Parental sources of high-alumina alkaline melts: Nd, Sr, Pb, and O isotopic evidence from the Devonian Kiya-Shaltyr gabbro-urtite intrusion, South Siberia

The isotope geochemistry (Nd(t) 4.8–5.4, 206Pb/204Pbin 18.05–18.36, 207Pb/204Pbin 15.53–15.57, 208Pb/204Pbin 37.59–37.83, 87Sr/86Sr(t) 0.7048–0.7057, 18OSMOW 8–10.5‰) and trace element compositio of the Kiya–Shaltyr gabbro–urtite pluton allow us to suggest a heterogeneous source and complex geodynamic settings of the Devonian alkali magmatism in the Kuznetsk Alatau. It is assumed that its evolution took place under conditions of partial mingling of matter of the depleted (PREMA) and enriched (EM) mantle with crustal contamination of the evolving melt. Such an interaction could have been a result of superposition of a mantle plume and an active margin (IOB and IAB components). In fold belts this led to the formation of hybrid high-alumina foidoite magmas

Mineralogy and geochemistry of triassic carbonatites in the Matcha alkaline intrusive complex (Turkestan-Alai Ridge, Kyrgyz Southern Tien Shan), SW Central Asian orogenic belt

Postorogenic intrusions of essexites and alkaline and nepheline syenites in the Turkestan-Alai segment of the Kyrgyz Southern Tien Shan coexist with dikes and veins of carbonatites dated at ∼220 Ma by the Ar–Ar and Rb–Sr age methods. They are mainly composed of calcite and dolomite (60–85%), as well as sodic amphibole, phlogopite, clinopyroxene, microcline, albite, apatite, and magnetite, with accessory niobate, ilmenite, Nb-rutile, titanite, zircon, baddeleyite, monazite-(Ce), barite, and sulfides. The rocks share mineralogical and geochemical similarity with carbonatites that originated by liquid immiscibility at high temperatures above 500 °C. Alkaline silicate and salt-carbonate melts are derived from sources with mainly negative bulk εNd(t) ∼ from −11 to 0 and high initial 87Sr/86Sr ratios (∼0.7061–0.7095) which may be due to mixing of PREMA and EM−type mantle material. Pb isotopic ratios in accessory pyrrhotite (206Pb/204Pb = 18.38; 207Pb/204Pb = 15.64; 208Pb/204Pb = 38.41) exhibit an EM2 trend. The intrusions bear signatures of significant crustal contamination as a result of magma genesis by syntexis and hybridism. Concordant isotope composition changes of δ13C (−6.5 to −1.9‰), δ18O (9.2–23‰), δD (−58 to −41‰), and δ34S (12.6–12.8‰) in minerals and rocks indicate inputs of crustal material at the stage of melting and effect of hot fluids released during dehydration of metamorphosed oceanic basalts or sediments. The observed HFSE patterns of the oldest alkaline gabbro may be due to interaction of the primary mafic magma with IAB-type material. The isotope similarity of alkaline rocks with spatially proximal basalts of the Tarim large igneous province does not contradict the evolution of the Turkestan-Alai Triassic magmatism as the “last echo” of the Tarim mantle plume

Mineralogy and geochemistry of triassic carbonatites in the Matcha alkaline intrusive complex (Turkestan-Alai Ridge, Kyrgyz Southern Tien Shan), SW Central Asian orogenic belt

