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The Hongtoushan Archean Cu-Zn volcanogenic massive sulfide (VMS) deposit, which was metamorphosed (3.0-2.8 Ga) to upper amphibolite facies at temperatures between 600 and 650°C, occurs in the Hunbei granite-greenstone terrane, Liaoning Province of NE China. Stratiform cordierite-anthophyllite gneiss (CAG) that occurs hundreds of meters below the ore horizon in the Hongtoushan district corresponds to the metamorphosed semi-conformable alteration zone of the VMS hydrothermal system, whereas the CAG that contains abundant deformed sulfide-bearing quartz veins immediately below the main ore layer represents the metamorphosed discordant alteration zone. Whole-rock geochemistry indicates that stratiform CAG was derived ultimately from five lithologies (basalt, basaltic andesite, andesite, dacite, and rhyolite), while discordant CAG derived from a single lithology (rhyolite). Amphibolite and biotite-rich gneiss are identified as a metamorphosed least-altered precursor for these CAGs. Mass change calculation indicates that, compared to the least-altered rocks, stratiform CAG is enriched in Fe and Mg, and depleted in Na, K, Ca, Cu, Pb and Zn, while discordant CAG is enriched in Fe, Mg, Si, Na, Pb, Cu and Zn, and depleted in K. HREE and HFSE (Zr, Ti, Nb and Ta) behaved inertly during submarine alteration, whereas Rb, Sr, Ba and LREE (especially Eu) were leached off.Both stratiform and discordant CAGs are depleted in 18 O, with values up to 7‰ lower than their corresponding least-altered precursors. Addition of Fe, Mg, and depletion of Ca, K, Sr, and 18 O, indicate that hydrothermal alteration for both types of CAGs was characterized by chloritization prior to metamorphism. Stratiform CAG could be used to evaluate the mineralization potential of VMS in metamorphic terranes, while discordant CAG containing sulfide-bearing quartz veins could be a good indication for overlying stratiform massive sulfide ores as well as an exploration target itself.

Jiama is a giant, high‐grade porphyry copper system in the Gangdese metallogenic belt, Tibet. Multistage intermediate‐felsic porphyries intruded in this deposit, some of which are strongly associated with copper–polymetallic mineralization. These ore‐bearing porphyries include monzogranite, granodiorite, and quartz diorite porphyries. A new granite aplite dyke was found in the south of Jiama. Its age, genesis, and relationship with ore‐related magmatism are obscure. Here, its emplacement age and petrogenesis were determined using mineralogy, zircon U–Pb dating, geochemistry, and Sr–Nd–Pb isotope studies. The zircon LA–ICP–MS U–Pb age of the aplite dyke is 16.66 ± 0.21 Ma (n = 14, MSWD = 0.66), earlier than that of the ore‐bearing porphyries (∼15 Ma) in Jiama. Furthermore, the aplite exhibits high amounts of silicon (SiO2 = 73.39%–74.74%), potassium (K2O = 5.12%–6.61%), aluminum (Al2O3 = 14.25%–14.69%), and light/heavy rare earth elements (LREE/HREE = 12.12–16.19) as well as negative europium (δEu = 0.47–0.72) and weak negative cerium anomalies (δCe = 0.84–0.93). The aplite dyke is characteristic of metaluminous–peraluminous I‐type granite, which is rich in large‐ion lithophile elements (Rb, Ba, Th, and U) and depleted in high‐field‐strength elements (Nb, P, and Ti). The aplite dyke and ore‐bearing porphyries in the Jiama deposit are the results of a partial melting of the juvenile lower crust, according to whole‐rock geochemistry and Sr–Nd–Pb isotope data, but the dyke and ore‐bearing porphyries were emplaced from the same magma chamber at different times. Thus, the aplite dyke shows the composition of the early evolution stage of shallow magma in the Jiama deposit and is the product of rapid condensation and crystallization.

