Search

Neoproterozoic magmatism associated with the assembly and configuration of the Rodinia supercontinent is widely distributed in the India-Himalayan terrane. However, its petrogenesis and tectonic settings remain controversial. This study provides new geochronological and geochemical data on the Neoproterozoic bimodal magmatism from the eastern Himalayan orogen. In situ zircon U Pb dating revealed that the protoliths of amphibolites were emplaced at ca. 826 Ma and the granitic gneisses have crystallization ages of 825–820 Ma. The granitic gneisses exhibit geochemical features of A-type granites, with high initial (87Sr/86Sr)i ratio (0.7182–0.7394), low whole-rock eNd(t) (−8.4 to −6.6), and variable zircon eHf(t) (−7.4 to +1.0) values. They were probably generated by partial melting of the ancient lower crust with minor input of mantle components. The amphibolite samples are enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs), suggesting an arc affinity. They have relatively high initial (87Sr/86Sr)i ratios (0.7113–0.7136), low whole-rock eNd(t) (−1.1 to 1.4) and a wide range of zircon eHf(t) (−4.1 to 8.3) values, indicating that the protoliths of amphibolites were likely generated by partial melting of an enriched subduction-modified continental lithospheric mantle. Their geochemical signatures are similar to typical back-arc basin basalts. The presence of coeval A-type granites and arc-related mafic rocks is probably due to the existence of a back-arc system. We argue that the Neoproterozoic bimodal magmatism is a product of back-arc extension initiated at an early stage, resulting from the rollback of the Mozambique Oceanic slab. Combined with previous studies on Neoproterozoic magmas from India and the Himalayas, we suggest that an extensive Neoproterozoic back-arc system may have existed along the northwestern margin of the Rodinia supercontinent. This theory supports a scenario of an Andean-type continental margin for the India-Himalayan terrane during the middle Neoproterozoic.

The Cuonadong Sn-W-Be polymetallic deposit is the first Cenozoic leucogranite-related rare-metal deposit with giant metallogenic potential in the Himalayan orogen. However, controlling factors for the supernormal enrichment of beryllium, tin and tungsten in this deposit remain vague. In this study, we carried out systematic geochronological, whole-rock geochemical, and Sr-Nd isotopic analysis for the Cuonadong leucogranites, as well as detailed ore-forming geochronological analysis. The monazite U-Th-Pb, cassiterite U-Pb and muscovite Ar-Ar dating results, together with previously reported geochronological data, indicate that the major Cuonadong leucogranites (including, from old to young, weakly-oriented two-mica, two-mica granite and muscovite) were formed during ∼21-15 Ma, whereas the Sn-W-Be mineralization mainly occurred at ∼18-14 Ma. The Cuonadong leucogranites show strong peraluminous (A/CNK=1.09-1.22) features, and have high SiO2 (71.62-75.97 wt.%) and Al2O3 (14.04-16.09 wt.%) and low MgO (0.07-0.33 wt.%), MnO (0.01-0.15 wt.%) and total Fe2O3 (0.36-1.01 wt.%) contents, and are enriched in large ion lithophile elements (e.g., Rb, U, K, and Pb). These geochemical features together with enriched Sr-Nd isotopes (εNd(t) = -15.7 to -11.7; (87Sr/86Sr)i=0.71957-0.76313) indicate that the Cuonadong leucogranites belong to S-type granite and were derived from muscovite-induced dehydration melting of metapelites of the Higher Himalayan Crystalline Sequence. Perceptible linear variations of some major elements (e.g., Na2O, K2O, MnO, Fe2O3T, TiO2 and A/CNK) with increasing Rb/Sr ratios suggest these leucogranites experienced different degrees of evolution. Quantitative simulation calculations based on the whole-rock Rb, Sr, and Ba contents imply that the Cuonadong leucogranites experienced increasingly-strong fractional crystallization of plagioclase, K-feldspar and biotite from the weakly-oriented two-mica granite to two-mica granite and muscovite granite. Importantly, intense fractional crystallization leaded to notable enrichment of Sn, W and Be, although these elements are not obviously high in the relatively primitive magma for the Cuonadong leucogranites. Significantly, evident REE tetrad effects and deviation of twin-element pair ratios (K/Rb, K/Ba, Zr/Hf, Nb/Ta, and Y/Ho) from the chondritic values demonstrate that intense interaction between melts and F-rich aqueous fluids occurred during magmatic evolution. This implies that the Cuonadong leucogranites were derived from a volatile-rich magmatic system. The abundant volatiles probably remarkably facilitated and extended the fractional crystallization though lowering the solidus and viscosity of the magma. Thus, we propose that long-lived crystal fractionation (∼21-15 Ma) and mineralization (∼18-14 Ma) collectively leaded to supernormal enrichment of Sn, W, and Be in the Cuonadong Sn-W-Be polymetallic deposit. In contrast, the enrichment of Sn, W, and Be during the partial melting was insignificant.

We present in-situ zircon laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U–Pb ages, whole-rock geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern margin of the Qiangtang Block, Tibet, western China. The zircons yield a U–Pb age of ca. 123 Ma. The hornblende-bearing monzogranite shows metaluminous to weak peraluminous and high-K calc-alkaline characteristics exemplified by high silica (SiO2 = 67.57–70.57 wt%), high aluminium (Al2O3 = 14.68–15.78 wt%), high potassium (K2O = 4.00–5.14 wt%), high alkali (K2O + Na2O = 7.88–8.62 wt%), and low calcium contents (CaO = 1.72–2.17 wt%), with the aluminium saturation index (A/CNK) ranging from 0.98 to 1.09, suggesting that the Mugagangri monzogranite is a metaluminous to weak peraluminous I-type high-K calc-alkaline granite. Geochemically, similar to the arc magmas, the monzogranite is enriched in large-ion lithophile elements, and relatively depleted in high-field-strength elements. The monzogranite displays relatively high(87Sr/86Sr)i values (0.70972–0.71240), uniform eNd(t) values (−2.24 to −3.40), variable zircon eHf(t) values (−14.1 to +8.0), and high radiogenic Pb isotopic values (206Pb/204Pb = 18.588–18.790, 207Pb/204Pb = 15.616–15.642, and 208Pb/204Pb = 38.838–39.053). These geochemical characteristics indicate that the monzogranite was derived from a mixed source comprising ancient crustal and mantle materials, and experienced frac- tional crystallization during emplacement. We propose that the parental magma of the Mugagangri monzogranite was most likely generated during northward subduction of the Bangong Coujiang Meso-Tethys Ocean.

