Canal fossils give clue to formation of Americas

[Judi Lynn]

Canal fossils give clue to formation of Americas
Fri Jul 18, 2008 5:24am EDT
By Andrew Beatty

PANAMA CITY (Reuters) - Scientists in Panama have unearthed hundreds of animal fossils dating back 20 million years, which could shed more light on how and when the American continent became connected.

Geologists from the U.S. Smithsonian Institution, which has a permanent base in Panama, say engineers digging to widen the Panama Canal have uncovered more than 500 fossils including teeth and bones of rodents, horses, crocodiles and turtles that lived before a land bridge linked North and South America.

"With these discoveries we will be able to get more information about the process by which the continual land bridge was formed," Smithsonian geologist Camilo Montes told Reuters.

Since February, the geologists accompanied engineers on excavations to expand the canal, having been invited by the government to make sure nothing of value was destroyed.

Scientists believe the South American and Caribbean tectonic plates collided around 15 million years ago, causing volcanic activity that eventually formed a thin strip of land linking the Americas and separating the Pacific and Atlantic oceans.

The bridge was probably fully formed, in a way that mammals could walk over it, some 3 million years ago.

More:
http://www.reuters.com/article/scienceNews/idUSN1744507120080718?sp=true

[Judi Lynn]

1. Fossils to Shed Light on the Time When the Americas Connected - Remains of animals that lived as far

Fossils to Shed Light on the Time When the Americas Connected - Remains of animals that lived as far as 20 million years ago unearthed in Panama
By: Gabriel Gache, Science News Editor

More than 500 fossils of teeth and bones belonging to species of rodents, horses, crocodiles and turtles found near the Panama Canal, dated to have lived as far as 20 million years ago could provide some information regarding the period when the North and South American continents became connected to each other, say geologists of the Smithsonian Institution. The fossils have been found during the digging phase in the Panama Canal, which is currently going through a modernization stage that will end with the widening of the canal in order to accommodate bigger commercial ships.

"With these discoveries we will be able to get more information about the process by which the continual land bridge was formed," said Camilo Montes of the Smithsonian Institution. To ensure that valuable items are not destroyed during digging, the local government invited researchers of the Smithsonian Institution to accompany the engineers involved in the project.

Current estimations place the date of the collision between the South American and the Caribbean tectonic plates somewhere around 15 million years ago, a phenomenon that eventually created the thin strip connecting the South and North American continents about 3 million years ago. This provided the bridge that brought the mammals on both sides together.

However, there is not much that we know about which individual species came from which of the two continents, but by studying the layers of rock that contained the fossils researchers could get an idea about the time when the animals where found on one side of the strip only. "We will be able to get a much more precise date for when the continents started to close together," said Montes.

More:
http://news.softpedia.com/news/Fossils-to-Shed-Light-on-the-Time-When-the-Americas-Connected-90284.shtml