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11.
M. K. Pavićević V. Cvetković G. Amthauer A. Bieniok B. Boev F. Brandstätter M. Götzinger R. Jelenković D. Prelević T. Prohaska 《Mineralogy and Petrology》2006,88(3-4):527-550
Summary Results of a multidisciplinary study on quartz concentrates (mineralogically separated) and etched concentrates (stoichiometric
quartz) from three locations at Allchar (Macedonia) are presented. The investigation of quality and composition of these quartz
samples is of great interest because the same material has been previously used as monitor for 26Al Acceleration Mass-Spectrometry (AMS) erosion rate estimates. Two genetically different types of quartz are distinguished
in the studied samples which petrologically can be described as hydrothermally altered dacites or quartz latites; i.e. volcanic
(QV) and hydrothermal (QH) quartz with relative proportions of QH:QV around 3:2. QH is genetically related to the Allchar Sb–As–Tl–S mineralization having very high Sb (85–785 ppm), As (7.6–78 ppm) and (Tl
3.3–4.0 ppm) contents. This type of quartz is also characterized by very high Li (129–138 ppm), Al (2424–2520 ppm) and Ti
(153–219 ppm) concentrations. QV appears to be much less enriched in trace elements having Al and K contents ranging from 0 to 280 ppm and from 50 to 85 ppm,
respectively. 26Al AMS measurements were done on the samples containing two genetically different types of quartz but this had no effects
on the interpretation and erosion rate determinations. However, the extremely high Al concentrations in the analyzed quartz
have generally negative effects, mainly by decreasing 26Al/27Al ratios and thus causing an increase of the detection limit. The disagreement between the results of 26Al AMS analyses and quantitative geomorphologic data for one location is probably caused by different geographical position
with respect to the direction of cosmic rays. 相似文献
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13.
Vladica?Cvetkovi?Email author Hilary?Downes Dejan?Prelevi? Milivoje?Jovanovi? Marina?Lazarov 《Contributions to Mineralogy and Petrology》2004,148(3):335-357
Mantle xenoliths from Paleogene basanites of East Serbia were studied using EMP and LA-ICP-MS techniques in order to better understand mantle characteristics in this region. Five different mantle lithologies have been distinguished: a dunite/harzburgite/lherzolite (D/HZ/L) group, clinopyroxene-rich lherzolites (Cpx-L), clinopyroxene megacrysts (Cpx-M), spinel-rich olivine websterites (OWB1) and spinel-poor olivine websterites (OWB2). D/HZ/L xenoliths are the most common and represent normal mantle composed of typical anhydrous spinel peridotites with well equilibrated, unzoned silicates characterized by high Mg# s. Negative correlations between Mg# and TiO2, Al2O3 and CaO wt% in clinopyroxenes (cpx) and orthopyroxenes (opx) and the Cr–Al trend in spinel (sp) suggest depletion via extraction of basaltic melts. The modal composition of D/HZ/L xenoliths and unusual low-Al opx suggest that the lithospheric mantle underneath East Serbia is more depleted than normal European lithosphere. D/HZ/L xenoliths contain numerous pockets and veins filled by Cr-rich cpx, Ti-rich spinel, altered glass, apatite and rare ilmenite and phlogopite. Petrographic observations, supported by major element contents in sp and cpx, and modelling using trace element contents in cpx, indicate that the pockets and veins formed from infiltration of alkaline melts and reaction with peridotite wall-rock causing opx and spinel replacement. The same alkaline melt-related metasomatism gave rise to the Cpx-L and OWB1 mantle xenoliths and Cpx-M xenocrysts. Trace element contents of cpx in these xenoliths show a distinctively concave downwards REE pattern with a HFSE depletion, very similar to cpx megacrysts from the Pannonian Basin and to vein cpx from Eifel. In contrast, the OWB2 xenoliths show evidence of precipitation from subduction-related mafic to ultramafic melts, as inferred from their opx-rich lithology and unusual Cr-rich spinels. They are probably related to subduction magmatism during the Late Cretaceous.Milivoje Jovanovi: deceased in April 2004 相似文献
14.
