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Parentage identification technology is of great significance in the selective breeding of aquatic animals. Procambarus clarkii, at present, is an important freshwater economic species in China, and its genetic breeding is quite urgent for its aquaculture. In this study, 18 novel polymorphic microsatellite markers were developed for P. clarkii from 144 potential primers. The efficiency of 16 developed tetrameric markers with higher PIC values and two published tetrameric markers for parentage identification was evaluated in 15 maternal half-sib families. Ten highly polymorphic markers (mean HE = 0.720 and PIC = 0.669) were identified as being suitable for inclusion in the parentage marker suite. Simulation analysis indicated that the cumulative exclusion probabilities for the ten loci were 97.55% and 99.86%, respectively, when no parental information or only one parental information was available. In actual parentage assignments, 94.67% of offspring were correctly assigned to their mothers, which confirmed the application value of this marker suite in the parentage identification of P. clarkii. [ABSTRACT FROM AUTHOR]

Porphyry Mo deposits are the most important type of Mo resource. They result from a high oxygen fugacity of the parent magma, which acts as an effective indicator for evaluating the mineralization. In the ore-forming system of porphyry Mo deposits, sulfur exists mainly as sulfate in highly oxidized magma but as sulfide in ores. What triggers the reduction in the mineralization system that leads to sulfide precipitation has not yet been determined. Most of the previous studies have focused on the origin and evolution of the ore-forming parent magma, and the effects of reductive surrounding rocks on porphyry mineralization have been ignored. In this study, a comprehensive geological–geochemical investigation and review have been performed on the typical porphyry Mo deposits, the Nannihu-Sandaozhuang, Yuchiling, and Shapingou deposits in China, and the Mt. Emmons deposits in America. Black carbonaceous sedimentary layers commonly surround porphyry Mo ores, which are widely altered and discolored during mineralization. CH4 is commonly present in fluid inclusions in the main mineralization stage, and the δ13CV-PDB values of calcite and fluid inclusions from the altered surrounding rocks and ore minerals are generally low and significantly different from those of marine sedimentary carbonate rocks, indicating that the involvement of reductive components from carbonaceous surrounding rocks might be key to the redox state transformation leading to mineral precipitation. On the other hand, the CH4 produced by the thermal decomposition of organic matter or carbonaceous reaction with H2O can diffuse into the ore-forming system along the structural fractures and reduce the SO42− in the ore-forming hydrothermal fluids to form sulfide precipitation without direct contact between the intrusion and the carbonaceous surrounding rocks. Moreover, the CH4 content controls the location of the orebody formation with the high content producing orebodies mainly in the porphyry intrusion, while the low CH4 content results in the orebodies mainly occurring at the contact zone between the porphyry and carbonaceous surrounding rocks. Compared to the magmatic stage of mineralization, the involvement of reductive components in the carbonaceous surrounding rocks during the hydrothermal stage is more favorable for forming giant/large Mo deposits. The highly oxidized porphyry with reductive carbonaceous surrounding rocks or Fe-rich volcanic rocks offers a new indicator for efficiently evaluating porphyry Mo mineralization. [ABSTRACT FROM AUTHOR]

