Nr.2 - ALPA - Albanian Papers
Nr.2 - ALPA - Albanian Papers Nr.2 - ALPA - Albanian Papers
Elezaj et al.retardation of the ophiolite forming processesand the intraoceanic paleo displacement of thedifferent ophiolite segment limited by thetransform faults largely developed into theMirdita-Gjakove ophiolite belt (Kodra et al.1995).In the light of the age data provided by themetamorphic sole, the radiolarite chertsequences found within the Mirdita-Gjakoveophiolite belt and by its primary radiolarite cover,a very close age span is evidenced (Kodra et al.1995, Xhomo et al. 2002). The time span of themetamorphic soles indicates that its production ismade parallel to ophiolite forming processes andradiolarite chert sedimentation.Figura. 4. Metamorphich sole and its deformationsSimilar age indicate also the garnet pyroxenitesenclaves in a serpentinite breccia that crosscutsthe ophiolite volcanics near Derveni (Albania)(Gjata et al. 1992). According to geochemicaldata, the garnet pyroxenites probably originatefrom oceanic gabbro protoliths.Thermobarometric considerations show hightemperature (1200º C) and high pressure 1.5GPa). It s inferred that they are formed on theinitiation of a subduction process or near theoceanic ridge. Analogous age span show also theplagiogranites of SSZ type ophiolites (Ivanaj,1992).Genetic implicationsSummarizing the available data, it is inferred thatthe oceanic spreading producing the Jurassicophiolites, the successive intraoceanicsubduction and the ophiolite paleo emplacementonto the Middle Triassic-Lower Jurassic volcanosedimentary diabas radiolarite formation leadingto the metamorphic sole generation areAKTET Vol. IV, Nr 2, 2011 245
Elezaj et al.developed in very short time interval (Kodra andGjata 1982, Kodra et al. 2000, Elezaj and Kodra,2008).It seems that in the Mirdite - Gjakove narrowoceanic basin, the ophiolite detachment and thetwo margins decoupling of the young oceaniclithosphere is not developed above the oceanicridge. However, in the oceanic crust sequence ispreserved the necessary thermal flux for themetamorphic sole formation. Its setting may be isclose to the oceanic ridge or intraoceanicsubduction zone. As consequence, the suggestedscenario implies that the initial displacement ofyoung, hot, ocean crust and mantle occur withinan oceanic setting.The petrological and structural evidence from themetamorphic sole supports also theinterpretation that during the intraoceanic stage,the ophiolite emplacement (thrusting anddecoupling) is developed. The Early Jurassic-Middle Jurassic young and thick oceaniclithosphere is set onto the Middle Triassic-EarlyJurassic precedent oceanic lithosphere. Theemplacement movement is associated withproduction of the amphibolites, gneisses andmica schists with or without garnet.On the other side, the obducted ultramafics aresubjected at their basement to intensivemetamorphism. It is expressed by rockdehydration and the mylonitization. In moreadvanced phases the intensive serpentinizationprocesses are developed. At the lowest part ofthe ultramafic sheets a strong serpentinizationand the squeezing phenomena occurred and theshear zones are developed (Fig. 4). At theultrabasic massif bottom the cutting deformationpasses to ductile deformation, which iscontemporaneous to ophiolite solemetamorphism. The last one is affected by thefoliation S1, splitting schistosity S2 andmultiphase micro folds (Meshi 1995, Nicolas et al.1999).Some time, the metamorphic sole is cross cut bythe garnet, quartz-garnet etc. thin veins (from 2-5cm, to 10-15 cm). They are considered asproducts related to the metamorphic processesoccurred during the ophiolite emplacement.In general, a structural concordance between theultrabasic allochthonous massifs foliation,metamorphic sequence foliation, the structurallyunderlying basalt radiolarite series (βT 2 -J 1 )stratification and the Jurassic ophiolitesemplacement plane on volcano-sedimentaryseries is observed (βT 2 - J 1 ). Some time, it isdifficult to retrace the boundary between themetamorphic sequence and the underlyingvolcano sedimentary formation, because a lightmetamorphic imprint is evidenced also into thevolcano sedimentary members.CONCLUSIONS1. In the example of the Mirdita – Gjakovaophiolite, it is inferred that during the MiddleJurassic, the bidivergent emplacement of theyoung oceanic lithosphere onto the oldlithosphere (Triassic-Lower Jurassic ophiolites)occurred. The ophiolite displacement producedthe subjacent metamorphic sole developed alongside the ophiolite margins.2. The initial displacement of the oceanic andmantle crust occurs within an oceanic setting.3. The time span of the metamorphic solesindicates that its production is made parallel toophiolite forming processes and radiolarite chertsedimentation.4. The very short age span of the Jurassicophiolites, accompanied with their bidivergentemplacement onto Triassic-Liassic ophiolites(volcano-sedimentary formation, βT 2 -J 1 ) supportsthe suggestion on the existence of very narrowoceanic basin suggested by Kodra and Gjata1982, Vergély et al. 1998, Kodra et al. 1994, 1995,2000 etc.REFERENCES1. Ciric B.A., Eric V. (1996) – Contactmetamorphism beneath the peridotite of BorovVrh-Brezovica, Eds. Knezhevic et al. 359-264.2. Dimo A. (1997) – Le mécanisme de mise enplace des ophiolites d’Albanie. Ph.D. thesis, Univ.Paris-Sud, 307.3. Dimo A., Monie, Vergely P., Kodra A., andGjata K. (1998) – Mosha radiometrike eshkembinjve te shtrojes metamorfike dhe te246AKTET Vol. IV, Nr 2, 2011
- Page 29 and 30: AKTET ISSN 2073-2244Journal of Inst
- Page 31: DushiBazuar në kushtet e dhëna ë
- Page 35 and 36: AKTET ISSN 2073-2244Journal of Inst
- Page 38 and 39: Caslli et al.way that will serve us
- Page 40 and 41: Caslli et al.weight. This approach
- Page 42 and 43: AKTET ISSN 2073-2244Journal of Inst
- Page 44 and 45: Karaj et alvlerat përkatëse të R
- Page 46 and 47: Rryma (nA)Rryma (nA)Karaj et al.Opt
- Page 48 and 49: Karaj et al Metodat optimale për p
- Page 50 and 51: Kullolli et almekanizma të tjerë
- Page 52 and 53: Kullolli et alF3 er1n*cos1 2esin1
- Page 54 and 55: AKTET ISSN 2073-2244Journal of Inst
- Page 56 and 57: Lajqi et alFig. 3. Paraqitja skemat
- Page 58 and 59: Lajqi et aledhe te automjetet që k
- Page 60 and 61: Lajqi et alNë fig. 10. dhe 11 jan
- Page 62 and 63: AKTET ISSN 2073-2244Journal of Inst
- Page 64 and 65: Durmishaj & HyseniElementikimikPër
- Page 66 and 67: Durmishaj & Hysenie Fe në sfalerit
- Page 68 and 69: Durmishaj & Hysenikarakterizohen m
- Page 70 and 71: Dushi & LameThe goal of this paper
- Page 72 and 73: Dushi & Lamedecrease with lapse tim
- Page 74 and 75: Dushi & Lamewith depth is due to th
- Page 76 and 77: Elezaj et al.cases its tectonic fra
- Page 78 and 79: Elezaj et al.Figura. 2 Goleshi ophi
- Page 82 and 83: Elezaj et al.dhena te reja mbi meka
- Page 84 and 85: Elshani & Veselise prodhuar, dhe n
- Page 86 and 87: Elshani & Veselimbetje, normalisht
- Page 88 and 89: AKTET ISSN 2073-2244Journal of Inst
- Page 90 and 91: Ibrahimi et al.paraqitjen e gëlqer
- Page 92 and 93: Ibrahimi et al.plotësojë kushtet
- Page 94 and 95: Ibrahimi et al.duke stimuluar kësh
- Page 96 and 97: AKTET ISSN 2073-2244Journal of Inst
- Page 98 and 99: Imeri et al.Which means that for th
- Page 100 and 101: Imeri et al.process of obtaining Fe
- Page 102 and 103: Kokalari & Haxhimatematikore, janë
- Page 104 and 105: Kokalari & HaxhiLagështia Hiri Fuq
- Page 106 and 107: Kokalari & HaxhildQ i(Kkal/kg)a α
- Page 108 and 109: AKTET ISSN 2073-2244Journal of Inst
- Page 110 and 111: Lajçi & Lajçi2.1.4. Koha e vdekje
- Page 112 and 113: Lajçi & Lajçi56°C 58°C 60°C 62
- Page 114 and 115: Lajçi & LajçiFigura 3.6. Grafiku
- Page 116 and 117: AKTET ISSN 2073-2244Journal of Inst
- Page 118 and 119: Gumeniet alkolonave të modifikuara
- Page 120 and 121: Gumeniet alDuke iu referuar rezulta
- Page 122 and 123: AKTET ISSN 2073-2244Journal of Inst
