【摘要】 文中介绍了江苏和山东沿海一带平原和丘陵区钙质结核的分布、外部形态、内部构造以及矿物成分和化学成分,进而将钙质结核分为四个类别.同时讨论了钙质结核的形成时代、物质来源、形成条件和机制以及后生变化.更多还原

【Abstract】 This paper presents the general distribution of calcretes in the plains and hills along the coastal zone in Jiangsu and Shandong provinces, their morphological features, internal structures and textures, mineralogical and chemical compositions and the mineralogical and chemical composition of sediments around them. We discuss the ages, material sources, conditions and mechanism of formation and later changes of the calcretes. We consider that the climates which is favourable to formation of the calcretes in the coastal zone occurred during the Middle Pleistocene-Holocene, i. e. the moderately temperate and slightly arid climate was followed by the arid and cool one. Therefore due to infiltrating and leaching of the surface water the calcretes were formed in the perched ground water zone. The material sources of calcretes were not only CaCO3, but also d’etrital minerals.The studied calcretes are divided into 4 types:1. DLDLSL = Low content of detrital grains, Low crystallinity and low con tent of sparry calcite.2. DmD’Sm = Medium content of detrital grains, first degree of crystallinity and medium content of sparry calcite.3. DmD2Sn = Medium content of detrital grains, second degree of crystallinity and low content of sparry calcite.4. DLSh = Low content of detrital grains, high content of sparry calcite. From 1st to 4th types crystallinity gradually raises.更多还原