Добрый день, Коллеги. Важное сообщение, просьба принять участие. Музей Ферсмана ищет помощь для реставрационных работ в помещении. Подробности по ссылке
Since the University of Oulu bought last year a LA-ICP-MS to expand their ways of research concerning corrosion and agglomeration problems in fluidized bed boilers. The objective of this thesis was to give a review about LA-ICP-MS, what are its capabilities, how to calibrate, what are the start up procedures and what kind of measurements can we make? The thesis will discus every step of the LA-ICP-MS; ablation, ionisation and detection applied on the LA-ICP-MS of the University of Oulu. After the literature part we try to improve our measurement strategies with the LAICP-MS, in order to get better results out of it. I would like to thank the University of Oulu for giving me the opportunity to write my thesis here. While writing my thesis I had a lot of help from Risto Laitinen, Minna Tiainen, Harri Kola, Heikki Ollila, Mirja Piispanen and Susanna Arvilommi, I would like to thank them for that. Thanks go also to Andoni Michelena and Bert De Smet for reading my thesis through. Finally I would like to thank my parents for their financial and mental support. <...>
Lasi II was the second in a series on international meetings dealing with the physical geology of subvolcanic systems and demonstrated the diversity of techniques utilised in the analysis of shallow intrusions. These included both numerical and analogue modelling of magmatic processes, the analysis of magnetic fabrics to understand magma flow, the interpretation of seismic reflection data as well as outcrop-based studies. This diversity of research methodologies was applied to a range of shallow intrusions including sills, dykes and laccoliths as well as the interaction of magma with sediments. The presentations provided new insights into the morphological development of igneous intrusions, in particular re-assessments of the controls on their emplacement; the interactions between propagating magma bodies, between intrusions and overlying volcanic centres as well as magma-sediments interactions and their potential climatic effects. <...>
In the Late Cambrian-Ordovician, Gondwana-derived microcontinents such as Kokchetav, Altai-Mongolian, Tuva-Mongolian, and Barguzin, as well as the Kazakhstan-Tuva-Mongolian island arc or a system of island arcs were involved in intense accretion-collision processes in similar geodynamic settings on a vast territory of Central Asia — from West Kazakhstan to Lake Baikal. The processes were likely to be the result of a large rebuilding of the Earth’s crust possibly related to the increased mantle impact on the lithosphere as they were simultaneous to the opening of the Uralian and Mongolian-Okhotsk (Turkestan) Oceans. The 970–850 Ma breakup of Rodinia and the 760–700 Ma important tectonic events were followed by the Late Cambrian-Early Ordovician plume magmatism impulse at 500–480 Ma, which led to the opening of new oceans and accelerated the accretion of the Gondwana-derived blocks to the island arc and subsequent formation of an extended — more than 6000 km long — Kazakhstan-Baikal orogenic belt.
A comparative analysis of the Late Cretaceous–Paleocene volcanism was conducted for four areas of Kamchatka: the Pravyi Tolbachik–Levaya Shchapina–Adrianovka interlfuve (the northern part of the Tum-rok Range), the area south of the Ipuin River and Mt. Khrebtovaya (the northern Valaginsky Range), the area of Mt. Savul’ch (the upper reaches of the Kitil’gina River, northern Valaginsky Range), and the Kirganik– Levaya Kolpakova interfluve (the Sredinny Range). New petrochemical, geochemical, and isotopic data on the volcanic rocks from these areas are reported. The examination of this material, together with already published data on volcanic and plutonic rocks of similar composition and age, made it possible to establish the following: (1) the considered basaltoids are ascribed to the subalkali basalt–trachyandesite series with transition toward a meymechite–picrite rock association; (2) the alkali content in the rocks of the Valaginsky–Tumrok–Sredinny ranges increases simultaneously with the increase of the Rb content, while the contents of HFSE and radioactive elements decrease and then again increase. Two trends are identified in the Ybn–Cen diagram: a positive trend spanning most of the volcanic and plutonic rocks and a negative trend defined by the data points of the meyme-chite–picrite association. The first trend reflects the rock evolution during crystallization differentiation, while the second trend was produced by different degrees of melting of initial protolith. The possible geodynamic reconstructions of this volcanism are discussed as well
The Fossil Bluff Group of eastern Alexander Island was deposited in the fore-arc basin of an active magmatic arc, which formed the present-day Antarctic Peninsula. Cephalopods are common throughout the group. Ammonites and belemnites of several localities within the northern half of the outcrop are described, and previously described cephalopods are revised. Nine genera and seventeen species of ammonites (of which Raimondiceras alexandrensis and Blanfordiceras weaveri are new), and two genera and sixteen species of belemnites (including two new subgenera: Belemnopsis {Parabelemnopsis) and B. (Telobelemnopsis), and four new species: B. {Belemnopsis) launceloti, B. (T.) rymilli, B. (T.) bertrami and B. (T.) stephensoni) are described. This detailed study of the cephalopods indicates that the Fossil Bluff Group ranges in age from Kimmeridgian (late Jurassic) to at least Aptian (early Cretaceous), and enables seven ammonite biozones and three belemnite biozones (including two sub-biozones) to be erected within the group. By comparing this new biozonation with other Southern Hemisphere schemes, the positions of the stage boundaries within the succession can be recognized.