- Page 124 and 125: Lajçi & Metikos-HukovicProblemi i
- Page 126 and 127: Lajçi & Metikos-HukovicPbSO 4 /H 2
- Page 128 and 129: Lajçi & Metikos-HukovicPrania e ka
Elezaj et al.developed in very short time interval (Kodra andGjata 1982, Kodra et al. 2000, Elezaj and Kodra,2008).It seems that in the Mirdite - Gjakove narrowoceanic basin, the ophiolite detachment and thetwo margins decoupling of the young oceaniclithosphere is not developed above the oceanicridge. However, in the oceanic crust sequence ispreserved the necessary thermal flux for themetamorphic sole formation. Its setting may be isclose to the oceanic ridge or intraoceanicsubduction zone. As consequence, the suggestedscenario implies that the initial displacement ofyoung, hot, ocean crust and mantle occur withinan oceanic setting.The petrological and structural evidence from themetamorphic sole supports also theinterpretation that during the intraoceanic stage,the ophiolite emplacement (thrusting anddecoupling) is developed. The Early Jurassic-Middle Jurassic young and thick oceaniclithosphere is set onto the Middle Triassic-EarlyJurassic precedent oceanic lithosphere. Theemplacement movement is associated withproduction of the amphibolites, gneisses andmica schists with or without garnet.On the other side, the obducted ultramafics aresubjected at their basement to intensivemetamorphism. It is expressed by rockdehydration and the mylonitization. In moreadvanced phases the intensive serpentinizationprocesses are developed. At the lowest part ofthe ultramafic sheets a strong serpentinizationand the squeezing phenomena occurred and theshear zones are developed (Fig. 4). At theultrabasic massif bottom the cutting deformationpasses to ductile deformation, which iscontemporaneous to ophiolite solemetamorphism. The last one is affected by thefoliation S1, splitting schistosity S2 andmultiphase micro folds (Meshi 1995, Nicolas et al.1999).Some time, the metamorphic sole is cross cut bythe garnet, quartz-garnet etc. thin veins (from 2-5cm, to 10-15 cm). They are considered asproducts related to the metamorphic processesoccurred during the ophiolite emplacement.In general, a structural concordance between theultrabasic allochthonous massifs foliation,metamorphic sequence foliation, the structurallyunderlying basalt radiolarite series (βT 2 -J 1 )stratification and the Jurassic ophiolitesemplacement plane on volcano-sedimentaryseries is observed (βT 2 - J 1 ). Some time, it isdifficult to retrace the boundary between themetamorphic sequence and the underlyingvolcano sedimentary formation, because a lightmetamorphic imprint is evidenced also into thevolcano sedimentary members.CONCLUSIONS1. In the example of the Mirdita – Gjakovaophiolite, it is inferred that during the MiddleJurassic, the bidivergent emplacement of theyoung oceanic lithosphere onto the oldlithosphere (Triassic-Lower Jurassic ophiolites)occurred. The ophiolite displacement producedthe subjacent metamorphic sole developed alongside the ophiolite margins.2. The initial displacement of the oceanic andmantle crust occurs within an oceanic setting.3. The time span of the metamorphic solesindicates that its production is made parallel toophiolite forming processes and radiolarite chertsedimentation.4. The very short age span of the Jurassicophiolites, accompanied with their bidivergentemplacement onto Triassic-Liassic ophiolites(volcano-sedimentary formation, βT 2 -J 1 ) supportsthe suggestion on the existence of very narrowoceanic basin suggested by Kodra and Gjata1982, Vergély et al. 1998, Kodra et al. 1994, 1995,2000 etc.REFERENCES1. Ciric B.A., Eric V. (1996) – Contactmetamorphism beneath the peridotite of BorovVrh-Brezovica, Eds. Knezhevic et al. 359-264.2. Dimo A. (1997) – Le mécanisme de mise enplace des ophiolites d’Albanie. Ph.D. thesis, Univ.Paris-Sud, 307.3. Dimo A., Monie, Vergely P., Kodra A., andGjata K. (1998) – Mosha radiometrike eshkembinjve te shtrojes metamorfike dhe te246AKTET Vol. IV, Nr 2, 2011