Publications
Filter Total Items: 921
Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut
New 40Ar/39Ar ages for hornblende and muscovite from the Orange-Milford belt in southern Connecticut reflect cooling from Acadian amphibolite facies metamorphism between ∼380 to 360 Ma followed by retrograde recrystallization of fabric-forming muscovite and chlorite during lower greenschist facies Alleghanian transpression at ∼280 Ma. Reported field temperature and pressure gradients are
Authors
Michael J. Kunk, Gregory J. Walsh, Martha L. Growdon, Robert P. Wintsch
Sea-level change during the last 2500 years in New Jersey, USA Sea-level change during the last 2500 years in New Jersey, USA
Relative sea-level changes during the last ∼2500 years in New Jersey, USA were reconstructed to test if late Holocene sea level was stable or included persistent and distinctive phases of variability. Foraminifera and bulk-sediment δ13C values were combined to reconstruct paleomarsh elevation with decimeter precision from sequences of salt-marsh sediment at two sites using a multi-proxy...
Authors
Andrew C. Kemp, Benjamin P. Horton, Christopher H. Vane, Christopher E. Bernhardt, D. Reide Corbett, Simon E. Engelhart, Shimon C. Anisfeld, Andrew C. Parnell, Niamh Cahill
Reconnaissance investigation of the rough diamond resource potential and production capacity of Côte d’Ivoire Reconnaissance investigation of the rough diamond resource potential and production capacity of Côte d’Ivoire
Ethnic and political conflict developed into open civil war in Côte d’Ivoire in 2002, leading to a de facto partitioning of the country into the government-controlled south and the rebel-controlled north. Côte d’Ivoire’s two main diamond mining areas, Séguéla and Tortiya, are located in the north, under what was, until recently, rebel-controlled territory. In an effort to prevent...
Authors
Peter G. Chirico, Katherine C. Malpeli
Bedrock geologic and joint trend map of the Pinardville quadrangle, Hillsborough County, New Hampshire Bedrock geologic and joint trend map of the Pinardville quadrangle, Hillsborough County, New Hampshire
The bedrock geology of the Pinardville quadrangle includes the Massabesic Gneiss Complex, exposed in the core of a regional northeast-trending anticlinorium, and highly deformed metasedimentary rocks of the Rangeley Formation, exposed along the northwest limb of the anticlinorium. Both formations were subjected to high-grade metamorphism and partial melting: the Rangeley during the...
Authors
William C. Burton, Thomas R. Armstrong
A 600-ka Arctic sea-ice record from Mendeleev Ridge based on ostracodes A 600-ka Arctic sea-ice record from Mendeleev Ridge based on ostracodes
Arctic paleoceanography and sea-ice history were reconstructed from epipelagic and benthic ostracodes from a sediment core (HLY0503-06JPC, 800 m water depth) located on the Mendeleev Ridge, Western Arctic Ocean. The calcareous microfaunal record (ostracodes and foraminifers) covers several glacial/interglacial cycles back to estimated Marine Isotope Stage 13 (MIS 13, ∼500 ka) with an...
Authors
Thomas M. Cronin, L.V. Polyak, D. Reed, E. S. Kandiano, R. E. Marzen, E. A. Council
The influence of geomorphology on the role of women at artisanal and small-scale mine sites The influence of geomorphology on the role of women at artisanal and small-scale mine sites
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...
Authors
Katherine C. Malpeli, Peter G. Chirico
Rates and probable causes of freshwater tidal marsh failure, Potomac River Estuary, Northern Virginia, USA Rates and probable causes of freshwater tidal marsh failure, Potomac River Estuary, Northern Virginia, USA
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...
Authors
Ronald J. Litwin, Joseph P. Smoot, Milan J. Pavich, Helaine W. Markewich, Erik T. Oberg, Brent W. Steury, Ben Helwig, Vincent L. Santucci, Geoffrey Sanders
The Sunny Point Formation: a new Upper Cretaceous subsurface unit in the Carolina Coastal Plain The Sunny Point Formation: a new Upper Cretaceous subsurface unit in the Carolina Coastal Plain
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...
Authors
Audra E. Balson, Jean Self-Trail, Dennis O. Terry
The origin of conodonts and of vertebrate mineralized skeletons The origin of conodonts and of vertebrate mineralized skeletons
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...
Authors
Duncan J.E. Murdock, Xi-Ping Dong, John E. Repetski, Federica Marone, Marco Stampanoni, Philip C.J. Donoghue
Bedrock geology and outcrop fracture trends in the vicinity of the Savage Municipal Well Superfund site, Milford, New Hampshire Bedrock geology and outcrop fracture trends in the vicinity of the Savage Municipal Well Superfund site, Milford, New Hampshire
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...
Authors
William C. Burton, Philip T. Harte
Reconstructing vegetation response to altered hydrology and its use for restoration, Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida Reconstructing vegetation response to altered hydrology and its use for restoration, Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida
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...
Authors
Christopher E. Bernhardt, Laura A. Brandt, Bryan D. Landacre, Marci E. Marot, Debra A. Willard
Reconnaissance investigation of the alluvial gold deposits in the North Takhar Area of Interest, Takhar Province, Afghanistan Reconnaissance investigation of the alluvial gold deposits in the North Takhar Area of Interest, Takhar Province, Afghanistan
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...
Authors
Peter G. Chirico, Katherine C. Malpeli, Thomas W. Moran