Secular mantle cooling controlled late appearance of global kimberlite magmatism. Abstract Kimberlite magmatism has occurred in cratonic regions on every continent. The global age distribution suggests that this form of mantle melting has been more prominent after 1. Although preservation bias has been discussed as a possible reason for the skewed kimberlite age distribution, new treatment of an updated global database suggests that the apparent secular evolution of kimberlite and related CO2-rich ultramafic magmatism is genuine and probably coupled to lowering temperatures of Earth’s upper mantle through time. These conditions occur within the convecting asthenospheric mantle directly beneath thick continental lithosphere. However, extraction of low-volume melts to Earth’s surface requires tectonic triggers. Abrupt changes in the speed and direction of plate motions, such as typified by the dynamics of supercontinent cycles, can be effective in the creation of lithospheric pathways aiding kimberlite magma ascent. Provided that CO2- and H2O-fluxed deep cratonic keels, which formed parts of larger drifting tectonic plates, existed by 3 Ga or even before, kimberlite volcanism could have been frequent during the Archean. At around this time kimberlites replace komatiites as the hallmark mantle-derived magmatic feature of continental shields worldwide.
Dipl.-Geol. Milica Bozovic
Fractionation of Cu and Mo isotopes caused by vapor-liquid partitioning, evidence from the Dahutang W-Cu-Mo ore field, Geochemistry Geophysics Geosystems , 17, , doi: Three-dimensional imaging of a single fluid inclusion in sphalerite by nano X-ray tomography. Ore Geology Reviews, 71, 8.
論文 年 年. Geochemistry of A-type Granites in the Huangshaping Polymetallic Deposit (South Hunan, China): Implications for Granite Evolution and Associated Mineralization.
Implications for the Cenozoic mantle replacement in southwestern China. Implications for geodynamic change of the accretionary orogenic belt. Mesoproterozoic emplacement and enriched mantle derivation of the Racherla alkali syenite, Palaeo-Mesoproterozoic Cuddapah basin, southern India: Insights from in situ Sr-Nd isotopic analysis on apatite.
Palaeoproterozoic of India ed. Late Cretaceous-Paleogene stratigraphic and basin evolution in the Zhepure Mountain of southern Tibet: Identification of Early Carboniferous granitoids from Southern Tibet and implication for terrane assembly related to the Paleo-Tethyan evolution. Early Eocene crustal thickening in southern Tibet: New age and geochemical constraints from the Gangdese batholith. New constraints on the last residue of the Lunar Magma Ocean. Mesozoic accretion of juvenile sub-continental lithospheric mantle beneath South China and its implications: Preservation of ancient Os isotope signatures in the Yungbwa ophiolite southwestern Tibet after subduction modifications.
The Xinchang peridotite xenoliths reveal mantle replacement and accretion in southeastern China. Neodymium isotopic compositions of the standard monazites used in U—Th—Pb geochronology.
Triggers on sulfide saturation in Fe-Ti oxide-bearing, mafic-ultramafic layered intrusions in the Tarim large igneous province, NW China. The provenance of late Permian karstic bauxite deposits in SW China, constrained by the geochemistry of interbedded clastic rocks, and U—Pb—Hf—O isotopes of detrital zircons. Lithos, , Hong LB; Y. Hydrous orthopyroxene-rich pyroxenite source of the Xinkailing high magnesium andesites, Western Liaoning:
In this article, we present whole-rock geochemical and Sr-Nd isotopic data, zircon U-Pb age data, and in situ Hf isotope analyses for both the host rocks and the mafic enclaves in the Chongmuda-Mingze granitoids from southern Tibet.
This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision.
The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.
Introduction In situ radiogenic isotope determinations with microscale resolution, especially of Sr, can represent a powerful tool in different fields of geological and life sciences. In particular, this technique is nowadays one of the most important methods for the investigation and interpretation of magmatic processes, as well as of environmentally-induced responses of terrestrial mammals; it has the potential to greatly enhance our understanding of not only volcanic systems and the related magma genesis and evolution, but also of the physiological mechanisms behind specific organic adaptations.