A high sulfur coal was desulfurized and removed ash by microwaved oxidation process. Microwave oxidation experiments were designed with Box Behnken design (BBD) and the main process variables and t...

The Cuonadong Sn-W-Be polymetallic deposit is the first rare-metal deposit with an extraordinary metallogenic potential that has been discovered in the Tethyan Himalayan metallogenic belt. The deposit shows a wide range of different mineralization types, including greisen-, pegmatite-, skarn-, and hydrothermal vein-type mineralization. Of these mineralization types, the skarn-type has the largest inferred resources. In order to constrain the source and evolution of the ore-forming fluid, we conducted a detailed study of the skarn-hosted scheelite, including cathodoluminescence imaging, in-situ trace elemental analysis, and bulk Sr isotope analysis. In addition, bulk Sr isotope analysis of fluorite, phlogopite 40Ar-39Ar dating, and marble whole-rock geochemical analysis were also conducted. Phlogopite 40Ar-39Ar dating indicates that the skarn was formed at ca. 15 Ma, which is close to the formation age of the Cuonadong muscovite granite reported in previous studies. Cathodoluminescence images indicate that skarn-hosted scheelite can be subdivided into an older type 1 scheelite and a younger type 2 scheelite. Type 1 scheelite is characterized by a negative Eu anomaly, whereas type 2 scheelite shows a positive Eu anomaly. Considering the close temporal and spatial relationship between the Cuonadong Miocene leucogranite and the ore-bearing skarn, and their similar lanthanide tetrad effect as observed in the REE patterns, we propose that the negative Eu anomaly was inherited from the Cuonadong Miocene leucogranite, while the positive Eu anomaly resulted from the addition of Eu2+ to the ore-forming fluid during greisenization. Sr isotope data show that the fluorite (87Sr/86Sr)i value of 0.728885 is within the range of the Cuonadong Miocene leucogranite (87Sr/86Sr)i values, while scheelite (87Sr/86Sr)i values (0.709717-0.713480) are similar to those of the Cuonadong marble (0.709525-0.712146). Since scheelite is intergrown with fluorite, we propose that the hydrothermal fluid that exsolved from the Cuonadong Miocene leucogranite is responsible for formation of both fluorite and scheelite. Water-rock interaction between this magma-derived fluid and the marble is responsible for the loss of the scheelite magmatic Sr isotopic signature.

The Tethys Himalaya sedimentary sequence (THS) is characterized by N–S trending extensional rifts (NSTR) and the North Himalayan gneiss domes (NHGD). The Cuonadong dome, as one of the NHGD, is located at the N–S trending Cuona rift in the eastern part of the Tethys Himalaya. The dome had undergone four major deformation events: D1, characterized by top-to-S thrust resulting in N–S shortening and vertical thickening; D2, characterized by vertical thinning and N–S extensional deformation; D3, approximately E–W extensional deformation associated with intrusion of leucogranites; and D4, late collapse structural deformation around the core of the Cuonadong dome. There are numerous granitic dykes at the contact zone between the granite and surrounding rocks in the middle unit of the Cuonadong dome. Field observations show that granite intrusion occurred in part synchronously with D3, E–W extensional deformation. U–Pb–zircon dating shows that the granite crystallization took place at ca. 17.5–15.6 Ma, while muscovite Ar–Ar geochronological data from the deformed pegmatite and mylonitic schist in the Cuonadong dome show that the onset of the E–W extensional deformation is between 16.5 and 14.8 Ma, and suggesting that granite intrusion was synchronous with the E–W ductile extensional deformation in the Cuonadong dome, southern Tibet. Combined with previously published ages of the South Tibetan Detachment System (STDS), our study shows that granite intrusion was at least locally contemporaneous with both the E–W and N–S extensional deformation, especially with the E–W extension.

The flotation mechanisms of molybdenite fines by neutral oils were investigated through microflotation test, turbidity measurements, infrared spectroscopy, and interfacial interaction calculations. The results of the flotation test show that at pH 2−11, the floatability of molybdenite fines in the presence of transformer oil is markedly better than that in the presence of kerosene and diesel oil. The addition of transformer oil, which enhances the floatability of molybdenite fines, promotes the aggregation of molybdenite particles. Fourier transform infrared measurements illustrate that physical interaction dominates the adsorption mechanism of neutral oil on molybdenite. Interfacial interaction calculations indicate that hydrophobic attraction is the crucial force that acts among the oil collector, water, and molybdenite. Strong hydrophobic attraction between the oily collector and water provides the strong dispersion capability of the collector in water. Furthermore, the dispersion capability of the collector, not the interaction strength between the oily collectors and molybdenite, has a highly significant role in the flotation system of molybdenite fines. Our findings provide insights into the mechanism of molybdenite flotation.

