Density, porosity, and magnetic properties of rock specimens from southwestern Arizona

Abstract

Petrophysical data on 364 rock specimens from southwest Arizona are tabulated and summarized by major rock suites for that part of southwest Arizona covered by the Ajo 1° x 2° quadrangle and the Papago Indian Reservation. Data for 202 of these specimens are new and previously unreported. The tabulation also contains data from theses by B. A. Hargan and B. T. May, University of Arizona. iii Density, porosity, and magnetic properties of rock specimens from southwestern Arizona

Mineral resources of the Harcuvar Mountains Wilderness Study Area, La Paz County, Arizona

“…Thus, the 140-nT high is caused largely by a source at depth which can be modeled. Our model for this hidden source is based on an assumed total magnetization (sum of induced and remanent magnetization dipole moment per unit volume assuming normal polarity) of 2.25 A/m (ampheres per meter) and a ratio of remanent to induced magnetization of 0.25, both values consistent with data from southwestern Arizona (Klein and Johnson, 1983). Modeling shows that the principal part of the regional magnetic high could be caused by a magnetic source about 1 mi below sea level that is, about 1.5 mi beneath much of the variable terrain that is 5 mi wide, 4 mi in strike length, and 5 mi thick.…”

“…Amphibolite, which constitutes about 70 percent of the Early Proterozoic gneissic rocks, has a specific gravity of about 3.3 g/cm3 . Early Proterozoic pelitic schist, granite gneiss, and granodiorite to granite average about 2.8 (Klein and Johnson, 1983;Ed DeWitt, unpub. data., 1988).…”

Geogenic sources and chemical controls on fluoride release to groundwater in the Independence Basin, Mexico

“…La Puerta Ranch contained overall greater concentrations of Fthan SJIII samples, likely due to rock type or irrigation return flow recycling Ffrom groundwater below. Irrigation return flow undergoing evapotranspiration may have enhanced Fconcentrations in soils and contributed to increased amounts of leachable F -.Assuming a porosity of 0.10 (typical of fractured rock aquifers(Klein and Johnson, 1983)) and solid phase particles with a density of 2.65 g (cm 3 ) -1 , only 0.066% of environmentally available Fwould need to be released from andesitic rocks to create groundwater Fconcentrations of 1.5 mg L -1 , the WHO standard. Biotite, hornblende, and apatite minerals in these rocks are likely primary sources of F -(Mahlknecht et al, 2004b; Ortega-Guerrero, 2009; Shephard, 2018; Vasak, 1992).…”

Mineral resources of the West Potrillo mountains-Mount Riley and the Aden Lava Flow Wilderness Study Areas, Dona Ana and Luna Counties, New Mexico

“…Assumed contrasts of rock density and total magnetization (sum of remanent and induced magnetization or average dipole moment per unit volume) are based on measurements made in nearby areas (Ramberg and others, 1978;Klein and Wynn, 1984;Bath, 1976;Klein and Johnson, 1983), including the Gila Lower Box Wilderness Study Area, N. Mex. In order of increasing density, the groupings of interest are: (1) Quaternary basin fill and Tertiary unconsolidated sediments, (2) Quaternary basalt, which has a high vesicle content and consequent high porosity, Tertiary volcanic rocks and consolidated sedimentary rocks, and Mesozoic sedimentary rocks, (3) Tertiary intrusive rocks, and (4) Paleozoic sedimentary rocks, which are carbonate rich, and Precambrian granitic rocks.…”