Diabase is the preferred name in North America, while dolerite is the preferred name in the rest of the English-speaking world, where sometimes the name diabase refers to altered dolerites and basalts. Some geologists prefer to avoid confusion by using the name microgabbro.
The name diabase comes from the French diabase, and ultimately from the Greek διάβασις (meaning "act of crossing over, transition")[2] whereas the name dolerite comes from the French dolérite, from the Greek doleros (“deceitful, deceptive”), because it was easily confused with diorite.
A diabase dike crosscutting horizontal limestone beds in ArizonaDiabase boulders at Devil's Den on the Gettysburg Battlefield, Pennsylvania, USDolerite rocks and Quiver trees near Keetmanshoop (Namibia)Dolerite forms tall vertical columns throughout Tasmania. These columns form steep vertical features through its alpine areas.
Diabase is usually found in smaller, relatively shallow intrusive bodies such as dikes and sills. Diabase dikes occur in regions of crustal extension and often occur in dike swarms of hundreds of individual dikes or sills radiating from a single volcanic center.
In the Death Valley region of California, Precambrian diabase intrusions metamorphosed pre-existing dolomite into economically important talc deposits.[7]
In the Thuringian-Franconian-Vogtland Slate Mountains of central Germany the diabase is entirely of Devonian age.[8] They form typical domed landscapes, especially in the Vogtland. One geotourist attraction is the Steinerne Rose near Saalburg, a natural monument, whose present shape is due to the typical weathering of lava pillows.
Gondwanaland and Australia
A geological event known as the Oenpelli Dolerite intrusive event occurred about 1,720 million years ago in western Arnhem Land, in the Northern Territory,[9] forming curved ridges of Oenpelli Dolerite stretching over 30,000 square kilometres (12,000 sq mi).[10] Further west, on the northern coast of Arnhem Land, a "subsurface radial dyke swarm" known as Galiwinku Dolerite, taking its name from the Aboriginal name for Elcho Island, occurs on the Gove Peninsula and continues under the Arafura Sea and on Wessel Islands, including Elcho and Milingimbi Islands.[11]
The vast areas of mafic volcanism/plutonism associated with the Jurassic breakup of the Gondwana supercontinent in the Southern Hemisphere include many large diabase/dolerite sills and dike swarms. These include the Karoo dolerites of South Africa, the Ferrar Dolerites of Antarctica, and the largest of these, the most extensive of all dolerite formations worldwide, are found in Tasmania. Here, the volume of magma which intruded into a thin veneer of Permian and Triassic rocks from multiple feeder sites, over a period of perhaps a million years, may have exceeded 40,000 cubic kilometres.[16] In Tasmania, dolerite dominates much of the landscape, particularly alpine areas, with many examples of columnar jointing.
Diabase is crushed and used as a construction aggregate for road beds, buildings, railroad beds (rail ballast), and within dams and levees.[20][21]
Diabase can be cut for use as headstones and memorials; the base of the Marine Corps War Memorial is made of black diabase "granite" (a commercial term, not actual granite). Diabase can also be cut for use as ornamental stone for countertops, facing stone on buildings, and paving.[21] A form of dolerite, known as bluestone, is one of the materials used in the construction of Stonehenge.[22]
Diabase also serves as local building stone. In Tasmania, where it is one of the most common rocks found,[23] it is used for building, for landscaping and to erect dry-stone farm walls. In northern County Down, Northern Ireland, "dolerite" is used in buildings such as Mount Stewart together with Scrabo Sandstone as both are quarried at Scrabo Hill.
Balls of diabase were used by the ancient Egyptians as pounding tools for working softer (but still hard) stones.[24]
^Miller, MB, and Wright, LA. 2007, "Geology of Death Valley National Park (Third Edition)", Kendall Hunt Publishing, p 19.
^Henningsen, Dierk; Katzung, Gerhard (2006). Einführung in die Geologie Deutschlands (in German) (7th ed.). Munich: Spektrum Akademischer Verlag. p. 69. ISBN3-8274-1586-1.
^Hill R.E.T, Barnes S.J., Gole M.J., and Dowling S.E., 1990. Physical volcanology of komatiites; A field guide to the komatiites of the Norseman-Wiluna Greenstone Belt, Eastern Goldfields Province, Yilgarn Block, Western Australia., Geological Society of Australia. ISBN0-909869-55-3
^O'Connor-Parsons, Tansy; Stanley, Clifford R. (2007). "Downhole lithogeochemical patterns relating to chemostratigraphy and igneous fractionation processes in the Golden Mile dolerite, Western Australia". Geochemistry: Exploration, Environment, Analysis. 7 (2): 109–27. doi:10.1144/1467-7873/07-132. S2CID140677224.
^Wanga Q.; Campbella I. H. (1998). "Geochronology of supracrustal rocks from the Golden Grove area, Murchison Province, Yilgarn Craton, Western Australia". Australian Journal of Earth Sciences. 45 (4): 571–77. Bibcode:1998AuJES..45..571W. doi:10.1080/08120099808728413.
^Travis, G.A.; Woodall, R.; Bartram, G.D. (1971), "The Geology of the Kalgoorlie Goldfield", in Glover, J.E. (ed.), Symposium on Archaean Rocks, Geological Society of Australia (Special Publication 3), pp. 175–190
^Jones, I., and Verdel, C. (2015). Basalt distribution and volume estimates of Cenozoic
volcanism in the Bowen Basin region of eastern Australia: Implications for a waning mantle plume. Australian Journal of Earth Sciences, 62(2), 255–263.
^"Tasmanian Viticultural Soils and Geology"(PDF). Tasmania Department of Primary Industries, Water and Environment / University of Tasmania / Tasmanian Institute of Agricultural Research. Retrieved 8 November 2019.
