Title | Plio-Pleistocene pumice floods in the ancestral Rio Grande, southern Rio Grande rift, USA |
Publication Type | Book Chapter |
Year of Publication | 1996 |
Authors | Mack GH, McIntosh WC, Leeder MR, Monger CH |
Editor | Crook K.A.W., Miall A.D., Sellwood B.W. |
Book Title | Sedimentary Geology |
Volume | 103 |
Pagination | 1-8 |
Publisher | Elsevier Science B.V. |
City | Amsterdam, the Netherlands |
Accession Number | JRN00215 |
Call Number | 00670 |
Keywords | book, books, chapter, chapters, geomorphology, processes, geomorphology, pumice flood, pumice flood, report, reports, volcano, pumice flood |
Abstract | At least four times during the late Pliocene and early Pleistocene pyroclastic eruptions in the Jemez volcanic field, northern Rio Grande rift, flooded the ancestral Rio Grande with gravel-size pumice. Following as much as 400 km of fluvial transport, the pumice was deposited in beds 0.2 to 2.0 m thick in the Camp Rice Formation of the southern Rio Grande rift. A combination of reversal magnetostratigraphy and single-crystal sanidine 40Ar/39Ar dating constrains the ages of pumice-clast conglomerates at 3.1, ~ 2.0, 1.6, and 1.6 Ma. The coarsest pumice beds (cobbles, boulders) were deposited as antidune-like bedforms in a fluvial channel and as a crevasse-play sheet. Granule and pebble-sized pumice was deposited as dune bedforms in a fluvial channels and as ripple bedforms on the floodplain. The abundance of pumice clasts in the gravel fraction (60-100%) suggest very rapid transport downriver, probably in a few days or weeks. The two older pumice-clast conglomerates correlate with the Puye Formation in the Jemez volcanic field, whereas the younger two are coeval to the Lower Bandelier Tuff and Cerro Toledo Rhyolite. |
URL | files/bibliography/JRN00215.pdf |
DOI | 10.1016/0037-0738(96)00009-7 |