Postorogenic intrusions of essexites and alkaline and nepheline syenites in the Turkestan-Alai segment of the Kyrgyz Southern Tien Shan coexist with dikes and veins of carbonatites dated at ∼220 Ma by the Ar–Ar and Rb–Sr age methods. They are mainly composed of calcite and dolomite (60–85%), as well as sodic amphibole, phlogopite, clinopyroxene, microcline, albite, apatite, and magnetite, with accessory niobate, ilmenite, Nb-rutile, titanite, zircon, baddeleyite, monazite-(Ce), barite, and sulfides. The rocks share mineralogical and geochemical similarity with carbonatites that originated by liquid immiscibility at high temperatures above 500 °C. Alkaline silicate and salt-carbonate melts are derived from sources with mainly negative bulk εNd(t) ∼ from −11 to 0 and high initial 87Sr/86Sr ratios (∼0.7061–0.7095) which may be due to mixing of PREMA and EM−type mantle material. Pb isotopic ratios in accessory pyrrhotite (206Pb/204Pb = 18.38; 207Pb/204Pb = 15.64; 208Pb/204Pb = 38.41) exhibit an EM2 trend. The intrusions bear signatures of significant crustal contamination as a result of magma genesis by syntexis and hybridism. Concordant isotope composition changes of δ13C (−6.5 to −1.9‰), δ18O (9.2–23‰), δD (−58 to −41‰), and δ34S (12.6–12.8‰) in minerals and rocks indicate inputs of crustal material at the stage of melting and effect of hot fluids released during dehydration of metamorphosed oceanic basalts or sediments. The observed HFSE patterns of the oldest alkaline gabbro may be due to interaction of the primary mafic magma with IAB-type material. The isotope similarity of alkaline rocks with spatially proximal basalts of the Tarim large igneous province does not contradict the evolution of the Turkestan-Alai Triassic magmatism as the “last echo” of the Tarim mantle plume

The Khairkhan dunite-troctolite-gabbro massif (Lake Zone of the Western Mongolia) - example of syncollision Middle Cambrian mafic intrusion

Geological, mineralogical, petrochemical and geochronological data are considered for the Khairkhan dunite-troctolite-gabbro massif in the Lake zone of Western Mongolia. The massif intrude the Lower Cambrian molasse stratum and intruded by the Middle Cambrian diorite-plagiogranite bodies (507 Ma). Mineralogical, petrographic and geochemical data show typical suprasubduction characteristics: high An component of plagioclases with increased iron content of olivines, high whole-rock alumina content, low contents of titanium and alkalis, Ta, Nb, Zr and Hf minima. The layered series is characterized by a layers of orbicular gabbros, which can be considered as gabbro-gabbro mingling. At the same time, high-temperature viscous-plastic deformations are characteristic of the layered series, which cover the entire volume of the intrusion. These observations, together with geological and geochronological data related to the melting of the suprasubduction mantle in the Cambrian-Ordovician time, allow treating the Khairkhan massif as an example of syncollisional stratified gabbroids

Geochemical evidence for multi-depth magma generation for Permian-Triassic dolerite and Late Cretaceous basanite of the Minusa Paleorift, Siberia

The chemical composition of alkaline (Late Cretaceous basanite) and subalkaline (Permian-Triassic dolerite) basaltoids of different ages in the northern part of the Minusa Trough was studied by optical emission spectroscopy and mass spectrometry with inductively coupled plasma. The revealed differences of subvolcanic rocks in the nature of enrichment in HFS- and LIL-elements may indicate the generation of primary magmas at different depths and small degrees of melting of garnet and spinel mantle peridotite. The model of decompression partial melting of the subcontinental lithospheric mantle under the garnet stability conditions is applicable to the formation of basanite. It is assumed that the formation of dolerite magma was due to the interaction of the melt from shallower spinel peridotite with the OIB component of the sublithospheric mantle plume

Immune response to opiates: new findings in heroin addicts investigated by means of an original enzyme immunoassay and morphine determination in hair

In the early 1970's, some papers appeared reporting an immune response to opiates in animals treated with morphine and in heroin addicts, but further researches failed to confirm these results in humans. The aim of the present work is investigating with a newly developed enzyme immunoassay the existence of specific antibodies to morphine in a group of opiate chronic users, controlled by means of the toxicological analysis of hair. Twenty five opiate addicts inpatients for detoxication treatments were investigated for the presence of morphine specific antibodies and for the morphine content in hair, as a marker of addiction to opiates. Antibodies to morphine were investigated using an original ELISA method using a morphine-human serum albumin conjugate immobilized into the wells of polystyrene microtiter plates. Morphine determinations in hair were accomplished by a radioimmunologic screening followed by HPLC confirmation of positive results. The group of opiate users, in which all the subjects resulted positive for morphine content in hair, showed in the ELISA test an average D OD% value significantly higher than the control group (p < 0.001); in particular, 16 out of 25 addicts could be classified positive for anti-morphine antibodies, which were identified as IgM. Inhibition studies demonstrated Ka's for morphine ranging from 10(4) to 10(10) M-1 and a high cross reactivity for codeine. The presence of circulating antibodies specific to morphine in chronic users of opiates is strongly supported by the present findings