Gabbro

Classification：Igneous Rock

A basic deep intrusive rock, usually gray black, medium to coarse-grained, mainly composed of clinopyroxene and plagioclase, similar to diabase and basalt.

Gabbro is a basic deep intrusive rock consisting mainly of monoclinopyroxene (diopside, diopyroxene, common pyroxene, etc.) and basic plagioclase (elongate and plagioclase). Secondary minerals include amphibole, olivine, biotite, and plagioclase, and a small amount of quartz and alkaline feldspar. Gabbro is gray medium grained to coarse grain structure, associated mineral iron, titanium, copper, nickel and phosphorus etc..
Gabbro is one of the representative rocks of the deep oceanic crust.

Name source:
Gabbro, the English name gabbro, was called "gabbro" in 1768 by the name of T..

The cause of formation:
Gabbro is formed by intrusive action of basaltic magma derived from deep crust or upper mantle, and is widely distributed in various tectonic environments and the moon on the earth's crust. The Gabbro produced on the moon is characterized by poor silicon, alkali, calcium and titanium, and contains cosmic minerals such as meteorite, natural metallic iron and so on. 

Chemical composition:
Gabbro is the most widely distributed rock in the basic intrusive rocks. The chemical composition of the rock is: the content of SiO2 is 45% to 52%, the average of K2O+Na2O is 3.6% +, and the content of iron and magnesium minerals is 40% ~ 90%. The main mineral components are basic plagioclase and monoclinopyroxene. Secondary minerals are olivine, plagioclase, brown common hornblende, biotite, and some contain a small amount of potassium feldspar and quartz. The content of dark minerals and light colored minerals is almost equal, the former is slightly higher, so it is dark black, the color rate is generally 35% ~ 70%, the rock is in the medium to coarse grain structure, and the typical Gabbro has long long structure.

Physical property：
The volume density of Gabbro is 2.8 ~ 3.1g/cm3, the porosity is very small, the compressive strength is 200 to 280MPa, the coarse grained people are lower, the durability is very high, the structure and structure are uniform, and sometimes it has beautiful pattern patterns, after polishing, the decoration is very rich, so it is often used as the high-grade ornamental stone.

Mineral composition:
Gabbro is mainly composed of pyroxene (augite, diopside, perilla and so on), and calcium rich plagioclase. The secondary minerals are olivine, hornblende, biotite, quartz, orthosite and iron oxides. According to the relative percent content of the light colored mineral plagioclase and the dark mineral pyroxene and olivine, it is divided into light color Gabbro (chromatic rate 10~35), Gabbro (chromatic rate 35~60) and dark Gabbro (chromatic rate 65~90). The species of secondary minerals can be further named as olives Gabbro, hornblende Gabbro, ortho feldspar Gabbro, quartz Gabbro and iron Gabbro (rich in ilmenite and magnetite). The chemical composition of Gabbro is the same as that of basalt, but the latter is mainly vitreous.
If the alteration, as sodium zoisitization of plagioclase and pyroxene, grape petrochemical uralitization.

Structural features:
Gabbro has a long structure, a secondary green structure, a reaction side structure and an exsolution structure. Gabbro is usually massive and partially Gabbro has stratified structure, reflecting the rhythmic change of mineral composition or granularity in the process of magma separation and crystallization. The layered Gabbro is mostly found in the stratiform complex and the ophiolite suite.

Mineral distribution:
Gabbro is produced in various tectonic settings, often composed of rock basins, rock covers and rock bed intrusions with different sizes, which are closely associated with the shallow diabase rock walls and rock beds with similar components. The main minerals related to Gabbro are copper, nickel, vanadium, titanium and iron. Gabbro is a good building material. The Gabbro on the moon is poor in alkali. It contains calcium rich plagioclase (An80 ~ 90) and ilmenite (about 10 to 18%) and a small amount of exotic minerals, such as meteorite, metallic iron and so on. Therefore, the gabbro on the moon is characterized by poor SiO2, rich CaO, TiO2 and FeO, which is formed in the environment of poor water and CO2, and lack of hydrothermal alteration.
The large size of Gabbro, small or tens of kilometers, appeared in the various geological periods, a large number of up to hundreds of square kilometers, such as the famous Shandong "Ji'nan green" Gabbro is such. The fresh surface of rock is dark grey, black gray, long and bright green, and massive structure is the main form. Mineral composition is plagioclase, clinopyroxene, olivine, biotite and a small amount of magnetite, a small amount of amphibole, apatite and so on.
Class Gabbro plays a very important role in granite. The black granite is composed of such rocks, including rare and rare varieties, such as "Ji'nan green" in Shandong, Inner Mongolia "Fengzhen black", Hebei "Fuping black", Shanxi "Taibai green", Zhejiang "bamboo pool green" and so on.

Scientific research:
Gabbro is one of the representative rocks of deep oceanic crust. In December 2015, 30 scientists from 12 countries, such as the United States, the United Kingdom, China and other countries, took the ocean drilling ship, which was designed to wear the mantle boundary of the earth's crust, on the "Atlantis shoal" in the middle of the India ocean in the southwest of the Southwest of the southwest of the southwest of the southwest of China. By December 2015, it had drilled nearly 300 meters to the bottom of the sea.