· 수록지 정보 : 한국지리학회지 / 9권 / 2호 / 265 ~ 279페이지
· 저자명 : 정아라

초록

About tens of meters thick fine sand and silt deposits are observed at the top of the sedimentary logs of hundreds of drilling wells throughout Phoenix metropolitan area, Arizona, USA, situated in north-central Sonoran Desert, and likely deposited after ~ 836ka. A hypothesis to explain the paleo-deposits is that the deposits are a wind-blown deposits derived from the floodplains of nearby rivers developed in response to the aeolian-fluvial interactions. The purpose of this study is to reconstruct paleoenvironment and to understand the processes of transport and deposition of the paleo-deposits using modern analogues. This is accomplished via the identification of the paleo-deposits by comparison with modern source-bordering dune sediments and fluvial sediments using the analyses of grain size distribution and grain shape parameters. Overall, the results of sediment drift potential, grain size distribution and shape analyses provide evidence to support the hypothesis, and the deposition of the paleo-deposits may be related with the change of regional climates. Grain shape parameters may better reflect the mechanism of transport when grains traveled over short distance. Given the advantage, the grain shape analysis may provide a new insight to solve the issue associated with the provenance of Korean loess-like sediments whether it was originated from far-distant the Chinese Loess Plateau and peripheral areas or from nearby floodplains of local river or from exposed fine materials in the Yellow Sea.

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