The red swamp crayfish, Procambarus clarkii (Girard, 1852), is currently an economically important aquaculture animal. Its genetic basis has been scarcely reported, however, partly due to the absence of abundant molecular markers in the genome. In this study, Simple Sequence Repeat (SSR) loci were mined, based on genome survey sequencing via the next generation sequence of the red swamp crayfish. A total of 4897 SSR loci were identified, with the most abundant type being the di-nucleotide repeat motifs (75.2%), followed by tri- (20.4%), tetra- (3.8%), penta- (0.5%), and hexanucleotide (0.2%) repeats. In total, 1546 SSR markers were validated to be amplified, and 721 of these were identified as polymorphic SSR markers. Fifty polymorphic SSR markers were randomly selected for the identification of the genetic diversity of the 14 red swamp crayfish populations in China. The expected and observed heterozygosity and polymorphism information content were 0.39, 0.30, and 0.29, respectively, on average. The results indicated a medium genetic diversity among the 14 investigated populations. These probably cluster into three genetic populations. The current study provides abundant genetic markers and information on the 14 populations, which can be helpful for genetic diversity estimation and molecular breeding of the red swamp crayfish. Résumé: L'écrevisse rouge de Louisiane, Procambarus clarkii (Girard, 1852), est une espèce d'aquaculture importante économiquement. Sa base génétique est peu connue, due en partie à l'absence de marqueurs moléculaires abondants dans son génome. Dans cette étude, l'analyse des microsatellites (SSR) de l'écrevisse rouge a été effectuée, sur la base d'un séquençage du génome par séquençage nouvelle génération (NGS). Un total de 4897 loci SSR ont été identifiés, le type le plus abondant de motifs répétés étant les di-nucléotides (75,2%), suivi par les répétitions à tri- (20,4%), tétra- (3,8%), penta- (0,5%), et hexa-nucléotides (0,2%). Au total, 1546 marqueurs ont été validés pour être amplifiés, et 721 d'entre eux ont été identifiés comme marqueurs SSR polymorphiques. 50 marqueurs SSR polymorphiques ont été sélectionnés au hasard pour l'identification de la diversité génétique des 14 populations d'écrevisse rouge de Louisiane en Chine. L'hétérozygotie attendue et observée et l'indice de polymorphisme ont été, en moyenne, respectivement de 0,39, 0,30, et 0,29. Les résultats montrent une diversité génétique moyenne parmi les 14 populations étudiées, qui se regroupent probablement dans trois populations génétiques. Cette étude fournit des marqueurs génétiques abondants et des informations sur les 14 populations, qui peuvent être utiles pour l'estimation de la diversité génétique et la sélection moléculaire de l'écrevisse rouge de Louisiane. [ABSTRACT FROM AUTHOR]

The red swamp crayfish, Procambarus clarkii (Girard, 1852), is a paradox in China because it has developed as a popular aquaculture species while becoming a notorious invasive species. We investigated the population genetic diversity and population dynamics of wild Chinese populations of P. clarkii based on proPO fragments and the morphological traits across these populations. The results showed that the populations of P. clarkii exhibit high genetic diversity and significant population structure, inferring that the crayfish was artificially transferred rapidly among different locations for different reasons. Results also revealed distinct phenotypic differentiation, with individuals of some populations having a shorter pleon and wider carapace width, whereas other populations have a small length to width ratio. This study provided comprehensive insights into the population dynamics and morphological variations of P. clarkii , which contribute to understanding the rapid evolution of phenotypic traits after its successful invasion. Results should help establish efficient management strategies for the control of the invasion and at the same time using the genetic information in crayfish aquaculture. [ABSTRACT FROM AUTHOR]

