陕北侏罗纪煤田崔家沟煤矿古环境分析研究
Analysis on the Paleoenvironment of Cuijiagou Coal Mine in Jurassic Coalfield,Northern Shaanxi
邵银川 1李道勇 1毕垒 1梁兴光 1陈永梅 1李继宝1
作者信息
- 1. 山东省煤田地质局第一勘探队,山东黄岛 266500
- 折叠
摘要
为查明研究区延安组煤在成煤时期的古气候特征、古水体盐度和古氧化还原程度,对研究区延安组的煤做了元素测试和分析,采用元素地球化学方法恢复研究区煤在成煤时期的古环境.据数据分析显示,自下而上延安组三个煤层中Sr/Ba值、B元素含量、Sr含量的垂向变化趋势一致,即呈现先增大后减少的趋势,Sr/Ba值都大于1,反映了延安组三个煤层在沉积时期,古水体盐度均较高,主要处于咸水-半咸水的沉积环境.由Sr/Ba值、Mg/Ca值、Na元素含量等参数的垂向变化特征显示,1号煤在沉积时对应的古气候相对潮湿,2号煤在沉积时古气候则偏向干燥气候,而3号煤在沉积时处于潮湿的气候,在沉积时期古气候经历了潮湿气候-偏干燥气候-相对潮湿气候的演变历程.V/Cr值、V/(V+Ni)值、Cu/Zn值和V元素含量等参数的垂向变化特征指示了这三个煤层沉积时期古水体经历了还原-偏氧化-偏还原的变化过程,但主要以贫氧环境为主.
Abstract
In order to ascertain the palaeoclimate characteristics,paleo-water salinity and paleo-oxidation-reduction degree of the coal seams in Yan'an Formation in the study area,elemental testing and analysis were performed on the Yan'an Formation coal,and element geochemistry was used to restore the ancient environment,which is one of the commonly used methods.According to data analysis,the Sr/Ba ratio,the content of B element and the content of Sr in the three coal seams have the same vertical trend of increasing first and then decreasing.The Sr/Ba ratio is more than 1.0,These indicate the high salinity of the ancient water bodies,mainly in the salt-brackish water environment.The vertical variation of the parameters such as Sr/Ba ratio,Mg/Ca ratio and the content of Na element reflect that the No.1 coal seam deposited in relatively humid environment,the No.2 coal seam deposited tended to dry Climate,and No.3 coal seam deposited in humid climate.They experienced a humid climate-partial dry climate-relatively humid climate evolution.The vertical variation of V/Cr ratio,V/(V+Ni)ratio,Cu/Zn ratio,the content of V element and other parameters indicate that the ancient water bodies experienced a reduction-partial oxidation-partial reduction but mainly oxygen deficiency environment during the deposition history.
关键词
元素地球化学/古水体盐度/古气候/古氧化还原程度/崔家沟煤矿Key words
element geochemistry/paleosalinity/paleoclimate/paleo oxidation-reduction degree/Cuijiagou coal mine引用本文复制引用
出版年
2024
NETL
NSTL
万方数据