Marano volcanic rocks, East Azarbaijan Province, Iran, and associated Fe mineralisation
Abstract
There are two main types of economic iron ore deposits in Iran: (1) magmatic segregation deposits and (2) skarns. Most of the hydrothermal iron deposits in Iran, except for the skarns, are uneconomic. One of these uneconomic hydrothermal deposits is the Marano Fe deposit, located in East Azarbaijan Province (NW Iran). This deposit is considered to have been formed by an epithermal style of mineralisation related to a volcanic-dome. There are 5 volcanic domes in the Marano area, ranging in composition from dacite to rhyolite. The volcanic rocks show geochemical evidence of fractionation of biotite, hornblende, magnetite, apatite and feldspars. The Marano volcanic domes crystallised from an I-type magma, formed in a volcanic arc setting. Fe mineralisation has occurred around one of these Marano domes (MA dome) in which the igneous rocks contain more biotite and hornblende and are less fractionated than in the other domes. The main Fe oxide, hematite, occurs as veins and disseminations in sedimentary wall rocks. Alteration of the minerals in the host rocks suggests aS2<10-9.5, aO2>10-34.2 and pH<5.5. The small size and shallow-level of emplacement of magma, together with the absence of extensive hydrothermally altered zones, shows that the hydrothermal system was not voluminous enough to form an economic iron deposit.
- Publication:
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Journal of Asian Earth Sciences
- Pub Date:
- October 2004
- DOI:
- 10.1016/S1367-9120(03)00152-4
- Bibcode:
- 2004JAESc..24...11K