Abstract: Long‐standing controversy persists over the presence and role of iron–rich melts in the formation of volcanic rock‐hosted iron deposits. Conjugate iron–rich and silica–rich melt inclusions observed in thin‐sections are considered as direct evidence for the presence of iron‐rich melt, yet unequivocal outcrop‐scale evidence of iron‐rich melts are still lacking in volcanic rock‐hosted iron deposits. Submarine volcanic rock‐hosted iron deposits, which are mainly distributed in the western and eastern Tianshan Mountains in Xinjiang, are important resources of iron ores in China, but it remains unclear whether iron‐rich melts have played a role in the mineralization of such iron ores. In this study, we observed abundant iron‐rich agglomerates in the brecciated andesite lava of the Heijianshan submarine volcanic rock–hosted iron deposit, Eastern Tianshan, China. The iron‐rich agglomerates occur as irregular and angular masses filling fractures of the host brecciated andesite lava. They show concentric potassic alteration with silicification or epidotization rims, indicative of their formation after the wall rocks. The iron‐rich agglomerates have porphyritic and hyalopilitic textures, and locally display chilled margins in the contact zone with the host rocks. These features cannot be explained by hydrothermal replacement of wall rocks (brecciated andesite lava) which is free of vesicle and amygdale, rather they indicate direct crystallization of the iron‐rich agglomerates from iron‐rich melts. We propose that the iron‐rich agglomerates were formed by open‐space filling of volatile‐rich iron‐rich melt in fractures of the brecciated andesite lava. The iron‐rich agglomerates are compositionally similar to the wall‐rock brecciated andesite lava, but have much larger variation. Based on mineral assemblages, the iron‐rich agglomerates are subdivided into five types, i.e., albite‐magnetite type, albite‐K‐feldspar‐magnetite type, K‐feldspar–magnetite type, epidote‐magnetite type and quartz‐magnetite type, representing that products formed at different stages during the evolution of a magmatic‐hydrothermal system. The albite‐magnetite type represents the earliest crystallization product from a residual iron‐rich melt; the albite‐K‐feldspar‐magnetite and K‐feldspar‐magnetite types show features of magmatic‐hydrothermal transition, whereas the epidote‐magnetite and quartz‐magnetite types represent products of hydrothermal alteration. The occurrence of iron‐rich agglomerates provides macroscopic evidence for the presence of iron‐rich melts in the mineralization of the Heijianshan iron deposit. It also indicates that iron mineralization of submarine volcanic rock‐hosted iron deposits is genetically related to hydrothermal fluids derived from iron‐rich melts. [ABSTRACT FROM AUTHOR]

A large number of Paleoproterozoic borate deposits are hosted by the lower units of a volcanic-sedimentary sequence in Liaoning Province, northeastern China, and are a major source of boron in China. The ore-bearing wall rocks in the deposits are serpentinized ultrabasic rocks and carbonates, with layered leptynites, leptites, amphibolites, and migmatites adjacent to the ore. Both the borate ores and country rocks contain tourmaline, although the country rocks have much lower abundances of the mineral. Based on in situ boron isotope measurements using laser ablation–multi-collector–inductively coupled plasma–mass spectrometry (LA–MC–ICP–MS), boron isotope data show that: (1) δ 11 B values of borate ores range from + 6.8‰ to + 13.9‰ (mean + 10.8‰); (2) tourmalines from the borate ores have δ 11 B values from + 9.5‰ to + 12.7‰; and (3) the wall rocks within the borate ores yield slightly lower δ 11 B values ranging from + 5.7‰ to + 7.6‰, and those outside the deposits from − 9.9‰ to − 5.9‰. Positive δ 11 B values in borates as well as in tourmalines inside the mining area indicate that boron in these Paleoproterozoic borate deposits was derived from marine evaporites. δ 34 S V-CDT (where V-CDT is Vienna Canyon Diablo Troilite) values of borate ores, serpentinized marbles, and anhydrites range from + 16.1‰ to + 24.7‰, whereas δ 13 C V-PDB (where V-PDB is Vienna Pee Dee Belemnite) values of marbles range from + 3.2‰ to + 5.9‰. These isotopic characteristics are interpreted to reflect formation in a marine evaporative environment. LA–MC–ICP–MS zircon weighted 207 Pb/ 206 Pb ages of leptite and serpentinized olivine basalt from the hanging wall of the borate deposits are 2139 ± 13 Ma and 2130 ± 19 Ma, respectively. Therefore, the (~ 2.2 Ga) borate deposits may have originated from marine evaporative boron-bearing sediments, which were interbedded within bimodal volcanic rocks during the early stages of development of the Liaoji rift. [ABSTRACT FROM AUTHOR]

