Digital data sets that describe aquifer characteristics of the High Plains aquifer in western Oklahoma

This data set consists of digitized water-level elevation contours for the High Plains aquifer in western Oklahoma. This area encompasses the panhandle counties of Cimarron, Texas, and Beaver, and the western counties of Harper, Ellis, Woodward, Dewey, and Roger Mills. The High Plains aquifer underlies approximately 7,000 square miles of Oklahoma and is used extensively for irrigation. The High Plains aquifer is a water-table aquifer and consists predominately of the Tertiary-age Ogallala Formation and overlying Quaternary-age alluvial and terrace deposits. In some areas the aquifer is absent and the underlying Triassic, Jurassic, or Cretaceous-age rocks are exposed at the surface. These rocks are hydraulically connected with the aquifer in some areas. The High Plains aquifer is composed of interbedded sand, siltstone, clay, gravel, thin limestones, and caliche. The proportion of various lithological materials changes rapidly from place to place, but poorly sorted sand and gravel predominate. The rocks are poorly to moderately well cemented by calcium carbonate. The water-level elevations were measured in January, February, and March 1980 and ranged from about 4,650 feet above sea level in Cimarron County to about 2,000 feet above sea level in Woodward County. The water-level elevation contours were digitized from folded paper maps in a published report. The source maps were published at a scale of 1:250,000.本数据集包含俄克拉荷马州西部高平原含水层（High Plains aquifer）的数字化水位高程等值线。该区域涵盖锡马龙（Cimarron）、德克萨斯（Texas）、比弗（Beaver）三个狭长地带县，以及哈珀（Harper）、埃利斯（Ellis）、伍德沃德（Woodward）、杜威（Dewey）和罗杰·米尔斯（Roger Mills）等西部县份。高平原含水层覆盖俄克拉荷马州约7000平方英里的范围，被广泛用于农业灌溉。该含水层为潜水含水层（water-table aquifer），主要由第三纪奥加拉拉组（Ogallala Formation）及上覆第四纪冲积与阶地沉积物构成。部分区域内含水层缺失，下伏的三叠纪、侏罗纪或白垩纪岩层裸露于地表；在部分区域，这些岩层与含水层存在水力联系。 高平原含水层由互层状的砂、粉砂岩、黏土、砾石、薄层石灰岩与钙结壳（caliche）组成。各类岩性物质的占比在空间上快速变化，但分选较差的砂和砾石占据主导地位。岩层的胶结程度介于较差至中等之间，胶结物为碳酸钙。 本次水位高程测量于1980年1月至3月间进行，测量值范围为锡马龙县的约4650英尺海拔至伍德沃德县的约2000英尺海拔。水位高程等值线数据源自已发表报告中的折叠纸质地图，经数字化处理获取。源地图的出版比例尺为1:250000。