The Xitieshan deposit (~ 64 Mt at 4.86% Zn, 4.16% Pb, 58 g/t Ag, and 0.68 g/t Au) is hosted by the Middle to Late Ordovician Tanjianshan Group of the North Qaidam tectonic metallogenic belt, NW China. This belt is characterized by island arc volcanic, ultra-high pressure (UHP) metamorphic and ophiolitic rocks. The Tanjianshan Group constitutes a succession of metamorphosed bimodal volcanic and sedimentary rocks, which are interpreted to have formed on the margin of a back-arc ocean basin between the Qaidam block and the Qilian block. Four stratigraphic units are identified within the Ordovician Tanjianshan Group. From northeast to southwest they are: 1) unit a, or the lower volcanic-sedimentary rocks, comprising bimodal volcanic rocks (unit a-1) and sedimentary rocks (unit a-2) ranging from carbonates to black carbonaceous schist; 2) unit b, or intermediate-mafic volcaniclastic rocks, characterized by intermediate to mafic volcaniclastic rocks intercalated with lamellar carbonaceous schist and minor marble lenses; 3) unit c, a purplish red sandy conglomerate that unconformably overlies unit b, representing the product of the foreland basin sedimentation during the Early Silurian; 4) unit d, or mafic volcanic rocks, from base to up, comprising the lower mafic volcaniclastic rocks (unit d-1), middle clastic sedimentary rocks (unit d-2), upper mafic volcaniclastic rocks (unit d-3), and uppermost mafic volcanic rocks (unit d-4). Unit a-2 hosts most of the massive sulfides whereas unit b contains subordinate amounts. The massive stratiform lenses constitute most of the Xitieshan deposit with significant amount of semi-massive and irregularly-shaped sulfides and minor amounts in stringer veins. Pyrite, galena and sphalerite are the dominant sulfide minerals, with subordinate pyrrhotite and chalcopyrite. Quartz is a dominant gangue mineral. Sericite, quartz, chlorite, and carbonate alteration of host rocks accompanies the mineralization. U-Pb zircon geochronology yields three ages of 454 Ma, 452 Ma and 451 Ma for the footwall felsic volcanic rocks in unit a-1, sedimentary host rocks in unit a-2 and hanging-wall unit b, respectively. The Xitieshan deposit is considered to be coeval with the sedimentation of unit a-2 and unit b of the Tanjianshan Group. The Xitieshan deposit has been intensely deformed during two phases (main ductile shear and minor ductile-brittle deformation). The main ductile shear deformation controls the general strike of the ore zones, whereas minor deformation controls the internal geometry of the ore bodies. 40 Ar- 39 Ar age of muscovite from mylonitized granitic gneisses in the ductile shear zone is ~ 399 Ma, which is interpreted to date the Xitieshan ductile shear zone, suggesting that Early Devonian metamorphism and deformation post-dated the Tanjianshan Group. The Xitieshan deposit has many features similar to that of the Bathurst district of Canada, the Iberian Pyrite Belt of Spain, the Wolverine volcanogenic massive sulfide deposit in Canada. Based on its tectonic setting, host-rock types, local geologic setting, metal grades, geochronology, temperatures and salinities of mineralizing fluid and source of sulfur, the Xitieshan deposit has features similar to sedimentary exhalative (SEDEX) and VMS deposits and is similar to volcanic and sediment-hosted massive sulfide (VSHMS) deposits.

The Cuonadong super-large Be-W-Sn rare metals deposits are hosted by skarns and marbles in the middle unit of the Cuonadong Dome. Rocks in the Cuonadong Dome record four major deformational events: D1, top-to-S thrust; D2, top-to-N extension; D3, approximately E–W extensional deformation; and D4, late collapse structural deformation. Skarns and/or marbles featured by the directional alignment of skarn minerals are exposed in garnet-staurolite-bearing mica schist, and are closely related to the deformed leucogranites and pegmatites. The boundary between leucogranites and skarns is locally gradual or sharp, which suggests that skarns and the deformed leucogranites resulted from the synkinematic magmatism and the strong activity of the STDS. Ar-Ar dating of muscovite from the deformed granites in the middle unit and biotite from granitic gneiss in the core yielded Ar-Ar plateau ages of 15.0 ± 0.2 Ma and 13.9 ± 0.4 Ma, respectively, which reflects the age of syntectonic magmatism, and the activity time of the STDS at the Cuonadong Dome, respectively. Ar-Ar dating of biotite from marble in the middle unit yielded Ar-Ar plateau age of 16.1 ± 0.2 Ma, which was interpreted as the formation age of the synkinematic skarns. Skarns in the Cuonadong Dome were related to the detachments and formed in association with the emplacement of leucogranites. Therefore, we suggest that the formation of the Cuonadong Be-W-Sn skarn deposit was contemporaneous with the intrusion of leucogranitic magma and the top-to-north extensional deformation along the STDS.

The Cuonadong dome exposes in east-southern margin of the North Himalayan gneiss domes (NHGD), which is reported first time in this study. The Cuonadong dome is located at the southern part of the Zhaxikang ore concentration area, which is divided into three tectono-lithostratigraphic units by two curved faults around the dome geometry from upper to lower (or from outer to inner): the upper unit, middle unit and lower unit, and the outer fault is Nading fault, while the inner fault is Jisong fault. The Cuonadong dome is a magmatic orthogneiss and leucogranite mantled by orthogneiss and metasedimentary rocks, which in turn are overlain by Jurassic metasedimentary and sedimentary rocks. The grades of metamorphism and structural deformation increase towards the core, which is correspondence with the Ridang Formation low-metamorphic schist, tourmaline granitic–biotite gneiss, garnet–mica gneiss and mylonitic quartz–mica gneiss. The Cuonadong dome preserves evidences for four major deformational events: firstly top-to-S thrust (D1), early approximately N–S extensional deformation (D2), main approximately E–W extensional deformation (D3), and late collapse structural deformation (D4) around the core of the Cuonadong dome, which are consistent to three groups lineation: approximately N–S-trending lineation including L1 and L2, E–W trending L3, and L4 with plunging towards outside of the dome, respectively. The formation of the Cuonadong dome was probably resulted from the main E–W extensional deformation which is a result of eastward flow of middle or lower crust from beneath Tibet accommodated by northward oblique underthrusting of Indian crust beneath Tibet. The establishment of the Cuonadong dome enhanced the E–W extension of the NHGD, which is further divided into two structural dome zones according to the different extensional directions: approximately N–S extensional North Himalayan gneiss domes (NS-NHGD) and E–W extensional North Himalayan gneiss domes (EW-NHGD). The NS-NHGD developed by a dominantly N–S contraction and locally extensional regime and keep a close relationship to the South Tibetan Detachment System, whereas the EW-NHGD formed by an E–W extensional deformation along the north–south-trending rifts.

