A Fossil that Records an Earthquake

Charl · Mar 17, 2013

My wife found this just as is, no splitting required. It is a fossil of a Pecopterus sp. seed fern.
it dates to the Upper Carboniferous, about 290 million years old, and the shale is a member of the Rhode Island Formation. Sometime after the formation, and when this chunk of shale was part of a rock unit thousand of feet thick, a tectonic event occurred, causing the displacement seen. Later, the pieces recemented together, some type of "crystalline" vein is at the juncture of the displaced pieces. Only fossil We have ever found that records an ancient tectonic event as well as a fossil.

Charl · Mar 17, 2013

Showing how the separate sides of the "fault" shifted in relation to each other:

TJE · Mar 17, 2013

Charl said:
My wife found this just as is, no splitting required. It is a fossil of a Pecopterus sp. seed fern.
it dates to the Upper Carboniferous, about 290 million years old, and the shale is a member of the Rhode Island Formation. Sometime after the formation, and when this chunk of shale was part of a rock unit thousand of feet thick, a tectonic event occurred, causing the displacement seen. Later, the pieces recemented together, some type of "crystalline" vein is at the juncture of the displaced pieces. Only fossil We have ever found that records an ancient tectonic event as well as a fossil.

Very nice and well defined (info too!).