Since crystals record changes occurring in the environment in which they grow e. In addition, variation of Sr-isotope composition from core to rim within the same crystal can shed light on the complex pre-eruptive history of active volcanoes. Therefore, combining micro- small-scale isotope data with textural and petrographic data provides significant information on crystals residence time, magma production rates, and recharge dynamics e.
CV Theofilos Toulkeridis
Godthelp in Hill, Robert S. White, , The Nature of Hidden Worlds: Australian Conservation Foundation, Melbourne. Michael Archer, Suzanne J. Gehling, Kathleen Grey, Guy M.
内蒙古镶黄旗哈达庙地区晚古生代中酸性侵入岩的年代学、地球化学、Sr-Nd同位素组成及其地质意义. 岩石学报, 30(1): The SHRIMP U-Pb dating of zircons from granite porphyry and diorite of the Hadamiao area yields ages of ±3Ma and ±3Ma.
Jena Verlag von Gustav Fischer. Bivalve paleogeography and the Hispanic corridor: Paleogeography, Paleoclimatology and Paleoecology, Ridge collision, slab-window formation, and the flux of Pacific asthenosphere into the Caribbean realm. Palabras de apertura , Palabras , Comunicaciones , Notas. Acevedo del Monte, E. Ciencias de la Tierra y el Espacio, 7: Influencia del Cuaternario en el desarrollo del relieve de Cuba occidental: Bulletin of the Venezuelan Speleology Society, 5 El Sistema Cavernario Majaguas-Cantera.
El valle de San Carlos y sus inmediaciones:
The Geological and Tectonic Framework of Europe
Cenozoic volcanic rocks show two clusters of compositions compilation in Lucassen et al. The regional distribution of the clusters indicates Pb provinciality Mamani et al. The unradiogenic Midproterozoic Arequipa source is already an endmember in the compositional array of the Early Palaeozoic basement rocks. The spatial distribution and related to the huge area still sparse geochronological data does not unequivocally allow to distinguish between continuous high temperatures or episodes of thermal relaxation.
Show Summary Details Preview The Middle Latin Valley volcanic field forms part of the Roman Magmatic Province and includes Pleistocene monogenetic volcanism characterized by the emplacement of small lava flows and minor pyroclastic ejecta and flows. The absence of a main volcanic edifice and of a large, shallow-level magma reservoir allows the eruption of primitive magmas. Geochemical and petrological data suggest that at least four types of mafic parental magmas are present within the volcanic field: The Middle Latin Valley volcanic field forms part of the Roman Magmatic Province and includes Pleistocene monogenetic volcanism characterized by the emplacement of small lava flows and minor pyroclastic ejecta and flows.
Incompatible trace element contents strictly follow K2O, but overall the groups of rocks show similar trace element fractionation, with high field strength elements less enriched than large ion lithophile elements. Intermediate isotopic compositions between these two end-members are shown by leucitites—plagio-leucitites and shoshonites.
A clear, time-dependent trend of isotopic variation is observed.
Geology of Japan
Geological setting of the study; Mineral composition of the dykes; Discussion of findings. The Sr, Ba, and rare earth elements REEs concentrations and Sr isotopic composition of anhydrite and gypsum have been determined for samples from the Matsumine, Shakanai, and Hanaoka Kuroko-type massive sulfide? Antarctic continental weathering changes during Eocene-Oligocene cryosphere expansion Robert, Christian; Kennett, James P. Effects of weathering on the structures of the area; Indications of chemical weathering in the area; Variations in the clay minerals in the area.
Origin of iron-oxide and silicate melt rocks in Paleogene sediments of southern Ellesmere Island, Canadian Arctic Archipelago, Nunavut.
Evolution of Taapaca volcano, N. Chile: evidence from major and trace elements, Sr-, Nd-, Pb-isotopes, age dating and chemical zoning in sanidine megacrysts.
