四川广元志留纪晚期车家坝组中线形植物的发现及其意义

DISCOVERY OF THE NEMATOPHYTE FOSSILS FROM THE LATE SILURIAN CHEJIABA FORMATION,GUANGYUAN,SICHUAN,SOUTH CHINA,AND THEIR STRATIGRAPHICAL SIGNIFICANCE

四川广元地区志留纪晚期车家坝组以碎屑岩沉积为主,产出牙形刺、腕足类、几丁虫、三缝孢、隐孢子、植物类表皮等化石,具有可靠地质时代证据;对该组的进一步研究,为扬子区志留纪晚期地层划分和对比研究提供了标杆。首次报道了车家坝组下部发现的线形植物化石,确定该植物代表的时代为志留纪晚期。根据扬子区多个产地的志留纪晚期线形植物和虫管遗迹化石,结合岩性变化,认为:在扬子区,野外确定志留纪晚期地层的化石识别标志有2个,即大量虫管遗迹化石和线形植物化石。

The late Silurian Chejiaba Formation in the Guangyuan region of Sichuan Province is mainly composed of clastic rocks and yields conodonts,brachiopods,chitinozoans,trilete spores,cryptospores,and cuticle-likes phytodebris.This formation is Late Silurian（Ludlow and Pridoli）in age.A detailed study of this formation can provide a regional standard for late Silurian stratigraphy in the Yangtze Platform.This study reports nematophyte fossils from lower part of the Chejiaba Formation,and confirms that these nematophyte fossils are Late Silurian（Ludlow-Pridoli）in age.Based on the analysis of upper Silurian nematophytes and tubular trace fossils,we propose that nematophytes and tubular trace fossils can be used for biostratigraphic correlation of Late Silurian strata this region.