Search

Improving total factor carbon emission efficiency (TCE) is the key to achieving carbon emission reduction targets while ensuring economic growth. In this paper, the global Malmquist index based on the SBM model is used to measure TCE of 283 cities in China from 2011 to 2019. On this basis, this paper uses the spatial econometric model and intermediary effect model to empirically analyze the impact of industrial co-agglomeration on TCE and its transmission mechanism. Furthermore, considering the differences in geographical location and resource endowment among regions, this paper analyzes the heterogeneous effect of industrial collaboration agglomeration on TCE in different regions and cities. The results show that: (1) Industrial co-agglomeration can improve TCE, and its main transmission channel is technological innovation. (2) Industrial co-agglomeration has a positive spatial spillover effect. Industrial co-agglomeration in one region can improve the TCE in the surrounding regions. (3) Industrial co-agglomeration of cities with different geographic locations and resource endowments has a heterogeneous effect on TCE. Regarding geographical heterogeneity, the industrial co-agglomeration in the eastern region has the greatest promoting effect on TCE, followed by the central region. However, the impact of industrial co-agglomeration in the western region on TCE is not significant. Regarding resource endowment heterogeneity, the industrial co-agglomeration in non-resource-based cities has a greater promoting effect on TCE than that in resource-based cities. [ABSTRACT FROM AUTHOR]

High-purity N was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and purification, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) analysis. For Cu isotope separation, our results indicated that at a gas flow rate >60 mL/min, the separation chromatographic peaks broadened and the recovery rate decreased to <99.2%. On the other hand, no significant change in the Cu peaks was observed at a gas flow rate of 20 mL/min and the recovery rate was determined to be >99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a ±2 SD error range. The separation time was reduced from the traditional 10 h (without N) to 4 h (with N), indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 (US Geological Survey andesite standard sample) accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N, the purified liquid comprised Rb/Sr and Sm/Nd ratios of <0.000 049 and <0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a ±2 SD error range and the total separation time was shortened from 2 d to <10 h. [ABSTRACT FROM AUTHOR]

Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level of instrumental stability required for the analysis process and provides a valid solution for high-precision and accurate studies of Si isotopic compositions. Rock samples were dissolved by using alkali fusion and acidification. Silicon isotopes were purified with an ion exchange resin. Interfering peaks for isotopes were separated by using a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometry (MS) system in high-resolution mode ( M/Δ M > 8000 RP). Two magnesium isotopes (Mg and Mg) and three silicon isotopes (Si, Si, and Si) were analyzed in the same data collection cycle. Mg isotopes were used as an internal standard to calibrate the mass discrimination effects in MS analysis of Si isotopes in combination with the SSB method in order to reduce the effects of MS interference and instrumental mass discrimination on the accuracy of measurements. The conventional SSB method without the Mg internal standard and the proposed SSB method with Mg calibration delivered consistent results within two standard deviations. When Mg was used as an internal standard for calibration, the analysis precision was better than 0.05 ‰ amu. [ABSTRACT FROM AUTHOR]

An in-situ microanalysis of Pb isotopic compositions in sulfide minerals is carried out by using femtosecond laser-ablation multi-collector inductively coupled plasma mass spectrometry (fsLA-MC-ICP-MS). High-temperature-activated carbon was used to filter Hg contained in the carrier gas, which reduced the Hg background signal by 48% and also lowered the detection limit of the analysis. Fractionation and mass discrimination effects existing in the ICP-MS analytical processes were corrected using an internal reference Tl in conjunction with an external reference NIST SRM 610. The proposed method was used to analyze the Pb isotopic compositions of chalcopyrite, pyrite, and sphalerite from the Dulong Sn-Zn-In polymetallic ore district. The results showed that in this ore district, the sulfide minerals and different grains of the same sulfide mineral show a large variation in Pb content up to 1000-fold. The studied pyrites show relatively higher Pb contents and homogeneous Pb isotopic compositions, whereas the sphalerites have low Pb contents but most variable Pb isotopic compositions. It is suggested that the large variation of Pb isotopic composition may reflect a late hydrothermal superimposition on the primary sulfide formation. In addition, radiogenic Pb accumulated by radioactive decay of trace amounts of U over time in the host minerals may also be one of the causes for the large variation range of Pb content and Pb isotopic composition of those low-Pb sphalerites. Chalcopyrite and sphalerite grains with Pb content greater than 10 ppm presented a consistent Pb isotopic distribution, whereas all the sulfide grains with Pb content greater than 100 ppm had consistent Pb isotopic composition within 2s measurement uncertainties. The in-situ analysis of Pb isotopic composition agreed well with the results obtained by conventional chemical methods within 2s measurement uncertainties, indicating that the data obtained by fsLA-MC-ICP-MS are reliable. Additionally, this study indicates that the Pb isotopic composition could truthfully record the source of ore-forming minerals only for sulfide minerals with high Pb content. On the contrary, the Pb isotopic composition of low-Pb sulfide minerals may be affected by trace amounts of U in the host minerals that may lead to a highly radiogenic Pb isotope ratio. Alternatively, it is also possible that late fluid metasomatic overprinting may alter the Pb isotopic compositions. [ABSTRACT FROM AUTHOR]

