【摘要】：位于華北地臺(tái)南緣、以雜礫巖沉積為特征的羅圈組自命名起就一直倍受地質(zhì)學(xué)界的關(guān)注。關(guān)于其是否為冰川成因以及形成時(shí)代的問(wèn)題,一直沒有得出統(tǒng)一的意見。而羅圈組雜礫巖之上的東坡組,普遍為一套以成熟度較高的細(xì)碎屑巖為主的地層,該地層與具有生物地層依據(jù)的寒武紀(jì)地層呈不整合接觸關(guān)系。本文在野外剖面考察以及室內(nèi)的礫石數(shù)據(jù)統(tǒng)計(jì)分析的基礎(chǔ)上,可以認(rèn)為層狀及紋層狀雜礫巖中含有的特殊“上凸下繞”現(xiàn)象為冰筏沉積的墜石構(gòu)造,特別是發(fā)現(xiàn)了微觀砂級(jí)碎屑的“墜石”現(xiàn)象,能夠反映當(dāng)時(shí)為寒冷的冰川環(huán)境。加上羅圈組地層中其他與冰川作用相關(guān)的現(xiàn)象和證據(jù),如漂礫現(xiàn)象,以及礫石的形態(tài)特征等,再結(jié)合地層本身的層位、分布規(guī)律,可以認(rèn)為羅圈組應(yīng)為冰川作用所形成。而于東坡組發(fā)現(xiàn)的Skolithos、Arenicolites、Treptichnus、Palaeophycus、Planolites等遺跡化石,表明東坡組不低于早寒武世的第一個(gè)遺跡化石帶,為晚于Treptichnus(Phycodes)pedum生物帶的寒武紀(jì)沉積�？烧J(rèn)為東坡組的形成年代應(yīng)晚于震旦紀(jì),為寒武紀(jì)早期。而其下伏的羅圈組與東坡組整合接觸,形成時(shí)代應(yīng)為寒武紀(jì)早期或震旦紀(jì)晚期(埃迪卡拉紀(jì)末期或之后)。
[Abstract]:The Luohuan formation, which is located in the southern margin of North China platform and characterized by complex conglomerate deposits, has been paid close attention to since its naming. There has been no unified opinion as to whether or not it was a glacier and the age of its formation. The Dongpo formation above the complex conglomerate of Luohuan formation is generally a set of fine clastic rocks with high maturity, which is unconformable with the Cambrian strata based on biostratigraphy. On the basis of field profile investigation and statistical analysis of gravel data in the laboratory, it can be concluded that the special "upwelling and underwinding" phenomenon contained in layered and lamellar conglomerates is a falling stone structure of ice raft deposition. In particular, the "falling stone" phenomenon of micro-sand clastic is found, which can reflect the cold glacial environment at that time. In addition, other phenomena and evidences related to glaciation, such as boulder phenomenon and gravel morphology, in the strata of Luohuan formation, combined with the stratigraphic layer and distribution law, can be considered to be formed by glaciation. However, the fossils such as Skolithoso Arenicolitesus Treptichnus Palaeophycus-Planolites found in the Yudongpo formation indicate that the Dongpo formation is not lower than the first trace fossil belt of the early Cambrian and is a Cambrian deposit later than the Treptichnus (Phycodes) pedum biosphere. It can be considered that the formation of Dongpo formation should be later than that of Sinian, and it is early Cambrian. The forming age of the underlying Luohuan formation and Dongpo formation should be the early Cambrian or the late Sinian (late or post-Ediacaran).
【學(xué)位授予單位】：貴州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P588.212.5;P535

【參考文獻(xiàn)】

相關(guān)期刊論文 前6條

1 王約;王平麗;;貴州臺(tái)江凱里組的遺跡化石Treptichnus[J];地質(zhì)論評(píng);2006年01期

2 羅惠麟，，陶永和，高順明;昆明附近早寒武世遺跡化石[J];古生物學(xué)報(bào);1994年06期

3 王志宏;羅圈期—東坡期地層格架研究及時(shí)代討論[J];河南地質(zhì);1996年04期

4 H.G.Reading;陸松年;;冰川環(huán)境[J];國(guó)外前寒武紀(jì)地質(zhì);1981年02期

5 張艷;王璞s

本文編號(hào)：2144248