Why is diabase/dolerite erosion resistant?

Asked by: Janelle Froemming

What is unique about diabase?

Diabase is an intrusive igneous rock with the same mineral composition as basalt. It cools under basaltic volcanoes, like those at mid-ocean ridges. Diabase cools moderately quickly when magma moves up into fractures and weak zones below a volcano.

What is the importance of diabase rock?

Diabase is crushed and used as a construction aggregate for road beds, buildings, railroad beds (rail ballast), and within dams and levees. 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).

What are the properties of dolerite?

no orientation, even-grained,



Fine grained, ophitic texture. Primary minerals – plagioclase, pyroxene, hornblende and quartz. Acicular and lath-like plagioclase, equant grains of pyroxene – some alteration to chlorite along cleavage and fissures. Secondary minerals (10%) include chlorite.

What is the difference between diabase and gabbro?

Diabase is actually a variety of gabbro which consists mainly of labradorite feldspar, augite, magnetite, and olivine. The grain size of diabase is on the smaller side. Diabase and gabbro have the same general mineral composition as basalt, but they have a larger grain size.

Is diabase the strongest rock?

The strongest rock in the world is diabase, followed closely by other fine-grained igneous rocks and quartzite. Diabase is strongest in compression, tension, and shear stress. If mineral hardness is the determining factor of strength then diamond is technically the strongest rock in the world.

How is diabase rock formed?

Diabase is a fine-grained igneous rock that would have formed when molten rock material cooled rapidly on or near the surface of the Earth.

What texture is diabase?

ophytic texture

Diabase have a ophytic texture, with slender to broad plagioclase laths wrapped or molded by anhedral to subhedral pyroxene, tha larger plates of witch may also enclose the plagioclase.

What minerals are found in diabase?

Diabase typically has a mineral composition that is dominated by the plagioclase feldspar known as labradorite (approximately 40% to 70% of the rock). Most of the remainder is made up of pyroxene minerals (usually augite). Minor amounts of hornblende, olivine, magnetite, and quartz can be found in some diabase rocks.

What is the hardest rock on earth?

Diamond

Diamond is the hardest known mineral, Mohs’ 10. Notes: It must be noted that Mohs’ scale is arbitrary and non-linear, i.e. the steps between relative hardness values are not necessarily equal. Rather, it is a method of gauging the relative hardness of a mineral.

What’s diabase mean?

Definition of diabase



1 archaic : diorite. 2 chiefly British : an altered basalt. 3 : a fine-grained rock of the composition of gabbro but with an ophitic texture.

How can you tell if a rock is dolerite?

diabase, also called Dolerite, fine- to medium-grained, dark gray to black intrusive igneous rock. It is extremely hard and tough and is commonly quarried for crushed stone, under the name of trap.

What is the weakest rock in the world?

Diamond is the hardest mineral and will scratch all other minerals, without getting scratched itself, Talc is at the other end of the scale, being the weakest mineral.

What is the second hardest rock on earth?

The colors seen in moissanite from the Mount Carmel area of northern Israel range from dark blue to light green. photo by Aurélien Delaunay. Moissanite is the name given to naturally occurring silicon carbide and to its various crystalline polymorphs.

What is the sharpest rock in the world?

Obsidian

Obsidian has been used across history to make weapons, implements, tools, ornaments, and mirrors. Because of its conchoidal fracture (smooth curved surfaces and sharp edges), the sharpest stone artifacts were fashioned from obsidian.

What is the chemical composition of dolerite?

The olivine dolerites contain euhedral to sub hedral phenocrysts of olivine (up to 2 mm) and plagioclase (up to l cm) set in a finer-grained ma trix which contains augite, plagioclase, olivine, Fe-Ti oxides and minor apatite.

What is the difference between dolerite and basalt?

Basalt is a volcanic rock that cooled rapidly when erupted from a volcano, so the crystals did not have much time to grow. . Dolerite was intruded into existing rocks as sills and dykes so it was more insulated than basalt and developed larger crystals.

What are the properties of basalt?

basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium. Some basalts are quite glassy (tachylytes), and many are very fine-grained and compact.

What are 3 facts about basalt?

Basalt is a common extrusive rock found on Mars, Earth, and Venus. Basaltic rocks are also found on Earth’s surface as they erupt in the form of lava. More than half of the ocean floor is basalt. It is one of the most abundant volcanic rocks on Earth.

Which rock will weather faster granite or basalt?

Basalt

Basalt weathers faster than granite because it is not as hard and it’s easier for outside substances to impact and manipulate its structure.