河北涞源白石山地质公园“1.5Ga前地裂缝”新解  

New Interpretation for the “1.5 Ga Old Fissure”in the Bashi Mountain Geopark,Lai Yuan,Hebei Province

作　　者：刘江[1,2] 李海兵[3,4] 乔秀夫[3,4] 

机构地区：[1]中国地质调查局西安地质调查中心,西安710054 [2]国土资源部岩浆作用成矿与找矿重点实验室,西安710054 [3]中国地质科学院地质研究所,北京100037 [4]大陆构造与动力学国家重点实验室,北京100037

出　　处：《地质论评》2016年第1期17-28,共12页Geological Review

基　　金：国家自然科学基金资助项目(编号41402181)的成果~~

摘　　要：梁定益等(2002)研究认为太行山北段河北省涞源县白石山地质公园内存在一条与中元古代雾迷山组沉积时代相当的地裂缝构造,且地裂缝内填充由地震触发,重力垮塌形成的震积岩(含软沉积变形)。近期实地考察后,笔者等得出与上述观点不同的认识,即先前认为的地裂缝实为一条断裂带:震积岩为断裂带构造岩;断层主滑移带内发育S—C面理构造;断层角砾复杂结构是构造变形和压溶作用的结果;断裂整体表现为含正断层分量的走滑断层。结合太行山北段区域构造演化历史,本文提出该断裂最早形成于燕山运动期间,此后在区域构造应力作用下可能多次活动。Objectives： Liang Dingyi et al. （2002＆） proposed that a ground fissure cropped out in the Baishi Mountain Geological Park, Laiyuan County, belonging to the northern segment of the Taihang Mountain. And the ground fissure formed at the same time when the Wumishan formation deposited in Middle Proterozoic and filled by seismically collapsed breccias, including soft -sediment deformation structures. However, this idea is likely controversial. Methods： In this paper, we restudy the ＂fissure＂ by carefully field survey and propose its formation mechanism based on the structural evolution history of the Northern Taihang Mountain. Furthermore, another structural evolution model is suggested. Results ： Field work displayed that the ＂fissure＂ had a typical architecture of a fault zone ： S - C fabrics were found in the slip zone; the fault zone consisted of fault breccias which were heavily modified by pressure solution process during deformation; the whole of the fault appear as a strike - slip with normal fault component. On the other side, there~ no overlying stable strata above the ＂fissure＂ was observed and the ＂fissure＂ might be very hard to be preserved during the long and complicated structural evolution. Conclusions： Combining with the regional tectonic evolution history of the north Taihang Mountain, we suggested that the Baishi Mountain fault likely formed as early as the stage of the Yanshan movement, then it experienced one or more phased faulting with different ratio of strike - slip, normal fault and thrust components.

关 键 词：地裂缝 震积岩 断层角砾 白石山 

分 类 号：P315.2[天文地球—地震学]