Compound and Elemental Analysis At Valles Caldera - Redondo Geothermal Area (Chipera, Et Al., 2008)
Exploration Activity: Compound and Elemental Analysis At Valles Caldera - Redondo Geothermal Area (Chipera, Et Al., 2008)
|Exploration Activity Details|
|Location||Valles Caldera - Redondo Geothermal Area|
|Exploration Technique||Compound and Elemental Analysis|
|Activity Date||- 2008|
|Usefulness||useful regional reconnaissance|
Characterization of previously unrecognized shallow zeolitic alteration throughout the Valles caldera resurgent dome complex. Differentiation of lacustrine and volcaniclastic lithologic units within the caldera and investigation of alterations associated with formation of the post-eruption intracaldera paleo lake.
Roughly 80 samples of fresh and altered rocks from early volcanic and lacustrine rock units were collected from the middle to the lower flanks of the resurgent dome and from various locations in the caldera moat (including from the VC-3 core hole) to study mineral abundances using X-ray powder diffraction analysis (XRD), examine specific mineral texture/morphology using Scanning electron microscopy (SEM), and to determine the trace element geochemistry of representative Valles zeolites using Electron microprobe analyses (EPMA). The sample set included 20 samples of Upper Bandelier Tuff; 20 samples of Intracaldera Fluvial/Lacustrine rocks; 30 samples of Deer Canyon Lavas, Deer Canyon Tuffs, and Redondo Creek Lavas; and 10 samples of Moat Lacustrine Deposit rocks. The distribution of zeolites throughout the earliest Valles caldera rocks is non-uniform, with high concentrations of zeolites only occuring in isolated outcrops. The "high grade" zeolite outcrops are of little to no economic importance due to their limited areal extent and fragmented nature. Characterization of the zeolites revealed that mordenite and clinoptilolite are the most commonly occuring zeolites at the Valles caldera. Erionite, an extremely carcinogenic zeolite linked with mesothelioma, was not identified at Valles caldera, confirming that the zeolites present at Valles do not pose health and safety risks for those who visit the Valles Caldera National Preserve.
- Steve J. Chipera, Fraser E. Goff, Cathy J. Goff, Melissa Fittipaldo (2008) Zeolitization Of Intracaldera Sediments And Rhyolitic Rocks In The 1.25 Ma Lake Of Valles Caldera, New Mexico, USA