Conference Papers

Cretaceous-Paleocene porphyry Cu(±Mo±Au) occurrences are scattered throughout the Yukon-Tanana upland in eastern Alaska. Known occurrences in eastern Alaska are poorly characterized, despite a resurgence in exploration. Porphyry deposits in the upland are emplaced into structurally complex metamorphic rocks representing a variety of tectonic environments, resulting in diverse alteration and minera

This presentation summarizes the proposed updates to earthquake design ground motions for the 2020 edition of the NEHRP Recommended Seismic Provisions, expected to be incorporated into the ASCE 7-22 Standard. The implications of these updates on the values of design ground motions for example locations in both conterminous and nonconterminous U.S. cities are shown and discussed.

The introduction of snakeheads from their origins in Asia is relatively recent to the conterminous United States with the first of many collections beginning in the late 1990s. For decades they have been commercially fished and aquacultured around the world for human food and, to a lesser degree, for the aquarium trade. Over a dozen snakehead species known to be of economic importance outside the

Northern Snakehead Channa argus weighing 188.54+13.80 g were fed live Oriental Weatherfish Misgurnus anguillicaudatus at five rations (starvation, 1, 2, 4% body weight per day and satiation) at 28 oC under laboratory conditions to determine its growth and energy budget in relation to ration. The specific growth rate increased linearly with increasing ration and food conversion efficiencies also te

The orogenic gold veins of Grass Valley, California, USA, compose the historically richest lode gold district in the North American Cordillera. Petrographically, the veins exhibit a range of primary textural relationships allowing the reconstruction of the paragenetic sequence of mineral formation. Two generations of quartz are distinguished by optical cathodoluminescence microscopy and fluid incl

The paragenesis, textures, and chemical compositions of secondary hematite in regional potassic altered rhyolites, four IOA deposits, the sedimentary iron deposit at Pilot Knob and the Boss IOCG deposit in SE Missouri were determined and compared to primary magnetite from the IOA and IOCG deposits. Magnetite is composed of elements characteristics of mafic to intermediate intrusions whereas hemati

The paragenesis, textures, and chemical compositions of magnetite in two mafic to intermediate intrusions and four IOA deposits in SE Missouri were studied to discriminate between igneous and hydrothermal sources. In this study, we found that replacement magnetite with mineral inclusion-rich cores yields erroneously high Ti, Al, Si, Mg, and Mn contents as determined by EMP and LA-ICP-MS due to ru

Changing climate has resulted in increasingly unreliable weather patterns with prolonged dry-seasons in some parts of Sub-Saharan Africa. Food production in these areas is under threat because the people depend mostly on rain-fed farming. Enabling dry-season farming, in light of the prolonged dry-seasons, is central to sustainable food production and poverty alleviation in these areas. Efficient w

Recent increase in the production of high-resolution digital elevation models (DEMs) from lidar data has led to interest in their use for terrain mapping. Although the impact of different resolutions has been studied relative to terrain characteristics like roughness, slope and curvature, its relationship to the extraction of terrain features remains unclear. To address this question, this study t

Measuring suspended-sand flux in rivers is a challenge since sand concentrations are highly variable in time and space throughout a river cross section. Most of the present methodologies rely on point or depth-integrated sampling (Nolan et al., 2005, Topping et al., 2016). The standard method estimates mean concentration and multiply it by discharge to compute the suspended-sand discharge. Here, w

The use of side-looking acoustic Doppler velocity meters (ADVMs) to estimate fluvial suspended-sediment concentrations (SSC) has become more operational by the U.S. Geological Survey in recent years; however, direct transfer of these techniques to down-looking acoustic Doppler current profilers (ADCPs) currently is not widely feasible. Key assumptions in the sidelooking ADVM method related to sedi

The US Coastal Research Program (USCRP) was founded in 2016 through a grassroots initiative of scientists, researchers, and practitioners to address nearshore coastal research priorities of greatest relevance to coastal communities and build a skilled US coastal workforce. The USCRP supports academic research to address challenges identified through thematic workshops and pair academic researchers