地质学报
地質學報
지질학보
ACTA GEOLOGICA SINICA
2014年
6期
52-59
,共8页
西藏多格错仁地区%盐泉%硫同位素%锶同位素%钾盐
西藏多格錯仁地區%鹽泉%硫同位素%鍶同位素%鉀鹽
서장다격착인지구%염천%류동위소%송동위소%갑염
Dogai Coring area,Tibet%salt springs%sulphur isotpe%strontium isotope%potash
西藏北羌塘盆地是我国侏罗系海相找钾的主要远景区之一，在多格错仁地区发育有一系列具有明显的含钾异常的现代盐泉，研究这些盐泉水的物质来源具有重要的找钾意义和科学价值。野外采集了40个盐泉水的样品，并在室内测定了其化学组分、δ34 S 和87 Sr/86 Sr。分析结果显示，盐泉水具有富 Na＋、Ca2＋、K＋、Cl-，贫Mg2＋、SO2-4、HCO-3的特征，其 Cl-含量约占矿化度的50％以上，并与矿化度呈正相关关系，Na＋、Ca2＋、K＋浓度也与矿化度呈正相关关系。根据盐泉水的钠氯系数和溴氯系数判断，盐泉水属于地层溶滤水；源泉河、东温泉、多格错仁湖南岸3处的盐泉水具有与侏罗纪海水相一致的硫同位素特征，表明其在地下运移时，很可能溶解了地层中的石膏沉积；盐泉水的1000/Sr-87 Sr/86 Sr 投点图说明各处盐泉水在地下的运移路径和形成过程明显不同；盐泉水的87 Sr/86 Sr 值与其区域背景值对比显示，盐泉水在形成过程中可能溶滤了夏里组二段和索瓦组一段中的蒸发岩，区内夏里组和索瓦组最有可能蕴含有成盐成钾层系。
西藏北羌塘盆地是我國侏囉繫海相找鉀的主要遠景區之一，在多格錯仁地區髮育有一繫列具有明顯的含鉀異常的現代鹽泉，研究這些鹽泉水的物質來源具有重要的找鉀意義和科學價值。野外採集瞭40箇鹽泉水的樣品，併在室內測定瞭其化學組分、δ34 S 和87 Sr/86 Sr。分析結果顯示，鹽泉水具有富 Na＋、Ca2＋、K＋、Cl-，貧Mg2＋、SO2-4、HCO-3的特徵，其 Cl-含量約佔礦化度的50％以上，併與礦化度呈正相關關繫，Na＋、Ca2＋、K＋濃度也與礦化度呈正相關關繫。根據鹽泉水的鈉氯繫數和溴氯繫數判斷，鹽泉水屬于地層溶濾水；源泉河、東溫泉、多格錯仁湖南岸3處的鹽泉水具有與侏囉紀海水相一緻的硫同位素特徵，錶明其在地下運移時，很可能溶解瞭地層中的石膏沉積；鹽泉水的1000/Sr-87 Sr/86 Sr 投點圖說明各處鹽泉水在地下的運移路徑和形成過程明顯不同；鹽泉水的87 Sr/86 Sr 值與其區域揹景值對比顯示，鹽泉水在形成過程中可能溶濾瞭夏裏組二段和索瓦組一段中的蒸髮巖，區內夏裏組和索瓦組最有可能蘊含有成鹽成鉀層繫。
서장북강당분지시아국주라계해상조갑적주요원경구지일，재다격착인지구발육유일계렬구유명현적함갑이상적현대염천，연구저사염천수적물질래원구유중요적조갑의의화과학개치。야외채집료40개염천수적양품，병재실내측정료기화학조분、δ34 S 화87 Sr/86 Sr。분석결과현시，염천수구유부 Na＋、Ca2＋、K＋、Cl-，빈Mg2＋、SO2-4、HCO-3적특정，기 Cl-함량약점광화도적50％이상，병여광화도정정상관관계，Na＋、Ca2＋、K＋농도야여광화도정정상관관계。근거염천수적납록계수화추록계수판단，염천수속우지층용려수；원천하、동온천、다격착인호남안3처적염천수구유여주라기해수상일치적류동위소특정，표명기재지하운이시，흔가능용해료지층중적석고침적；염천수적1000/Sr-87 Sr/86 Sr 투점도설명각처염천수재지하적운이로경화형성과정명현불동；염천수적87 Sr/86 Sr 치여기구역배경치대비현시，염천수재형성과정중가능용려료하리조이단화색와조일단중적증발암，구내하리조화색와조최유가능온함유성염성갑층계。
North Qiangtang Basin in Tibet is one main Jurassic marine area of potash exploration.There is a series of modern springs with a potassium anomaly in Dogai Coring area.Research on origin of salt springs has an important significance for potash exploration and scientific value.For this study forty salt springs water samples were taken from field.Chemical composition,δ34 S and 87 Sr/86 Sr of salt springs were determined in laboratory.Analysis results indicate that salt springs water have a high concentration of Na+ ,Ca2 + ,K+ ,Cl- ,and a poor concentration of Mg2 + ,SO2 -4 ,HCO-3 .Content of Cl- has more than 50% TDS and positive correlation with TDS.Moreover,Na+ ,Ca2 + ,K+ have a positive correlation with TDS.According to nNa+/nCl- and Br- · 103/Cl- of salt springs,springs water are from stratum lixiviation water.The δ34 S value of water samples from Yuanquanhe,Dongwenquan and south bank of Dogai Coring are consistent withδ34 S value of Jurassic seawater.It demonstrates that springs water might dissolve gypsum of stratum when springs water travelled under the ground.The figure of 1000/Sr-87 Sr/86 Sr illustrates that migration path and forming process of springs water from every sampling location are different from each other.The comparison for 87 Sr/86 Sr of salt springs and its background value shows that groundwater might lixiviate evaporite from 2 nd Member of Xiali Formation and 1 st Member of Suowa Formation.Xiali Formation and Suowa Formation are the most possible stratum of forming potash.
