Grain-size Characteristics of Quaternary Sediments in Zhangzhou City,Fujan Province and Their Environmental Implication

Key words: 
• grain size analysis /
• sedimentary environment /
• Quaternary /
• Zhangzhou City /
• Fujian Province

Abstract: On the basis of the grain size data from the samp les of two bore holes in the Zhangzhou City, Fujian Province, and the stream channel facies belt and estuarine facies belt, the Quaternary sedimentary environment and its evolution are discussed in details. The grain size parameters of 91 sediment samples obtained from MS 22000 Laser Grain Size Analyzer have been illustrated in frequency curves, cumulative frequency curves on probability scale, and modal curves. For the imp lication of the grain size distribution, the results show that the segments of the modal curves are obvious and have concordance with the segment of the cumulative frequency curves on probability scale, so that modal curves have an important significance in explanation of hydrodynamic sorting. The four evolutional stages during the Quaternary in the Zhangzhou basin are recognized as follows: 1) the alluvial facies and pluvial facies of the Longhai Formation during the middle Late Pleistocene; 2) the alluvial facies of the Dongshan Formation during the late Late Pleistocene; 3) the bay milieu or estuarine facies of lower part of the Changle Formation in the early and middle Holocene in age; 4) the alluvial facies and pluvial facies of upper part of the Changle Formation in the late Holocene in age.