R. Ernest Anderson J. D. Humphrey Paul J. Umhoefer L. Sue Beard Melissa Lamb Sharon F. Diehl 2010 <div class="widget widget-BookChapterMainView widget-instance-BookChapterMainView"><div class="content-inner-wrap"><div class="book-chapter-body"><div id="ContentTab" class="content active"><div class="widget widget-BookSectionsText widget-instance-BookChaptertext"><div class="module-widget"><div class="widget-items" data-widgetname="BookSectionsText"><div class="category-section content-section js-content-section" data-statsid="4791127"><p>Dissolution has removed large volumes of rock at low-angle normal faults, i.e., detachment faults, in the Mormon Mountains and the Tule Springs Hills in the eastern Basin and Range Province, southeastern Nevada. Evidence for major dissolution includes widespread solution-collapse breccias, meter-scale stylolite structures, and high-angle accommodation faults that terminate at or merge with dissolution seams. Chemically reactive fluids moving along the fault zones led to a strong depletion of<span>&nbsp;</span>¹⁸O in the detachment fault breccias (e.g., a δ¹⁸O decrease of 8‰ relative to the unaltered rocks). These strong chemical shifts, demonstrated by (1) negative oxygen isotope values and (2) steep compositional gradients marked by metal enrichment in elements such as Au, Ag, Ti, Pb, Zn, and Cu, are generally restricted to the narrow (&lt;1 m to 8 m) microbreccia zones.</p><p>Extensional faulting and fracturing, accompanying regional uplift, opened conduits for the influx of meteoric waters from above and hydrothermal fluids from below. As the largest, most permeable structures that formed during uplift, detachment faults focused the fluid flow. In this deformation and hydrogeologic model, dissolution-caused stratal thinning is a major complement to detachment faulting and is an important process that resolves void space issues in the reconstruction of cross section.</p></div></div></div></div></div></div></div></div> application/pdf 10.1130/2010.2463(19) en Geological Society of America Fluid flow, solution collapse, and massive dissolution at detachment faults, Mormon Mountains, Nevada chapter