Ultra-high pressure (UHP) and high pressure (HP) metamorphism have been reported from eclogite an... more Ultra-high pressure (UHP) and high pressure (HP) metamorphism have been reported from eclogite and garnet peridotite within migmatitic granitic gneisses (Liverpool Land Eclogite Terrane) in the footwall of an N-dipping shear zone (Gubbedalen Shear Zone) in southern Liverpool Land, East Greenland Caledonides. The hanging wall is dominated by a Silurian (c. 430 Ma) intrusive complex, not present in the footwall. Appearance of ultramafic rocks, including garnet peridotite, eclogite and country rock migmatite with a protolith age of ˜ 1640 Ma and eclogite facies metamorphism at ˜ 400Ma make a correlation with the Western Gneiss Region in Norway likely. LLET is thus considered to be an exotic terrane relative to the surrounding rocks of Laurentian affinity. Widespread(?) eclogite bodies show compositional variations, with omphacite in the range <Jd20 to Jd45. Small polycrystalline quartz inclusions in garnet, possibly representing pseudomorphs after coesite(?) indicate P>~2.7 GPa a...
The common occurrence of marble and calc silicate gneiss interlayered with garnet mica schist and... more The common occurrence of marble and calc silicate gneiss interlayered with garnet mica schist and quartz- feldspathic hosting UHP mafic and ultramafic bodies within the uppermost allochthonous unit of the Scandinavian Caledonides of northern Norway is well known (Krogh et al. 1990; Ravna et al., 2006; Ravna & Roux, 2006), and the UHP (730 oC/3.36 GPa) event is dated to
... fax: (+47) 77645600 K re Kullerud, e-mail: kare.kullerud@uit.no Dmitry Zozulya, e-mail: zozul... more ... fax: (+47) 77645600 K re Kullerud, e-mail: kare.kullerud@uit.no Dmitry Zozulya, e-mail: zozulya@geoksc.apatity.ru Steffen G. Bergh, e-mail: steffen.bergh@uit.no ... The geochemistry and petrogenesis of K-rich alkaline volcanics from the Batu Tara volcano, eastern Sunda arc. ...
ABSTRACT The Seiland Igneous Province of the North Norwegian Caledonides consists of a suite of d... more ABSTRACT The Seiland Igneous Province of the North Norwegian Caledonides consists of a suite of deep-seated rift-related magmatic rocks emplaced into paragneisses during late Precambrian to Ordovician time. In the south-eastern part of the province, contact metamorphism of the paragneisses and later reworking of intrusives and associated contact aureoles have resulted in the development of three successive metamorphic stages. The contact metamorphic assemblage (M1) Opx + Grt + Qtz + Pl + Kfs + Hc + Ilm ± Crd is preserved in xenolithic rafts of paragneiss within metagabbro. Geothermobarometric calculations yield 930-960d̀ C and 5-6.5 kbar for the contact metamorphism. M1 was followed by cooling, accompanied by strong shearing, formation of the gneiss foliation and recrystallization at intermediate-P granulite facies conditions (M2). Stable M2 phases are Cpx + Opx + Pl +Ilm ± Hbl in metagabbro and Grt ± Sil ± Opx + Kfs + Qtz + Pl ± Bt + Ilm in host paragneiss. The M2 conditions are estimated to 700-750d̀ C and 5-7 kbar. A subsequent pressure increase is recorded in the M3 episode, which is associated with recrystallization in narrow ductile shear zones and secondary growth on M2 minerals. M3 is defined by the assemblages Grt + Cpx ± Opx + Pl + Ru + Qtz in metagabbro, and Grt ± Ky + Qtz + Pl ± Kfs + Bt + Ru in host paragneiss. M3 conditions are estimated to 650-700d̀ C and 8-10 kbar. The substantial pressure increase related to the M2 → M3 transition is interpreted to be a result of (early?) Caledonian overthrusting. Chemical zoning in cordierite and biotite suggest rapid cooling following the M3 event. The proposed P-T-t evolution implies that the tectonic evolution of the Seiland Igneous Province was long (at least 330 Ma) and complex and involved initial rifting and extension followed by crustal thickening and compression.
Granulite facies migmatitic gneisses from the Seiland Igneous Province (northern Norway) were def... more Granulite facies migmatitic gneisses from the Seiland Igneous Province (northern Norway) were deformed during deep crustal shearing in the presence of melt, which formed by dehydration melting of biotite. Partial melting and deformation occurred during the ...
The Seiland Igneous Province (Northern Norway) is a rift-related magmatic suite emplaced in the s... more The Seiland Igneous Province (Northern Norway) is a rift-related magmatic suite emplaced in the span from 570 to 520 Ma. The magmatic province comprises dominantly alkaline mafic and ultramafic intrusives. The high-grade paragneisses from the Øksfjord peninsula represent ...
Archean alkaline complexes are extremely rare but are of particular interest because the magmas h... more Archean alkaline complexes are extremely rare but are of particular interest because the magmas have a mantle origin. Given their high Sr and Nd contents, crustal contamination has only a minor impact on the mantle-derived isotopic signatures. Therefore, they can provide valuable information on the isotopic composition of the subcontinental mantle and geodynamics in Archean. The previously reported Late Archean alkaline complexes (2.7-2.6 Ga) from the Canadian and Australian shields belong to the potassic series, are depleted in LIL and HFS elements, and are related to subduction, thereby forming in a compressive tectonic environment and having a depleted mantle source. The absence of Archean sodic alkaline complexes forming in extensional environments was mainly ascribed to the absence of metasomatic processes in the mantle and lower lithosphere (Blichert-Toft et al., 1996). Greenland Archean alkaline complexes (2698-2664 Ma syn- to post-kinematic pyroxenites, hornblendites, norite...