Abstract: Banded iron formations (BIFs) are Precambrian chemical marine sedimentary formations that record major transitions of chemical composition, and oxidation–reduction state of oceans at the time of their deposition. In this paper, we report silicon and oxygen isotope compositions of a variety of BIFs from the North China Craton (NCC) in order to deduce the mechanism of their formation. Quartz in the various types of BIFs from the NCC are generally depleted in 30Si, where δ30SiNBS-28 values range from −2.0‰ to −0.3‰ (average, −0.8‰), similar to δ30SiNBS-28 values measured from modern submarine black chimneys and sinters. The δ18OV-SMOW values of quartz in the BIFs are relatively high (8.1‰–21.5‰; average, 13.1‰), similar to those of siliceous rock formed by hydrothermal activities. The δ30SiNBS-28 values of quartz in magnetite bands are commonly lower than those of quartz in adjacent siliceous bands within the same sample, whereas δ18OV-SMOW values are higher in the magnetite bands. A negative correlation is observed between δ30SiNBS-28 and δ18OV-SMOW values of quartz from siliceous and magnetite bands in BIF from Fuping, Hebei Province. The isotopic compositions of silicon and oxygen of quartz in BIFs provide insights for the formation mechanisms of silicon–iron cyclothems in BIFs. After the silicon- and iron-rich hydrothermal solution was injected onto the seabed, the abrupt temperature drop caused oversaturation of silicic acid, resulting in rapid precipitation of SiO2 and deposition of siliceous layers. Ferric hydroxide was precipitated later than SiO2 because of low free-oxygen concentration in the ocean bottom. Progressive mixing of hydrothermal solution with seawater caused a continuous drop in temperature and an increase in Eh values, resulting in gradual oxidation of hydrothermal Fe2+ and deposition of iron-rich layers. In summary, each silicon–iron cyclothem marks a large-scale submarine hydrothermal exhalation. The periodic nature of these exhalations resulted in the formation of regular silicon–iron cyclothems. The widespread distribution of BIFs indicates that volcanism and submarine hydrothermal exhalation were extensive; the low δ30SiNBS-28 and high δ18O V-SMOW values of the BIFs indicate that the temperature of seawater was relatively high at the time of BIF formation, and that concentrations of Fe2+ and H4SiO4 in seawater were saturated. [Copyright &y& Elsevier]

Misgurnus anguillicaudatus has several natural ploidy types. To investigate whether nuclear polyploidy have an impact on mitochondrial DNA (mtDNA), the complete mitochondrial genomes (mitogenomes) of five distinct ploidy M. anguillicaudatus (natural diploid, triploid, tetraploid, pentaploid and hexaploid), which were collected in central China, were sequenced and analyzed. The five mitogenomes share the same gene arrangement and have similar gene size, base composition and codon usage pattern. The most variable regions of the mitogenome were the protein-coding genes, especially the ND4L (5.39% mutation rate). Most variations occurred in tetraploids. The phylogenetic tree showed that the tetraploid M. anguillicaudatus separated early from other ploidy loaches. Meanwhile, the mitogenomes from pentaploids, and hexaploids have the closest phylogenetic relations, but far from that of tetraploids, implying that pentaploids and hexaploids could not be formed from tetraploids, possibly from the diploids and triploids. The genus Misgurnus species were divided into two divergent inter-genus clades, and the five ploidy M. anguillicaudatus were monophyletic, which support the hypotheses about the mitochondrial introgression in loach species. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evaporite layer is an important oxidation barrier for the formation of Fe deposits. • Pyrite ores/deposits and Fe ores/deposits belong to the same Fe mineralization system. • A new genesis model of IOA and skarn Fe deposits has been proposed. Iron oxide – apatite (IOA) and skarn Fe deposits are important sources of Fe in China. During the Mesozoic, a large number of large IOA and skarn Fe deposits formed in the Middle–Lower Yangtze River Metallogenic Belt (MLYRMB) in a short period. These deposits genetically show a close spatial relationship to Triassic evaporite layers. In this study, the S isotope values of IOA deposits and Fe skarn deposits in the MLYRMB were collected and summarized. Most of the sulfides from Fe deposits have higher S isotope values (5–10‰), and the sulfates have S isotope values (17–21‰) that are similar to those of the evaporite layers (28–30‰), indicating the involvement of the evaporite layers. The effects of the evaporite layers on the mechanism of Fe ore formation are discussed. Evaporite layers are the most important oxidation barrier in the formation of Fe ores, as they can oxidize Fe2+ to Fe3+ in magmatic melts and magmatic-hydrothermal fluids, promoting Fe accumulation. Evaporite layers can also provide Na, Ca, K, Cl, and other agents of mineralization that facilitate the formation and transformation of Fe-bearing fluids and cause the deposits to display large-scale Na and Cl alterations. When sulfate from evaporite layers oxidizes Fe2+ to Fe3+, S6+ is reduced to S2−, becoming a major sulfur source for the formation of either sulfide ores or pyrite deposits after Fe mineralization. Sulfate (gypsum) from evaporite layers could be activated and transferred to the upper or side part of the ore system, forming anhydrite/gypsum ores (veins). Therefore, pyrite, anhydrite, and Fe ores often appear in single deposit. [ABSTRACT FROM AUTHOR]

