Diabase
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Diabase, also called dolerite or microgabbro, is a mafic, holocrystalline, subvolcanic rock chemically equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow i
Diabase
Fair Head, Northern Ireland, a sill of dolerite
A diabase dike crosscutting horizontal limestone beds in Arizona
Diabase boulders at Devil's Den on the Gettysburg Battlefield, Pennsylvania, US
Prospect dolerite intrusion
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The Prospect dolerite intrusion, or Prospect intrusion, is a Jurassic picrite or dolerite laccolith that is situated in Sydney, New South Wales, Australia. Lying in the heart of Cumberland Plain, in t
Dolerite intrusion overlying Ashfield Shale and the Hawkesbury sandstone
Diagram of igneous structures (laccolith is C on top-right).
Exposed shale from Prospect Highway
The quarried hill today, with dolerite intrusion on sandstone and shale.