四川盆地中三叠统雷口坡组雷三、雷四段盐岩沉积环境与成因研究

Triassic Leikoupo Formation of T2l3,T2l4 Salt Sedimentary Environment and Genesis Study in Sichuan Basin

中文关键词:  雷三²期  雷四²期  沉积微相  盐岩成因  成盐环境  四川盆地

英文关键词::T₂l₃² period  T₂l₄² period  Sedimentary micro facies  Causes of salt rock  The salt forming environment  Sichuan basin

中文摘要:

      四川盆地雷口坡组大量钻井资料揭示中三叠统雷口坡组主要成盐期分别为雷三²期和雷四²期。岩性组合特征、沉积环境研究表明,在川中的平昌—南充—遂宁一带发育雷三²期浓缩盐膏质蒸发泻湖微相,在川中-川西地区的南部—盐亭—成都—邛崃地区发育雷四²期盐膏湖盆微相。两期盐岩差异主要表现是,雷三²期时,盆地处于频繁的海进、海退过程中,沉积环境变化较快,成盐环境相对开放,盐盆往往多次蒸发浓缩、补给、淡化,海水表现出接近或者达到盐岩沉积浓度,其间往往夹杂石膏和云质团块沉积。雷四²期时,四川盆地处于持续的海退蒸发期,蒸发量远远大于补给量,海水以蒸发浓缩为主,海水表现为超过石盐沉积浓度,沉积石盐中夹杂卤石,局部地区钾含量极高。

英文摘要:

      :The large number of drilling data from Leikoupo indicate that the period of the Leikoup salt is T₂l₃² and T₂l₄².The study of sedimentary environment of the lithologic features show that in Sichuan Pingchang-Nanchong-Suining area development T₂l³ period of concentrated salt gypsumevaporite lagoon facies,and in Sichuan to Western Sichuan region of the Nanbu-Yanting-Chengdu-Qionglai area development T₂l₄²salt lake facies,there are two major different periods of the salt lock:the T_2l³ period, the basin is in frequent transgression, regression process, the sedimentary environment changes rapidly, salt forming environment is relatively open, often repeated evaporation salt basin, recharge, desalination, seawatershowed close to or reached the salt rocks concentration, which tend to be the mixture of gypsum and cloud matterclumps;the T₂l₄² period:Sichuan Basin is a regression evaporation duration, evaporation is far greater than the supply, sea water to evaporation, the water is more than halite deposition concentration, deposition of halite inclusions carnallite in localarea, high potassium content.