CAJ | 학술논문

对老挝他曲地区钻孔中石盐流体包裹体特征、类型以及氢氧同位素组成进行了研究，用以重塑盆地成盐过程中的古环境，并在此基础上对盆地成盐物质的补给方式进行了探讨。结果显示，钻孔中塔贡组下盐段原生石盐岩主要包括人字形和漏斗形晶体两种类型。其中人字形石盐晶体在下盐段中广泛发育，漏斗形晶体数量较少，但通常与人字形石盐晶体产于同一层位，指示了下盐段沉积时盆地处于一种极浅水环境。石盐原生流体包裹体氢氧同位素组成明显偏离全球大气降水线，集中分布于其右下方，反映盆地成盐过程中处于强烈蒸发条件之下。氢氧同位素组成在纵向上的变化，可能揭示了在盐湖演化至钾盐沉积阶段大气温度具有升高趋势。白垩纪中期全球海平面达到极大值，而在呵叻盆地内部，持续的坳陷和强烈的蒸发作用将导致湖平面快速下降。这样，外海与盐盆之间则会产生水位差，由此产生的水力梯度将为外海海水通过障壁向盆地方向进行渗透提供潜在的动力。此外，早白垩世呵叻高原广泛发育的沙漠沉积，则为外海海水大规模的侧向渗透进入盐盆提供了可能的通道。因此，结合现有的资料，本文提出，除海侵补给外，外海通过障壁侧向渗透补给对老挝钾盐盆地成盐物质的供给也具有重要作用。
대로과타곡지구찬공중석염류체포과체특정、류형이급경양동위소조성진행료연구，용이중소분지성염과정중적고배경，병재차기출상대분지성염물질적보급방식진행료탐토。결과현시，찬공중탑공조하염단원생석염암주요포괄인자형화루두형정체량충류형。기중인자형석염정체재하염단중엄범발육，루두형정체수량교소，단통상여인자형석염정체산우동일층위，지시료하염단침적시분지처우일충겁천수배경。석염원생류체포과체경양동위소조성명현편리전구대기강수선，집중분포우기우하방，반영분지성염과정중처우강렬증발조건지하。경양동위소조성재종향상적변화，가능게시료재염호연화지갑염침적계단대기온도구유승고추세。백성기중기전구해평면체도겁대치，이재가력분지내부，지속적요함화강렬적증발작용장도치호평면쾌속하강。저양，외해여염분지간칙회산생수위차，유차산생적수력제도장위외해해수통과장벽향분지방향진행삼투제공잠재적동력。차외，조백성세가력고원엄범발육적사막침적，칙위외해해수대규모적측향삼투진입염분제공료가능적통도。인차，결합현유적자료，본문제출，제해침보급외，외해통과장벽측향삼투보급대로과갑염분지성염물질적공급야구유중요작용。
Characteristics,classification and hydrogen-oxygen compositions of halite fluid inclusion of core sample were used to reconstruct paleo-environments during salt deposition of the Thakhek area,Laos,and based on which the way of supply of salt materials was explored.The results show that,primary halite in the Lower Member of the Tagon Formation mainly includes two types,the chevron halite and the cumulate halite.The chevron halite crystals largely occur in the Lower Member of the Tagon Formation,and the cumulate halite crystals is relatively few but usually coexisted with chevron halite crystals in the same layers,indicating an extremely shallow water environment during halite formation.Hydrogen-oxygen isotopic compositions of halite fluid inclusion obviously deviated from the global mean meteoric line and mainly concentrated at the bottom right of the line,suggesting a strong evaporative condition during halite deposi-tion.The vertical variability of hydrogen-oxygen isotope probably implies an increasing trend of air temperature from halite to potash salt deposition.The sea level peaked at the middle Cretaceous. However,water level of salt basin dropped significantly due to continuous subsidence of salt basin and strong evaporation concentration of salt lake,When this occurred,the difference in water level between the sea and salt basin created a horizontal hydrostatic head gradient that had the potential to drive water through the barrier.Moreover,desert sediments occurred widely in Khorat Plateau during the early Cretaceous,providing a necessary passageway for the large-scale sea water.Therefore,combining with the existing data,we proposed that,in addition to marine intrusion,seepage of seawater through barrier played a significant role in supplying of salt materials of basin in Laos.