Publications

The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked...

Dyke Marsh, a distal tidal marsh along the Potomac River estuary, is diminishing rapidly in areal extent. This study documents Dyke Marsh erosion rates from the early-1860s to the present during pre-mining, mining, and post-mining phases. From the late-1930s to the mid-1970s, Dyke Marsh and the adjacent shallow riverbottom were mined for gravel, resulting in a ~55 % initial loss of area...

This paper formally defines the Sunny Point Formation, a new Upper Cretaceous subsurface unit confined to the outer Atlantic Coastal Plain of North and South Carolina. Its type section is established in corehole NH-C-1-2001 (Kure Beach) from New Hanover County, North Carolina. The Sunny Point Formation consists of light-olive-gray to greenish-gray, fine to coarse micaceous sands and...

Conodonts are an extinct group of jawless vertebrates whose tooth-like elements are the earliest instance of a mineralized skeleton in the vertebrate lineage, inspiring the ‘inside-out’ hypothesis that teeth evolved independently of the vertebrate dermal skeleton and before the origin of jaws. However, these propositions have been based on evidence from derived euconodonts. Here we test...

The Savage Municipal Well Superfund site consists of an eastward-directed plume of volatile organic compounds, principally tetrachloroethylene (PCE), in alluvium and glacial sand and gravel in the Souhegan River valley, just south of the river and about 4 kilometers west of the town of Milford, New Hampshire. Sampling of monitoring wells at the site has helped delineate the extent of the...

We present reconstructed hydrologic and vegetation trends of the last three centuries across the Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida in order to understand the effects of 20th century water management. We analyzed pollen assemblages from cores at marsh sites along three transects to document vegetation and infer hydroperiod and water depth both before and...

This study is a reconnaissance assessment of the alluvial gold deposits of the North Takhar Area of Interest (AOI) in Takhar Province, Afghanistan. Soviet and Afghan geologists collected data and calculated the gold deposit reserves in Takhar Province in the 1970s, prior to the development of satellite-based remote-sensing platforms and new methods of geomorphic mapping. The purpose of...

This study is a reconnaissance investigation of the placer gold deposits in the Zarkashan Area of Interest (AOI) in Ghazni Province, Afghanistan. Detailed investigations of the Zarkashan gold deposits were conducted by Soviet and Afghan geologists in the 1960s and 1970s, prior to the development of satellite-based remote-sensing platforms and new methods of geomorphic mapping. The...

Afghanistan is endowed with a vast amount of mineral resources, and it is believed that the current economic state of the country could be greatly improved through investment in the extraction and production of these resources. In 2007, the “Preliminary Non-Fuel Resource Assessment of Afghanistan 2007” was completed by members of the U.S. Geological Survey and Afghan Geological Survey...

Shallow marine ecosystems are experiencing significant environmental alterations as a result of changing climate and increasing human activities along coasts. Intensive urbanization of the southeast Florida coast and intensification of climate change over the last few centuries changed the character of coastal ecosystems in the semi-enclosed Biscayne Bay, Florida. In order to develop...

Because of this association between the richness of a deposit and its geomorphology, high-resolution DEMs are a critical dataset in developing alluvial geomorphic models of the deposit zones.

An alert-level system for communicating volcano hazard information to the aviation industry was devised by the Alaska Volcano Observatory (AVO) during the 1989–1990 eruption of Redoubt Volcano. The system uses a simple, color-coded ranking that focuses on volcanic ash emissions: Green—normal background; Yellow—signs of unrest; Orange—precursory unrest or minor ash eruption; Red—major ash...