Vladica Cvetkovi Hilary Downes Dejan Prelevi Marina Lazarov Kristina Resimi-ari 《Journal of Geodynamics》2007,43(4-5):504-527
A suite of highly depleted peridotite xenoliths in East Serbian Palaeogene basanites represents the lithospheric mantle beneath the Balkan Peninsula. The xenoliths are harzburgites, clinopyroxene-poor lherzolites and rare dunites. They contain mostly <5 vol.% of modal clinopyroxene and are characterized by high Mg# in silicates (>91), high Cr# in spinel (mostly 0.5–0.7), and by distinctively low Al2O3 contents in orthopyroxene (mostly 1–2 wt.%). They have experienced some mantle metasomatism which has slightly obscured their original composition. Nevertheless, the general characteristics of the xenoliths imply a composition which is significantly more depleted than most non-cratonic sub-continental mantle xenolith suites, as well as orogenic peridotites and abyssal peridotites. Geological and compositional evidence suggests that the xenoliths do not represent Archean mantle. The existence of Proterozoic mantle cannot be entirely excluded, although it is in disagreement with geological evidence. On the other hand, the studied xenoliths are compositionally very similar to peridotites of modern oceanic sub-arc settings. The existence of such a depleted lithospheric mantle segment is also inferred from the presence of rare orthopyroxene-rich xenoliths in the same suite. These are interpreted to have originated as lithospheric precipitates of high-Mg, SiO2-saturated magmas that require a highly depleted mantle source. Such source is typically required by boninitic-like magmas of intraoceanic suprasubduction settings. A proposed geodynamic model to explain these observations involves accretion or underplating of the lower parts of the Tethyan oceanic lithosphere during the Upper Jurassic closure of the eastern branch of the Vardar ocean. 相似文献
15.
Senecio Schefer Vladica Cvetković Bernhard Fügenschuh Alexandre Kounov Maria Ovtcharova Urs Schaltegger Stefan M. Schmid 《International Journal of Earth Sciences》2011,100(5):1181-1206
Two age groups were determined for the Cenozoic granitoids in the Dinarides of southern Serbia by high-precision single grain
U–Pb dating of thermally annealed and chemically abraded zircons: (1) Oligocene ages (Kopaonik, Drenje, Željin) ranging from
31.7 to 30.6 Ma (2) Miocene ages (Golija and Polumir) at 20.58–20.17 and 18.06–17.74 Ma, respectively. Apatite fission-track
central ages, modelling combined with zircon central ages and additionally, local structural observations constrain the subsequent
exhumation history of the magmatic rocks. They indicate rapid cooling from above 300°C to ca. 80°C between 16 and 10 Ma for
both age groups, induced by extensional exhumation of the plutons located in the footwall of core complexes. Hence, Miocene
magmatism and core-complex formation not only affected the Pannonian basin but also a part of the mountainous areas of the
internal Dinarides. Based on an extensive set of existing age data combined with our own analyses, we propose a geodynamical
model for the Balkan Peninsula: The Late Eocene to Oligocene magmatism, which affects the Adria-derived lower plate units
of the internal Dinarides, was caused by delamination of the Adriatic mantle from the overlying crust, associated with post-collisional
convergence that propagated outward into the external Dinarides. Miocene magmatism, on the other hand, is associated with
core-complex formation along the southern margin of the Pannonian basin, probably associated with the W-directed subduction
of the European lithosphere beneath the Carpathians and interfering with ongoing Dinaridic–Hellenic back-arc extension. 相似文献
16.
Lj. Cvetković V. A. Boronikhin M. K. Pavićević D. Krajnović I. Gržetić E. Libowitzky G. Giester E. Tillmanns 《Mineralogy and Petrology》1995,53(1-3):125-131
Summary A hitherto unknown TI-sulfosalt, containing antimony and arsenic, was discovered by ore microscopy (including quantitative reflectance measurements) and electron microprobe analysis in samples from the Allchar TI-Sb-As sulfide ore deposit (Macedonia). The chemical formula is TI5Sb9(As,Sb)4S22, X-ray single crystal and powder diffration data gave the lattice parameters
o = 7.393(4) Å, b0 = 8.707(2) Å, co = 17.584(3) Å, = 103.81(1)°, = 91.79(1)°, = 109.50(1)°; space group
, Z = 1. The new mineral and the new mineral naine jankoviéite have been approved by the IMA/CNMMN.
Jankoviit, Tl5Sb9(As,Sb)4S22, ein neues TI-Sulfosalz aus Allehar, Macedonien
Zusammenfassung Ein bislang unbekanntes Thallium-Antimon-Arsen-Sulfosalz wurde mittels Erzmikroskopie (inklusive quantitativer Reflexionsmessungen) und Elektronenstrahl-Mikrosonde in Proben aus der TI-Sb-As-Sulfid-Lagerstätte Allchar in Macedonien entdeckt. Die chemische Formel lautet Tl5Sb9(As,Sb)4S22, aus Röntgen-Einkristallaufnahmen und Pulverdiffraktogrammen konnten folgende Gitterkonstanten bestimmt werden: ao = 7.393(4) Å, bo = 8.707(2) _Å, co = 17.584(3) Å, a = 103.81(1)°, = 91.79(1)°, = 109.50(1)°; Raumgruppe , Z = 1. Das neue Mineral, sowie der neue Mineralname Jankoviit wurden durch die IMA/CNMMN anerkannt.相似文献