Bowling Ball Concretions

May 05, 2005

Concretion_alley_50 copy

Referred by: Kenneth J. Holm
Summary authors & editors: Kenneth J. Holm

The "bowling ball" concretions pictured above were discovered in the open hills near Haines Junction, Yukon Territory, Canada. They were encased in a mudstone cliff and gradually eroded out, rolling down the slope toward a small mountain stream. They seem to have formed around a small chip of shale and were all sizes, up to about sixteen inches (40 cm) in diameter. Concretions are sometimes mistaken for fossil eggs or bones, but instead they're a rather common geologic phenomenon that can be found in all types of sedimentary rock. Photo by Peter Pawloff.

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