Ultra-high pressure (UHP) and high pressure (HP) metamorphism have been reported from eclogite an... more Ultra-high pressure (UHP) and high pressure (HP) metamorphism have been reported from eclogite and garnet peridotite within migmatitic granitic gneisses (Liverpool Land Eclogite Terrane) in the footwall of an N-dipping shear zone (Gubbedalen Shear Zone) in southern Liverpool Land, East Greenland Caledonides. The hanging wall is dominated by a Silurian (c. 430 Ma) intrusive complex, not present in the footwall. Appearance of ultramafic rocks, including garnet peridotite, eclogite and country rock migmatite with a protolith age of ˜ 1640 Ma and eclogite facies metamorphism at ˜ 400Ma make a correlation with the Western Gneiss Region in Norway likely. LLET is thus considered to be an exotic terrane relative to the surrounding rocks of Laurentian affinity. Widespread(?) eclogite bodies show compositional variations, with omphacite in the range <Jd20 to Jd45. Small polycrystalline quartz inclusions in garnet, possibly representing pseudomorphs after coesite(?) indicate P>~2.7 GPa a...
The common occurrence of marble and calc silicate gneiss interlayered with garnet mica schist and... more The common occurrence of marble and calc silicate gneiss interlayered with garnet mica schist and quartz- feldspathic hosting UHP mafic and ultramafic bodies within the uppermost allochthonous unit of the Scandinavian Caledonides of northern Norway is well known (Krogh et al. 1990; Ravna et al., 2006; Ravna & Roux, 2006), and the UHP (730 oC/3.36 GPa) event is dated to
... fax: (+47) 77645600 K re Kullerud, e-mail: kare.kullerud@uit.no Dmitry Zozulya, e-mail: zozul... more ... fax: (+47) 77645600 K re Kullerud, e-mail: kare.kullerud@uit.no Dmitry Zozulya, e-mail: zozulya@geoksc.apatity.ru Steffen G. Bergh, e-mail: steffen.bergh@uit.no ... The geochemistry and petrogenesis of K-rich alkaline volcanics from the Batu Tara volcano, eastern Sunda arc. ...
ABSTRACT The Seiland Igneous Province of the North Norwegian Caledonides consists of a suite of d... more ABSTRACT The Seiland Igneous Province of the North Norwegian Caledonides consists of a suite of deep-seated rift-related magmatic rocks emplaced into paragneisses during late Precambrian to Ordovician time. In the south-eastern part of the province, contact metamorphism of the paragneisses and later reworking of intrusives and associated contact aureoles have resulted in the development of three successive metamorphic stages. The contact metamorphic assemblage (M1) Opx + Grt + Qtz + Pl + Kfs + Hc + Ilm ± Crd is preserved in xenolithic rafts of paragneiss within metagabbro. Geothermobarometric calculations yield 930-960d̀ C and 5-6.5 kbar for the contact metamorphism. M1 was followed by cooling, accompanied by strong shearing, formation of the gneiss foliation and recrystallization at intermediate-P granulite facies conditions (M2). Stable M2 phases are Cpx + Opx + Pl +Ilm ± Hbl in metagabbro and Grt ± Sil ± Opx + Kfs + Qtz + Pl ± Bt + Ilm in host paragneiss. The M2 conditions are estimated to 700-750d̀ C and 5-7 kbar. A subsequent pressure increase is recorded in the M3 episode, which is associated with recrystallization in narrow ductile shear zones and secondary growth on M2 minerals. M3 is defined by the assemblages Grt + Cpx ± Opx + Pl + Ru + Qtz in metagabbro, and Grt ± Ky + Qtz + Pl ± Kfs + Bt + Ru in host paragneiss. M3 conditions are estimated to 650-700d̀ C and 8-10 kbar. The substantial pressure increase related to the M2 → M3 transition is interpreted to be a result of (early?) Caledonian overthrusting. Chemical zoning in cordierite and biotite suggest rapid cooling following the M3 event. The proposed P-T-t evolution implies that the tectonic evolution of the Seiland Igneous Province was long (at least 330 Ma) and complex and involved initial rifting and extension followed by crustal thickening and compression.
Granulite facies migmatitic gneisses from the Seiland Igneous Province (northern Norway) were def... more Granulite facies migmatitic gneisses from the Seiland Igneous Province (northern Norway) were deformed during deep crustal shearing in the presence of melt, which formed by dehydration melting of biotite. Partial melting and deformation occurred during the ...
The Seiland Igneous Province (Northern Norway) is a rift-related magmatic suite emplaced in the s... more The Seiland Igneous Province (Northern Norway) is a rift-related magmatic suite emplaced in the span from 570 to 520 Ma. The magmatic province comprises dominantly alkaline mafic and ultramafic intrusives. The high-grade paragneisses from the Øksfjord peninsula represent ...
Archean alkaline complexes are extremely rare but are of particular interest because the magmas h... more Archean alkaline complexes are extremely rare but are of particular interest because the magmas have a mantle origin. Given their high Sr and Nd contents, crustal contamination has only a minor impact on the mantle-derived isotopic signatures. Therefore, they can provide valuable information on the isotopic composition of the subcontinental mantle and geodynamics in Archean. The previously reported Late Archean alkaline complexes (2.7-2.6 Ga) from the Canadian and Australian shields belong to the potassic series, are depleted in LIL and HFS elements, and are related to subduction, thereby forming in a compressive tectonic environment and having a depleted mantle source. The absence of Archean sodic alkaline complexes forming in extensional environments was mainly ascribed to the absence of metasomatic processes in the mantle and lower lithosphere (Blichert-Toft et al., 1996). Greenland Archean alkaline complexes (2698-2664 Ma syn- to post-kinematic pyroxenites, hornblendites, norite...
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