Free Republic

Analyses of pelagic limestones indicate that the flux of extraterrestrial helium-3 to Earth was increased for a 2.5-million year (My) period in the late Eocene. The enhancement began ~1 My before and ended ~1.5 My after the major impact events that produced the large Popigai and Chesapeake Bay craters ~36 million years ago. The correlation between increased concentrations of helium-3, a tracer of fine-grained interplanetary dust, and large impacts indicates that the abundance of Earth-crossing objects and dustiness in the inner solar system were simultaneously but only briefly enhanced. These observations provide evidence for a comet shower triggered by an...

The true impact of an asteroid or comet crashing near the Chesapeake Bay 35 million years ago has been examined in detail for the first time. The analysis reveals the resilience of life in the aftermath of disaster. The impact crater, which is buried under 400 to 1,200 feet (120 to 365 meters) of sand, silt and clay, spans twice the length of Manhattan. The sprawling depression helped create what would eventually become Chesapeake Bay. About 10,000 years ago, ice sheets began to melt and once-dry river valleys filled with water. The rivers of the Chesapeake region converged directly over...

CAPE CHARLES, Va. - Geologists drilling half a mile below Virginia's Eastern Shore say they have uncovered more signs of a space rock's impact 35 million years ago. For more than two weeks, scientists drilled around the clock alongside a parking lot across the harbor from Cape Charles. They stopped at 2,700 feet. From the depths came jumbled, mixed bits of crystalline and melted rock that can be dated, as well as marine deposits, brine and other evidence of an ancient comet or asteroid that slammed into once-shallow waters near the Delmarva Peninsula. Cape Charles is considered Ground Zero for...

Chesapeake Bay Crater Offers Clues to Ancient Cataclysm Hillary Mayell for National Geographic News November 13, 2001 About 35 million years ago—the dinosaurs are dead, but the Appalachian Mountains are still covered in tropical rain forests—a rock from space that was more than a mile wide and moving at supersonic speed crashed into the Atlantic Ocean off North America. Traveling at about 70,000 miles (113,000 kilometers) an hour, the asteroid or comet (bolide) splashed through several hundred feet of water and several thousand feet of mud and sediment. Drilling for Knowledge A trailer hauls drilling rods the U.S. Geological Survey ...

Thirty-eight million years ago, tropical jungles thrived in what are now the cornfields of the American Midwest and furry marsupials wandered temperate forests in what is now the frozen Antarctic. The temperature differences of that era, known as the late Eocene, between the equator and Antarctica were half what they are today. A debate has been ongoing in the scientific community about what changes in our global climate system led to such a major shift from the more tropical, greenhouse climate of the Eocene to modern and much cooler climates. New research results published in this week's issue of the...

Four fossilized monkey teeth discovered deep in the Peruvian Amazon provide new evidence that more than one group of ancient primates journeyed across the Atlantic Ocean from Africa. The teeth are from a newly discovered species belonging to an extinct family of African primates known as parapithecids. Fossils discovered at the same site in Peru had earlier offered the first proof that South American monkeys evolved from African primates.

Some 90 million years ago, a temperate rainforest grew near the South Pole. Scientists recovered fossil traces of the ancient rainforest from seafloor sediment cores collected near West Antarctica's Pine Island Glacier. Seismic data suggested the sediment layer was unique, but researchers weren't expecting to find the remnants of a Cretaceous forest. "The finding of this well preserved 'forest soil' layer was actually a lucky dip," researcher Ulrich Salzmann, professor of palaeoecology at the University of Northumbria in Britain, told UPI. "We did not know of the existence of this layer before." Among the sediment layers, Salzmann and his research...

A fossilized skull and teeth from a newly described species of beaver that lived 28 million years ago have been unearthed in eastern Oregon. The fossils worked their way out of the soil within a mile of the visitor center at the John Day Fossil Beds National Monument, said the monument's paleontologist, Joshua Samuels. The find is significant, he said, because unlike the other species of ancient beavers found at the monument, this one appears related to the modern beaver, a symbol of Oregon found on the state flag. The others all went extinct. The species is named Microtheriomys brevirhinus....

'The remora sucker is a truly amazing anatomical specialisation but, strange as it may seem, it evolved from a spiny fin,' said Dr Matt Friedman of Oxford University's Department of Earth Sciences, lead author of the report. 'In this fossil the fin is clearly modified as a disc but is found on the back of the fish. It enables us to say that first fin spines on the back broadened to form wide segments of a suction disc. After the disc evolved, it migrated to the skull, and it was there that individual segments became divided in two, the number...