Geology topics
Donald Grybeck
Publications and source records attributed to Donald Grybeck.
Mineral resources of the Tracy Arm-Fords Terror Wilderness Study Area and vicinity, Alaska
The Wilderness Study Area consists of about 322,300 hectares (1,250 square miles or 796,400 acres) on the southwest side of the Coast Range in southeastern Alaska about 72 km (45 miles) southeast of Juneau, Alaska (fig. 1). An additional 142,800 hectares (550 square miles or 352,900 acres) lying in part between the study area and the International Boundary and in part contiguous to the southwest of the study area were studied because of their importance to the evaluation of the study area itself. Unless otherwise specified, the term Study Area as used in this report includes both the formally designated study area and these contiguous areas. The general area is one of spectacular scenery, with fiords, forests, glacier-covered peaks to 2,470 m (8,095 feet) high, tidewater glaciers, icebergs, and some broad river valleys. No roads or maintained trails or permanent residents are present, and access is only by specially arranged water or air transport. Present human use of the area is related to recreation or mineral-resource exploration.
Radiometric dates from Alaska: A 1975 compilation
The following table of radiometric dates from Alaska includes published material through 1972 as well as some selected later data. The table includes 726 mineral and whole-rock dates determined by the K-Ar, Rb-Sr, fission-track U-Pb, and Pb-alpha techniques. The data are organized in alphabetical order of the 1:250,000 scale quadrangles in which the dated rocks are located. The latitude and longitude of each sample are given. In addition, each sample is located on a 1:250,000 quadrangle map by a grid system. The initial point of the grid is taken as the southwest corner of the quadrangle and the location of the sample is measured in inches east and inches north from that corner, e.g., "156E 126N" indicated 15.6 inches east and 12.6 inches north of the southwest corner of the quadrangle. Zeroes in the location columns for some dates indicate that accurate locations are not available. Rock type, dating method, mineral dated, radiometric age, sample identification number, and reference are also listed where possible. Short comments, mostly geographic locality names, are given for some dates. These comments have been taken from the original references. Sample identification numbers beginning with "AA" or "BB" have been assigned arbitrarily in cases where sample numbers were not assigned in the original references. Abbreviations are explained in the appendix at the end of table 1.
Results of geochemical sampling in the northern Darby Mountains, Seward Peninsula, Alaska
Explore the source record for details and available documents.
Reconnaissance geology and geochemistry of Forrester Island National Wildlife Refuge, Alaska
Explore the source record for details and available documents.