A novel sulphate-reducing, Gram-stain-negative, anaerobic strain, isolate XJ01^T, recovered from production fluid at the LiaoHe oilfield, PR China, was the subject of a polyphasic study. The isolate together with Desulfovibrio oxamicus NCIMB 9442^T and Desulfovibrio termitidis DSM 5308^T formed a distinct, well-supported clade in the Desulfovibrionaceae 16S rRNA gene tree. The taxonomic status of the clade was underscored by complementary phenotypic data. The three isolates comprising the clade formed distinct phyletic branches and were distinguished using a combination of physiological features and by low average nucleotide identity and digital DNA–DNA hybridization values. Consequently, it is proposed that isolate XJ01^T represents a novel genus and species for which the name Cupidesulfovibrio liaohensis gen. nov., sp. nov. is proposed with the type strain XJ01^T (=CGMCC 1.5227^T=DSM 107637^T). It is also proposed that D. oxamicus and D. termitidis be reclassified as Cupidesulfovibrio oxamicus comb. nov. and Cupidesulfovibrio termitidis comb. nov., respectively.

The microbial community in oil reservoirs plays important roles in carbon, sulfur, and nitrogen cycling. We identified the microbial composition, abundance, and diversity in two heavy oil wells (W1 and W2) located at Liaohe oilfield, China, that were flooded with higher temperatures, forming a decreasing gradient-temperature field (DGTF) from the steam chamber to the original surrounding formation. The two wells were connected to each other at a depth of 650 m and with temperatures of 249 °C (W1) and 259 °C (W2) in the steam chamber. Water and oil samples were collected from both wells, and 16S rRNA genes were sequenced using Illumina MiSeq (Illumina, San Diego, CA). The number of operational taxonomic units (OTUs) was 5499 and 5938 for W1 and W2, respectively, at 97% clustering. In both wells, the dominant bacterial phylum was Proteobacteria. Euryarchaeota and Crenarchaeota were the only two archaeal phyla detected. Terrimonas and Fluviicola were more abundant in the water sample W1–W, whereas Thermomonas, Nitrosomonas, and Sphingobacterium were more abundant in the oil sample W2-O. Aquificae was the only phylum detected in these wells that had not been detected in other oilfields. Excluding exogenous contamination, the results of this study showed abundant in-situ microbial diversity. The heavy oil reservoir has a large DGTF in higher temperature heavy oil reservoirs, potentially affecting the inner environment.

The Wulanba granite, consisting of biotite monzogranite and syenogranite, is located in the southern part of the Great Xing’an Range, NE China. Whole-rock major- and trace-element geochemistry suggests the Wulanba granite is a high-K–shoshonitic, slightly peraluminous and highly differentiated I-type granite. The Sr–Nd–Hf isotopes indicate that it originated from partial melting of juvenile crust derived from the depleted mantle with a minor input of old crust. The relatively young T_2DM and t_DM2 ages indicate it was most likely derived from a Late Neoproterozoic to Early Palaeozoic source. We have demonstrated that the biotite monzogranite is the ore-related intrusion of the Haobugao Zn–Fe mineralization based on the following geological, geochronological and geochemical evidence: (1) the chalcopyrite/pyrite in the biotite monzogranite and the continuous mineralization of drill core ZK2508; (2) the consistence of the emplacement age of the biotite monzogranite (~141–140/138 Ma) with the skarn mineralization age (~142 Ma); and (3) the presence of rich ore-forming elements (Fe–Zn–Cu) in the biotite monzogranite, and the similar Pb compositions of the sulfides from the Haobugao deposit and the biotite monzogranite. Compared to the barren syenogranite, the fertile biotite monzogranite is more oxidized, while the edges of the apatite grains in the biotite monzogranite are more oxidized than the centres. The average F/Cl ratio of the fertile biotite monzogranite (~123.45) is much higher than that of the barren syenogranite (~73.98). We conclude that these differences reflect unique geochemical signatures, and the geochemical composition of the apatite can be used to infer the economic potential of granites.