In situ U–Pb geochronology, Lu–Hf isotopes and REE geochemical analyses of detrital zircons from Cambrian–Devonian sandstones in the Truong Son Belt, central Vietnam, are used to provide the information of provenance and tectonic evolution of the Indochina Block. The combined detrital zircon age spectra of all of the samples ranges from 3699 Ma to 443 Ma and shows with dominant age peaks at ca. 445 Ma and 964 Ma, along with a number of age populations at 618–532 Ma, 1160–1076 Ma, 1454 Ma, 1728 Ma and 2516 Ma. The zircon age populations are similar to those from time equivalent sedimentary sequences in continental blocks disintegrated from the East Gondwana during the Phanerozoic. The younger zircon grains with age peaks at ca. 445 Ma were apparently derived from middle Ordovician–Silurian igneous and metamorphic rocks in Indochina. Zircons with ages older than about 600 Ma were derived from other Gondwana terrains or recycled from the Precambrian basement of the Indochina Block. Similarities in the detrital zircon U–Pb ages suggest that Paleozoic strata in the Indochina, Yangtze, Cathaysia and Tethyan Himalayas has similar provenance. This is consistent with other geological constrains indicating that the Indochina Block was located close to Tethyan Himalaya, northern margin of the India, and northwestern Australia in Gondwana.

The Cuonadong deposit is located in the Cuonadong gneiss dome of the eastern Tethyan Himalaya and is characterized as a large- to superlarge-scale Sn polymetallic deposit in the Himalaya orogen. The mineralization pattern includes skarn W-Sn mineralization in the strong shear zone of the dome mantle, hydrothermal Sn-W veins controlled by north-south-trending rifts (NSTRs), and Be-Rb mineralization in pegmatitic leucogranite. The results of this study show that the zircon U-Pb age of undeformed (postkinematic) leucogranites is 15.5 ± 0.1 Ma (n = 28, MSWD = 1.4), the cassiterite U-Pb age of the vein-type Sn-W orebody is 14.3 ± 0.5 Ma (n = 40, MSWD = 3.2), and the muscovite Ar-Ar age of beryl-bearing pegmatitic leucogranite is 15.2 ± 0.2 Ma (MSWD = 1.5). The isotopic dating results demonstrate that the Cuonadong Sn-W-Be-Rb mineralization has a close genetic relationship with the Miocene (ca. 16–14 Ma) leucogranite magmatic hydrothermal activity in the Cuonadong dome. The deformed (synkinematic) two-mica granite (18 Ma) was cut by the Sn-W ore veins (14 Ma) faulted by NSTRs, indicating that the E-W-trending extension of the NSTRs initiated at ca. 18–14 Ma. The Himalaya leucogranite belongs to a highly fractionated granite with high Sn content (>15 ppm). In conclusion, the Himalaya leucogranite is considered to be tin granite in this study, and therefore, the Himalaya presents high potential for Sn polymetallic mineralization prospecting.

Petrological, geochemical and in-situ zircon U–Pb dating and Hf-isotope analyses have been carried out on a suite of basalt–andesite–rhyolite volcanic rocks exposed in the Liuluocun area, Hainan Island, SE China. Zircon analyses show that these volcanic rocks crystallized in the Early Cretaceous (ca. 102 Ma). The basalts are characterized by low MgO contents and mg-numbers but high rare earth element, high field strength element and large ion lithophile element contents and Nb–Ta negative anomalies. They have relatively uniform Sr–Nd isotope compositions with e Nd (t) values of − 4.09 to − 3.63. The andesites show enrichment of high field strength element and rare earth element with negligible Eu anomalies. They have e Nd (t) values of − 2.35 to − 3.88 and e Hf (t) values of − 9.73 to − 1.13. The rhyolites have high K 2 O and SiO 2 contents. They are characterized by prominent Eu, P and Ti negative anomalies and enrichment in large ion lithophile element, and show e Hf (t) values of − 7.51 to + 0.47 and e Nd (t) values of − 2.49 to − 2.69. Petrogenetic analysis indicates that the Liuluocun volcanic rocks were produced by incomplete reaction of the mantle wedge peridotite with felsic melts derived from partial melting of subducted sediment. All these characteristics, combined with geological observations, suggest that their formation was related to regional lithospheric extension in the South China Craton during the Early Cretaceous, which may have been caused by subduction of the Paleo-Pacific plate beneath the continental plate of China.

Neoproterozoic granitic rocks in the Dakendaban Group are widely distributed throughout the Xitieshan area as the old basement in North Qaidam, NW China. The granitic rocks are composed predominantly of K-feldspar, plagioclase, quartz, muscovite and biotite, with subordinate zircon, garnet, titanite and sillimanite. Two granitic rock samples yielded ages of 930 ± 6 Ma and 918 ± 6 Ma using LA-ICPMS zircon U–Pb dating, which are interpreted as the protolith formation age of the granitic rocks, and reflecting an important Neoproterozoic magmatic event in the Xitieshan area. Geochemical data suggest that the granitic rocks are characterized by high SiO2, K2O, and CaO/Na2O ratios (0.48–1.04), with LREE enrichment and strong Eu negative anomalies (Eu/Eu* = 0.44–0.51), and negative anomalies of Nb, Ta, Ti, Zr, and Hf. These rocks have consistent Nd isotope compositions with ɛNd(t) values ranging from −4.83 to −4.27, while the sample 2011ZJ18-3 yielded the negative ɛHf(t) values ranging from −6.7 to −1.3, and tDM2(Hf) model ages ranging from 1.9 to 2.2 Ga. These geochemical and zircon Lu–Hf isotopic features suggest that the granitic rocks in the Xitieshan area belong to the S-type granite, which were mainly derived from the partial melting of the Paleoproterozoic continental crust material (1.9–2.2 Ga) that were predominantly composed of metagreywackes and subordinate metapelitic sources. Based on the regional tectonic reconstruction, we propose that the studied rocks occurred as syn-orogeny on an active continental margin in a compressional environment, which resulted from the Neoproterozoic arc-continent collision and subsequently continent–continent collision, leading to the significant continental growth. The Early Neoproterozoic tectonothermal event in North Qaidam shares many affinities with that of the Tarim block and South China block (Yangtze block) that were associated with the final consolidation of block at the Jinning orogeny, showing an agreement with the formation of Rodinia. The Early Neoproterozoic S-type granitic magmatism in NW China, including the Qaidam and adjacent blocks, is an important episode of continental crust reworking.

