世界地质
世界地質
세계지질
WORLD GEOLOGY
2010年
1期
33-44
,共12页
白龙江隆起%碳酸盐碎屑流%古地理
白龍江隆起%碳痠鹽碎屑流%古地理
백룡강륭기%탄산염쇄설류%고지리
Bailongjiang uplift%carbonate debris flow%palaeogeography
白龙江隆起地区可见泥盆纪至中三叠世的碳酸盐碎屑流,其中泥盆纪至早三叠世的碳酸盐碎屑流沉积主要见于白龙江隆起北翼,中三叠世的碳酸盐碎屑流则见于白龙江隆起南北两翼和西缘.这些碳酸盐碎屑流沉积有两种类型:一种为仅含深水砾屑的碎屑流沉积,另一种为深水和浅水砾屑兼有的碎屑流沉积.通过对这些碎屑流沉积进行详细的野外和室内研究,分析其沉积特征,认为这些碳酸盐碎屑流形成于碳酸盐台地斜坡环境.结合前人的研究成果分析认为,白龙江地区北侧自泥盆纪开始,存在一个大致东西走向,向北倾斜的碳酸盐斜坡,斜坡向南则为松潘-甘孜地块的主体部分,从侧面佐证了松潘-甘孜地块的存在.至三叠纪安尼晚期,由于松潘地块主体部分沉陷,形成自东向西延伸的白龙江半岛,中三叠世白龙江隆起周缘碳酸盐碎屑流沉积的环状分布则指示出白龙江半岛的空间展布特征.
白龍江隆起地區可見泥盆紀至中三疊世的碳痠鹽碎屑流,其中泥盆紀至早三疊世的碳痠鹽碎屑流沉積主要見于白龍江隆起北翼,中三疊世的碳痠鹽碎屑流則見于白龍江隆起南北兩翼和西緣.這些碳痠鹽碎屑流沉積有兩種類型:一種為僅含深水礫屑的碎屑流沉積,另一種為深水和淺水礫屑兼有的碎屑流沉積.通過對這些碎屑流沉積進行詳細的野外和室內研究,分析其沉積特徵,認為這些碳痠鹽碎屑流形成于碳痠鹽檯地斜坡環境.結閤前人的研究成果分析認為,白龍江地區北側自泥盆紀開始,存在一箇大緻東西走嚮,嚮北傾斜的碳痠鹽斜坡,斜坡嚮南則為鬆潘-甘孜地塊的主體部分,從側麵佐證瞭鬆潘-甘孜地塊的存在.至三疊紀安尼晚期,由于鬆潘地塊主體部分沉陷,形成自東嚮西延伸的白龍江半島,中三疊世白龍江隆起週緣碳痠鹽碎屑流沉積的環狀分佈則指示齣白龍江半島的空間展佈特徵.
백룡강륭기지구가견니분기지중삼첩세적탄산염쇄설류,기중니분기지조삼첩세적탄산염쇄설류침적주요견우백룡강륭기북익,중삼첩세적탄산염쇄설류칙견우백룡강륭기남북량익화서연.저사탄산염쇄설류침적유량충류형:일충위부함심수력설적쇄설류침적,령일충위심수화천수력설겸유적쇄설류침적.통과대저사쇄설류침적진행상세적야외화실내연구,분석기침적특정,인위저사탄산염쇄설류형성우탄산염태지사파배경.결합전인적연구성과분석인위,백룡강지구북측자니분기개시,존재일개대치동서주향,향북경사적탄산염사파,사파향남칙위송반-감자지괴적주체부분,종측면좌증료송반-감자지괴적존재.지삼첩기안니만기,유우송반지괴주체부분침함,형성자동향서연신적백룡강반도,중삼첩세백룡강륭기주연탄산염쇄설류침적적배상분포칙지시출백룡강반도적공간전포특정.
There are a lot of carbonate debris flows in Bailongjiang uplift from Devonian to Middle Triassic. The carbonate debris flow deposition from Devonian to Early Triassic are mainly found in the north wing of Bailongjiang uplift, and carbonate debris flow deposition in Middle Triassic are mainly located in the both wings and the western edge of this area. The carbonate deris flow depositions can be divided into two types, including the deposition containing only deep water gravels and the deposition containing both shallow and deep water gravels. Through detailed investigation in field and laboratory of these carbonate debris flow depositions, the authors analyse their sedimentary characteristics and consider that these carbonate flows formed in carbonate slope environment. Combining with the previous research, the authors draw a conclusion that there was a carbonate slope with east-west striking and north trending in the north edge of Bailongjiang uplift from Devonian, and the main part of Songpan-Ganzi block southward from Bailongjiang uplift, which evidenced the existence of Songpan-Ganzi block. Due to the subsidence of the main part of Songpan block, Bailongjiang peninsula formed with east-west striking in late Anisian of Triassic. The ring distribution of the carbonate debris flow depostion enclosing Bailongjiang uplift in Middle Triassic showed the spatial distribution characteristics of Bailongjiang peninsula.