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With rocks ferromagnesians, especially serpentinites ultramafic peridotite and dunite, as magma segregations of large or spread as accessory mineral; also detrital; common in meteorites and Lunar basalts.
Association: olivine, enstatite, plagioclase, serpentine, magnetite, ilmenite, pyrrhotite, pentlandite, ulvöspinel.
Manifestations of chromite:
The manifestations of chromite are located in the environment of the crystalline basement along a strip that extends the eastern slope of the Sierra de Comechingones, from the height of Alta Gracia by the North to the town of Alcira Gigena South.
The chromite occurs in bodies or stocks of geology, preferably in the areas of border, which reached a development of up to 1300 meters by a maximum width of 450 meters. These bodies caused by autohidratacion of peridotitic rocks, occupy a position consistent with the schists enclosing them, represented by garnets, mass gneisses of amphiiboles and sometimes very powerful lenticular bodies of pure or impure limestones. His intrusion predates the granitic rocks, since those are traversed by pegmatites carriers, usually of corundum.
The chromite caused by processes of magma segregation appears inside the serpentine body as nests, eyes, guides lenticular and irregular bodies of varied size, found in some cases bodies of ore up to 300 tons, and although less frequent, disseminated in the coil.
Presents texture granular thin to medium black to dark brown, contains in its mass as a filling of cracks, serpentine fibrous, carbonate of calcium and magnesium.
It's a chromite low-grade where good apart from its Cr2O3 content is replaced by Al2O3 and the FeO by MgO. The analysis of some samples of high purity resulting in maximum tenor of 44.5% of Cr2O3.
Sierras de Córdoba Center-South area. The Cambrian ultramafic rocks,
they are presented as a strip of dismembered bodies and extend South of the Batholith of Achala from the permanent, until the locality of Inti Yaco on Los Reartes River site in which are underdeveloped outcrops. They correspond to the so-called Western ultramafic Strip and strip plant of rocks ultramafic of Sierras Pampeanas of Córdoba. Ultramafic rocks emerge in a roughly North-South direction bullfight, and extending south of the Batholith of Achala from "Los Permanentes" Atos Pampa. These outcrops found would be related to structural guidelines, what was also studied. From South to North the main outcrops are as follows: "Los Permanentes" (mine "El Cromo"); "12 de November"; "Resistencia y El Destino"; "Árbol seco"; "Ume Pay"; "El Rodeo"; "25 de Mayo"; 'Tigre Muerto'; "Saucesita"; "Lutti"; "Los Guanacos"; "La Belgica", "La Gaucha"; "Benjamina"; "Mabel"; "Piedras Negras"; "Los Congos". In these outcrops ultramafic bodies matching cromitas to subconcordantes podiformes are recognized.
The most important mining districts are:
- Atos Pampa: located 3 Km to the SW of Atos Pampa, Department Calamuchita. More intense exploitation was developed in the decades of the 1940s and 1950s in mines "Los Congos", "El Coquito", "Los Huequitos", etc., the chromite mineralization occurs in lenses and pockets of varied size.
"El Cromo" and "Los Congos" mines: at bands of ultramafic and mafic serpentinizadas and/or anfibolitizadas housed in a metamorphic sequence rocks. The mineral is disseminated or in concentrations of up to 85% with less than 5 mm grain size; in deposits podiformes, IARC and mineralized belts along with magnetite, magnetite, ilmenite, titanifera, rich espinelos in Al, Fe and Mg, hematite, cromomagnetita and Ni-Fe - minority proportions Cu sulfides. The zonalidad is common. Studied by optical and electronic microprobe.
- "Los Guanacos": located 12 Km to the South of the village of Yacanto, Department Calamuchita. more intense exploitation was developed in the decades of the 40 and 50 in the mines "Los Guanacos", "Árbol seco", "EMU Pay", "El Rodeo", etc., the chromite mineralization occurs in concentrations (nests, eyes, guides and disseminated as grains in the geology).
Mineral ListMineral list contains entries from the region specified including sub-localities
23 entries listed. 13 valid minerals.
Localities in this Region
- Calamuchita Department
- Atos Pampa
- Calamuchita Department
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