Bedrock, soils, and hillslope hydrology in the Central Texas Hill Country, USA: implications on environmental management in a carbonate-rock terrain |
| |
| Authors: | C M Woodruff Jr L P Wilding |
| |
| Institution: | (1) Woodruff Geologic Consulting, Inc., 711 West 14th Street, Austin, TX 78701, USA;(2) Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843, USA |
| |
| Abstract: | The Hill Country of Central Texas, USA, is undergoing rapid socioeconomic development, but environmental management of this
region is hampered by misconceptions about local bedrock, soils, terrain, and hydrologic processes. The Hill Country is underlain
mostly by Glen Rose Limestone (Lower Cretaceous) and exhibits a stepped terrain, which has been incorrectly attributed to
alternating hard and soft bedrock strata. Other characteristics mistakenly attributed to this landscape include thin soils
with scant water-retention capabilities, and rapid runoff as the dominant hydrologic process. This report presents new findings:
unweathered bedrock is well indurated, but interbeds exhibit variable weathering rates. Recessive slopes (“risers”) on this
stepped terrain result from rapid deterioration of strata having generally heterogeneous depositional fabrics (bioturbation
and irregular clay partings) in contrast to ledge-forming strata having homogeneous fabrics. A stony regolith is thus formed
beneath risers, providing porous and permeable ground that retards runoff and promotes the formation of moderately deep to
deep (two-tiered) regolith/soil zones. These surficial materials on local steep slopes compose important natural environmental
buffers; they support diverse biota and enhanced geochemical cycling of nutrients; they also exhibit significant water retention
and enhanced erosion abatement. Proper land management demands recognition of these attributes in the siting, design, and
construction of facilities. |
| |
| Keywords: | Regolith Caliche Stepped landforms Vadose zone |
| 本文献已被 SpringerLink 等数据库收录！ |
|
