{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "David C Lampe", "hasEmail": "mailto:dclampe@usgs.gov"}, "description": "The hydrogeologic framework for the Lake Michigan Basin model was developed by grouping \nthe bedrock geology of the study area into hydrogeologic units on the basis of the functioning \nof each unit as an aquifer or confining layer within the basin. Available data were evaluated \nbased on the areal extent of coverage within the study area, and procedures were established \nto characterize areas with sparse data coverage. Top and bottom altitudes for each hydrogeologic \nunit were interpolated in a geographic information system for input to the model and compared \nwith existing maps of subsurface formations. Fourteen bedrock hydrogeologic units, making \nup 17 bedrock model layers, were defined, and they range in age from the Jurassic Period red \nbeds of central Michigan to the Cambrian Period Mount Simon Sandstone.\n\t\t\t\nEach hydrogeologic unit is referred to as its model layer number as represented in the report \nU.S. Geological Survey Scientific Report 2009-5060 (SIR2009-5060). They are listed below for \nreference as to the model layer number, and the hydrogeoloigc unit name. Dataset values \nrepresent the bottom of the layer.\nLSD\t\tLand surface\nL1_3\tQuaternary unit (Bottom of Quaternary unit is Layer 3 in the model)\nL4      Jurassic unit\nL5 \t\tUpper Pennsylvanian unit \nL6      Lower Pennsylvanian unit\nL7      Michigan Formation unit\nL8      Marshall Formation unit\nL9      Devonian-Mississippian unit\nL10_12\tSilurian-Devonian unit (Bottom of Silurian-Devonian unit is Layer 12 in the model)\nL13     Maquoketa Formation unit\nL14     Sinnipee Formation unit\nL15     St. Peter Formation unit\nL16     Prairie du Chien-Franconia unit\nL17     Ironton-Galesville unit\nL18     Eau Claire unit\nL19_20\tMt Simon Formation unit (Bottom of Mt Simon Formation unit is Layer 20 in the model)\n\t\t\t\nThe Lake Michigan Basin groundwater model is discretized into a grid of 391 by 261 cells. The \nmodel has 20 layers: 3 that simulate the glacial and unconsolidated sediments and 17 that \nsimulate the bedrock units. The model provides additional detail in the area of greatest interest, \nin this case, the Lake Michigan Basin, by use of smaller grid spacing in the innermost model \ndomain  compared with the grid spacing at the model boundaries. The smallest interior grid \ncells are 5,000 by 5,000 ft. At the model boundaries, the size of grid cells reaches approximately \n68,930 ft (13 mi) from north to south by 116,490 ft (22 mi) from east to west.\nThe grid cells each have values for the altitude to the bottom of each layer. The layer numbers \nare from top to bottom of the aquifer system. Three hydrogeologic units are represented by the \nmultiple layers", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P98M2BBI", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.2a89ecc9-b6b8-4fdb-a762-b99b0edf89ae.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_2a89ecc9-b6b8-4fdb-a762-b99b0edf89ae", "keyword": ["Great Lakes Basin", "Lake Michigan", "Lake Michigan Basin", "Michigan", "USGS:2a89ecc9-b6b8-4fdb-a762-b99b0edf89ae", "Wisconsin", "aquifer", "bedrock", "confining unit", "geology", "groundwater", "hydrogeologic framework", "hydrogeology", "inlandWaters", "northern Illinois", "northern Indiana", "salinity"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-90.35726851, 40.45467207, -81.748867037, 46.981958599", "theme": ["geospatial"], "title": "Digital Polygon Model Grid of the Hydrogeologic Framework of Bedrock Units for a Simulation of Groundwater Flow for the Lake Michigan Basin"}