Late Pleistocene Calcretes from Central Anatolia (Lakes Eymir and Mogan, G?lba?? Basin):Comparison t

来源 :Journal of Earth Science | 被引量 : 0次 | 上传用户:jiaonimaqubao110
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
This study is the first to report the radiocarbon ages, mineralogical, morphological, geochemical and stable isotope compositions of calcretes from Neogene sediments around lakes Eymir and Mogan in the G?lba?? Basin of Central Anatolia. Morphologically different forms of calcretes in the G?lba?? Basin include powdery, nodular, fracture infill, laminar and hardpan types. Calcite is the dominant mineral of calcrete compositions; the diagnostic features of dessication cracks, random fractures, Mn O linings and dense sparitic infillings are observed. Chemical analyses show arid conditions with mean annual precipitation of <50 mm. δ13C compositions of the calcretes range from-6.77‰ to-9.32‰ PDB, typical for most pedogenic calcretes, reflecting the development under seasonally arid climates and C3-dominated vegetation cover. δ18O values are between-5.57‰ and-7.80‰ PDB, indicating the formation from meteoric water in a vadose zone environment. The results suggest that the Middle Pleistocene was arider and warmer, favouring the formation of palygorskite in association with the different forms of calcrete occurrences, whereas the Late Pleistocene was dryer and cooler, supporting the development of calcretes. This study is the first to report the radiocarbon ages, mineralogical, morphological, geochemical and stable isotope compositions of calcretes from Neogene sediments around lakes Eymir and Mogan in the G? Lba ?? Basin of Central Anatolia. Morphologically different forms of calcretes in the G ? lba ?? Basin include powdery, nodular, fracture infill, laminar and hardpan types. Calcite is the dominant mineral of calcrete compositions; the diagnostic features of dessication cracks, random fractures, Mn O linings and dense sparitic infillings are observed. δ13C compositions of the calcretes range from-6.77 ‰ to-9.32 ‰ PDB, typical for most pedogenic calcretes, reflecting the development under seasonal and arid climates and C3-dominated vegetation cover. δ18O values ​​are between-5.57 ‰ and-7.80 ‰ PDB, indicating the formation from meteoric water in a vadose zone environment. The results suggest that the Middle Ple istocene was arider and warmer, favoring the formation of palygorskite in association with the different forms of calcrete occurrences, but the Late Pleistocene was dryer and cooler, supporting the development of calcretes.
其他文献
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
Chunguang oilfield is a new focus of the exploration in Junnggar Basin with the heavy crude oil distributing in Jurassic, Cretaceous and Tertiary strata. Based
现阶段,随着经济的全球化,资源匮乏、环境污染严重成为整个世界所面临的严峻问题,各行各业都把节能环保提到日程上.公路桥梁建设也不例外,在不断提高技术水平,重视施工安全的
To maintain gas hydrate stability, low-temperature drilling fluids and high drilling speeds should be used while drilling in gas hydrate-bearing sediments. The
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
在我们平时坐火车出行中,可以明显感受到我国的铁路运行提速之快,特别是以高速动车组为首的全方位提速更是方便了人们出行,节约了时间成本.本文根据高速动车组的特点进行分析
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
现如今,随着我国社会经济的飞速发展,公路事业的发展突飞猛进.在公路中,交通安全设施占据着非常重要的位置,它是保障司机、乘客人员交通安全的配套设施,同时也是改善公路运输
Cerium is one of multivalent rear earth elements, which can transfer from trivalence to tretavalence at oxidizing environment. This process may cause variable d