Maria Mine, Cananea, Mun. de Cananea, Sonora, Mexico
|Latitude & Longitude (WGS84):||31° 2' 35'' North , 110° 25' 9'' West|
|Latitude & Longitude (decimal):||31.04303,-110.41918|
|Name(s) in local language(s):||Mina Maria (Minera Maria)|
|Other regions containing this locality:||Sonoran Desert, North America|
Mina Maria is a breccia pipe which was mined for molybdenum and base metals in the 1980s and 1990s. The current status of the mine is unknown. It is located within 20 km to the northwest of the town of Cananea, in Sonora, Mexico. I visited the mine and collected there in the 1990s with Stan Esbenshade. The mine was developed by a spiral decline driven large enough to accomodate LHD (load-haul-dump) vehicles. Levels were driven from the main decline to access the breccia pipe and remove the ore. The best crystallized sulfides came from level 5. One weekend, during the mining operation, a significant cave-in occurred and collapsed a major portion of the workings, including level 5. The cave-in occurred when no one was in the mine and there were no injuries, but it did occur in the heart of the orebody.
The ore minerals are chalcopyrite, sphalerite, molybdenite and possibly scheelite (unknown if the mining company had a recovery circuit for it). The gangue minerals are quartz, tourmaline, sericite, and pyrite.
Top Gem Minerals (Tucson, Arizona) was the first mineral company to obtain specimens from the mine beginning in the late 1980s or early 1990s. The mine produced some of the best pyrite and chalcopyrite crystals I have ever seen. Unfortunately, there was usually an inordinate amount of damage to specimens, and there are not a lot of specimens that survived, damaged or undamaged.
Pyrites occur as simple lustrous cubes up to 30 cm on an edge, usually as groups and associated with crystallized quartz. Chalcopyrite occurs with or without the other minerals, and are also well crstyallized. They usually are modified flattened sphenoidal clusters to 3 cm on an edge with a beautiful natural patina. Sphalerite is dark brown to black crystallized in groups to a couple of centimeters and almost always growing on quartz. They apparently were not as abundant as the other sulfides, and should be considered uncommon in occurrence from this mine. Dravite (Dutrow, written communication) (tourmaline) is found in fibrous mats growing interspersed inside and between the quartz crystals. It is a common inclusion in the quartz crystals, occurring as fibrous appearing felt laths usually radiating from a central point and forming fans or elongate fibers (similar to "byssolitic" occurrences of pyroxene or amphibole). Sericite occurs up to 1-2 mm and is intimately mixed with molybdenite flakes and specks, and is yellowish and micaceous in appearance. In protected pockets in the quartz, it forms small bladed rosettes. A peculiar light orange to flesh color develops after a few days when the sericite oxidizes or dehydrates. Black fibrous tourmaline, scheelite and sulfides also occur with the sericite. Quartz varies from milky to clear and occurs in associations as previously described above, and grew up to 20 cm, either in groups and less commonly as singles. Pockets of quartz crystals occurred cleanly or filled with a slightly brown-colored clay. Finally, scheelite is found as tan-colored dipyramidal crystals with quartz, sericite, and molybdenite. The largest crystal seen approached 2 cm.
11 valid minerals.
GeochronologyMineralization age: Paleocene : 60.7 Ma to 60.1 Ma
Important note: This table is based only on rock and mineral ages recorded below and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.
|Geologic Time||Rocks, Minerals and Events|
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
0 - 2.588 Ma
Wodzicki, Wojtek A., 1992, Geology and origin of high-grade porphyry and pegmatite copper mineralization: Maria mine, Cananea, Sonora, Mexico: unpublished M.S. thesis, University of California, Los Angeles, 50 p
Certain analyses run at the SEM lab at University of Nevada Reno by Martin Jensen in 1996
Wodzicki, Wojtek A., 1995, The evolution of Laramide igneous rocks and porphyry copper mineralization in the Cananea district, Sonora, Mexico: unpublished Ph.D. thesis, University of Arizona, 181 p.