Topographic Map of the Bedrock Surface, Aurora North Quadrangle, Kane and Du Page Counties, Illinois

Computer generated mapIncludes 1 ancillary map, 1 3-D model, 1 table, text, col. ill., index to adjoining 7.5-minute quadrangles, and location mapIncludes bibliographical reference

Evidence for Stagnation of the Harvard Sublobe (Lake Michigan Lobe) in Northeastern Illinois, U.S.A., from 24 000 to 17 600 BP and Subsequent Tundra-Like Ice-Marginal Paleoenvironments from 17 600 to 15 700 BP

Glacial deposits of the last glaciation associated with the Harvard sublobe (Lake Michigan lobe) in northeastern Illinois, U.S.A., occur between sediment with dateable organics. The lower organics include fragments of Picea sp. as young as 24 000 ± 270 BP. The supraglacial organics occur sparsely in laminated silt and fine sand in landforms that are positioned relatively high on the landscape, such as deposits from ice-walled lakes. These terrestrial organics yield ages that are 2500 to 1300 14C years older than organics at the base of sediment successions in nearby kettle basins. Basal 14C ages from four upland sites range from 17 610 ± 270 to 16 120 ± 80 BP. Our revised time-distance diagram of the Harvard sublobe now reflects a period of stagnation from 24 000 to about 17 600 BP. The supraglacial lacustrine silt yielded plant macrofossil assemblages of primarily tundra plants, including Salix herbacea and Dryas integrifolia. These plants likely grew in supraglacial and ice-marginal environments. The ostracode fauna include Cytherissa lacustris and Limnocythere friabilis. Geomorphic relations and ostracode ecology indicate that more than 17 m of ice buttressed some of the supraglacial lakes.Les sédiments glaciaires associés au sous-lobe de Harvard, dans le Nord-Est de l’Illinois, sont intercalés dans des sédiments dont la matière organique peut être datée. Des fragments de Picea sp. sont présents dans les couches sous-jacentes et remontent au plus à 24 000 ± 270 BP. La matière organique sus-jacente est disséminée dans les limons laminés et les sables fins de dépôts de lacs de barrage glaciaire perchés. Cette matière organique livre des âges 14C qui sont de 2500 à 1300 ans plus vieux que la matière organique de la base des sédiments des marmites glaciaires (kettles). Les âges 14C de quatre sites perchés vont de 17 610 ± 270 à 16 120 ± 80 BP. Notre révision du diagramme distance-temps du sous-lobe de Harvard traduit l’existence d’une période de stagnation glaciaire entre 24 000 et 17 600 BP. Le limon lacustre sus-jacent contient des assemblages macrofossiles de toundra, avec Salix herbacea et Dryas integrifolia. Ces plantes croissaient dans des milieux proches des glaces. Le contexte géomorphologique et l’écologie des ostracodes (Cytherissa lacustris et Limnocythere friabilis) indiquent que certains lacs supraglaciaires étaient étayés par plus de 17 m de glace

Drift Thickness of Elgin Quadrangle, Kane and Cook Counties, Illinois

Relief shown by contours and spot heights"Geology based on field work by B. Curry, 2004.""Digital cartography by J. Carrell, J. Domier, M. Barrett, and A. Tovey, Illinois State Geological Survey."Includes text and index to adjoining quadranglesIncludes bibliographical reference

Bedrock topography of Crystal Lake Quadrangle, McHenry and Kane Counties, Illinois

Relief shown by contours"Geology based on field work by B. Curry, 1998-2001.""Digital cartography by M. Barrett and J. Domier ... .""Base map compiled by Illinois State Geological Survey ... ."Includes location map, index to adjoining quadrangles, text, and reference

Drift Thickness of Crystal Lake Quadrangle, McHenry and Kane Counties, Illinois

Relief shown by contours"Geology based on field work by B. Curry, 1998-2001.""Digital cartography by M. Barrett and J. Domier ... .""Base map compiled by Illinois State Geological Survey ... ."Includes location map, index to adjoining quadrangles, text, references, and shaded relief ancillary map of the quadrangl

Data Point Locations of Crystal Lake Quadrangle, McHenry and Kane Counties, Illinois

Relief shown by contours"Field work by B. Curry, 1998-2001.""Digital cartography by M. Barrett and J. Domier ... .""Base map compiled by Illinois State Geological Survey ... ."Includes location map, index to adjoining quadrangles, and 4 inset

Data Point Locations of Hampshire Quadrangle, DeKalb and Kane Counties, Illinois

Relief shown by contours and spot heights"Field work by B. Curry, 1998 and 2005.""Digital cartography by J. Carrell and J. Domier, Illinois State Geological Survey."Includes 1 cross section, location map, and index to adjoining quadranglesFunded in part by the USGS National Cooperative Geologic Mapping Program 98HQAG205

Surficial geology of Crystal Lake Quadrangle, McHenry and Kane Counties, Illinois

Relief shown by contours"Geology based on field work by B. Curry, 1998-2001.""Digital cartography by M. Barrett and J. Domier ... .""Base map compiled by Illinois State Geological Survey ... ."Includes location map and index to adjoining quadranglesSheets 2 includes 6 cross sections and sheet 3 includes text, 3 ancillary maps, 1 model, 1 schematic, and reference

Surficial Geology of Elgin Quadrangle, Kane and Cook Counties, Illinois

Relief shown by contours and spot heights"Geology based on field work by B. Brandon Curry, 1998, 2003, 2004, and 2005.""Digital cartography by J. Carrell, M. Barrett, J. Baty, A. Tovey, and J. Domier, Illinois State Geological Survey."Includes index to adjoining quadranglesIncludes 9 cross sections on 2 sheetsIncludes bibliographical references (p. 11-12 of text

Data point locations of Elgin Quadrangle, Kane and Cook Counties, Illinois

Relief shown by contours and spot heights"Geology based on field work by B. Curry, 2004.""Digital cartography by J. Carrell, J. Domier, M. Barrett, and A. Tovey, Illinois State Geological Survey."Includes ancillary maps A-D and index to adjoining quadrangle