Integrated in situ U–Pb dating and Hf-isotope analysis on detrital zircons from six sandstone samples from Hainan Island have been used to identify clastic sedimentary provenances, regional magmatic activity and crustal evolution processes. Four samples (2011XL-1, 2011JB-1, 09HN54 and 2011GB-1) are from previous mapped Silurian strata and the other two samples (2011TD-1 and 09HN39) belong to Ordovician and Cambrian strata, respectively. A total of 463 concordant U–Pb zircon analyses of the six samples define five major age populations: 2598–2320 Ma (a peak of 2480 Ma), 1944–1606 Ma (peak-1750 Ma), 1600–1406 Ma (peak-1502 Ma), 1288–902 Ma (peak-957 Ma), 470–427 Ma (peak-442 Ma) and two subordinate populations at 898–710 Ma (peak-730 Ma) and 618–513 Ma (peak-578 Ma). The combination of age peaks within the samples provide a record of igneous activity in the source region: the 2480 Ma peak is consistent with those ages reported for Neoarchean global continental growth; the 1944–1606 Ma population correlates with the time of assembly of the supercontinent Nuna (Columbia); the 1502 Ma peak with documented magmatic activity on Hainan Island; and the 1288–902 Ma and 898–710 Ma populations with global tectonothermal activity associated with assembly and breakup of Rodinia. Our data also reveal a 618–513 Ma population that may relate with the assembly of Gondwana. The distinctive age peak at 442 Ma indicates input from a region affected by the Kwangsian orogeny. The combined ages and Hf-isotope data for each population suggest that generation of juvenile crust occurred at 1900–1400 Ma, 940–740 Ma and 470–430 Ma. Most of the other age populations that display negative e Hf (t) values suggest reworking of older crust.

Zircon U–Pb geochronological, geochemical and petrological analyses have been carried out on the Xitian granite emplaced in the middle part of Shi-Hang zone, which is closely related to the economically important Xitian tungsten–tin deposit in Hunan Province, Southeast China. LA-ICP-MS zircon U–Pb dating of two representative samples yielded weighted means 206 Pb/ 238 U age of 151.7 ± 1.2 Ma and 151.8 ± 1.4 Ma. These granites are comprised mainly of K-feldspar, quartz, plagioclase, Fe-rich biotite and minor fluorite, and are characterized by enrichments in Rb, Th, REEs (total REE = 159–351 ppm), and HFSEs (e.g., Zr and Y) but depletions in Ba, Sr, P, Eu and Ti. They are metaluminous to weakly peraluminous and show a clear A-type granite geochemical signature with high SiO 2 (73.44–78.45 wt.%), total alkalis (Na 2 O + K 2 O = 2.89–8.98 wt.%), Fe 2 O 3 ∗ /MgO ratios and low P 2 O 5 , CaO, MgO and TiO 2 contents. In-situ zircon Hf isotope analysis suggests their e Hf ( t ) values ranging from –7.43 to –14.69. Sr–Nd isotope data show their e Nd ( t ) values in the range of –9.2 to –7.3, with corresponding T DM2 ages of 1.72–1.56 Ga. These characteristics indicate that the Xitian granite originated from partial melting of metamorphic basement rocks with a certain amount of mantle-derived materials. Combined with previous geochemical and isotopic data, it is derived that mantle–crust interaction was gradually enhanced from the early to late stages of magmatism. The ore-forming materials and fluids of the Xitian W–Sn deposit are mainly produced by the Early Yanshanian granitic magmatism, which is also responsible for the Late Jurassic (ca. 152 Ma) A-type granitic rocks that host the W–Sn polymetallic deposits distributed along the Shi-Hang zone, implying a significant Mesozoic extensional event in Southeast China likely caused by the subduction of the Paleo-Pacific plate.

Understanding the provenance of the reservoir in a sedimentary basin is of great importance in hydrocarbon exploration and production. The Yinggehai-Song Hong Basin is one of the most important Cenozoic petroliferous basins in the South China Sea. To better understand the provenance characteristics of the Upper Miocene Huangliu Formation (Tortonian-Messinian) on the eastern margin of the basin and test the influence of uplift of the Tibetan Plateau in the South China Sea, 172 single zircons from two sandstone samples in the Lingtou gas field were dated by U–Pb chronometer, and 54 of these grains were spot analyzed for Hf isotopes. The results indicate that the upper member of the Huangliu Formation in this gas field shows two major peaks of U–Pb ages at ca. 250 Ma and ca. 432 Ma, along with four subordinate peaks at ca. 757 Ma, ca. 1926 Ma, ca. 2529 Ma and ca. 2775 Ma. The initial Hf isotope ratios [eHf (t)] of these zircons are negative to positive for each age group, suggesting that existing crustal materials were mixing with new mantle melts in some magmatic episodes. In contrast, the lower member of the Huangliu Formation show two major age peaks at ca. 98 Ma and 248 Ma, with a subordinate peak at ca. 1453 Ma. The eHf(t) values are concentrated between −11.6 and −3.4, revealing that they were derived from older crust. Comparing with the source characteristics of tectonic units surrounding the basin, the source of the upper member in the gas field was mainly from the southern Yangtze Block, whereas the lower member was derived from the Hainan Uplift. Together with the change of climate and sedimentation rate after 10 Ma on the northern margin of the South China Sea, we attribute the provenance change to the uplift of the Tibetan Plateau at the same time.

