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凌家卫(Langkawi)群岛位于马来西亚西北,区内地层由古生代沉积岩组成。自下而上分为4组:Machinchang组、Setul组、Singa组和Chuping组,主要为浅海相沉积。经在该群岛Tanjung Mali地区(6°17′11.5″N,99°43′42″E)详细的野外观察,我们发现Singa组中的砾石的大小、形状差异很大。砾石的直径,大者可达10～20cm,小者仅1～2cm;砾石形状,大的为滚圆状至半滚圆状,小的呈棱角状;砾石成分除有沉积岩外,最值得注意的是其中见有片麻岩和花岗伟晶岩砾石,根据所见砾石的上述特证可以得出如下看法:①Singa组的砾石具有冰川漂砾的特征,地层时代来看,它们应与冈瓦纳岩系底部石炭—二叠纪冰积岩相当。因此该区所处大地构造位置应为冈瓦纳古陆北缘。②该区不仅存在着显生宙的沉积岩,而且存在着前寒武纪变质岩和变质基底。Singa组的砾石中见有黑云片麻岩砾石,可能来自前寒武纪变质基底。这一变质基底亦即冈瓦纳古陆的基底。③除三叠纪与白垩纪花岗岩外,在Singa组中见到由伟晶状白云母,长石及石英组成伟晶岩砾石。表明该区的变质基底中至少存在着前寒武纪花岗质岩浆活动
The Langkawi archipelago is located in northwestern Malaysia and the strata in the area consist of Paleozoic sedimentary rocks. It is divided into four groups from bottom to top: Machinchang Formation, Setul Formation, Singa Formation and Chuping Formation, mainly of shallow marine sediments. Through detailed field observations in the Tanjung Mali area of the archipelago (6 ° 17’11.5 “N, 99 ° 43’42” E), we found that the gravel in the Singa Formation varies widely in size and shape. Gravel diameter, the largest up to 10 ~ 20cm, the smaller ones only 1 ~ 2cm; gravel shape, the larger rounded to semi-rounded, small angular; gravel composition in addition to sedimentary rocks, the most noteworthy is There are gneisses and granitic pegmatite gravel. According to the above-mentioned special certificates of gravel, we can draw the following opinions: (1) The gravels of the Xinga Formation have the characteristics of glacial boulders. In the age of the strata, they should be similar to Gondwana Carboniferous-Permian igneous rocks at the bottom of the rock series are quite similar. Therefore, the tectonics of the area where the area is located should be the northern margin of Gondwanaland. ② There are not only Phanerozoic sedimentary rocks, but also Precambrian metamorphic rocks and metamorphic basalts. There are dark-graded gneiss gravels in the Singa Formation gravel, probably from the Precambrian metamorphic basement. This metamorphic base is also the base of the Gondwanaland. ③ In addition to the Triassic and Cretaceous granites, in Singa group to see the pegmatite mica, feldspar and quartz pegmatite gravel. It shows that there are at least Precambrian granitic magmatic activities in metamorphic basalts in this area