Tas Walker on May 4th, 2009

These solid spherical stones, scattered over the beach on the South Island of New Zealand, look like the remains of a monster game of marbles. (Click image to enlarge.)
They are spectacular examples of concretions, which form when a mineral precipitates from the ground water cementing the loose grains of sediment into solid rock. As [...]

Continue reading about Moeraki Boulders, New Zealand

Tas Walker on April 8th, 2009

A dramatic contrast between blocks of black basalt overlying an outcrop of light-brown sandstone at Greenmount Beach, Gold Coast, Australia. (Click image to enlarge.)
The sandstone was deposited rapidly in the first part of Noah’s Flood, about 4,500 years ago as the waters were rising. Shortly afterward, the sediments were uplifted and folded, and [...]

Continue reading about Greenmount Beach, Gold Coast, Australia