Conference Papers
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Gold deposit styles and placer gold characterisation in northern and east-central Madagascar Gold deposit styles and placer gold characterisation in northern and east-central Madagascar
Microchemical characterisation of bedrock and placer gold grains from six gold districts within the Archaean domains and intervening Neoproterozoic Anaboriana-Manampotsy belt of northern and east-central Madagascar show few opaque inclusions (e.g pyrrhotite, Bi tellurides) but wide range of Ag contents (40wt%). Some districts exhibit multiple source populations of grains. The...
Authors
Peter E. J Pitfield, Michael T. Styles, Cliff D. Taylor, Roger M. Key, Wilfried Bauer, A Vonimanitra Ralison
The source of Witwatersrand gold: Evidence from uraninite chemistry The source of Witwatersrand gold: Evidence from uraninite chemistry
An in-situ LA-ICP-MS study of different generations of uraninite from the Mesoarchaean Witwatersrand gold palaeoplacer deposits revealed unusually high Au concentrations in rounded, detrital uraninite grains but no detectable Au in secondary, hydrothermally mobilised uraninite. A Au-enriched uraninite-bearing magmatic host is suggested as a significant source for detrital gold in the...
Authors
Hartwig E. Frimmel, Poul Emsbo, Alan E. Koenig
Discharge and other hydraulic measurements for characterizing the hydraulics of Lower Congo River Discharge and other hydraulic measurements for characterizing the hydraulics of Lower Congo River
The first direct measurements of discharge of the Lower Congo River below Malebo Pool and upstream from Kinganga, Democratic Republic of Congo (DRC) were made in July 2008 using acoustic Doppler current profilers, differential GPS, and echo sounders. These measurements were made in support of research that is attempting to understand the distribution of fish species in the Lower Congo...
Authors
Kevin Oberg, John M. Shelton, Ned Gardiner, P. Ryan Jackson
Laboratory evaluation of an OTT acoustic digital current meter and a SonTek Laboratory acoustic Doppler velocimeter Laboratory evaluation of an OTT acoustic digital current meter and a SonTek Laboratory acoustic Doppler velocimeter
Recently, an acoustic current meter known as the OTT * acoustic digital current meter (ADC) was introduced as an alternative instrument for stream gaging measurements. The Bureau of Reclamation and the U.S. Geological Survey collaborated on a side- by-side evaluation of the ADC and a SonTek/YSI acoustic Doppler velocimeter (ADV). Measurements were carried out in a laboratory flume to...
Authors
T.B. Vermeyen, Kevin A. Oberg, Patrick Ryan Jackson
The effect of channel shape, bed morphology, and shipwrecks on flow velocities in the Upper St. Clair River The effect of channel shape, bed morphology, and shipwrecks on flow velocities in the Upper St. Clair River
In the Great Lakes of North America, the St. Clair River is the major outlet of Lake Huron and conveys water to Lake St. Clair which then flows to Lake Erie. One major topic of interest is morphological change in the St. Clair River and its impact on water levels in the Upper Great Lakes and connecting channel flows. A combined multibeam echosounder (MBES) bathymetric survey and acoustic...
Authors
Jonathan A. Czuba, Kevin Oberg, Jim Best, Daniel R. Parsons
Using a StreamPro acoustic doppler current profiler in moving-bed conditions: Problems and solutions Using a StreamPro acoustic doppler current profiler in moving-bed conditions: Problems and solutions
No abstract available.
Authors
David S. Mueller, Mike S. Rehmel, Chad R. Wagner
Use of multi-temporal Landsat images to monitor forest disturbance (1987-2007) in the Black Hills of South Dakota Use of multi-temporal Landsat images to monitor forest disturbance (1987-2007) in the Black Hills of South Dakota
Monitoring forest disturbance is important for studying carbon pools and fluxes. The goal of this study is to observe forest disturbance of different burn severity levels using multi-temporal Landsat images. The Jasper Fire occurred in the Black Hills National Forest, South Dakota, during August and September of 2000. The fire disturbance to ecosystem characteristics has a widespread and...
Authors
Xuexia Chen, Donald O. Ohlen
Vegetation change detection and quantification: linking Landsat imagery and LIDAR data Vegetation change detection and quantification: linking Landsat imagery and LIDAR data
Measurements of the horizontal and vertical structure of vegetation are helpful for detecting and monitoring change or disturbance on the landscape. Lidar has a unique ability to capture the three-dimensional structure of vegetation canopies. In this preliminary study, we present the results of a series of exploratory data analyses that tested our assumptions about the links between the...
Authors
Birgit E. Peterson, Kurtis J. Nelson
Assessment of the short-term radiometric stability between Terra MODIS and Landsat 7 ETM+ sensors Assessment of the short-term radiometric stability between Terra MODIS and Landsat 7 ETM+ sensors
Short-term radiometric stability was evaluated using continuous ETM+ scenes within a single orbit (contact period) and the corresponding MODIS scenes for the four matching solar reflective visible and near-infrared (VNIR) band pairs between the two sensors. The near-simultaneous earth observations were limited by the smaller swath size of ETM+ (183 km) compared to MODIS (2330 km). Two...
Authors
Taeyoung Choi, Xiaoxiong Xiong, Gyanesh Chander, A. Angal
Forest and forestry insect pests in Hawaii: past, present, and future Forest and forestry insect pests in Hawaii: past, present, and future
No abstract available.
Authors
Patrick Contant, Robert Hauff, Lloyd Loope, Cynthia King
Protecting Hawaii's forests from harm: an argument for strong measures to prevent arrival of pests of Hawaii's Myrtle family Protecting Hawaii's forests from harm: an argument for strong measures to prevent arrival of pests of Hawaii's Myrtle family
No abstract available.
Authors
Lloyd Loope, Anne Marie La Rosa
Acid neutralizing capacity and leachate results for igneous rocks, with associated carbon contents of derived soils, Animas River AML site, Silverton, Colorado Acid neutralizing capacity and leachate results for igneous rocks, with associated carbon contents of derived soils, Animas River AML site, Silverton, Colorado
Mine planning efforts have historically overlooked the possible acid neutralizing capacity (ANC) that local igneous rocks can provide to help neutralize acidmine drainage. As a result, limestone has been traditionally hauled to mine sites for use in neutralizing acid drainage. Local igneous rocks, when used as part of mine life-cycle planning and acid mitigation strategy, may reduce the...
Authors
Douglas B. Yager, Mark R. Stanton, LaDonna M. Choate, Alison Burchell