發(fā)布時間：2018-10-07 19:05

【摘要】：龍門峽南剖面位于四川盆地東部,廣安市東北的光輝鄉(xiāng)境內(nèi),構造位置處于川東高陡構造帶西側,華鎣山帚狀構造背斜的軸部,有連續(xù)的三疊系地層出露地表。本文選擇龍門峽南剖面嘉陵江組為研究對象,采用野外觀察與室內(nèi)分析相結合的方法,以沉積巖石學、碳酸鹽巖沉積學、巖相古地理等理論為指導,通過野外剖面的實測資料,綜合運用薄片鑒定、陰極發(fā)光分析等技術手段,對研究區(qū)下三疊統(tǒng)嘉陵江組碳酸鹽巖的巖石學特征及成巖作用進行了系統(tǒng)研究:查明巖石組分、組構及類型,并簡述了巖石中的成巖作用類型。龍門峽南剖面嘉陵江組總厚度669.44m,比川東其他地區(qū)出露的嘉陵江組地層稍厚。結合野外剖面測量和室內(nèi)薄片觀察分析,按巖性把嘉陵江組分為四段,其中嘉一段厚度319.04m,以石灰?guī)r為主;嘉二段厚70.13m,以白云巖和鹽溶角礫巖為主;嘉三段厚196.86m,以石灰?guī)r為主;嘉四段厚83.41m,以白云巖和鹽溶角礫巖為主。在野外觀察和室內(nèi)薄片分析的基礎上,將研究區(qū)下三疊統(tǒng)嘉陵江組的巖石類型劃分為灰?guī)r、白云巖和鹽溶角礫巖三大類,并在此基礎上細分為亮晶顆粒灰?guī)r、微晶顆粒灰?guī)r、顆粒微晶灰?guī)r-含顆粒微晶灰?guī)r、紋層狀微晶灰?guī)r、蠕蟲狀微晶灰?guī)r、結晶灰?guī)r、微晶白云巖、結晶白云巖等8個亞類。在巖石學特征的基礎上,認為研究區(qū)嘉陵江期主要發(fā)育局限臺地和蒸發(fā)臺地兩種沉積相。在漫長的地質(zhì)歷史中,嘉陵江組地層經(jīng)歷了復雜的成巖過程,成巖作用類型豐富,主要有泥晶化作用,壓實、壓溶作用,方解石膠結作用,白云石化作用,重結晶作用,破裂作用,溶解作用,硅化作用,去石膏化作用,以及黃鐵礦、螢石、天青石等自生礦物的形成。在成巖過程的元素遷移方面,總體上表現(xiàn)為Sr的丟失和Mn、Fe的獲取,大多數(shù)白云巖因具有相對較高的Mn含量而具有比石灰?guī)r強的陰極發(fā)光性。
[Abstract]:The south section of Longmenxia is located in the eastern part of Sichuan basin and the territory of Guanghui Township in the northeast of Guangan City. The tectonic position is located in the west of the high-steep structural belt in eastern Sichuan and the axis of Huayingshan broom-like structural anticline with continuous Triassic strata appearing on the surface. In this paper, the Jialingjiang formation in the south section of Longmenxia is selected as the research object, the field observation and laboratory analysis are combined, and the theories of sedimentary petrology, carbonate sedimentology, lithofacies and paleogeography are taken as the guidance, and the field profile data are measured. The petrological characteristics and diagenesis of carbonate rocks of the Lower Triassic Jialingjiang formation in the study area were systematically studied by means of thin slice identification and catholuminescence analysis. The types of diagenesis in rocks are briefly described. The total thickness of Jialing River formation in the south section of Longmenxia is 669.44 m, which is a little thicker than that of Jialing River formation exposed from other areas in East Sichuan. The Jialing River formation is divided into four sections according to lithology, which is 319.04 m thick in Jia-1 member, 70.13 m thick in dolomite and salt-soluble breccia, 196.86 m in thickness in Jia-3 member, mainly limestone in Jia-1 formation, 70.13 m in thickness and 70.13 m in thickness in Jialingjiang formation. The thickness of Jiaxi formation is 83.41 m, mainly dolomite and salt solution breccia. On the basis of field observation and laboratory sheet analysis, the rock types of the Lower Triassic Jialingjiang formation in the study area are divided into three types: limestone, dolomite and salt-soluble breccia. On this basis, they are subdivided into bright grained limestone and microcrystalline granular limestone. Granular microcrystalline limestone-granular-bearing microcrystalline limestone, lamellar microcrystalline limestone, wormlike microcrystalline limestone, crystalline limestone, microcrystalline dolomite, crystalline dolomite, etc. On the basis of petrological characteristics, it is considered that two sedimentary facies, limited platform and evaporative platform, mainly developed in Jialing River period in the study area. In the long geological history, the formation of Jialingjiang formation has experienced complicated diagenesis process, and the diagenesis is rich in types, such as mud crystallization, compaction, pressure-dissolution, calcite cementation, dolomitization, recrystallization, etc. Rupture, dissolution, silicification, degypsum, and the formation of pyrite, fluorite, celadite and other authigenic minerals. In the aspect of element migration in diagenetic process, the loss of Sr and the acquisition of Mn,Fe are the main manifestations. Most dolomite has stronger cathodic luminescence than limestone because of its relatively high Mn content.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.13

【參考文獻】

相關期刊論文 前2條

1 時志強;安紅艷;伊海生;張華;曾德勇;;上揚子地區(qū)早三疊世異常碳酸鹽巖的分類與特征[J];古地理學報;2011年01期

2 祝幼華;羅輝;蔡華偉;許波;楊昊;趙媛媛;陳迪舒;周志澄;陳金華;;四川廣安謝家槽海相早、中三疊世地層劃分[J];地層學雜志;2012年04期

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本文編號：2255334