Lead isotopic compositions of international silicate glasses, feldspar and copper-based samples are obtained using femtosecond laser ablation multiple collector inductively coupled plasma mass spectrometry (fLA-MC-ICPMS). Some international glass standards for the microanalysis are applied to evaluate the method reported here. The Pb isotopic composition of these NIST glasses (SRM 610, 612, 614), USGS (BHVO-2G, BCR-2G, BIR-1G and GSD-1G) and MPI-DING glasses (GOR132-G, KL2-G, T1-G, StHs60/80-G) agree well with recommended values in 2 s error. One of 15 copper-based metals is found to have homogenized Pb isotope data and can be used as an external calibration standard and quality control sample for chalcopyrite, ancient coins, etc., to trace the genesis of metal deposit and culture exchange among different dynasties (GBW02137, 208Pb/ 204Pb = 37.9661 ± 0.0005 (2 s), 207Pb/ 204Pb = 15.5770 ± 0.0002 (2 s), 206Pb/ 204Pb = 17.7462 ± 0.0002 (2 s)). We also prepared a feldspar glass to serve as the external calibration standard/QC for Pb isotope analysis using fLA-MC-ICPMS. [ABSTRACT FROM AUTHOR]

U-Pb zircon dating by LA-ICP-MS and SHRIMP for one olivine pyroxenite yields complex age populations including Mesozoic ages of 97-158 Ma and 228 ± 8.7 Ma, Early Paleozoic ages of 418-427 Ma, Paleoproterozoic age of 1844±13 Ma, Neoarchean age of 2541 ± 54 Ma and middle Archean age of 3123 ± 4.4 Ma. The 97-158 Ma and 228 ± 8.7 Ma zircons show typical igneous oscillatory zonation in CL images, suggesting two episodes of magmatic events. Overlapping of the 97-158 Ma ages with that of granulite xenoliths indicates that the Mesozoic granulite-facies metamorphism was induced by heating from the basaltic underplating at the base of the lower crust. Both processes lasted at least from about 158 to 97 Ma. Ages of 418 -427 Ma could be records of the subduction of Mongolia oceanic crust under the North China craton. Ages of 1.84 Ga, 2.54 Ga and 3.12 Ga correspond to the three important crust-mantle evolutionary events in the North China craton, and imply preservation of Precambrian lower crust in the present-day lower crust. [ABSTRACT FROM AUTHOR]

Presents an analyzation about the use of the in situ zircon U-Pb dating method of LA-ICPMS. Consideration of the investigation of a 31 Ma old SHRIMP U-Pb age of the Yongsheng nepheline syenite from southern Jilin Province under different spot sizes; Reference to how the obtained ages are comparable with that of SHRIMP in both accuracy and precision; Findings that the age is also identical to that of the Yinmawanshan gabbro from the Liaodong Peninsula within error; Trend for both the Yongsheng nepheline syenite and the Yinmawanshan gabbro to represent the youngest known exposed intrusions in northeastern and even eastern China; Indication from the results that the Eocene mantle-derived magmatic underplating, and the rapid crustal uplifting of this region since 30 Ma; How the analyses also document extremely high LREE concentrations and relatively flat REE patterns for the zircons from the Yongsheng nepheline syenite, which represent a new type of zircon REE pattern.

