geology · July 31, 2014
Cross-section of a stretched pebble, one of many examples in a large outcropping at Distant Hill Gardens
Stretched pebbles are formed from a specific combination of pressure, heat, and a linear movement of the earth's sub-surface as a type of rock called a metaconglomerate is being formed. A metaconglomerate is a metamorphic rock composed of pebbles and gravel that have been flattened due to directed pressure. Sometimes, strongly directed metamorphism results in a stretched-pebble conglomerate. The parent rock for a metaconglomerate is a sedimentary rock conglomerate. The rock forms from large,...