山东临朐柳山地区发现早白垩世冰碛砾岩及其意义

Discovery of Early Cretaceous Moraine Conglomerate and Its Significance in Liushan Area in Linqu County of Shandong Province

摘要:

20世纪90年代在山东临朐县柳山镇地区的早白垩世莱阳群城山后组底部砾岩中发现具压坑、冰川擦痕、压裂张裂隙、压磨蚀平面的石英岩质、石灰岩质砾石和塑性变形形成的灯盏石、马鞍石石灰岩质砾石，经研究认为其成因属冰碛砾石，组成了冰碛砾岩。并探讨分析该冰川事件形成的古地理和古气候条件，指出为大陆上升局部形成的高山寒冷气候小冰期，形成了大陆型高原山岳山谷冰川。依据古生物和同位素地质年龄推断该小冰期发生在距今128~130Ma早白垩世热河期早期，建议称为临朐柳山小冰期。推断在我国东部地区其分布具一定区域性，应引起广大工作者的关注和研究。

Abstract:

In the 1990's of 20 century,quartzite, limestone and plastic deformed breccia and Ma'anshi limestone conglomerates with craters, glacial scratches, fracturing cracks, compression and abrasion planes have been found in the bottom conglomerate of Chengshanhou formation of early Cretaceous Laiyang group in Liushan town in Linqu county of Shandong province. It is believed that the origin of these conglomerates is moraine and composed of moraine conglomerates. The Palaeogeographic and Palaeoclimatic conditions of the formation of the glacier event have been discussed and analyzed. It is pointed out that the alpine cold climate microclimate formed locally for the rising of the continent formed the continental plateau mountain valley glacier. Based on Paleontological and isotopic geological ages, it is inferred that little ice age should occur in the early stage of early Cretaceous Jehol period (128~130) Ma, which is called Liushan little ice age. It is inferred that its distribution in eastern China has certain regional characteristics. It should arouse the attention of the workers, and related research should be carried out.