The Yinggehai-Song Hong (Y-SH) Basin, located on the northwestern shelf of the South China Sea, is one of the world's largest pull-apart basins. In order to identify the provenance of the Upper Miocene to Quaternary sediments of the basin, ten sediment samples were collected from drill cores in the Dongfang gas field. U–Pb dating of detrital zircon grains extracted from the ten samples using a laser ablation inductively coupled mass spectrometer (LA-ICP-MS) yields ages ranging from the Archean to Cenozoic (2898 ± 46 Ma to 26 ± 1 Ma). The zircon U–Pb age spectra of the Upper Miocene to Quaternary show a similar pattern with major peaks clustered at ca. 32 Ma, ca. 99 Ma, ca. 160 Ma, ca. 247 Ma, ca. 422 Ma and three “broad” age groups, 600–1000 Ma, 1700–2100 Ma and 2200–2800 Ma, suggestive of a wide range of igneous rock ages in the source areas. The detrital zircon ages provide diagnostic criteria for identification of the various source areas and reveal that the detritus was derived from multiple sources. Comparison of the results with the rock types and their ages surrounding the potential source areas indicates that the clastic material was derived from three dominant age sources: (1) Yangtze Craton, (2) Hainan Island and (3) Indochina Block. The Yangtze Craton was a major and continuous source area contribution to the basin. Comparing the age characteristics and its source areas since 10 Ma, the largely stable provenance also suggests that if the Red River capture ever existed it should have happened before the Late Miocene.

In order to utilize low-grade manganese ore resources effectively, a hydrometallurgical process was developed for manganese extraction in dilute sulfuric acid medium, and the kinetics of leaching manganese was also investigated. At room temperature, manganese from low-grade manganese carbonate ores was extracted by sulfuric acid leaching without reductants. During the extracting process, single-factor analysis method was used to evaluate the effects of grinding fineness, sulfuric acid concentration, liquid-to-solid ratio, agitation rate and leaching time on the leaching efficiencies of Mn and Fe. The optimal leaching conditions are determined as coarse particles of below 2 mm size (without ball-milling), sulfuric acid concentration of 0.86 mol/L, liquid-to-solid ratio of 5:1, agitation rate of 150 r/min and leaching for 180 min at room temperature. Under the optimal conditions, the leaching efficiencies of Mn and Fe are 96.21% and 13.35%, respectively. In addition, through the experiments at different temperatures, it is found that the leaching process follows the shrinking core model under the conditions of changing acid concentration and intermittent reaction device. Moreover, the apparent activations of effective diffusion and chemical reaction in the kinetic model are calculated to be 18.83 and 27.15 kJ/mol, respectively. Keywords: Low-grade manganese ore, Leaching, Kinetics, Model

The Tanjianshan Group, which was previously divided into a, b, c and d formations, has been controversial for a long time. It mainly distributes in the northern margin of Qaidam Basin and is an important early Paleozoic greenschist facies metamorphic volcanic sedimentary rock formation. Detailed field investigation and zircon LA-ICPMS U-Pb dating of the key strata suggest that the original lower part of a Formation (a-1) versus the original middle upper of d Formation (d-3 and d-4), the original upper part of a Formation (a-2) and b Formation versus the original lower part of d Formation (d-1 and d-2) of Tanjianshan Group are contemporaneous heterotopic facies volcanicclasolite deposit, respectively. The former formations formed during the middle-late Ordovician (463–458 Ma), while the latter ones formed in the late Ordovician (about 445 Ma). The original c formation of Tanjianshan Group, which formed after 430 Ma, is similar to the Maoniushan Formation of Kunlun Mountains and north Qaidam Basin. According to the rules of stratigraphic division and naming, new stratum formations of Tanjianshan Group are re-built and divided into Duancenggou (O1–2td), Zhongjiangou (O2–3tz) and Xitieshan (O3tx) formations. The original c Formation is separated from Tanjianshan Group and is renamed as the Wuminggou Formation (S3-D1w), which shows a discordant contact with underlying Tanjianshan Group and overlying Amunike Formation (D3a). The zircon U-Pb age frequency spectrogram of Tanjianshan Group indicates three prominent peaks of 430 Ma, 460 Ma and 908 Ma, which is consistent with the metamorphic and magmatic crystallization ages obtained from para- and orthogneisses in north Qaidam HP-UHP metamorphic belt, implying that strong Caledonian and Jinningian tectonic and magmatic events have ever happened in North Qaidam.

Houttuynia cordata Thunb is an important medicinal plant widely distributed in East Asia. The collected information is an attempt to cover recent developments in the pharmacology, phytochemistry and quality control of this species. During the past several decades, the medicinally important phyto-constituents have been identified including essential oil, flavonoids and other polyphenols, fatty acids and alkaloids. A survey of the literatures shows H. cordata possesses a variety of pharmacological activities including antiviral, antitumor, antimicrobial, anti-inflammatory, and antioxidative effects. Little attempt has been done to review the techniques used for its quality control. Future efforts should concentrate more on in vitro, in vivo studies and clinical trials in order to confirm traditional wisdom in the light of a rational phytotherapy. The information summarized here is intended to serve as a reference tool to practitioners in the fields of ethnopharmacology and natural products chemistry.

The Xitian tungsten–tin (W–Sn) polymetallic deposit, located in eastern Hunan Province, South China, is a recently explored region containing one of the largest W–Sn deposits in the Nanling W–Sn metallogenic province. The mineral zones in this deposit comprise skarn, greisen, structurally altered rock and quartz-vein types. The deposit is mainly hosted by Devonian dolomitic limestone at the contact with the Xitian granite complex. The Xitian granite complex consists of Indosinian (Late Triassic, 230–215 Ma) and Yanshanian (Late Jurassic–Early Cretaceous, 165–141 Ma) granites. Zircons from two samples of the Xitian granite dated using laser ablation-inductively coupled mass spectrometer (LA-ICPMS) U–Pb analysis yielded two ages of 225.6 ± 1.3 Ma and 151.8 ± 1.4 Ma, representing the emplacement ages of two episodic intrusions of the Xitian granite complex. Molybdenites separated from ore-bearing quartz-veins yielded a Re–Os isochron age of 149.7 ± 0.9 Ma, in excellent agreement with a weighted mean age of 150.3 ± 0.5 Ma. Two samples of muscovites from ore-bearing greisens yielded 40Ar/39Ar plateau ages of 149.5 ± 1.5 Ma and 149.4 ± 1.5 Ma, respectively. These isotopic ages obtained from hydrothermal minerals are slightly younger than the zircon U–Pb age of 151.8 ± 1.4 Ma of the Yanshanian granite in the Xitian area, indicating that the W–Sn mineralization is genetically related to the Late Jurassic magmatism. The Xitian deposit is a good example of the Early Yanshanian regional W–Sn ore-forming event (160–150 Ma) in the Nanling region. The relatively high Re contents (8.7 to 44.0 ppm, average of 30.5 ppm) in molybdenites suggest a mixture of mantle and crustal sources in the genesis of the ore-forming fluids and melts. Based upon previous geochemical studies of Early Yanshanian granite and regional geology, we argue that the Xitian W–Sn polymetallic deposit can be attributed to back-arc lithosphere extension in the region, which was probably triggered by the break-off of the flat-slab of the Palae-Pacific plate beneath the lithosphere.

