沉积物粒度分析在厦门市第四纪 环境研究和地层划分对比中的应用

采用MS-2000型激光粒度分析仪进行测试,利用计算机粒度分析软件对数据进行整理和计 算,绘制出样品的频率曲线、概率累积曲线以及粒度众数位值曲线等图件并进行沉积环境分析。厦门地 区第四纪环境演化经历了中更新世同安组(含泥中粗砂、含泥细中砂、砂为主)海积冲积→更新统上部 龙海组(含泥粗中砂、含泥细中砂、含泥粗砂、粗砂、细中砂、含细砾中粗砂、中细砂等)冲积洪冲积→更 新世上部东山组(砂、砂砾、含泥中粗砂、粗砂、泥质中细砂、细砂、中粗砂等)冲洪积及部分海积(粉砂、 细粉砂、含碳质泥、粘土、淤泥质粘土、粉砂质粘土等)→全新世长乐组(粉砂,淤泥质粘土、粉砂质粘土、 碳质粘土、含砂淤泥质粘土,粉砂质亚粘土、粉细砂亚粘土等)海湾沉积。在解释环境变化的同时,说明 粒度变化曲线在一定程度上可以作为地层划分的依据之一,并以此对研究区地层进行了详细划分。

Application of sediments grain-size analysis in Quaternary environmental research and its stratum compartmentalization and contrast function in Xiamen island,Fujian province

The grain size parameter of 64 sediment samples obtained from MS-2000 Laser Grain Size Analyzer has been illus- trated in the frequency curves, cumulative frequency curves on probability scale, and modal curves. The four evolutional sta- ges during the Quaternary of the Xiamen island basin are recognized as follows: 1)the bay milieu or estuarine facies of mid- dle part of the Tongan Formation(argilliferous coarse medium sand、argilliferous fine medium sand、sand etal) during the Pleistocene; 2)the alluvial facies and pluvial facies of top of the Longhai Formation(argilliferous coarse medium sand、argil- liferous fine medium sand、argilliferous coarse sand、coarse sand、fine medium sand、fine gravel medium coarse sand、medium fine sand etal)during the Pleistocene; 3)the alluvial facies and pluvial facies and part of the bay milieu or estuarine facies of top of the Dongshan Formation(sand、sand gravel、argilliferous medium coarse sad、coarse sand、silt medium fine sand、fine sand、medium sand etal)during the Pleistocene;4) the alluvial facies and pluvial facies of the Changle Formation(silt、silty sand、silty clay、carbonaceous clay etal)in the Holocene in age. For the implication of the grain size distribution, the results show that the segments of the modal curves are obvious and have concordance with the stratum, so that modal curves have an important significance in compartmentlization of Quaternary stratum to a certian extent.