本文選題：四川盆地 + 震旦系�。� 參考：《巖石學(xué)報(bào)》2017年04期

【摘要】：利用震旦紀(jì)燈影期沉積較為連續(xù)的樂山市峨邊地區(qū)先鋒剖面燈二、燈三段的沉積特征與地球化學(xué)特征,分析該時(shí)期的沉積環(huán)境,探討存在爭論的桐灣運(yùn)動(dòng)Ⅰ幕的起始時(shí)限。通過對(duì)先鋒剖面燈二、燈三段地層進(jìn)行實(shí)測,發(fā)現(xiàn)燈二段下部為富微生物巖沉積特征,上部為菌藻類減少的貧微生物巖沉積特征,燈三段為藍(lán)灰色、深灰色泥巖沉積,與燈二段的突變接觸關(guān)系明顯。燈二段原巖的地球化學(xué)分析結(jié)果表明該時(shí)期為海水沉積環(huán)境,巖石類型為潮坪亞相沉積的白云巖,并可分為兩大類與8小類。δ~(13)C在燈二段內(nèi)部出現(xiàn)了明顯負(fù)異常,依據(jù)δ~(13)C與海平面的變化及微生物的關(guān)系,認(rèn)為桐灣運(yùn)動(dòng)Ⅰ幕應(yīng)起源于燈二段內(nèi)部富藻層-貧藻層之間。該構(gòu)造抬升事件是造成海平面下降,古海水溫度降低,古鹽度降低,沉積環(huán)境轉(zhuǎn)變,微生物數(shù)量減少,燈二段富藻-貧藻轉(zhuǎn)變,δ~(13)C負(fù)異常的主要因素。
[Abstract]:Based on the sedimentary and geochemical characteristics of the second and third member of the Pioneer Section of the Ebian area of Leshan, where the Dengying period of the Sinian was relatively continuous, the sedimentary environment of the period was analyzed, and the time limit for the initiation of the controversial first episode of the Tongwan movement was discussed. By measuring the strata of the second and third sections of the Xianfeng section, it is found that the lower part of the second member of the section is characterized by the sedimentary characteristics of the rich microbe, the upper part of the section is the sedimentary characteristic of the depleted microbe rock which is reduced by bacteria and algae, and the third member of the lamp section is composed of blue-gray and dark gray mudstone deposits. The sudden contact relation with the second stage of the lamp is obvious. The geochemical analysis results of the original rocks of the second member of the Chang Chang show that this period is a seawater sedimentary environment, and the rock type is dolomite deposited in the tidal flat subfacies, and can be divided into two categories and eight subclasses. There are obvious negative anomalies in the interior of the second member. Based on the relationship between 未 ~ (13) C and sea level change and microorganism, it is concluded that the first episode of Tongwan movement originated between the rich and poor algal layers in the second stage of the lamp. The tectonic uplift event is the main factor causing the sea level to fall, the paleo-seawater temperature to decrease, the paleosalinity to decrease, the sedimentary environment to change, the microorganism quantity to decrease, the algae-rich algae-poor algae transition in the second stage of the lamp, the 未 ~ (13) ~ (13) C negative anomaly.
【作者單位】： 中國石油大學(xué)地球科學(xué)學(xué)院;油氣藏地質(zhì)及開發(fā)工程國家重點(diǎn)實(shí)驗(yàn)室成都理工大學(xué);成都理工大學(xué)沉積地質(zhì)研究院;
【基金】：中國地質(zhì)調(diào)查項(xiàng)目(1212011220762) 國家自然科學(xué)青年基金項(xiàng)目(41602107)聯(lián)合資助
【分類號(hào)】：P534.31;P618.13

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