Analysis of volatile components in herbal pair (HP) Semen Persicae-Flos Carthami (SP-FC) was performed by GC-MS coupled with chemometric resolution method (CRM). Furthermore, temperature-programmed retention indices were used together with mass spectra for identification of the volatile components. With the help of CRM, the two-dimensional data obtained from GC-MS instruments were resolved into a pure chromatogram and a mass spectrum of each chemical compound. By use of these methods upon two-dimensional data, 26, 49, and 59 volatile chemical components in essential oils of single herb Semen Persicae, Flos Carthami, and HP SP-FC were determined qualitatively and quantitatively, accounting for 78.42, 81.08, and 82.48% total contents of essential oil of single herb Semen Persicae, Flos Carthami, and HP SP-FC, respectively. It is shown that the accuracy of qualitative and quantitative analysis can be enhanced greatly by means of CRM. It is further demonstrated that the numbers of volatile chemical components of HP SP-FC are almost the addition of those of two single herbs, but the main volatile chemical components of the former are completely different from those of single herb Semen Persicae or Flos Carthami because of chemical reactions and physical changes occurring in the process of decocting two single herbs. This means that chemical components especially pharmacologically active compounds in the recipe might be different from those of single herbs.

Chemical Manganese Dioxide (CMD) was prepared by an alkali-oxidation method. There are several virtues to this environmental friendly and clean process, including the nontoxic and harmless reagents and products, easy operations, no pollutants, easily obtained raw materials and moderate reaction conditions. The synthesized manganese dioxide was characterized by XRD and SEM. The particles were small, consisting primarily of α-MnO2 and γ-MnO2. Experimental results showed that the optimum conditions were: MnSO4·H2O to NaOH ratio, 1.0:2.4; catalyst concentration (catalyst TF-2), 6% of the MnSO4; initial solution pH, 11; reaction time and temperature, 20 min and 80 °C; air flow, 0.20 m3/h; and, agitation rate, 700 r/min. The conversion of MnSO4 can exceed 80% under these optimum conditions.

Background Genetic amplification of HER2 drives tumorigenesis and cancer progression in a subset of patients with gastric cancer (GC), and treatment with trastuzumab, a humanized HER2-neutralizing antibody, improves the overall survival rate of HER2-positive patients. However, a considerable portion of the patients does not respond to trastuzumab and the molecular mechanisms underlying the intrinsic resistance to anti-HER2 therapy in GC is not fully understood. Methods We performed whole-transcriptome sequencing on 21 HER2-positive tumor specimens from Chinese GC patients. Whole genome sequencing was performed on the three samples with HER2 fusion to discover the DNA integration structure. A multicolor FISH assay for HER2 split screening was conducted to confirm HER2 fusion and IHC (HercepTest™) was used to detect the membranous expression of HER2. Fusion cDNA were transfected into NIH/3T3 cells and generate stable cell line by lentivirus. The expression of exogenous HER2 fusion proteins and pHER2 were examined by western blot analysis. In vitro efficacy studies were also conducted by PD assay and softagar assay in cell line expression wild type and fusion HER2. T-DM1 was used to assess its binding to NIH/3T3 cells ectopically expressing wild-type and fusion HER2. Finally, the anti-tumor efficacy of trastuzumab was tested in NIH/3 T3 xenografts expressing the HER2 fusion variants. Results We identified three new HER2 fusions with ZNF207, MDK, or NOS2 in 21 HER2-amplified GC samples (14%; 3/21). Two of the fusions, ZNF207-HER2, and MDK-HER2, which are oncogenic, lead to aberrant activation of HER2 kinase. Treatment with trastuzumab inhibited tumor growth significantly in xenografts expressing MDK-HER2 fusion. In contrast, trastuzumab had no effect on the growth of xenografts expressing ZNF207-HER2 fusion, due to its inability to bind to trastuzumab. Conclusions Our results provide the molecular basis of a novel resistance mechanism to trastuzumab-based anti-HER2 therapy, supporting additional molecule stratification within HER2-positive GC patients for more effective therapy options. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0476-2) contains supplementary material, which is available to authorized users.

Protein phosphatase methylesterase 1 (PPME1) is a protein phosphatase 2A (PP2A)-specific methyl esterase that negatively regulates PP2A through demethylation at its carboxy terminal leucine 309 residue. Emerging evidence shows that the upregulation of PPME1 is associated with poor prognosis in glioblastoma patients. By performing an array comparative genomic hybridization analysis to detect copy number changes, we have been the first to identify PPME1 gene amplification in 3.8% (5/131) of Chinese gastric cancer (GC) samples and 3.1% (4/124) of Chinese lung cancer (LC) samples. This PPME1 gene amplification was confirmed by fluorescence in situ hybridization analysis and is correlated with elevated protein expression, as determined by immunohistochemistry analysis. To further investigate the role of PPME1 amplification in tumor growth, short-hairpin RNA-mediated gene silencing was employed. A knockdown of PPME1 expression resulted in a significant inhibition of cell proliferation and induction of cell apoptosis in PPME1-amplified human cancer cell lines SNU668 (GC) and Oka-C1 (LC), but not in nonamplified MKN1 (GC) and HCC95 (LC) cells. The PPME1 gene knockdown also led to a consistent decrease in PP2A demethylation at leucine 309, which was correlated with the downregulation of cellular Erk and AKT phosphorylation. Our data indicate that PPME1 could be an attractive therapeutic target for a subset of GCs and LCs.