The endangered shrub species Amygdalus pedunculata is distributed in Inner Mongolia Autonomous Region and Shaanxi Province, China. However, little is known about its resource quantity and conservation status. A field investigation was conducted to determine the natural distribution range of A. pedunculata. Eight environmental factors were chosen to build models with the genetic algorithm for rule-set prediction (GARP) model and maximum entropy (MaxEnt) model. We predicted the potential distribution of A. pedunculata in China. Using four model evaluation metrics (Kappa, true skill statistic (TSS), overall accuracy and area under the receiver operating characteristic curve (AUC)), we assessed the predictive performance of both models. The Jackknife method was used to investigate the most important environmental factors for the distribution of A. pedunculata. The results indicated that both models were effective for predicting the distribution of A. pedunculata, but MaxEnt performed better than GARP in terms of the four evaluation metrics. The species was predicted to have a broad suitable area, which ranged from the south of Daxing'anling to the east of Helan Mountains and the Ulan Buh Desert. Amygdalus pedunculata is mainly distributed in the middle regions of Inner Mongolia, including Mu Us Sandy Land, Kubuqi desert, Otindag Sandy Land, and the Wulashan and Daqingshan Mountains. Low suitable sites occurred in some regions of Liaoning, Hebei, Shanxi and Shaanxi. Besides, and there were some sporadic low suitable areas in the middle regions of the •研究报告• © 800 生物多样性 Biodiversity Science 第 25 卷 Ningxia Hui Autonomous Region and Gansu Province. Variable importance analysis showed that the variables relevant to precipitation had more significant effects on the geographic distribution of A. pedunculata. These results have important implications for resource conservation and ecology including the revegetation of semi-arid ecosystems.

The Hongtoushan Volcanogenic Massive Sulphide Deposit (VMSD) occurs in the Hunbei granite‐greenstone terrane, Liaoning Province, NE China. Rocks in the mining area have been metamorphosed around 3.0–2.8 Ga to upper amphibolite facies at temperatures between 600°C and 650°C. Cordierite‐anthophyllite gneiss (CAG) in the Hongtoushan mining area, which occurs hundreds of meters below the ore horizon, corresponds to the metamorphosed semi‐conformable alteration zone of the VMSD hydrothermal system, whereas the one immediately below the main ore layer represents the metamorphosed pipe‐like alteration zone. Whole‐rock oxygen isotope signatures were well preserved in both types of CAGs, although the mineral components have been entirely changed during regional metamorphism. Therefore, whole‐rock oxygen isotopes can be used to estimate the formation temperature of both types of alteration zone. Calculations show that the semi‐conformable and pipelike alteration zones for the Hongtoushan submarine hydrothermal system were formed at 290–360°C and 285–320°C, respectively, whereas estimates for the former were slightly higher than that of the latter, indicating that the semi‐conformable alteration zone represents the deep part of the Hongtoushan seafloor hydrothermal system, while the pipe‐like alteration zone represents the discharge conduits for metal‐rich fluids, which is closer to the seafloor.

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We conducted experiments to simulate sulfide remobilisation from sulfide ore. The starting material was from the Hongtoushan massive sulfide deposit, NE China, and is composed of pyrite, pyrrhotite, chalcopyrite, sphalerite, quartz, and silicate minerals. The ore was immersed in a solution of 20 wt.% NaCl for 260 h, and then was mounted in a Changjiang 500 triaxial rock stress machine. After the experiments were performed for 13 h at temperatures of 362, 464, 556 and 682°C, with corresponding confining and axial pressures, the samples were cooled at room temperatures. Our results from all the runs indicate that sulfides can be remobilised both mechanically and chemically, and that remobilisation is enhanced at higher temperatures. Mechanical remobilisation can only take place over limited distances and results in minor differentiation between various sulfide minerals. Distant external remobilisation to form new orebodies is most likely caused by chemical remobilisation. In contrast to plastically deformed areas, space resulting from cataclastic deformation could provide conduits for fluid transport and space for metal precipitation. Remobilised iron sulfides will precipitate as pyrrhotite at high temperatures, but as pyrite when temperature decreases. Furthermore, chalcopyrite is more easily remobilised than sphalerite under the conditions of the present experiments. Remobilisation accompanying deformation and metamorphism may add epigenetic features to syngenetic deposits.