珠江口海域全新统淤泥层的初步研究

PRELIMINARY STUDY OF HOLOCENE MUD LAYER IN PEARL RIVER MOUTH

淤泥层是一种特殊地层。本文研究了“淤泥层”的物质组成、时空分布规律及其物质来源和沉积作用。通过对岩性、生物组合和沉积环境的研究,讨论了沉积相。从不同沉积物在不同环境中不同运移方式的研究,探讨了沉积作用及过程。

The Holocene mud layer in Pearl River Mouth consists of clay and silty grained material. It's medium diameter of grain size changes approximately at 8ρ . The mud layer in the area is in wedge-dis- tribution and makes up 95 % in area. The granularity of sediments is from silty clay to clayey silt and a few sand-silt-clay from estuary to shallow sea shelf. The mud layer's thickness averages 5 to 26m but varies from place to place,generally less thickend at the estuary,and thicker and thicker from estuary mouth to outsea. It's sedimentary rate ranges from 1. 0 to 1. 9mm/a,and it's basal layer is mottled clay of late Pleistocene. The raw material of mud layer origins mainly from continent carried by river and transported mainly in suspension and dissolvent forms. When it happens to meet marine water, chemical reactions will take place,so that floccullent or gelatinous actions will produce,and the hard dissolvable materials deposit at last. Sedimentary squences of mud layer generally are coarse at the lower part and fine at the upper,e. i. from sandy clay through clayey silt to silty clay.