A GEOLOGIC “COVER UP”--IMPERILED ACCESS FOR FIELD RESEARCH AND EDUCATION ALONG HIGHWAY RIGHTS-OF-WAY IN TEXAS

Doing geologic fieldwork in Texas or teaching geology in the field presents challenges owing to the dearth of public lands in this large state and because private landowners commonly deny access to their properties. Hence, rights-of-way (ROWs) along public roads provide invaluable sites for geologists and students to view rock units and structures exposed in roadcuts. Now such local access is impeded in Texas because of roadcuts being covered as a routine part of highway construction or improvement. In some instances, the outcrop is blanketed by fill material to mimic a cut-and-fill embankment; elsewhere, exposures are covered by retaining walls, regardless of the need for slope stabilization. Ironically, specifications for these walls apparently stipulate the use of “faux rocks”--preformed wall segments that are manufactured to look like a sequence of sedimentary strata. This practice is presumably driven by the perceived need to mitigate slope-stability problems that are common in certain parts of the state (Blackland Prairies and other parts of the Gulf Coastal Plain, for example). But the practice has now spread to the Central Texas Hill Country, where carbonate rocks compose the predominant substrate and roadcut stability is not a widespread concern. In a particularly egregious example, a “faux fill” slope now covers the Marble Falls Fault in Burnet County, where vertical displacement of more than 3,000 ft has juxtaposed almost the entire local Paleozoic section against Precambrian Town Mountain Granite. That fault, where it crosses the public ROW, has great educational value, warranting display, not cover-up! The practice and teaching of geology require an ability to view rocks in the field, whereas cladding (or otherwise covering) rock outcrops impedes geologic work in the public domain (mapping as well as teaching). Such practices also require extra money from public tax revenues, although if extra money is available in highway-department budgets, it should be spent providing increased visibility of and safe public access to significant geologic features along roadways.