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THE KAKOPETROS AND RAVDOUCHA IRON-OXIDE DEPOSITS, WESTERN CRETE, GREECE: FLUID TRANSPORT AND MINERALIZATION WITHIN A DETACHMENT ZONE

Markus Seidel^,* and Andreas Pack^**

Institut für Mineralogie and Geochemie, Universität zu Köln, 50674 Köln, Germany

Zachary D. Sharp

Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116

Eberhard Seidel

Institut für Mineralogie and Geochemie, Universität zu Köln, 50674 Köln, Germany

View larger version (73K): [in a new window]   FIG. 1. A. Generalized geologic and tectonic map of western Crete (modified from Creutzburg et al., 1977; and Kopp and Ott, 1977), showing the tectonic units, the detachment fault, and the two major iron-oxide deposits, located in the roof of the Phyllite-Quartzite unit. B. and C. Detailed geologic maps and cross sections of the Kakopetros and Ravdoucha iron-oxide deposits. Note vertical exaggeration of the cross sections.

View larger version (45K): [in a new window]   FIG. 2. Schematic illustration of the tectonostratigraphy of Crete (modified after Seidel et al., 1982).

View larger version (69K): [in a new window]   FIG. 3. A. Outcrop of iron oxide in the wall of a small open pit, southwest of Kakopetros. Hammer for scale. B. Brecciated quartzites of the Phyllite-Quartzite unit within the detachment zone. Fissures are filled by goethite. Coin for scale (25 mm).

View larger version (71K): [in a new window]   FIG. 4. Backscattered electron photomicrographs of iron oxides. A. Fragments of phyllite, quartz (qtz), and goethite (gt) embedded in a fine-grained matrix composed predominantly of goethite (sample M2-215). B. Angular fragments of goethite and quartz in a matrix composed of goethite and small grains of quartz and phyllite (sample M2-218).

View larger version (56K): [in a new window]   FIG. 5. A. Backscattered electron photomicrograph of laminated goethite. Lamination is due to slight differences in chemical composition, such as variable concentrations of alumina and manganese (sample M2-296). See text for details. B. i. Reflected light photomicrograph of laminated hardbands of Ba-rich cryptomelane and goethite (sample M2-296). ii, iii, and iv. Electron microprobe mapping of the same area, showing the relative content of potassium, iron, and manganese, respectively. Note that the cryptomelane is almost free of iron. C. Reflected-light photomicrograph showing a quartzite breccia with angular clasts. The veins are filled predominantly by goethite (sample M2-215).

View larger version (89K): [in a new window]   FIG. 6. A. Interpreted fluid-flow pattern within the detachment zone. High fluid flow is restricted to intensely brecciated rocks leading to precipitation of vein-filling iron oxides. By contrast, the relatively homogeneous marble is pervasively impregnated by fine-grained goethite. See text for discussion. B. Schematic diagram (not to scale) showing detachment fault–related mineralization in the roof of the Phyllite-Quartzite unit in western Crete (for comparison, see Long, 1992, fig. 36).