Publications

The potential for carbon sequestration in coastal wetlands is high due to protection of carbon (C) in flooded soils. However, excessive flooding can result in the conversion of the vegetated wetland to open water. This transition results in the loss of wetland habitat in addition to the potential loss of soil carbon. Thus, in areas experiencing rapid wetland submergence, such as the...

We present here a comprehensive record of Miocene terrestrial ecosystems from exposures of the Monterey Formation along the Naples coastal bluffs, west of Santa Barbara, California. Constrained by an updated chronology, pollen analyses of 28 samples deposited between 18 and 6 Ma reflect the demise of mesophytic taxa that grew in a warm, wet environment during the late early and early...

No abstract available.

Continental shelves serve as critical transfer zones in sediment-routing systems, linking the terrestrial erosional and deep-water depositional domains. The degree to which clastic sediment is mixed and homogenized during transfer across broad shelves has important implications for understanding deep-sea detrital records. Wide continental shelves are thought to act as capacitors...

The Lucerne Valley is in the southwestern part of the Mojave Desert and is about 75 miles northeast of Los Angeles, California. The Lucerne Valley groundwater basin encompasses about 230 square miles and is separated from the Upper Mojave Valley groundwater basin by splays of the Helendale Fault. Since its settlement, groundwater has been the primary source of water for agricultural...

Microbial biofilms occur in all levels of the Critical Zone (CZ); they are on and in the vegetation, throughout the soil-saprolite zone, and along fractures in deep subsurface. Here we discuss biofilms in each level of the CZ with a focus in the soil-saprolite continuum. We show how scanning electron microscope (SEM) images provide an appropriate scale to explore microbe mineral...

The highest grade Pd-Pt deposit on Earth, the J-M Reef, is hosted in coarse-grained to pegmatoidal cumulates called the Reef Package. Decades of mine development of the J-M Reef have revealed that a distinct discontinuity in rock fabric marks the top of the rock unit that hosts economic-grade sulfide mineralization. Mine geologists refer to this discontinuity as the hanging wall contact...

Grain size is an important textural property of sediments and is widely used in paleoenvironmental studies as a means to infer changes in the sedimentary environment. However, grain size parameters are not always easy to interpret without a full understanding of the factors that influence grain size. Here, we measure grain size in sediment cores from the Bering slope and the Umnak...

Application of updated diatom biochronology to the Monterey Formation and related biosiliceous rocks reveals the imprint of both global paleoclimatic/ paleoceanographic and regional tectonic events. A rise in global sea level combined with regional tectonic deepening associated with the development of the transform California margin resulted in the abrupt onset of deposition of fine...

Hydrothermal explosions are significant potential hazards in Yellowstone National Park, Wyoming, USA. The northern Yellowstone Lake area hosts the three largest hydrothermal explosion craters known on Earth empowered by the highest heat flow values in Yellowstone and active seismicity and deformation. Geological and geochemical studies of eighteen sublacustrine cores provide the first...

The Stibnite mining area, as used herein, is bounded by the map extent that includes the Yellow Pine, West End, and Hangar Flats ore bodies. Other ore bodies are nearby, but the purpose of this map is to offer a detailed (1:8,000 scale) geologic map with new cross sections in the immediate area of Stibnite, Idaho. This geologic map is very similar to the Stibnite quadrangle map (Stewart...

Wildfire can impact soil-hydraulic properties by reducing saturated hydraulic conductivity and sorptivity, making recently burned landscapes prone to debris flows and flash floods. The post-fire hazard window can range from years to decades. In Northern California, where wildfire frequency is steadily increasing, the impact and soil-hydraulic recovery from wildfires is unknown. Following...