Transport of bedload sediment is one of the main processes that contribute to bedrock incision in a river and is therefore one of the key control parameters in the evolution of mountainous landscapes. In recent years, many studies have addressed this issue through experimental setups, direct measurements in the field, or various analytical models. In this article, we present a new direct numeri...

Despite evidence that weathering plays a role in forming intertidal, estuarine, and fluvial rock platforms, many publications uncritically refer to “wave-cut” or “stream-cut” rock platforms. The alternative explanations of chemical weathering and physical water erosion of rock platforms have been debated since 1839. Our new approach to this long-standing problem introduces data from fluvial as ...

We developed a process-based model to predict the probability of arsenic exceeding 5 microg/L in drinking water wells in New England bedrock aquifers. The model is being used for exposure assessment in an epidemiologic study of bladder cancer. One important study hypothesis that may explain increased bladder cancer risk is elevated concentrations of inorganic arsenic in drinking water. In easte...

Bioinformatics is central to biology education in the 21st century. With the generation of terabytes of data per day, the application of computer-based tools to stored and distributed data is fundamentally changing research and its application to problems in medicine, agriculture, conservation and forensics. In light of this 'information revolution,' undergraduate biology curricula must be rede...

Source lithologies and transport histories of materials within the Ephrata Fan are investigated. Data were collected using a variety of remote sensing, laboratory spectroscopic, and field observations and techniques. Laboratory thermal emission spectra were collected of bedrock within the Grand Coulee, dune samples, and clast deposits. Factor analysis, target transformation, and endmember recov...

Landscape evolution in the eastern Mojave Desert is recorded by sys1ematic changes in Pliocene to latest Pleistocene volcanic: land· forms that show discrete periods of eolian deposition, surface stabilization, drainage-network expansion, and erosion on basaltic lava nows. These processes are documented by K·Ar dating in conjunction with morphometric, sedimentologic. pedologic, and geophysica1 ...

Effectively addressing marijuana trade is aided by understanding marijuana geographic sources. We analyzed the (87)Sr/(86)Sr of marijuana samples grown in 79 counties across the United States to determine if a primary geologic signal is retained in marijuana, which could therefore be useful for geographic sourcing. The marijuana results were compared with modeled bedrock (87)Sr/(86)Sr values ba...

Elemental concentrations in tree-rings from red and white oak trees at six sites across Southern Ontario, Canada, were assessed to determine whether they passively record changes in geochemical cycling in the presence of environmental stress. Periods of stress were defined as sustained periods with elevated delta(13)C values in tree-rings relative to atmospheric CO(2) during the same period. In...

Landslides are one of the most common geologic hazards in the Loess Plateau of northwest China, especially with some of the highest landslide densities found in Shaanxi and adjacent provinces. Prior to assessing the landslide hazard, a detailed landslide inventory map is fundamental. This study documents the landslides on the northwest Loess Plateau with high accuracy using high-resolution Quic...

Introduction Glacial erratic boulders are plucked from bedrock by flowing ice, transported in the direction of ice flow, and deposited at the terminus of the glacier. If derived from a localized, distinctive region of bedrock, glacial erratics may be used as indicator stones to map the direction of ice flow. Furthermore, glacial erratics evolve during transport, becoming smaller and more rounde...