Presents an examination of field relationships along the northern margin of Baker Lake Basin, Nunavut, with the goal of establishing the stratigraphy of the Dubawnt Supergroup in relation to paleogeography, depositional setting, and provenance. Includes information on the regional geology, local geology (Christopher Island Formation sedimentary & volcanic rocks, the newly named Amarook Formation, and the overlying Pitz and Thelon formations), and discusses faulting during the development of the Baker Lake Basin.
This report is part of an ongoing study to characterize both sequence stratigraphy and chronostratigraphy of the Baker Lake Basin, Nunavut. The investigators examined well-exposed segments of the basin in detail, emphasizing sequence stratigraphic analysis to identify genetic packages of strata related to tectonically controlled basin-filling rhythms. Three sections exposed at the western edge of Thirty Mile Lake have been measured and correlated, yielding data on five depositional sequences. After an introduction on the geologic setting of the study area, the report provides facies assemblage descriptions and interpretations of the five depositional sequences of the lower Baker Lake Group. Finally, the accommodation (or space made available for a sedimentary system to fill) cycle in the basin is discussed and conclusions are drawn regarding the subsidence mechanism in the basin.
The QSP area represents a well-preserved segment of felsic volcanic stratigraphy within the Hope Bay volcanic belt in western Nunavut. This paper reports the result of a detailed mapping program carried out over the QSP area to outline volcanic stratigraphy and associated geochemistry & hydrothermal alteration. It includes information on the regional geology, the geology of the volcanic belt, the history of mineral exploration in the area, the volcanic & intrusive rocks in the QSP area and their alteration, and (briefly) structural geology.
The final year of the Nechako NATMAP project to study the geology of central British Columbia was used to research information collected in the field & laboratory, and to compile & document the study results. This article includes a review of upcoming publications & other products, by type of product: maps, journal articles, conference presentations, and computer products, as well as ongoing research on petrology, palaeontology, terrane characterization, tectonics & structure, and Quaternary geology.
A well-exposed section about 250 metres wide below the high water line of the Jennings River, Teslin Lake map area in northern British Columbia shows part of the Teslin Fault and provides an opportunity to constrain the fault's kinematic history by direct ground observations. This report describes preliminary structural observations of this section of the Teslin Fault, including the rock types involved, mylonitic & ultramylonitic structures, and deformation. Indications of two main episodes of shearing are discussed.
As the importance and dependence of specific mineral commodities increase, so does concern about their supply. The United States is currently 100 percent reliant on foreign sources for 20 mineral commodities and imports the majority of its supply of more than 50 mineral commodities. Mineral commodities that have important uses and face potential supply disruption are critical to American economic and national security. However, a mineral commodity's importance and the nature of its supply chain can change with time; a mineral commodity that may not have been considered critical 25 years ago may be critical today, and one considered critical today may not be so in the future. The U.S. Geological Survey has produced this volume to describe a select group of mineral commodities currently critical to our economy and security. For each mineral commodity covered, the authors provide a comprehensive look at (1) the commodity's use; (2) the geology and global distribution of the mineral deposit types that account for the present and possible future supply of the commodity; (3) the current status of production, reserves, and resources in the United States and globally; and (4) environmental considerations related to the commodity's production from different types of mineral deposits. The volume describes U.S. critical mineral resources in a global context, for no country can be self-sufficient for all its mineral commodity needs, and the United States will always rely on global mineral commodity supply chains. This volume provides the scientific understanding of critical mineral resources required for informed decisionmaking by those responsible for ensuring that the United States has a secure and sustainable supply of mineral commodities.
Rock Engineering is a valuable reference tool for geotechnical engineers, geologists, consultants, contractors, and advanced students on rock engineering and engineering geology courses.