In sample preparation and mass spectrometry analysis, sample dissolution, column chemistry, concentration mismatches, and matrix effects have significant potential for introducing analytical artifacts during Mg isotope analysis. Based on the low MgO content and undesirable matrix elements in felsic rocks, the development of well-characterized felsic standards is essential to reduce inter-laboratory mass bias, enable the assessment of data accuracy, and facilitate the comparison of chemical separation procedures in different laboratories. In this work, the homogeneity and long-term stability of two felsic rock standards, GSR-1 and RGM-2, were evaluated due to their low MgO contents. Furthermore, synthetic solutions with doped matrix elements were used to evaluate potential Mg isotope analytical artifacts using multi-collector inductively coupled plasma mass spectrometry. The accuracy and precision of Mg isotopic compositions in GSR-1 and RGM-2 were assessed by repeated measurements over twelve months. The long-term tests show that the Mg isotopic compositions of the two low MgO felsic rocks (GSR-1 and RGM-2) are homogenous among batches and can be used as low MgO reference materials for accuracy assessments of Mg isotopic analyses. The Mg isotopic compositions (δ26Mg) of GSR-1 and RGM-2 were marked as -0.223‰±0.053‰ (2s, n=50) and -0.184‰±0.058‰ (2s, n=50) respectively. [ABSTRACT FROM AUTHOR]

The copper isotopic compositions of 12 copper-rich minerals (including native copper, sulfides, carbonates, oxides, and copper chloride) have been determined using a 206 nm ultraviolet femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (UV-fs-LA-MC-ICP-MS). A pure copper wire NWU-Cu-B and a natural chalcopyrite TC1725 were used as bracketing standards for calibration. Reliable and precise (2SD<0.07‰) δ65Cu values can be obtained using matrix-matched standards under dry plasma condition and calibrated by the standard-sample bracketing method (SSB). However, the δ65Cu values calibrated by non-matrix-matched standards were seriously affected by matrix effect, with a deviation of up to 1.42‰. Therefore, matrix-matched standards are necessary for reliable in situ Cu isotope ratio measurement. Although the analytical precision (2SD) is slightly improved, the use of Ga as an internal standard combined with the SSB correction does not reduce the deviation caused by the matrix effect. However, the matrix effect can be significantly suppressed by adding 8.6 µL min−1 water into the carrier gas. The matrix-induced δ65Cu deviation of the TC1725 calibrated against the pure copper NWU-Cu-B was reduced from 0.99‰ in dry plasma mode to 0.03‰ in wet plasma mode and achieved a long-term reproducibility of 0.10‰ (2SD). For the Cu isotopic compositions of 12 natural copper-rich minerals determined under wet plasma mode, the deviation of δ65Cu was less than 0.13‰ if the mineral is homogeneous. These results indicate that the non-matrix-matched standardization can be achieved by fs-LA-MC-ICP-MS under wet plasma condition, whether using chalcopyrite or pure copper as the external bracketing standards. [ABSTRACT FROM AUTHOR]

The continent is the second largest carbon sink on Earth's surface. With the diversification of vascular land plants in the late Paleozoic, terrestrial organic carbon burial is represented by massive coal formation, while the development of soil profiles would account for both organic and inorganic carbon burial. As compared with soil organic carbon, inorganic carbon burial, collectively known as the soil carbonate, would have a greater impact on the long-term carbon cycle. Soil carbonate would have multiple carbon sources, including dissolution of host calcareous rocks, dissolved inorganic carbon from freshwater, and oxidation of organic matter, but the host calcareous rock dissolution would not cause atmospheric CO2 drawdown. Thus, to evaluate the potential effect of soil carbonate formation on the atmospheric pCO2 level, different carbon sources of soil carbonate should be quantitatively differentiated. In this study, we analyzed the carbon and magnesium isotopes of pedogenic calcite veins developed in a heavily weathered outcrop, consisting of limestone of the early Paleogene Guanzhuang Group in North China. Based on the C and Mg isotope data, we developed a numerical model to quantify the carbon source of calcite veins. The modeling results indicate that 4–37 wt% of carbon in these calcite veins was derived from atmospheric CO2. The low contribution from atmospheric CO2 might be attributed to the host limestone that might have diluted the atmospheric CO2 sink. Nevertheless, taking this value into consideration, it is estimated that soil carbonate formation would lower 1 ppm atmospheric CO2 within 2000 years, i.e., soil carbonate alone would sequester all atmospheric CO2 within 1 million years. Finally, our study suggests the C–Mg isotope system might be a better tool in quantifying the carbon source of soil carbonate. [ABSTRACT FROM AUTHOR]

