新疆哈山“山”区早白垩世吐谷鲁组的发现及其地质意义

Discovery and Geological Significance of Early Cretaceous Tugulu Formation in Hala' alt Mountain Area,Xinjiang

广泛出露于哈山之南、北两个盆地中的早白垩世吐谷鲁组,在哈山"山"区被新发现,确认其超覆于前白垩系之上,不整合界面产状平缓。吐谷鲁组产状近水平,层理层面清晰,构造极简单,无变形变质,而其下伏下二叠统或更早地层均褶皱变形强烈,断裂及节理等构造发育,二者差异显著。白垩纪之前哈山曾遭剥蚀但尚未夷平,可作为和什托洛盖盆地与准噶尔盆地的界山。哈山北煤南油的成矿差异可能受此构造格局的控制。到早白垩世,和什托洛盖盆地才与准噶尔盆地连为一体。"山"区吐谷鲁组的发现,为其提供了重要佐证。现今"盆-山-盆"的地貌格局是陆内差异隆升的产物。

Early Cretaceous Tugulu formation, which widely exposed in the southern and north- ern basin to the Hala＇ alt Mountain, was newly discovered in the Hala~ alt mountain area. The formation overlaps unconformably on the Pre-Cretaceous strata and the unconformity surface is gentle. The Tugulu formation has nearly horizontal attitude, clear bedding and very simple structure, without any deformation and metamorphism, while its underlying lower Permain or earlier strata are strongly folded deformation with fractures, joints and other structures. The differences are extremely significant. Eroded before Cretaceous but not flattened, Hala＇ alt Mountain can be regarded as boundary mountain between Hoxtolgay basin and Junggar basin. The difference of mineralization between northern coal and southern oil to the Hala＇ alt Mountain may be related with such structural framework. Till the early Cretaceous period, Hoxtolgay basin and Junggar basin collided and developed into a unified basin. The discovery of Tugulu formation in the Hala＇ alt mountain area provides an important evidence for such structural event. Nowadays, the land form pattern of basin-mountain-basin is the product of inconsistent inland uplift.