摘要
吉林晚石炭世威宁期石头口门裂陷槽位于长春市东50km。该裂陷槽以海底火山沉积—硅质岩沉积为主。早期以含锰结核的碎屑岩和泥岩、硅质岩为主,并有少量的凝灰岩和玄武岩;中期以海底火山喷发的高钠质细碧岩、角斑岩为主,并伴有规模不大的蛇纹岩;晚期以硅质岩、长石杂砂岩、泥岩、生物碎屑灰岩为主,在生物碎屑灰岩中首次发现Fusulina lanceolata、F.sp.、Pseudostaffella khotunensis、P.sp.、Schubertella sp.、Endothyrd sp.等晚石炭世威宁期标准化石。该裂陷槽具有典型的裂陷槽沉积特征,它不仅具有海底火山沉积的细碧-角斑岩组合的全部特征,而且具有完整的裂陷槽沉降—拉张—上升的全过程、具有拉张强度较大、较深、地壳相对较薄的特点。地层剖面中具有岩性、岩相、变质程度的一致性,并不同于省内和大区内其他岩石地层,故提出新建石头口门组,用以代表吉林省晚石炭世威宁期海底火山喷发沉积岩系。
The Shitoukoumen faulted trough basin is situated 50 km east of Changchun, Jilin, Northeast China. It is dominated by clastic rocks of manganese nodules, mudstone and silicalite intercalated with minor tuff and basalt in the lower part; by high sodium spilite and keratophyre from submarine volcanic eruptions, associated with serpentinite in the middle; and by silicalite, felds-pathic greywacke, mudstone and bioclastic limestone in the upper part. Rich fossils including Fusulina lanceolata, F. sp. , Pseudostaffella khotunensis, P. sp. , Schubertella sp. and En~ dothyre sp. have been found for the first time from the bioclastic limestone. The sediments can thus be dated to the Weining Age of Late Carboniferous. The sediments in the Shitoukoumen faulted trough basin have typical features of the spilite and keratophyre assemblage of submarine volcanic sediments. They display the process of sinking-rising and pull-apart of the faulted trough basin, reflecting the intensity of pull-apart and the comparatively thinner part of the Earth's crust. The sediments are distinct in the lithological characters, which are different from the contemporary strata in Jilin Province and other regions, therefore a new lithostratigraphic u-nit, the Shitoukoumen Formation is erected to represent the late Carboniferous volcanic rock series in Jilin.
出处
《地质论评》
CAS
CSCD
北大核心
1999年第6期632-639,共8页
Geological Review
关键词
石头口门
威宁期
裂陷槽
吉林
晚石炭世
地层
Shitoukoumen faulted trough basin
Late Carboniferous
Weining Age
Jilin
