{6A634C32-0928-4795-98CA-1D092D154976}2009080714120700FALSE20090814152415002009081415272000Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850enThe Pliocene-lower Pleistocene Ancha Formation consists of sand, gravel and silt that forms the upper portion of the Santa Fe Group basin fill in the southern Española Basin of the Rio Grande rift, northern New Mexico. The Ancha Formation forms a locally important shallow aquifer for the Santa Fe area. The thickness and characteristics of the formation's base are important to regional groundwater studies, and are also useful for other studies involving basin stratigraphy, structure, geophysical interpretations, and basin evolution. The base of the Ancha Formation coincides with a Pliocene erosional surface that bevels tilted and faulted beds of underlying (upper Oligocene-upper Miocene) Tesuque Formation, (Oligocene) Espinaso Formation, (late Paleocene-late Eocene) Galisteo Formation, and, locally, Mesozoic and Paleozoic units. In order to characterize the thickness and the basal contact of the Ancha Formation, three data sets were evaluated: (1) cuttings, core and/or geophysical logs of key exploration drill holes, monitor wells, and water wells; (2) generalized lithologic logs from water wells; and (3) outcrop exposures of the basal contact. Data points are uniquely symbolized to show data type and labeled with a point ID and elevation of the formation base.
These point data were systematically used to generate the elevation contours of the base of the formation. First, the Ancha Formation basal contact was clearly identified at key sites with cuttings, core, geophysical logs, and/or detailed lithologic logs generated by a geologist. Second, the basal contact was extrapolated to nearby low-resolution lithologic logs from water wells. Third, outcrop exposures of the basal contact were physically mapped and translated to point data. Fourth, the surface elevations of data sites were generated from a 10-m digital elevation model (DEM) and elevations of the base of formation in wells and drill holes were calculated from surface elevation minus depth to basal contact. Lastly, contours of the elevation of the formation base were interpolated from point data with a kriging function in ARC INFO 9.2. The line contours were used to create a Triangular Irregular Network (TIN) surface, and the Ancha_extent_boundary was used to clip the TIN to the area of study. Paleovalley divides were created manually from the paleotopography of the contoured surface.To characterize the base of the Ancha Formation.Daniel J. Koning (New Mexico Bureau of Geology) interpreted depth to base of Ancha Formation from cuttings, core and/or geophysical logs of key drill holes. Peggy Johnson (New Mexico Bureau of Geology) directed the research and interpreted depth to base of Ancha Formation in generalized logs from water wells. Daniel J. Koning and Paul Drakos of Glorieta Geoscience completed geologic maps of the basal contact from outcrop exposures. Brigitte Felix (New Mexico Bureau of Geology) generated elevations of outcrop exposures of the basal contact in ARCINFO 9.2. Peggy Johnson compiled the entire set of point data and generated surface and basal elevations. Kriging functions were performed by Brigitte Felix to generate elevation contours and Peggy Johnson manually generated final contours of the formation base. Brigitte Felix created a TIN surface of the base of the formation. Generation of the point data and basal contours spanned several years from 2006-2008. ancha_surface_ascii.txtancha_surface_ascii.txtThe data are not time-dependent and are current through 2008. New wells and exploration drill holes could generate minor changes to the surface.2008None plannedREQUIRED: Western-most coordinate of the limit of coverage expressed in longitude.REQUIRED: Eastern-most coordinate of the limit of coverage expressed in longitude.REQUIRED: Northern-most coordinate of the limit of coverage expressed in latitude.REQUIRED: Southern-most coordinate of the limit of coverage expressed in latitude.Española Basin; Ancha Formation; elevation contours of formation base; formation thickness; paleovalleyEspañola Basin, Santa Fe embayment, Rio Grande rift, northern New MexicoNoneUsers are requested to acknowledge the authors (P. Johnson, D. Koning & B. Felix, NMBGMR) in any public use of these data. Text FileMicrosoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850ancha_surface_ascii.txtenFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timePeggy Johnson and Brigitte FelixNew Mexico Bureau of Geology & Mineral Resourcesmailing and physical addressSocorroNM87801New Mexico Bureau of Geology & Mineral ResourcesNew Mexico Tech801 Leroy PlacePeggy Johnson, 575-835-5819peggy@gis.nmt.edu Brigitte Felix , 575-835-5177bfk@gis.nmt.edu 20090814http://www.esri.com/metadata/esriprof80.htmlESRI Metadata ProfileISO 19115 Geographic Information - MetadataDIS_ESRI1.0datasetDownloadable Data002Text File20090814