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Jean-Pierre Burg Luc-Emmanuel Ricou Zivko Ivano Ivan Godfriaux Dimo Dimov Laslo Klain 《地学学报》1996,8(1):6-15
Mylonitic gneisses of the Bulgarian and Greek Rhodope were deformed under medium pressure-type metamorphism. The kinematic information contained in these gneisses shows that shear-deformation occurred during development of a nappe complex. Lithologies and metamorphic histories allow a lower (footwall) and an upper (hanging wall) terrane to be distinguished that define a crustal-scale duplex. As oceanic crust is involved, collision between two continental units with subsequent crustal thickening is inferred. The blocks would be Moesia to the north, and the Lower-Rhodope promontory to the south, which collided in the Mesozoic to early Cenozoic. The nappe complex is characterized by south to southwestward (foreland directed) piling-up and is associated with both coeval and subsequent extension. The late extension is associated with the establishment of a high temperature-low pressure metamorphic gradient and plutonism that predates, but makes a transition to, the lithospheric extension of the Aegean Arc. 相似文献
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Bernard?HenryEmail author Kalin?Naydenov Dimo?Dimov Diana?Jordanova Neli?Jordanova 《International Journal of Earth Sciences》2012,101(3):747-759
The Kapitan-Dimitrievo pluton was emplaced within the 15 km wide Maritsa shear zone during the Late Cretaceous. It has well-known
U–Pb zircon age (78.54 ± 0.13 Ma) and appears as a late-syntectonic intrusion that marked the last ductile deformation in
the Maritsa shear zone. Magnetite is believed to be the main carrier of the magnetic fabric in this pluton, and crystallized
mainly late, after the main rock-forming minerals. Two fabrics are recorded, a visible syn-magmatic fabric (due to magma flow)
and magnetic late-magmatic fabric (related to regional stresses). Although different, both are mainly related to the shearing
along this shear zone. These results constrain in age the dextral strike-slip controlled emplacement and evolution of the
Late Cretaceous plutons from Central Bulgaria. 相似文献
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We synthesized series of polyfunctional aminooligomers by means of condensation from polychlorparaffine with ethylenediamine. After modifying them with dimethylsulphate watersoluble oligomers of (quaternary) polyamines are obtained, which can be successfully used as biocides for treating circulating cooling-waters from different refinery plants. The products have low foaming and formed foam is unsteady. The bactericide properties of the successful samples are good. For the interval time for two to twenty hours of treatment at static conditions the microbe number value decreases by more than 99.99% at a 50 mg/dm3 dose of a biological active substance. At dosing it up to seventy-two hours the biomass is finely dispersed and does not precipitate on the walls of the chemical set-equipment. 相似文献
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S. Kraus H. Miller D. Dimov E. Hegner M. McWilliams Z. Pecskay 《Journal of South American Earth Sciences》2008,26(4):498-512
The Antarctic Peninsula has been part of a magmatic arc since at least Jurassic times. The South Shetland Islands archipelago forms part of this arc, but it was separated from the Peninsula following the Pliocene opening of the Bransfield Strait. Dikes are widespread throughout the archipelago and are particularly accessible on the Hurd Peninsula of Livingston Island. The host rocks for the dikes are represented by the Miers Bluff Formation, which forms the overturned limb of a large-scale fold oriented 63/23 NW. The orientation of minor structures indicates a fold axis oriented NNE–SSW (24/0). Structural analysis of the dikes and their host rocks shows that the tectonic regime was similar to other parts of the archipelago and that only minor changes of the stress field occurred during dike emplacement.Based on crosscutting field relationships and geochemical data, six early Paleocene to late Eocene intrusive events can be distinguished on Hurd Peninsula. In contrast to calc-alkaline dikes from other parts of the South Shetland Islands, the majority of the Hurd Peninsula dikes are of tholeiitic affinity. Nd and Pb isotope data indicate a significant crustal component, particularly during initial magmatic activity.Plagioclase 40Ar/39Ar and whole rock K–Ar ages show that dike emplacement peaked during the Lutetian (48.3 ± 1.5, 47.4 ± 2.1, 44.5 ± 1.8 and 43.3 ± 1.7 Ma) on Hurd Peninsula and also further northeast on King George Island. Dike intrusion continued on Livingston Island at least until the Priabonian (37.2 ± 0.9 Ma). The type of magma sources (mantle, slab, crust and sediment) did not change, though their relative magmatic contributions varied with time.During Cretaceous and Early Paleogene times, the Antarctic Peninsula including the South Shetland Islands was situated southwest of Patagonia; final separation from South America occurred not before the Eocene. Thus, the geological evolution of Livingston Island is related as much to the development of Patagonia as of Antarctica, and needs to be considered within the history of southernmost South America. 相似文献
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B. Henry D. Jordanova N. Jordanova M. E. M. Derder B. Bayou M. Amenna D. Dimov 《Studia Geophysica et Geodaetica》2007,51(2):293-314
In a number of AMS studies, the presence and deciphering of composite magnetic fabrics is of major importance for a correct
interpretation of the data. On the basis of several examples from intrusive rocks (diorites and dolerites) we show that the
use of laboratory heatings can help to extract at least one component of the composite magnetic fabrics usually present. The
procedure includes comparison of the fabrics measured after stepwise laboratory heating with the fabrics determined by tensor
difference and by linear regression analysis.
In the diorite samples, the measured AMS results from the superimposition of different component fabrics and does not correspond
exactly to any of these fabrics. In these dykes, isolated magnetic fabric during thermal treatment corresponds to that of
the main magnetic mineral (Ti-poor titanomaghemite) and reveals an unknown structure. In volcanic flow or doleritic dykes,
a “parasitic” fabric related to late or post-magmatic evolution superimposed to the flow fabric can produce important scattering
of the AMS principal directions. Decomposition of magnetic fabric during thermal treatment allows isolation of the flow fabric. 相似文献
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