Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

This data set consists of digitized aquifer boundaries for the
Elk City aquifer in western Oklahoma. The aquifer covers an area
of approximately 193,000 acres and supplies ground water for
irrigation, domestic, and industrial purposes in Beckham,
Custer, Roger Mills, and Washita Counties along the divide
between the Washita and Red River basins.

The Elk City aquifer consists of the Elk City Sandstone and
overlying terrace deposits, made up of clay, silt, sand and
gravel, and dune sands in the eastern part and sand and gravel
of the Ogallala Formation (or High Plains aquifer) in the
western part of the aquifer. The Elk City aquifer is unconfined
and composed of very friable sandstone, lightly cemented with
clay, calcite, gypsum, or iron oxide. Most of the grains are
fine-sized quartz but the grain size ranges from clay to cobble
in the aquifer. The Doxey Shale underlies the Elk City aquifer
and acts as a confining unit, restricting the downward movement
of ground water.

The aquifer boundaries were digitized from a photocopy of a
paper map from a ground-water modeling thesis of Elk City
aquifer published at a scale of 1:63,360.

本数据集包含俄克拉荷马州西部埃尔克城含水层（Elk City aquifer）的数字化含水层边界。该含水层总面积约19.3万英亩，为坐落于沃希托河与雷德河（Red River）流域分水岭地带的贝克汉姆县、卡斯特县、罗杰米尔斯县及沃希托县提供灌溉、生活及工业用水补给。
埃尔克城含水层由埃尔克城砂岩（Elk City Sandstone）及其上覆阶地沉积物组成，阶地沉积物由黏土、粉砂、砂及砾石构成，东部区域还分布有沙丘砂；含水层西部则为奥加拉拉组（Ogallala Formation，又称高平原含水层（High Plains aquifer））的砂与砾石。该含水层为无压含水层，由极疏松砂岩构成，以黏土、方解石、石膏或氧化铁作为弱胶结物。含水层内多数颗粒为细粒石英，但粒径范围跨度较大，从黏土级至砾石级均有分布。多克西页岩（Doxey Shale）赋存于埃尔克城含水层下方，作为隔水层限制地下水的向下运移。
该含水层边界是从一份比例尺为1:63360的埃尔克城含水层地下水模拟学位论文的纸质地图复印件数字化得到的。