A Primary Research on Multiphase Development Pattern of “Old Red Sand” in Jingjiang Coast of South East Fujian
详细信息   
摘要

<FONT size=3>face="Times New Roman">Coastal aeolian sand is a common aeolian geomorphology in the sandy coastal,which recorded the evolution process of the aeolian landscape system,and reflect the complex interaction among land surface,atmosphere and ocean.The southeast coast of Fujian exhibits a number of Late Pleistocene coastal aeolian dunes so called font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> in China,This sand sediment,in the form of single or multiple sand embankments,consists of slightly cemented,medium to fine grained sands,and is characterized by its colors of redfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">10R4/8font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">,brown redfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">2.5YR4/8font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">,light reddish brownfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">5YR5/8font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">,dark yellowish orangefont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">5YR/5/8font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">,has continuous distribution along the coastal plains,or on hillslopes near the coastline,where the sediment record potentially provides important evidence for the palaeoenvironmental history of eustatic change and coastal dunefield activity.The lack of direct dating of these font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">,however,has veiled relationships between coastal aeolian sand deposition,sea level,and other controlling factors.In this paper,quartz single aliquot regenerative Optically-Stimulated Luminescencefont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">OSLfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">dating with high resolution sampling was applied to the Late Pleistocene KR font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂（face="Times New Roman">24font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">°face="Times New Roman">34font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＇face="Times New Roman">56.3font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">″face="Times New Roman">N,118font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">°face="Times New Roman">39font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＇face="Times New Roman">14.1font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">″face="Times New Roman">Efont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman"> at the Jingjiang coast,south East Fujian.Based on the OSL chronology and compare to global sea-level change and East Asian monsoon change sequence,combined with grain size character,we reveal the periods of font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition and their formation ages.The OSL age of the 26 samples range from 125ka to 12ka shows that KR font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> has existed since the last interglacial,six period of costal aeolian sand activity can be division,respectively in 125font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">115ka,105font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">97ka,84font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">74ka,61.5font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">52.0ka,39font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">29ka,and 15font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～face="Times New Roman">9ka,and the OSL age shows that the font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition existed five obvious hiatus.These reveal that the KR font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition mainly occurred in relation to the sea-level highstands,but lower sea-level of Last Glacial Maximumfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">（face="Times New Roman">LGMfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">）face="Times New Roman">have nondeposition.May be affected by the strong winter monsoon,which bring beach sand to coastal area deposition,so font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition also occurred during the secondary low sea-level in the high sea-level period.According to the depth variation of the Taiwan Strait,and global sea-level change sequence,it would appear that a sea level of ca.-70m relative to the present was the threshold for the coastal aeolian sand activation and font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition.When the sea level lower than ca.-70m,coastal aeolian sand activation is restricted due to longer sediment transport distances and decreased sediment supply; When the sea-level higher than ca.-15m,coastal aeolian sand and the font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman">Old Red Sandfont-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">＂face="Times New Roman"> deposition under strong or weak winter monsoon all can form,but mainly formed at times of a descent stage in the sea-level highstands.When the sea-level lower than ca.-15m and higher than ca.-70m,the coastal aeolian sand deposition of the study area must have a powerful winter monsoon.

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