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Geological processes and orchid biogeography with applications to southeast central America Geological processes and orchid biogeography with applications to southeast central America

This contribution owes its origins to a paper presentation by Dr. Calloway H. Dodson at the Second International Conference on Neotropical Orchidology held in San José, Costa Rica in May of2003 (Dodson 2003). Dr. Dodson outlined some ofthe reasons to suspect that regional geological fac-tors may play important roles in orchid speciation and biogeography and gave examples from the...
Authors
Stephen H. Kirby

Earthquake hazard in the heart of the homeland Earthquake hazard in the heart of the homeland

Evidence that earthquakes threaten the Mississippi, Ohio, and Wabash River valleys of the Central United States abounds. In fact, several of the largest historical earthquakes to strike the continental United States occurred in the winter of 1811-1812 along the New Madrid seismic zone, which stretches from just west of Memphis, Tenn., into southern Illinois. Several times in the past...
Authors
Joan Gomberg, Eugene Schweig

Community structure of foraminiferal communities within temporal biozones from the western Arctic Ocean Community structure of foraminiferal communities within temporal biozones from the western Arctic Ocean

Community structure is often an overlooked dimension of biodiversity. Knowledge of community structure, the statistical distribution of the relative species abundance vector, makes possible comparisons and contrasts across time, space, and/or environmental conditions. Our results indicate that species of Arctic foraminifera in age-correlated cores from abyssal depths are each best...
Authors
Lee-Ann C. Hayek, Martin A. Buzas, Lisa A. Osterman

Magnetic character of a large continental transform: an aeromagnetic survey of the Dead Sea Fault Magnetic character of a large continental transform: an aeromagnetic survey of the Dead Sea Fault

New high-resolution airborne magnetic (HRAM) data along a 120-km-long section of the Dead Sea Transform in southern Jordan and Israel shed light on the shallow structure of the fault zone and on the kinematics of the plate boundary. Despite infrequent seismic activity and only intermittent surface exposure, the fault is delineated clearly on a map of the first vertical derivative of the...
Authors
Uri S. ten Brink, Michael Rybakov, Abdallah S. Al-Zoubi, Yair Rotstein

Heavy-mineral provenance in an estuarine environment, Willapa Bay, Washington, USA: palaeogeographic implications and estuarine evolution Heavy-mineral provenance in an estuarine environment, Willapa Bay, Washington, USA: palaeogeographic implications and estuarine evolution

Modern sediments from representative localities in Willapa Bay, Washington, comprise two principal heavy-mineral suites. One contains approximately equivalent amounts of hornblende, orthopyroxene, and clinopyroxene; this is derived from the Columbia River, which discharges into the Pacific Ocean a short distance south of the bay. The other suite, dominated by clinopyroxene, is restricted...
Authors
Gretchen Luepke Bynum

Morphological evolution in the San Francisco Bight Morphological evolution in the San Francisco Bight

San Francisco Bight, located near the coast of San Francisco, USA, is an extremely dynamic tidal inlet environmental subject to large waves and strong currents. Wave heights coming from the Pacific Ocean commonly exceed 5 m during winter storms. During peak flow tidal currents approach 3 m/s at the Golden Gate, a 1 km wide entrance that connects San Francisco Bay to the Pacific Ocean...
Authors
Daniel M. Hanes, Patrick L. Barnard

Predicting longshore gradients in longshore transport: the CERC formula compared to Delft3D Predicting longshore gradients in longshore transport: the CERC formula compared to Delft3D

The prediction of longshore transport gradients is critical for forecasting shoreline change. We employ simple test cases consisting of shoreface pits at varying distances from the shoreline to compare the longshore transport gradients predicted by the CERC formula against results derived from the process-based model Delft3D. Results show that while in some cases the two approaches give...
Authors
Jeffrey H. List, Daniel M. Hanes, Peter Ruggiero
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