12/27/2022 0 Comments Bsnes 0.88![]() Locally, these deposits have distinct compositional characteristics. From west to east, these deposits can be subdivided into the Kaibab-Moenkopi dunes, Chinle Valley dunes, and Chaco dunes, all of which include relict, partly stable and mobile aeolian sand. With women increasingly achieving positions of influence both in the geo‐ and planetary sciences as in American society, this research allows us to celebrate these contributions of women and particularly women of color while looking forward to a more complete record of their past contributions and greater future achievements.Ī mantle of both active and stable aeolian sand covers approximately 34,000 km² of northern Arizona, western New Mexico and southern Utah on the southern Colorado Plateau. These contributions have occurred both as discoveries in terrestrial geomorphology leading to follow‐on discoveries in planetary geomorphology and through serving as educators and role models. We focused on women working in our scientific subdisciplines so that we can provide proper context for their work. We focused on women scientists who were working in the latter half of the 20th century, a revolutionary time for terrestrial geomorphology and the inception of the discipline of planetary geomorphology. In this work, some women – in particular, women of color – are highlighted to show a part of these foundational contributions. The density of quartz and basalt sediment samples were estimated by weighing samples and estimating their volume by the amount of water displaced in a graduated cylinder.ĭespite undeserved challenges to participation in the field of planetary geomorphology, women have made significant contributions in the fluvial, aeolian, and (cryo)volcanic subdisciplines. Additional quartz sediment was also sampled from the LCR riverbed for comparison. Methods: Dune sediment was sampled from four dunes distributed across the dunefield, with samples taken from the crest, toe and limbs of the barchan dunes (Figures 1, 3 and 4). ![]() Dunes become progressively higher in quartz sediment, smaller in size, and more closely spaced downwind (Figure 1.) The mixed source characteristics of sediment transported in the dune field offers an opportunity to conduct a field comparison of the transport characteristics of vesicular basaltic ash vs. The dune deposits consist of fine-grained quartz sand abundant in Little Colorado River deposits and local sandstones, and medium to coarse-grained basalt sand derived from local ash deposits of the San Francisco volcanic field. Migration rates have been as high as 35 m/yr in recent years, and the dunefield itself has grown in areal extent by more than 70% since 1992 (Redsteer et al. Dunes are typically from 500 m 2 to 4000 m 2 and 1 to 5 m high at the crest. Collectively the dunes form a mega-barchan complex of small and rapidly migrating dunes (Bogle et al. Individual dunes are primarily barchans, with a small number of zibars and coppice dunes on the leading edge of the dune field. ![]() Introduction: The Grand Falls dune field, located in semi-arid to arid northeastern Arizona, consists of source bordering dunes downwind of the Little Colora-do River (LCR), near Grand Falls, on the northeastern margin of the San Francisco Volcanic Field. ![]()
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