No abstract

No abstract

Gwmorphic features and Pleistocene deposits on Huangshan have been attributed to glaciation. Recent reassessment questions this interpretation. As part of the reassessment, quartz sand grains from deposits identified as glacial boulder clays (till composed of boulders in a clay or silt matrix) were analyzed by scanning electron microscope for evidence of their sedimentary history. Surface textures found on the boulder-clay grains were compared with those on grains with known sedimentary histories including glacial, grus, colluvial, and alluvial grains. The analysis shows that the grains lack typical glacial textures. The surface textures present indicate a complex history. Nonuniformly weathered grain surfaces point to chemical weathering of the source rock. This is supported by the deep weathering of the nonquartz clasts in the sand-sized fraction as well as in boulders at the outcrops. The close correspondence in surface-texture frequencies with those of the alluvial grains indicates an alluvial component to the grains' history. The similarity with the colluvial grains and the outcrops' structures suggest an alluviaUcolluvial origin for the deposits. The history indicated by the surface textures agrees with the recent reassessment of the geomorphic features and points to warm climatic conditions in east-central China for at least part of the Pleistocene. o 1997 University of Washington.

No abstract

The Duer Ranch locality is situated on either side of U.S. 26 in southeastern Merrill County, Nebraska, halfway between the villages of Lisco and Broadwater and about 54 mi (90 km)southeast of Scottsbluff, Nebraska. The Rush Creek Land and Livestock Company currentlyowns all of sections 28, 29, 33, 34, and 35 of T. 19 N., R.47 W., as well as parts of sections 2, 3, 4, 10, and 11 of T. 18N., R.47W. (Broadwater and Tar Valley SW, 7½-minute Quadrangles; Fig. 1). The owners have allowed geologists to study the exposures on ranch property providedthat visitors stop at the ranch headquarters (Fig. 1) and obtain permission from the ranch foreman. Vehicles shouldbe parked inside the gate on thenorth side of U.S. 26 in the SW¼ Sec. 3, T.18N., R47.W. (Fig. 1), and all study ofthe site should be done on foot.Be certain to closeany gates that you open, anddo not smoke on the property. Rattlesnakes are found on the ranch. If you have asmall group and wish to examine the exposures in the southeast corner of the locality, two vehicles can park safely along the north side of the road cut on U.S. 26 in the NE¼ NW¼ sec. 10, T.18N., R.47W.