一、概述庙岛群岛纵列于渤海海峡,其上广泛分布松散沉积物。该区沉积物厚度由几米到几十米不等,不整合复盖于基岩及棕红色角砾岩层之上。上层沉积物是所谓的黄土。“黄土”为粘土质粉沙,呈浅黄色,富含钙质。“黄土”中含有石英、长石、云母及暗色矿物;还夹杂有较多的钙质结核及棱角状碎石,常呈扁豆状分布。“黄土”中发现有少量个体较小的有孔虫化石,如毕克卷转虫Ammonia beccarii、异地希望虫Elphidium advenum、缝裂希望虫E·mage-llanicum、中华九字虫Nonion sinensis等。说明这些“黄土”曾受过海水的影响。而在沉积物下部的浅褐色粘土中未发现受海水影响的痕迹。总之,该区“黄土”与我国北方其他地区的黄 I. Overview Miao Island archipelago in the Bohai Strait, widely distributed on the loose sediments. The thickness of sediments in this area ranges from a few meters to tens of meters, and the unconformities cover the bedrock and brown red breccia. The upper sediment is called loess. Loess is a clay-based silt that is pale yellow and rich in calcium. “Loess” contains quartz, feldspar, mica and dark mineral; also mixed with more calcareous nodules and angular gravel, often lentil distribution. A few small foraminiferal fossils were found in “loess”, such as Ammonia beccarii, Elphidium advenum, E · mage-llanicum, Nonion sinensis and so on. It shows that these “loess” have been affected by sea water. No traces of seawater were found in the light brown clay beneath the sediments. In short, the area “loess” and other parts of northern China yellow