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What's a reef doing in a place like this?

What's reef doing in a place like this?

Within an hour after discovering the fossilized remains of a coral reef in the Wallowa Mountains in Oregon, two paleontologists decided that the reef could just as well have been in the Austrian and German Alps. The rock forms and fossils entombed in the Oregon reef were nearly identical to the reef formations in the European mountain chain. "As far as we're able to determine now, almost everything [in the Oregon reef] including the algae has counterparts over in the Alps," says George D. Stanley Jr. at the University of Montana in Missoula.

Now Stanley and Baba Senowbari-Daryan of Erlangen University in West Germany are faced with the problem of how the Oregon reef -- the first known coral reef of Triassic age (about 220 million years old) found in North America -- came to be.

While the reef is in North America Today, it's unlikely that it originated there, in part because the magnetic signature of the underlying volcanic rocks indicates that they formed at a much more southerly latitude. Sections of the Wallowa Mountains are thought to be parts of "suspect" or "displaced" terrains -- the 100 or so chunks of crust that have been grafted onto western North America in the last 200 million years as a result of plate tectonics. Over the last decade scientists have come to realize that when continents break up and crustal plates collide, the process is far from neat; silvers of continents and pieces of oceanic crust--from volcanic islands to ocean ridges--become plastered onto other continents, making a mosaic of lands that are alien to their surroundings.

One of Stanley's theories is that the Oregon reef originally formed much closer to the Alpine reefs. The Alpine reefs are thought to have grown along the banks of a dead-end seaway called the Tethys -- which extended from the present east coast of Japan across Asia and into the Alps region -- before it closed up to form the Alps. The coral reef now in Oregon might once have capped volcanic islands that formed close to Tethys in an ancestral ocean of the Pacific. But in the course of 220 million years the islands, anchored to the spreading seafloor, moved eastward toward the North American continent, eventually merging into it, according to the theory. Stanley also suspects that by the time they reached North America, the coral reefs had been drowned and killed.

Another possibility, says Stanley, is that the mobile larvae of the corals, sponges and other reef organisms moved across the ancestral Pacific by "island hopping," swimming from island to island along a chain of islands. A report of the researchers' findings will appear in an upcoming issue of PALAIOS, a new journal of the Society of Economic Paleontologists and Mineralogists.
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Title Annotation:fossilized coral reef found in Wallowa Mountains in Oregon
Author:Weisburd, Stefi
Publication:Science News
Date:Feb 8, 1986
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