Precisely dating different generations of mineralization is important for understanding the origin and tectonic environment of ore formation. In this study, we have dated two generations of sulfides from the Lala Fe-Cu deposit, SW China, using in situ Pb-Pb isotopic data obtained by the LA-MC-ICPMS technique. The Lala deposit is composed of Fe-Cu ore bodies hosted in sedimentary-volcanic rocks of the Paleoproterozoic Hekou Group. It has a paragenetic sequence of pre-ore banded pyrite (Stage I) and Na alteration (Stage II), followed by early Fe (Stage III) and late Cu (Stage IV) mineralization. The sulfides in the deposit have dominantly formed in two stages, including pyrite from stratiform pyrite bands in the host rocks (i.e., Stage I) and epigenetic pyrite-chalcopyrite in Fe-Cu ore (i.e., Stage IV). The sulfides of both stages have highly radiogenic Pb isotopic ratios which form linear trends in the 207Pb/204Pb versus 206Pb/204Pb diagram. The regression trend for Stage I pyrite grains defines an errorchron age of 1669 ± 110 Ma (MSWD = 32), undistinguishable from zircon LA-ICPMS U-Pb ages of volcanic rocks in the Hekou Group (i.e., ~ 1700 Ma). The regressions for Stage IV pyrite and chalcopyrite yield younger errorchron ages of 1088 ± 88 Ma (MSWD = 93) and 1053 ± 220 Ma (MSWD = 15), respectively. Taking pyrite and chalcopyrite together, an errorchron age of 1053 ± 75 Ma (MSWD = 108) is obtained. These errorchron ages agree well with the molybdenite Re-Os age of the Fe-Cu ore (1086 ± 8 Ma). Despite the large error and MSWD values that are interpreted to be related to the small variation of initial ratios, or post-ore open system behavior, the good agreement with the precise zircon U-Pb and molybdenite Re-Os ages indicates that the Pb-Pb errorchron ages for Stage I and IV sulfides are geologically meaningful. Therefore, this study shows that the in situ Pb isotopic analyses can yield geologically meaningful Pb-Pb ages for radiogenic Pb-rich sulfide minerals. We also propose that in situ Pb-Pb isotopic dating may be more promising for Precambrian deposits containing sulfides with ingrown Pb, particularly for those involving multiple mineralization/hydrothermal events but without relevant minerals for precise Re-Os or U-Pb dating. [ABSTRACT FROM AUTHOR]

In this study, we established a rapid acid digestion for determining Hf-Sr-Nd isotopic ratios of geological samples by using MC-ICP-MS. Conditions of 1600 °C for 1 min and 1400 °C for 1 min were adopted for fusing intrusive rocks and extrusive rocks, respectively. The rapid acid digestion technique is superior in digestion time compared with high-pressure PTFE bomb method. The procedural blanks of the method were also lower than that flux fusion. Replicate analyses of international certified reference materials (CRMs) indicate that isotopic ratios of 176Hf/177Hf, 87Sr/86Sr and 143Nd/144Nd agree well with previously published data. The external reproducibility (2SD, n = 5) of ten CRMs are ±0.000030 for 87Sr/86Sr, ±0.000030 for 143Nd/144Nd, and ±0.000018 for 176Hf/177Hf. [ABSTRACT FROM AUTHOR]

A method was developed for the rapid in situ analysis of major and trace elements and Pb isotopes in silicate glass samples that combines laser ablation quadrupole and multi-collector inductively coupled plasma mass spectrometry (LA-Q-ICP-MS/MC-ICP-MS). Major, trace elements, and Pb isotope ratio compositions were clearly affected by laser conditions. Using a laser spot size of 160 μm, a laser ablation frequency of 15 Hz, an energy density 18 J/cm, and a 1: 9 ratio of laser ablation aerosol to the corresponding makeup gas, we obtained accurate major and trace element contents and Pb isotope ratios. Using Ca as the internal standard element, and GSE-1G and NIST 610 as the external standards for calibration, element contents generally matched the preferred values within 15%. Higher relative errors for some elements (e.g., Cr, Ga, Ge) may have been caused by lower than recommended values in some standards. The exponential law correction method for Tl normalization, with optimum adjusted Tl ratio, was utilized to obtain Pb isotopic data with good precision and accuracy. Pb isotopic ratios of the glass reference materials were in good agreement with the reference or published values to within 2 s measurement uncertainties, and the analytical precision was better than 0.17% (e.g., Pb/Pb). The developed method is a simple, reliable, and accurate technique for determining major, trace elements, and Pb isotope compositions of silicate glasses and minerals within a single ablation event. [ABSTRACT FROM AUTHOR]

