贵州南部石炭纪古地磁初步研究

一、前言近年来对中国岩相古地理研究已取得不少研究成果,对中国板块也有不少新进展,1986年国际大陆边缘地质科学讨论会中已经广泛涉及到我国南方,北方各地质时代的构造变迁和海陆迁移以及板块、推覆体的演化过程。愈来愈多的资料表明,任何一个地质时期的地质事件出现,均以全球地质背景为前提。相带的变动,生物礁滩的出现,特殊环境里各种矿产的产出,无不与当时的古气候、古纬度有关。因此,研究古地磁学,将是研究岩相古地理中应当借鉴的一个重要方面。通过古地磁学研究,能得到某些有益的启示,以补充岩相古地理研究的某些不足。

Teh Preliminary Study of the Carboniferous Palaeomagnetism in Southern Guizhou

This paper deals with palaeomagnetic reconstruction of Guizhou in Southwest China. It is evident that the South China block drifted episodically northwards or southwards during its geological evolution. Being a part of the South China block, Guizhou is thought to be placed around 24° north latitude during the Late Devonian. Until well into the Early Carboniferous, the South China block continued to drift southwards to 15.1° north latitude during the Tangbagou stage, then returned northwards to 19.4° north latitude during the Xiangbai stage, migrated southwards again to 8.7° north latitude during the late Datang stage. and lastly to 7.8° north latitude during the Late Carboniferous. The block may be close to the equator during the Permian, and subsequently moved towards the southern hemisphere. It once migrated dramatically between 20° and 30° north latitude from Middle Triassic to Jurassic times. It follows that the drifting of the block may be regarded as a leading factor controlling the distribution of reefs and ore deposits, especially the bauxite deposits.
Detailed magnetic study may also serve as a useful tool for palaeogeographic reconstruction.