| Location: | Arequipa, Peru, South America |
| Lat / long: | -16.6394, -72.34132 |
| dep_id: | 60001614 |
| mrds_id: | W002270 |
| Commodity type: | nonmetallic |
| Major mineral: | Mica |
| Operation type: | Unknown |
| Deposit type: | PEGMATITES |
| Production size: | Production occurred |
| Development status: | Past Producer |
| alteration: | WALL ROCK ALTERATION IS STRONG NEAR THE PEGMATITES BUT DIMINISHES RAPIDLY IN INTENSITY AWAY FROM THEM. ALTERATION IS STRONGEST AT THE FOOTWALL. THE GNEISS APPEARS TO HAVE BEEN RATHER SUSCEPTIBLE TO ALTERATION, WHERE AS THE DIABASE DIKES WERE RESISTANT. ALTERATION PRODUCTS INCLUDE BIOTITE, MUSCOVITE, QUARTZ, AND CALCITE. |
| ore_ctrl: | THE PEGMATITES RANGE IN SHAPE FROM EVEN TABULAR BODIES TO PRACTICALLY EQUIDIMENSIONAL MASSES, BUT ARE GENERALLY IRREGULAR LENSES THAT COMMONLY ARE ONLY 25-30 M LONG. THE MOST ABUNDANT MINERALS OF THE PEGMATITES ARE QUARTZ, POTASH FELDSPAR, AND MUSCOVITE, AND THE MOST COMMON ACCESSORY MINERALS ARE TOURMALINE, ILMENITE, BIOTITE, AND GARNET. BERYL IS ASSOCIATED WITH TOURMALINE IN ONE PEGMATITE. GRAPHIC INTERGROWTHS OF QUARTZ AND FELDSPAR ARE FAIRLY COMMON. THE PEGMATITES COMMONLY SHOW A ROUGH MINERAL LAYERING OR ZONING. A CENTRAL CORE OF MASSIVE QUARTZ, WITH OR WITHOUT SCATTERED CRYSTALS OF FELDSPAR OR MUSCOVITE, COMMONLY GRADES OUTWARD INTO A ZONE WITH MORE ABUNDANT FELDSPAR AND MUSCOVITE AND AT THE WALLS TO A FINER-GRAINED ASSEMBLAGE. A FAIRLY WELL DEFINED LAYER OF FINE- TO MEDIUM-GRAINED MICA AND QUARTZ OFTEN MARKS THE FOOTWALL. |
| Structure: | ENTIRE REGION UNDERLAIN BY REDDISH OR PINK PREDOMINANTLY MASSIVE SYENITIC GNEISS OF POSSIBLE PRECAMBRIAN AGE. IT CONSISTS MAINLY OF PINK POTASH FELDSPAR, WITH MINOR HORNBLENDE, BIOTITE, AND A LITTLE QUARTZ THAT IS THOUGHT TO BE SECONDARY. INCLUDED IN THE GNEISS ARE NUMEROUS STREAKS OR LENSES OF DARKER MATERIAL, POSSIBLE METAMORPHOSED DIKES, AS WELL AS OF HIGHLY FELSIC ROCK MADE UP ALMOST ENTIRELY OF FELDSPAR WITH A LITTLE QUARTZ. CUTTING THE GNEISS ARE DIABASE DIKES OF AT LEAST TWO AGES. PEGMATITES ARE FOUND THROUGHOUT THE REGION BUT SEEM TO BE MORE ABUNDANT IN AREAS WHERE OLDER DIABASE DIKES ALSO ARE ABUNDANT. |
| Year first produced: | 1905 |
| References: |
- Deposit:: SIMONS, FRANK, 1960, UNPUBLISHED REPORT, P. 1701
- Deposit:: PERU-MAPA METALOGENETICO, 1969, AND, GUIA PARA EL MAPA METALOGENETICO DEL PERU, SOCIEDAD NACIONAL DE MINERIA Y PETROLEO, LIMA, PERU, NOV. 1969
- Deposit:: CAMMINATI, LUIS, 1944, INFORME SOBRE EL RECONOCIMIENTO PRACTICADO A LA ZONA MICACEA DE LOS DEPARTAMENTOS DEL SUR DEL PERU: CUERPO DE ING. DE MINAS DEL PERU BOL., NO. 130, P. 97-118
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