Procambarus clarkii is an important freshwater cultured crayfish in China. With the gradual development of its aquaculture industry, research on white spot disease, which is harmful to healthy culture of P. clarkii , increases gradually. The prophenoloxidase (proPO) system is an important part of crayfish's innate immunity and plays a role in virus resistance. In this study, based on the early discovery of three SNP sites in the intron of proPO gene, the linkage disequilibrium and haplotype were analyzed for the SNPs, and it was found that there was a strong linkage disequilibrium relationship among them. Through the analysis on association between the haplotypes and genotype of each SNP site with the WSSV-resistant traits, the detection of the SNP_7081 genotype was considered as the most convenient and efficient way for WSSV-resistant group selection. Furtherly, the high-resolution melting curve (HRM), which is a rapid and economic genotyping method, was chosen to establish for SNP_7081 site genotyping. The 68 bp target fragment with 27.94% GC content was amplified and melting curve analysis were performed. However, the appearance of false negatives which led to unable automatically grouped although the melting curves of genotypes CC, C>T and T>C were obviously different, and could be treated as standard to manually genotype the samples with an accuracy rate of 97.61%. The low GC content which correlated with the Tm value, was confirmed as the reason for the false negatives by the assay about the recombinant plasmid PMD18-T-SNP_7081 constructed with 45.24% GC content. Eventually, the adaptor primers were used to increase the GC content of the target fragment, and a modified HRM method for genotyping SNP_7081 site that could group automatically was established, which could provide a new insight for the HRM method to genotype SNPs. • The detection of SNP_7081 site was considered as an efficient way. • The false negatives in HRM were related to the low GC content. • Established a modified HRM method for genotyping SNP_7081 site. [ABSTRACT FROM AUTHOR]

• Magnetites crystallized rapidly and did not experience intense hydrothermal overprinting. • Magnetites precipitated in a hydrothermal environment, showing similar magmatic links. • Interactions between Fe-bearing fluids and country rocks increase during Fe mineralization. Iron oxide–apatite (IOA) deposits are an important type of iron deposit that may host large reserves of iron and other elements. The Washan deposit in the Ningwu Ore District is a classic giant IOA deposit hosted by porphyritic diorite. At Washan, four Fe mineralization stages have been identified with clear crosscutting relationships, forming four types of ores: disseminated ores, breccia ores, and magnetite–actinolite and magnetite–apatite–actinolite veins. Trace element concentrations and single-grain geochemical profiles of magnetite from the four Fe mineralization stages were obtained via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The geochemical profiles show consistent Ti, V, Mg and Al contents from cores to rims, indicating that magnetite might have crystallized quickly under relatively stable conditions in each stage. Compatible element (e.g., Co, V, Ni, and Cr) contents of the Washan magnetite are similar to those of magmatic Fe–Ti–V deposits, with high V and Ti contents, indicating a close magmatic link. Increasing Mg, Al, Mn, Ni and Ga contents and decreasing Cr content from early to late stages imply increasingly intense reactions between Fe-bearing fluids and country rocks (e.g., diorite and evaporites), which also suggests a magmatic-hydrothermal origin. We propose a new genetic model for ore formation at the Washan IOA deposit. First, an Fe-rich liquid, which may have formed via liquid immiscibility, ascended through the magma system, resulting in the disseminated ores and albite alteration in the porphyritic diorite. With cooling and crystallization of the magma, the intrusive rocks developed fractures and brecciation, which may have provided pathways for Fe-bearing fluids. After the breccia (or massive) ores formed, the pathways would have been quickly sealed by mineral precipitation. Continuous liquid immiscibility and magma crystallization may have produced similar fluids with more sedimentary material involved and its markers displayed. When the fluid pressure overcame the lithostatic pressure, the fractures that developed may have provided the necessary conduits for emplacement of the magnetite–actinolite and magnetite–actinolite–apatite veins. Subsequently, the magmatic-hydrothermal system might have remained active during cooling and differentiation, while pyrite–quartz and calcite veins formed. [ABSTRACT FROM AUTHOR]

