Publications

Aeromagnetic and radiometric data were used to map shallow Precambrian basement lithology and structure and determine the depth to magnetic basement, which in most cases, corresponds to the depth to crystalline basement of interest for mineral exploration. These depths, along with those determined from gravity data, help identify basins with hydrologic potential. In addition, the...

PRISM-I summary documents mention the presence of mafic-ultramafic igneous intrusive rocks in several areas of Mauritania and a number of chromium (Cr) and copper-nickel (Cu-Ni (±Co, Au)) occurrences associated with them. Permissive geologic settings generally include greenstone belts of any age, layered mafic-ultramafic and unlayered gabbro-anorthosite intrusive complexes in cratonic...

Previous PRISM reports discuss a variety of industrial minerals. Gypsum, phosphate, salt, stone, sulfur, and ilmenite command the majority of the attention in the earlier geologic reports. (Ilmenite is evaluated in a separate U.S. Geological Survey report in the current study). Asbestos, arsenic, barite, fluorite, and kaolin are listed in indices (occurrence datasets) as potential...

Although Mississippi Valley-type (MVT) deposits have not been recognized in Mauritania there are permissive tracts for these deposits in the regionally extensive Proterozoic carbonate rocks of the Taoudeni Basin. Permissive tracts for undiscovered MVT Pb-Zn-Ag deposits in the Proterozoic carbonate units are supported by the occurrences of MVT mineral and alteration assemblages, presence...

High-grade hematitic iron ores (or HIF, containing 60–65 percent Fe) have been mined in Mauritania from Superior-type iron deposits since 1952. Depletion of the high grade ores in recent years has resulted in a number of new projects focused on lower grade magnetite ores in Algoma-type banded iron formation (or BIF, containing approximately 35 percent Fe). Large deposits of oolitic-type...

The State of Alaska’s Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska’s statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data...

A hydrogeologic study was conducted to support mineral-resource assessment activities in Mauritania, Africa. Airborne magnetic depth estimates reveal two primary groundwater basins: the porous coastal Continental Terminal Basin (fill deposits); and the interior, fractured interior Taoudeni Basin. In the Continental Terminal Basin, there is uniform vertical recharge and localized...

Multispectral satellite data acquired by the Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors were processed and interpreted in support of the PRISM-II project (Second Projet de Renforcement Institutionnel du Secteur Minier de la Republique Islamique de Mauritanie). This...

No abstract available.

River water samples collected from 78 watersheds rivers along a 500-km transect across a Late Cretaceous-Tertiary andesitic volcanic arc terrane in west-central Panama provide a synoptic overview of riverine geochemistry, chemical denudation, and CO2 consumption in the tropics. D/H and 18O/16O relationships indicate that bedrock dissolution of andesitic arc crust in Panama is driven by...

Hyperacidic lakes and associated solfatara in active volcanoes are the expression of magmatic gas expansion from source to surface. Here we show for the first time, that the vein system that comprises the ~ 2 Ma high-sulfidation, Lepanto copper–gold deposit in the Mankayan district (Philippines) was associated with a contemporary hyperacidic volcanic lake complex—possibly the first such...

The Santa Cruz porphyry Cu-(Mo) system near Casa Grande, Arizona, includes the Sacaton mine deposits and at least five other concealed, mineralized fault blocks with an estimated minimum resource of 1.5 Gt @ 0.6% Cu. The Late Cretaceous-Paleocene system has been dismembered and rotated by Tertiary extension, partially eroded, and covered by Tertiary-Quaternary basin-fill deposits. The...