辽宁西部中白垩世火山旋回的划分与对比

辽宁西部地区中生代白垩纪存在两期火山旋回,时代分别属早白垩世早期和中白垩世早期。早白垩世火山旋同即义县组,中白垩世火山旋回本文称为大兴庄火山岩,该期火山岩火山活动微弱,火山岩分柑局限,主要出露于阜新—义县盆地的东侧上齐台一带,以宁静的侵出和次火山岩侵入为主,是早白垩世阜新组沉积之后,中白垩世孙家湾组沉积之前的一次火山活动,它与孙家湾组共同组成一个火山喷发—沉积旋回。

THE SUBDIVISION AND CORRELATION OF THE MIDDLE CRETACEOUS VOLCANIC CYCLE IN WESTERN LIAONING

The volcanic formation, located in Shangqitai District of Fuxin-Yixian Basin of Late Mesozoic in western Liaoning,has been considered as Dalinghe Fm.and Zhaoduba Fm. (overlying Sunjiawan Fm.of the Middle Cretaceous) or Yushugou Fm. (underlying Jiufotang Fm. of the Early Cretaceous). But the authors disapprove it.In fact, it is an intermediate-acidic volcanic sequence, covering Jiufotang Fm., discordantly lying under Sunjiawan Fm.,and forms a volcanic eruption and sediment cycle with Sunjiawan Fm..Thus it is temporarily named as Daxin.gzhu.ang Volcanic Rock Formation in this paper. As there is a tendency at present that Jiufolang Fm. and Fuxin Fm. are considered to be the Early Cretaceous, and the Cretaceous is subdivided into three parts, the age of Daxingzhuang Volcanic Rock Formation (it can be compared with Yuxin Fm. of Tieling-Faku andXifeng) is attributed to the early stage of the Middle Cretaceous in the paper.