Gastric cancer is the second leading cause of death from cancer worldwide, with an approximately 20% 5-year survival rate. To identify molecular subtypes associated with the clinical prognosis, in addition to genetic aberrations for potential targeted therapeutics, we conducted a comprehensive whole-genome analysis of 131 Chinese gastric cancer tissue specimens using whole-genome array comparative genomic hybridization. The analyses revealed gene focal amplifications, including CTSB, PRKCI, PAK1, STARD13, KRAS, and ABCC4, in addition to ERBB2, FGFR2, and MET. The growth of PAK1-amplified gastric cancer cells in vitro and in vivo was inhibited when the corresponding mRNA was knocked down. Furthermore, both KRAS amplification and KRAS mutation were identified in the gastric cancer specimens. KRAS amplification was associated with worse clinical outcomes, and the KRAS gene mutation predicted sensitivity to the MEK1/2 inhibitor AZD6244 in gastric cancer cell lines. In summary, amplified PAK1, as well as KRAS amplification/mutation, may represent unique opportunities for developing targeted therapeutics for the treatment of gastric cancer.

Analysis of volatile components in herbal pair (HP) Semen Persicae-Flos Carthami (SP-FC) was performed by GC-MS coupled with chemometric resolution method (CRM). Furthermore, temperature-programmed retention indices were used together with mass spectra for identification of the volatile components. With the help of CRM, the two-dimensional data obtained from GC-MS instruments were resolved into a pure chromatogram and a mass spectrum of each chemical compound. By use of these methods upon two-dimensional data, 26, 49, and 59 volatile chemical components in essential oils of single herb Semen Persicae, Flos Carthami, and HP SP-FC were determined qualitatively and quantitatively, accounting for 78.42, 81.08, and 82.48% total contents of essential oil of single herb Semen Persicae, Flos Carthami, and HP SP-FC, respectively. It is shown that the accuracy of qualitative and quantitative analysis can be enhanced greatly by means of CRM. It is further demonstrated that the numbers of volatile chemical components of HP SP-FC are almost the addition of those of two single herbs, but the main volatile chemical components of the former are completely different from those of single herb Semen Persicae or Flos Carthami because of chemical reactions and physical changes occurring in the process of decocting two single herbs. This means that chemical components especially pharmacologically active compounds in the recipe might be different from those of single herbs.

Thiourea as a kind of green and eco–friendly gold lixiviant, was employed to substitute cyanide in the present study of gold leaching. The investigation was carried out on a finely disseminated gold ore from Hongmiao (Hunan province, China) in alkaline thiourea solution with indispensable stable reagents of Na2SO3 and (NaPO3)6. The main aim was to seek suitable stable reagents and oxidising agents required in leaching gold. Na2SO3 and (NaPO3)6 were determined as the best stable reagents and Na2S2O8 was a more appropriate oxidant compared with K3[Fe(CN)6] in this study. Meantime, the effects of leaching parameters, i.e., the molar ratio of SO32−, PO3−, TU and S2O82−, pH, mixing time and grinding fineness were examined in detail and the optimum condition was obtained. The experimental results show that the molar ratio of SO32−, PO3−, TU and S2O82− greatly affected gold leaching extent and thiourea decomposition. No more than 72.6% leaching rate could be reached due to deactivation of elemental sulphur created by thiourea and other negative factors, while lower leaching rate (69.4%) of gold leaching rate was obtained in acidic thiourea media compared with alkaline media.

Protein phosphatase 2A (PP2A) is a human tumor suppressor, and it accounts for the majority of serine/threonine phosphatase activity which is tightly regulated via the methylation of carboxy-terminal of PP2A. Methylation at the carboxyterminal Leu 309 residue by S-adenosylmethionine-dependent leucine carboxyl methytransferase-1 (LCMT1) leads to the activation of PP2A, whilst demethylation of Leu 309 by specific protein phosphatase methylesterase-1 (PPME1) suppresses the PP2A activity. Recent evidence showed that PPME1 is up-regulated in glioblastoma patients and associated with a poor prognosis. In this study we profiled 131 Chinese gastric cancer (GC) samples and 124 Chinese non-small cell lung carcinoma (NSCLC) samples by Affy and aCGH to identify potential drug targets, and found PPME1 gene amplification in 3.8% of the GC samples and 3.1% of the NSCLC samples. The PPME1amplification correlated with its mRNA expression. In addition, we confirmed that PPME1 protein expressions were also elevated in the PPME1-amplified tumor samples indicated by immunohistochemistry as compared with corresponding adjacent non-tumor samples. To further investigate the role of PPME1 amplification in tumor growth, we utilized siRNA-mediated gene silencing approaches to specifically knock down PPME1 expression in the PPME1 amplified human cancer cell lines SNU668 (GC) and Oka-C1 (NSCLC). We found that suppression of the PPME1 expression resulted in significant inhibition of cell proliferation and induction of cell death in those cells. In contrast, little effects were observed on the cell growth and survival of non PPME1-amplified human cancer cells, MKN1 (GC) and HCC95 (NSCLC). Moreover, we showed that the PPME-1 knock-down also resulted in a decrease of PP2A demethylation at Leu309, which correlated with down-regulation of phosphorylation of MAPK and AKT in the cells. Taken together, our data indicate that PPME-1 could be an attractive therapeutic target for subsets of gastric and lung cancers. Citation Format: Jing Li, Sufang Han, Ziliang Qian, Xinying Su, Shuqiong Fan, Jiangang Fu, Charles Liu, Lucy Yin, Zeren Gao, Guanshan Zhu, Jingchuan Zhang, De-Hua Yu, Qunsheng Ji. PPME1 is a potential novel molecular target in gastric and lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5186. doi:10.1158/1538-7445.AM2013-5186