Originally named in by Johann Friedrich August Breithaupt as a group of micas showing biaxial characteristics and applied as a genus name to all of the known biaxial mica minerals then defined. In , Franz von Kobell discarded phengite as a genus name, partly because binomial nomenclature of minerals had been discarded, and he resurrected the name phengite and defined it as a muscovite with high silica contents, as a way of discussing mica formulas with varying fixed molecular forms.
Dana criticized the use of phengite in and von Kobell apparently abandoned the name. Winchell resurrected phengite in the same manner used by von Kobell in order to assign fixed molecular mixing to account for excess Si substitution in muscovite. Guidotti and others called slightly hypersilicic muscovite “phengitic muscovite” or simply phengite when Si was greater than 3. In , phengite was defined as a high silica variety of muscovite on the chemical join between muscovite, celadonite, and aluminoceladonite, depending on the composition of the octahedral substitutions, but phengite ceased to be considered an end-member composition.
Phengite is an aluminous true mica which contains a high amount of tetrahedrally co-ordinated Si. As this Si amount increases, additional octahedrally co-ordinated cations are necessary for charge balance. This is an uncommon condition as there is normally a composition gap between dioctahedral and trioctahedral micas.
University of Tasmania, Australia
Geochemical transition shown by Cretaceous granitoids in southeastern China: Implications for continental crustal reworking and growth. Petrogenesis of the Cretaceous Zhangzhou batholith in southeastern China: Zircon U—Pb age and Hf—O isotope evidence.
Phengite is an aluminous true mica which contains a high amount of tetrahedrally co-ordinated Si. As this Si amount increases, additional octahedrally co-ordinated cations are necessary for charge balance. This is an uncommon condition as there is normally a composition gap between dioctahedral and trioctahedral micas. The substitutions are not restricted to trivalent (Fe, Al) or divalent.
The Canary Islands developed in a geodynamic setting characterized by Jurassic oceanic lithosphere formed during the first stage of opening of the Atlantic at Ma and lying close to a passive continental margin on a very slow-moving tectonic plate — the African plate. In addition, the archipelago lies adjacent to a region of intense active deformation comprising the Atlas mountains, a part of the Alpine orogenic belt. Geographic and geodynamic setting of the NW African continental margin with the Canary Islands and other archipelagos from Carracedo et al.
Seismic refraction data and magnetic anomalies suggest that all the islands lie on oceanic crust and their limit is located between Lanzarote-Fuerteventura Figure 3 and the coast of Africa Roest et al. The continent-ocean boundary is characterized by the presence of a km-thick layer of sediments. The seismic sections show a number of discontinuities, interpretated as basement fractures, and some of them are seismically active.
September 2017 LIP of the Month
The volcano is also referred to by Mexicans as El Popo. The alternate nickname Don Goyo comes from the mountain’s association in the lore of the region with San Gregorio St. Gregory , “Goyo” being a nickname-like short form of Gregorio. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene , producing massive debris avalanche deposits covering broad areas south of the volcano.
The modern volcano was constructed to the south of the late- Pleistocene to Holocene El Fraile cone.
Popocatépetl (Spanish pronunciation: [popokaˈtepetl] (listen); Nahuatl: Popōcatepētl [popoːkaˈtepeːt͡ɬ] (listen)) is an active stratovolcano, located in the states of Puebla and Morelos, in Central Mexico, and lies in the eastern half of the Trans-Mexican volcanic 5, m (17, ft) it is the second highest peak in Mexico, after Citlaltépetl (Pico de Orizaba) at 5, m.
Landsat Image provided by Ronald W. Lunar and Planetary Science XX, pp. Impact evidence from Massignano, Arcona. Dense fluid inclusions and their petrological significance abstract. Russian , Mineralogicheskii Zhurnal, v. International Geology Review, v. Geological Society of America, Special Paper , pp. Mineralogicheskoye Obshchestvo Zapiski, v.
Large Meteorite Impacts and Planetary Evolution,.