本文選題：準(zhǔn)噶爾 + 湘中��； 參考：《北京大學(xué)學(xué)報(自然科學(xué)版)》2017年05期

【摘要】：針對新疆準(zhǔn)噶爾盆地西北緣洪古勒楞組下段是否存在弗拉-法門階界線的問題,對比研究布龍果爾剖面該段地層以及湖南中部錫礦山剖面上泥盆統(tǒng)法門階中下部碳酸鹽巖的碳同位素特征,并結(jié)合已有的生物地層學(xué)證據(jù),重新討論洪古勒楞組下段的時代。結(jié)果表明,布龍果爾剖面洪古勒楞組下段碳同位素的變化趨勢與國內(nèi)外諸多典型剖面弗拉-法門期之交的δ~(13)C偏移明顯不同:未見到顯著正偏移;布龍果爾剖面δ~(13)C在0~1‰范圍內(nèi)變化,小于國際上目前已知的弗拉-法門期之交δ~(13)C正偏移的幅度(2‰~3‰)。布龍果爾剖面洪古勒楞組下段可能不存在弗拉期地層,甚至可能缺失法門階底部(牙形石Pa.triangularis帶)。法門早中期,布龍果爾剖面碳同位素曲線可與湖南錫礦山剖面同時期地層進(jìn)行較好的對比,分為3個階段:2個完整的正偏—負(fù)偏旋回以及之上的小幅正偏。主量元素特征表明,布龍果爾剖面第3-1層的下半部受陸源物質(zhì)影響較大,推測可能與區(qū)域構(gòu)造活動變強烈有關(guān)。
[Abstract]:In view of the question whether there is a Fla-Famen boundary in the lower part of the Hongguleleng formation in the northwest margin of the Junggar Basin, Xinjiang, The carbon isotopic characteristics of carbonate rocks in the upper Devonian Famen stage of the Xikuang section of the Broonggoer section and in the Xikuang section of the central Hunan Province are studied. Combined with the existing biostratigraphic evidence, the age of the lower part of the Hongguleleng formation is rediscussed. The results show that the change trend of carbon isotopes in the lower part of Honguleleng formation in Bronggoer profile is obviously different from the 未 ~ (13) C migration at the juncture of Fla-Famen period in many typical sections at home and abroad: there is no significant positive migration; The variation of 未 ~ (13) ~ (13) C in the Bronggoer profile is less than that of the 未 ~ (13) ~ (13) C positive migration at the point of Fla-Famen period, which is less than 2 鈥，

本文編號：1931301