Inductively coupled plasma mass spectrometry (ICP-MS) has become a powerful tool for providing reliable analytical results in many laboratories around the word. In this study, the mixture of HF and HNO acids in high-temperature and high-pressure closed-vessel digestion technique were used to decompose some Chinese reference materials, and thirty seven elements were determined by ICP-MS. Most of the results for Chinese soil reference materials were found to be in reasonable agreement with the reference values, except Cs, Ta, Li, Ge, Zn, Nd, Tb and Ta whose values need to be revised. Their precisions were typically lower than 5% RSD. However, the Precisions of Chinese clay reference materials, especially for GBW03102 and GBW03102a, were significantly different with reference values, probably reflecting the existence of a coarser-grained fraction (>70 μm) in samples, and the formation of fluorides in Al-rich samples during sample decomposition by using the mixture of HF and HNO acids. Moreover, thirty-seven trace elements covering the mass range from Li to U in four Chinese clay reference materials were firstly provided with good precision and accuracy in this study. [ABSTRACT FROM AUTHOR]

This paper reports petrographic, mineral chemical, olivine oxygen isotopic, and whole-rock geochemical data for wehrlite xenoliths from the Early Cretaceous Tietonggou high-Mg diorites in western Shandong Province, in the eastern part of the North China Craton (NCC), and describes the origin of these wehrlites and the processes that affected the deep lithospheric mantle in this area. Wehrlite xenoliths are rounded and vary in size between 3 cm × 4 cm × 5 cm and 3 cm × 2 cm × 1 cm. Olivine within these xenoliths occurs as an isolated residual phase within clinopyroxene, has Fo contents between 89 and 91, and contains between 1414 and 3629 ppm Ni, similar to the values of olivine from peridotite xenoliths in the Cenozoic basalts of eastern China, but lower than the values of olivine from harzburgite xenoliths in the Early Cretaceous high-Mg diorites in western Shandong. In situ oxygen isotope analysis yielded δO values of olivine from (6.03±0.33)‰ to (6.82±0.35)‰, averaging (6.5±0.4)‰; this is higher than typical mantle-derived olivine ((5.2±0.3)‰). Compared with clinopyroxenes from peridotite xenoliths in the Late Cretaceous and Cenozoic basalts, clinopyroxenes in the wehrlites contain relatively low concentrations of NaO, TiO, and AlO, high concentrations of CaO, and higher Mg (91.2-94.1) and Ti/Eu ratios (2082-2845), being similar in composition to clinopyroxenes within harzburgite xenoliths in the Early Cretaceous high-Mg diorites. Clinopyroxenes from wehrlite xenoliths are characterized by low total REE abundance, enrichment in light REEs, and depletion in high field strength elements such as Nb, Ta, Zr, and Hf. Moreover, the Sr/Sr, Nd/Nd, and Os/Os (125 Ma) ratios of these wehrlites vary from 0.70596 to 0.70737, 0.512181 to 0.512416, and 0.12661 to 0.57650, respectively. These data suggest that these wehrlite xenoliths were formed by modification of the lithospheric mantle by melts derived from recycled continental crust. [ABSTRACT FROM AUTHOR]

Simultaneous in-situ determination of U-Pb ages and 20 trace elements of three international zircon standards (91500, GJ1 and TEMORA 1) and one laboratory zircon standard (SK1O-2) separated from Cenozoic fine-grained gabbro was carried out on quadrupole ICP-MS equipped with 193 nm excimer laser in 20 µm spot size. The weighted mean 206Pb/238U ages of 91500, GJ1 and TEMORA 1 are 1064.4±4.8 Ma (2σ), 603.2±2.4 Ma (2σ) and 418.2±2.4 Ma (2σ), respectively. The relative standard deviations (RSD5) of 206Pb/238U ages (2σ) are less than 2.2% for single measurements and 0.6% for weighted means. The obtained weighted mean 206Pb/238U ages of three standard zircons agree with the recommended values within 2σerror. The weighted mean 206Pb/238U age of Ski 0-2 is 31.42±0.25 Ma (2σ) and the RSDs of 206Pb/238U ages (2σ) are between 2.4% and 5.7% for single measurements and less than 0.8% for weighted mean. The obtained weighted mean 206Pb/238U age is in good agreement with the age obtained by Yuan (2004). Trace element concentrations of NIST612 and NIST614 obtained under the same LA-ICP-MS operating conditions agree with the recommended values within analytical error. The results indicate that it is possible to measure U-Pb age and trace elements simultaneously by LA-ICP-MS in a small spot size of 20 µm. [ABSTRACT FROM AUTHOR]