The origin of the Zhaoanzhuang serpentine-magnetite deposit in the southern North China Craton (NCC) is highly disputed, with some investigators having proposed an ultramafic origin, whereas others favor a chemical sedimentary origin. These discrepancies are largely due to the difficulty in determining the protolithic characteristics of the highly metamorphosed rocks. Sulfur, magnesium, and boron isotope geochemistry combined with detailed petrography was carried out in this study to constrain the original composition of the Zhaoanzhuang iron orebodies. Anhydrite is present as coarse crystals intergrown with magnetite, indicating that the anhydrite formed simultaneously with the magnetite during metamorphism rather than as a product of later hydrothermal alteration. The anhydrite has a narrow range of positive δ34S values from +19.8 to +22.5‰ with a mean value of +21.1‰. These values are significantly higher than that of typical magmatic sulfur (δ34S = 0 ± 5‰) and deviate away from primary igneous anhydrite towards mantle-sulfur isotopic values, but they are similar to those of marine evaporitic anhydrite and gypsum (~+21‰). The sulfur isotopic compositions of several samples show obvious signs of mass-independent sulfur fractionation (Δ33S = −0.47‰ to +0.90‰), suggesting that they were influenced by an external sulfur source through a photochemical reaction at low oxygen concentrations, which is consistent with the Neoarchean-Paleoproterozoic atmosphere. Coarse-grained tourmaline from the tourmaline-rich interlayers of the orebodies occurs closely with Mg-rich minerals such as phlogopite, talc, and diopside, indicating that it has a metamorphic origin. The δ11B values of the tourmaline range from −0.2‰ to +3.6‰ with a mean value of +2.0‰, which is much positive relative to that of magmatic tourmaline but is consistent with that of carbonate-derived tourmaline. The magnesium isotopic analyses of the serpentine–magnetite ores and the magnesium-rich wall rocks revealed a wide range of very negative δ26Mg values from −1.20‰ to −0.34‰ with an average value of −0.80‰. The value is higher than that of ultramafic rocks (δ26Mg = −0.25‰) and exhibits minor Mg isotopic fractionation. However, these values are consistent with those of marine carbonate rocks, which have lower δ26Mg values and larger Mg isotopic variations (δ26Mg = −0.45‰ to −4.5‰). Collectively, the S–Mg–B isotopic characteristics of the Zhaoanzhuang iron orebodies clearly indicate a chemical sedimentary origin. The protoliths of these orebodies most likely reflect a series of Fe–Si–Mg-rich marine carbonate rocks with a considerable evaporite component, indicating a carbonate-rich superior-type banded iron formation precipitated in an evaporitic shallow marine sedimentary environment. [ABSTRACT FROM AUTHOR]

The article presents a study of geochronological study of the Xuanlong Type Sedimentary Iron Deposits in North China Craton (NCC) by utilizing evidence from uranium-lead (U-Pb) dating ages of detrital zircons from the Chuanlinggou Formation, which is the hanging wall of iron ore bodies in the Jiangjiazhai and Pangjiapbu mines in China. It also states that banded iron formations (BIFs) represents the most important Precambrian mineralization in NCC.

