Document Type : Original Research Paper

Authors

School of Geology, University College of Sciences, Tehran University, Tehran, Iran

Abstract

      Qareaghaj mafic-ultramafic intrusion (QMUI) is located in northwest Iran, 36 km NW from Urmia city. The QUMI is composed mainly of non-mineralized mafic and Fe-Ti-P-rich ultramafic rocks (FTP). The mafic rocks, mainly coarse-grained gabbro, microgabbro, metagabbro and ortho-amphibolite, have simple mineral assemblage (plg + cpx + ilm). Based on field observations, petrography and geochemistry, they are directly related to each other (comagmatic). The FTP forms numerous layers and sill-like bodies, ranging in thickness from ~5cm to several meters. These rocks with high proportions of olivine, apatite, ilmenite and magnetite, show unusual bulk composition (e.g., SiO2~21-30 wt%, Fe2O3t ~ 26-42 wt%, TiO2~5-11 wt%, MgO~9-20 wt%, P2O5 up to 5.1 wt%, Cr~40-160 ppm, Ni~7-73ppm, ∑REE~10-340ppm). The FTP totally included by mafic rocks with sharp and concordant contact shows magmatic lamination and follows general NW-SE trend of the QMUI. Field relationship, petrography and geochemical data suggest that the FTP is not related to mafic host rocks and indeed intruded later into gabbros during plastic, high temperature deformation in local shear zone.
 

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References
Arebäck, H. & Stigh J., 2000- The nature and origin of an anorthosite associated ilmenite-rich leuconorite, Hakefjorden Complex, south-west Sweden. Lithos 51: 247-267
Ashwal, L. D., 1993- Anorthosites: Berlin, Heidelberg, New York, Springer-Verlag, 422 p
Buddington, A. F. & Lindsley D. H., 1964- Iron-titanium oxide minerals and synthetic equivalents. J petrol 5: 310-357
Duchesne, J. C., 1999- Fe-Ti deposits in Rogaland anorthosites (South Norway): eochemical characteristics and problems of interpretation. Mineral Deposita 34: 182-198
Dymek, H. F. & Owens, B. E., 2001- Petrogenesis of apatite-rich rocks (nelsonites and oxide-apatite gabbronorites) associated with massif anorthosites. Econ Geol 96: 797-815
Force, E. R., 1991- Geology of titanium mineral deposit: Geological Society of America Special Paper 259, 112p
Haggerty, S. E., 1991- Oxide textures: A mini-atlas. In: Lindsley DH (ed) Oxide Minerals: Petrologic and Magnetic Significance. Reviews in Mineralogy 25: 129-219
Haghipour, A. & Aghanabati, A., 1973- Geological quadrangle map of Iran No. A3. Serow sheet, Series 1:250000, Geological Survey of Iran (GSI), Tehran
Jiang, N., Chu, X., Mizuta, T., Ishiyama, D. & Mi, J., 2004- A magnetite-apatite deposit in the   Fanshan alkaline ultramafic complex, Northern China. Econ Geol 99: 397-408
Kärkkäinen, N. K. & Appelqvist, H., 1999- Genesis of a low-grade apatite-ilmenite-magnetite deposit in the Kauhajärvi gabbro, Western Finland. Mineral Deposita 34: 754-769
Kärkkäinen, N. K. & Bornhorst, 2003- The Svecofennian gabbro-hosted Koivusaarenneva magmatic ilmenite deposit, Kälviä, Finland. Mineral Deposita 38: 169-184
Kärkkäinen, N., Sarapää, O., Husskonen, M., Koistinen, E. & Lehtimäki, J., 1997- Ilmenite exploration in western Finland, and the mineral resources of the Kälviä ilmenite deposit. Geol Surv Finland Spec Paper 23: 15-24
Kolker, A., 1982- Mineralogy and geochemistry of Fe-Ti oxide and apatite (nelsonite) deposits and evaluation of the liquid immiscibility hypothesis. Econ Geol 77: 1146-1158
Lindsley, D. H., 2001- Do Fe–Ti oxide magmas exist? Geology: yes, experiments: no! In: Korneliussen A (ed) Abstracts – GEODE field workshop 8–12th July 2001 on
Markl, G., 2001- REE constraints on fractionation processes of massive-type anorthosites on the LofotenIslands, Norway. Mineral Petrol 72: 325-351
Markl, G., Frost, B. R. & Bucher, K., 1998- The origin of anorthosites and related rocks from the LofotenIslands, Northern Norway. I. Field relations and estimation of intrinsic ,variables. J Petrol 39: 1425–1452 McBirney, A. R., 1996- The Skaergaard intrusion. In: Cawthorn RG (ed) Layered intrusions. Amsterdam, Elsevier, pp: 147-180
Morse, S. A., 1990- The differentiation of the Skaergaard intrusion. Discussion of Hunter and Sparks (Contrib Min Petrol. 95:451-461). Contrib Min Petrol 104: 235
Owens, B. E. & Dymek, R. F., 1992- Fe-Ti-P-rich rocks and massif anorthosite: problems of interpretation illustrated from the Labrieville and St-Urbain plutons, Quebec. Can Mineral 30: 163-190
Philpotts, A. R., 1967- Origin of certain iron-titanium oxide and apatite rocks.  Econ Geol 62: 303-315 Reynolds IM., 1985- The nature and origin of titaniferous magnetite-rich layers in the Upper Zone of the Bushveld Complex: a review and synthesis. Econ Geol 80: 1089–1108
Rippley, E. M., Severson, M. J.& Hauck, S. A., 1998- Evidence for sulphide and Fe-Ti-P-rich liquid immiscibility in the Duluth Complex, Minnesota. Econ Geol 93: 1052-1062
Severson, M. J., 1988- Geology and structure of a portion of the PartridgeRiver intrusion: A progress report: Duluth, University of Minnesota, Natural Resources Research Institute, Technical Report NRRI/GMIN-TR-88-08, 78 p 
Toplis, M. J., Dingwell, D. B.& Libourel, G., 1994- The effect of phosphorus on the iron redox  ratio,viscosity, and density of an evolved ferro-basalt. Contrib Mineral Petrol 117: 293-304
Von, Gruenewaldt, G.,1993-Ilmenite-apatite enrichments in the Upper Zone of the Bushveld  Complex: a major titanium-rock phosphate resource. Int Geol Rev 35: 987-1000  
Watson, T. L. & Taber, S.,1913- Geology of the titanium and apatite deposits of Virginia: Virginia Geological Survey Bulletin 3A, 308 p
Watson, T. L. & Taber,S.,1913- Geology of the titanium and apatite deposits of Virginia: Virginia Geological Survey Bulletin 3A, 308 p