In this paper we present new geochronological and thermochronological data from the Turkestan-Alai segment of the southern Kyrgyz Tien Shan, the Ferghana Basin transition and the Trans-Alai Pamir foreland. In the southern and central parts of the Alai Range, towards the Alai Valley, mainly post-collisional granitoids were targeted for zircon U/Pb dating by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), apatite fission-track (AFT) and apatite (U-Th-Sm)/He (AHe) thermochronology. These granitoids, and their thermally metamorphosed contact aureole, yielded Middle Permian zircon crystallization ages of 284 ± 4 to 264 ± 5 Ma. AFT ages (both using the traditional external detector approach as well as using LA-ICP-MS) for these samples are constrained to the Miocene and range between 22.3 ±1.1 and 8.4 ±0.3 Ma, while the AHe ages are somewhat younger, between 12.5 ±0.8 and 5.0 ± 0.3 Ma. This low-temperature thermochronological data suggests an Early Miocene onset of denudation in this area in the Tien Shan orogen, continuing through the Miocene and Pliocene. This denudation is interpreted as a response to reactivation of the mountain belt in the framework of India-Eurasia convergence, and specific to this region, of the Pamir-Tien Shan interaction. On the northern slopes of the Alai Range, at the edge of the Ferghana Basin, a Late Palaeozoic conglomerate yielded a reset Early Cretaceous AFT age of 118 ± 7 Ma, pointing to an older denudation event with respect to those identified in the southern and central parts of the Alai Range. A Mesozoic sediment sample from the same region only contains a Late Triassic age component of ~223 Ma. Mesozoic and Cenozoic age components on the other hand are all detected in the Cenozoic sediments of the Trans-Alai Range, at the transition between the southern Alai Valley and the Pamirs, revealing several Meso-Cenozoic denudation events in the adjoining basement source rocks. The age components in these detrital apatites are ~207 Ma, ~75 Ma, ~18 Ma and ~3 Ma.
The Late Paleozoic Tien Shan fold belt was formed in the course of subduction of the crust underlying the past Turkestan ocean under the Kazakh continent and subsequent collision of the latter with the Alai and Tarim massifs. The onset of subduction is evidenced by development of flysch sequences and olistostromes in the accretionary complex of the South Tien Shan: in the terminal Visean–Serpukhovian (~330–325 Ma ago) in the west and in the second half of the Bashkirian Age (~315 Ma ago) in the east of the Kyrgyz Tien Shan [1].1 The onset of collision between the Kazakh continent and Tarim Massif is dated back to the terminal Late Carboniferous based on the initiation of a foredeep along the northern margin of the latter [6]. The mature collision stage began in the mid-Asselian, when the last sea basins disappeared in the Tien Shan and granitoids intruded in its southern segment [1, 9]. The position and age of the volcanic arc that was forming in the course of convergence between the Kazakh continent and the Tarim Massif remain unclear. Recently, this problem acquired particular significance, since the data available for the territory of China imply subduction under the Tarim Massif and an Early Carboniferous age of collision, i.e., substantially older as compared with that assumed for the Kyrgyz region [7].
ANDREWS, J. T., AUSTIN, W. A., BERGSTEN, H. & JENNINGS, A. E. Palaeoceanography of North Atlantic margins: an introduction KNUDSEN, K. L. & AUSTIN, W. E. N. Late glacial foraminifera Canadian North Atlantic margins ANDREWS, J. T., OSTERMAN, L. E. JENNINGS, A. E., SYVITSKI, J. P. M., MILLER, G. H. & Weiner, N. Abrupt changes in marine conditions, Sunneshine Fiord, eastern Baffin Island, NWT during the last deglacial transition: Younger Dryas and H-0 events JENNINGS, A. E., TEDESCO, K. A., ANDREWS, J. T. & KIRBY, M. E. Shelf erosion and glacial ice proximity in the Labrador Sea during and after Heinrich events (H-3 or 4 to H-0) as shown by foraminifera SYVITSKI, J. P. M., LEWIS, C. F. M. & PIPER, D. J. W. Palaeoceanographic information derived from acoustic surveys of glaciated continental margins: examples from eastern Canada
The geologic history of the San Manuel-Kalamazoo deposit has provided an opportunity for the examination of vertical and horizontal zoning relationships in a porphyry copper system. Precambrian Oracle "granite," a Laramide monzonite porphyry, and a Laramide dacite porphyry are hosts to zones of potassic, phyllic, argillic, and propylitic assemblages shown to be coaxially arranged outward from a potassic core through phyllic, argillic, and propylitic zones. Alteration zones at depth comprise an outer chlorite-sericite-epidote-magnetite assemblage yielding to an inner zone of quartz-K4eldspar-sericite-chlorite. Mineralization zones are conformable to the alteration zones, the ore zone (with a 0.5% Cu cutoff) overlapping the potassic and phyllic zones.
Folds and thrust faults formed by layer-parallel shortening coaxial with extensional structures such as normal dip-slip faults and ductile necking structures with orthorhombic fabric symmetry are usual, but little-recognised structures formed within normal dip-slip shear zones bounding rifts. They are generated because of the shear distribution in a zone of progressive deformation and may be later extended and disrupted depending on which part of the strain ellipsoid they may be located.