[Display omitted] • Mafic microgranular enclaves were the product of mafic and felsic magma mixing. • Tieshan batholith originated from partial melting of enriched lithospheric mantle. • Skarn-porphyry Cu deposits prefer thicker crust whereas Fe skarns prefer normal one. Mineralogy, geochemistry, and geochronology of the mafic microgranular enclaves (MMEs) and their host diorite from the Tieshan batholith, Edong district, eastern China, were studied to constrain their petrogenesis and relationship with Fe-Cu skarn mineralization. The MMEs are diorite in composition and characterized by mixed apatite morphologies (elongated thin needles and stubby prismatic form) and bladed biotite, as well as clots of host diorite and megacrystic alkali-feldspar xenocrysts. The MMEs have similar zircon U-Pb age as their host diorite (~139 Ma). Most of the major and trace elements of the MMEs show a linear trend on Harker diagrams and plot along the low-silica trend of the host diorite. They are also characterized by enrichment of LREE and large ion lithophile elements (LILE), but are depleted in high field strength elements (HFSE). The MMEs display similar initial Sr isotopes and ε Nd (t), and slightly lower ε Hf (t) compared to that of host diorite. These results indicate that the Tieshan batholith formed via partial melting of an enriched lithospheric mantle, which is believed to be in equilibrium with a garnet-bearing residue (>50 km), followed by contamination of low crustal materials and fractional crystallization, whereas the MMEs appear to be the products of magma mixing. The presence of Cu- and Ni-bearing minerals in the MMEs probably indicates upper mantle or lower crust accumulation of sulfide which may have played a key role in controlling the formation of the parental magma associated with the skarn-porphyry Cu deposit (148 to 135 Ma) from the Middle-Lower Yangtze River metallogenic belt (MLYRMB). In contrast, the thinner, normal crust (~30 km) at ~ 130 Ma, believed to be in equilibrium with a plagioclase-rich residue, was either unsuitable for producing Cu-bearing accumulations or failed to transfer the deep accumulations to shallower levels to form Cu-bearing skarn systems, resulting in Fe-only mineralization. This may imply that skarn-porphyry Cu deposits prefer to form under > 50 km crustal settings, whereas Fe skarns may preferentially occur under normal (~30 km) crustal thickness. [ABSTRACT FROM AUTHOR]

Cu and Fe skarns are two economically important types of skarn deposit worldwide, but the critical factors controlling the difference in metal associations remain enigmatic. The Edong ore district, China, presents an excellent opportunity to study the differences between Cu–Fe and Fe skarn deposits. We have measured He–Ar isotopes trapped in fluid released by crushing pyrite and chalcopyrite from four well known Cu–Fe and Fe deposits in the Edong district, Eastern China, with the aim of constraining their different fluid source and then discussing the factors controlling their variations between Cu–Fe and Fe skarns. He–Ar isotopic compositions are markedly different between the Cu–Fe and Fe skarn deposits in the Edong district. 3 He/ 4 He ratios in the Cu–Fe deposits are 0.75–1.87 Ra and 40 Ar/ 36 Ar ratios are 300–472. By contrast, He–Ar isotopic compositions in minerals from the Fe deposits have lower 3 He/ 4 He and 40 Ar/ 36 Ar ratios of 0.08–0.93 Ra and 299–361, respectively. These results suggest that noble gas of the Cu–Fe and Fe skarn deposits in the Edong district formed by variable degrees of mixing between a magmatic fluid containing a mantle component, and modified air–saturated water (MASW). Importantly, He–Ar isotope data provide compelling evidence that contrasting fluid sources were involved in the formation of the Cu–Fe and Fe deposits, i.e., mineralizing fluids of the Cu–Fe deposits could have a greater contribution from mantle component, and little involvement of MASW than those of the Fe deposits in the Edong district. This conclusion is consistent with obvious differences in the nature of the intrusions related to mineralization, as well as sulfur isotopic compositions of sulfides in the Cu–Fe and Fe deposits. It is most likely that different proportion of mantle-derived noble gases play an essential role in controlling differences between the Cu–Fe and Fe skarn deposits. [ABSTRACT FROM AUTHOR]

