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四川广元地区志留纪晚期地层曾被划分为金台观组、车家坝组和中间梁组,后被厘定合并为一个组,即车家坝组。通过对岩性组合特征和生物化石群面貌的分析,广元地区晚志留世地层在岩性、生物化石生物群面貌方面具有一致性,赞成将三组归入同一个岩石地层单元——车家坝组,代表近岸、正常浅海(平均浪基面以上)沉积(BA2—BA3)。对比分析表明,该组的牙形刺Ozarkodina crispa应鉴定为Ozarkodina snajdri。这是O.snajdri牙形刺带在中国的首次报道。依据牙形刺化石,车家坝组的时代被修订为中Ludlow世晚期—晚Ludlow世早期。该组上部发现几丁石Sphaerochitina sp.组合,可与O.snajdri牙形刺带和bohemicus tenus-kozlowskii笔石带进行对比。
Late Silurian strata in Guangyuan area of Sichuan have been divided into Jintaiguan Formation, Chejiaba Formation and Zhongzhongliang Formation, and later they were determined to be merged into one group, that is, Chejiaba Formation. Based on the analysis of lithologic assemblages and biofuels, the Late Silurian stratigraphy in Guangyuan area is consistent in lithology and biofacies biome. It is agreed that the three groups should be classified into the same lithostratigraphic unit Dam group, representing the nearshore, the normal shallow sea (average wave basal plane above) deposition (BA2-BA3). Comparative analysis showed that Ozarkodina crispa of this group should be identified as Ozarkodina snajdri. This is the first report of O.snajdri conodont tape in China. According to the conodonts, the age of the Chejiaba Formation was revised as late Ludlow-Late Ludlows. The upper part of the group was found with the combination of the Sphaerochitina sp. Chinensis compared with O.snajdri conodont and the bohemicus tenus-kozlowskii pen-stone.