Microfossils disclose geologic history of eastern California

Oct 04, 2007

The Bird Spring Shelf in southeastern California and basins to the west reveal a complex history of late Paleozoic sedimentation, sea-level changes, and deformation along the western North American continental margin. A new book published by the Geological Society of America captures insights into the tectonics and paleogeography of the region.

The Pennsylvanian-Early Permian Bird Spring Carbonate Shelf, Southeastern California: Fusulinid Biostratigraphy, Paleogeographic Evolution, and Tectonic Implications focuses on evidence from ancient seas across a considerable expanse of geologic time.

"Detailed correlations between fusulinid-bearing rocks of the Bird Spring Shelf and deep-water deposits to the northwest reveal the complex history of the area," said author Calvin Stevens of San Jose State University in California. "They confirm the late Paleozoic as a time of major tectonic instability on the continental margin."

Fusulinids, single-celled marine organisms with multiple chambers composed of calcite, typically resemble grains of wheat. They inhabited the world's seas 315 to 250 million years ago and disappeared during the end-Permian mass extinction. Today they are important guide fossils in understanding Pennsylvanian and Permian rocks and systems.

Stevens and co-author Paul Stone, U.S. Geological Survey, Menlo Park, recognized 69 fusulinid species which subsequently formed the basis of their correlations. They utilized recent data from the same area on conodonts, another extinct marine creature, to place their work in the context of standard Permian timescales.

According to Stevens a number of the fusulinid species were described as new while others allow comparison with those from other regions. The resulting reconstructions provide a more complete picture of the geology of western North America during the late Paleozoic.

Source: Geological Society of America

Explore further: Synchronization of North Atlantic, North Pacific preceded abrupt warming, end of ice age

add to favorites email to friend print save as pdf

Related Stories

Putin signs law seen as crimping social media

43 minutes ago

President Vladimir Putin on Tuesday signed a law requiring Internet companies to store all personal data of Russian users at data centres in Russia, a move which could chill criticism on foreign social networking ...

New launch date set for ISS delivery vessel

52 minutes ago

A robot ship will be launched from Kourou, French Guiana, after a five-day delay on July 29 to deliver provisions to the International Space Station, space transport firm Arianespace said Tuesday.

Recommended for you

Scientists stalk coastal killer

1 hour ago

For much of Wednesday, a small group of volunteers and researchers walked in and out of the surf testing a new form of surveillance on the biggest killer of beach swimmers - rip currents.

Fires in Central Africa During July 2014

15 hours ago

Hundreds of fires covered central Africa in mid-July 2014, as the annual fire season continues across the region. Multiple red hotspots, which indicate areas of increased temperatures, are heavily sprinkled ...

NASA's HS3 mission spotlight: The HIRAD instrument

Jul 24, 2014

The Hurricane Imaging Radiometer, known as HIRAD, will fly aboard one of two unmanned Global Hawk aircraft during NASA's Hurricane Severe Storm Sentinel or HS3 mission from Wallops beginning August 26 through ...

User comments : 0