Evaporites have played important role in the formation of diverse metallic ore deposits, especially in the case of magmatic–hydrothermal deposits. However, the relationship between evaporites and skarn Fe deposit remains poorly constrained. In this contribution, we present new sulfur isotope data of pyrite, as well as the composition of halogen-rich minerals (scapolite and amphibole) in the Jinshandian skarn Fe deposit. The data are used to evaluate the evidence for incursion of evaporites in the skarn Fe deposit. The δ 34 S values for pyrite from the early and late retrograde stage range from +17.4‰ to +18.7‰ ( n = 4) and +16.4‰ to +19.4‰ ( n = 13), respectively. Both these values are markedly heavier than the common δ 34 S values of sulfides from magmatic–hydrothermal fluid, indicating that sulfur in the Jinshandian ore-forming system was mostly derived from evaporites. Compared to the amphibole from endoskarn, the scapolite and amphibole from exoskarn show high Cl content up to 4.04% and 3.01%, respectively, suggesting that the hydrothermal fluid with high NaCl content was probably derived from evaporites. The amphiboles from endoskarn are more enriched in F which is probably of magmatic in origin. The data presented in our study suggest that the hydrothermal system of the Jinshandian skarn Fe deposit probably experienced significant incursion of evaporites before or during the late prograde stage. [ABSTRACT FROM AUTHOR]

Red swamp crayfish, Procambarus clarkii, presently is an important aquatic commercial species in China. The crayfish is a hot area of research focus, and its genetic improvement is quite urgent for the crayfish aquaculture in China. However, the knowledge of its genomic landscape is limited. In this study, a survey of P. clarkii genome was investigated based on Illumina's Solexa sequencing platform. Meanwhile, its genome size was estimated using flow cytometry. Interestingly, the genome size estimated is about 8.50 Gb by flow cytometry and 1.86 Gb with genome survey sequencing. Based on the assembled genome sequences, total of 136,962 genes and 152,268 exons were predicted, and the predicted genes ranged from 150 to 12,807 bp in length. The survey sequences could help accelerate the progress of gene discovery involved in genetic diversity and evolutionary analysis, even though it could not successfully applied for estimation of P. clarkii genome size.

The red swamp crayfish (Procambarus clarkii) is one of the most economically important farmed aquatic species in China. However, it is also a famous invasive species in the world. This invasive species was dispersed most via human activities including intentional or unintentional carry in China. Thus, P. clarkii naturally distributed in China provides us a desirable mode to investigate the genetic structure of an invasive species dispersed mainly by human-mediated factors. To reveal the impact of human-mediated dispersal on genetic structure of P. clarkii in China, a total of 22,043 genome-wide SNPs were obtained from approximately 7.4 billion raw reads using 2b-RAD technique in this study. An evident pattern of population genetic structure and the asymmetrical migrational rates between different regions were observed with 22 populations based on these SNPs. This study provide a better understanding of the population genetic structure and demographic history of P. clarkii populations in China, inferring that anthropogenic factors (aquaculture or by accident) and ecological factors (e.g., complicated topography and climatic environment), as well as its special biological traits could account for the current population structure pattern and dispersal history of P. clarkii.

The red swamp crayfish (Procambarus clarkii) was introduced to China in the early 20(th) century. It has been spread to almost all forms of fresh water bodies including lakes, rivers and even paddyfields in most provinces of China. To clarify issues such as the initial entry point(s), dispersal pattern, genetic diversity and genetic structure of Procambarus clarkii in China, the genetic structure and diversity of P. clarkii populations at 37 sampling sites (35 from China, one from the USA and one from Japan) were analyzed using both mitochondrial gene sequences (COI and 16S rRNA) and 12 nuclear microsatellites. Multiple tests including phylogenetic analyses, Bayesian assignment and analysis of isolation by distance showed that (i) the population from Japan and those collected from China, particularly from NanJing (BGt and XG) and its some neighboring sites (CJr, NT and NB), have similar genetic composition, (ii) relatively high genetic diversity was detected in Chinese populations, (iii) the P. clarkii populations in China did not experience significant population expansions. Taken together, Nanjing, Jiangsu province is the presumed initial entry point, and human-mediated dispersal and adaptive variation are likely responsible for the observed genetic pattern of P. clarkii in China.