准噶尔西北部塔尔巴哈台组早石炭世植物和遗迹化石的发现及其古地理意义*

首次在准噶尔西北部塔尔巴哈台组上部发现了早石炭世维宪期植物化石 Archaeocalamites scrobiculatus，Sublepidodendron grabaui，S. mirabile，S. cf. mirabile，Sublepidodendron sp.， Lepidodendropsis sp.， Mesocalamites sp.， Sigillaria sp.， Rhodiopteridium?sp.，Knorria sp.，证实了该组的时代可延续到早石炭世。根据研究区塔尔巴哈台组和上覆黑山头组的生物组合面貌及二者的接触关系，论证了塔尔巴哈台组顶部和黑山头组在准噶尔西北部具有明显的穿时性，前者从杜内期延续到维宪期，后者从杜内期延续到谢尔普霍夫期。与植物化石共同保存的深水相遗迹化石指示了塔尔巴哈台地区在早石炭世早中期为半深海-深海沉积环境，不同于东部吉木乃地区同期的滨浅海沉积环境，说明准噶尔西北部在早石炭世存在着不同的沉积体系。北疆地区早石炭世广泛的海侵活动以及额尔齐斯-斋桑洋向南侧哈萨克斯坦板块俯冲是造成这种沉积差异的主控因素，同时也造成了塔尔巴哈台组和黑山头组在区域上具穿时性。

Discovery of Early Carboniferous plant and trace fossils from the Ta′erbahatai Formation in northwestern Junggar and its palaeogeographical significance

The Early Carboniferous Visean plant fossils are reported for the first time from the upper part of the Ta′erbahatai Formation in northwestern Junggar，including Archaeocalamites scrobiculatus，Sublepidodendron grabaui，S. mirabile，S. cf. mirabile，Sublepidodendron sp.， Lepidodendropsis sp.， Mesocalamites sp., Sigillaria sp., Rhodeopteridium ?sp. and Knorria sp.. This floral assemblage demonstrates that the age of the Ta′erbahatai Formation can be extended to the Early Carboniferous. The uppermost Ta′erbahatai Formation and its overlaying Heishantou Formation are obviously diachronous on the basis of fossil evidences and contact relationships of strata. The age of the uppermost Ta′erbahatai Formation extends from the Tournaisian to Visean and the Heishantou Formation is from the Tournaisian to Serpukhovian. Deep-sea trace fossils preserved together with plant fossils indicate bathyal-abyssal environment in the Tarbgatay area during the early-middle Early Carboniferous，in contrast to the littoral and shallow marine conditions in the Jimunai area at the same time. The different sedimentary systems are largely attributed to the extensive transgression in northern Xinjiang and the subduction of the Irtysh-Zaysan Ocean Plate under the Kazakhstan Plate during the Early Carboniferous，which also account for the diachroneity of the uppermost Ta′erbahatai Formation and Heishantou Formation in northwestern Junggar.