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The paper deals with four new species of Arrenurus (Acari, Hydrachnidiae, Arrenuridae) from standing water habitats in China: Arrenurus (Arrenurus) pseudonemanisp. nov., Arrenurus (Arrenurus) circinatussp. nov., Arrenurus (Arrenurus) menglaensissp. nov., and Arrenurus (Megaluracarus) guantingensissp. nov. Arrenurus (Arrenurus) pseudonemanisp. nov. can be distinguished by the petiole membrane enlarged in the middle, making the middle part significantly wider than the front and rear ends. Arrenurus (Arrenurus) circinatussp. nov. can be distinguished by petiole bearing a circular petiole membrane at the end. Arrenurus (Arrenurus) menglaensissp. nov. can be distinguished by petiole with a pair of setae and split down the middle, forming a pair of pointed crescents at the ends. Arrenurus (Megaluracarus) guantingensissp. nov. can be distinguished cauda slightly convex basally, without lateral extensions, P-2 with 15 small medial setae near distoventral corner. All the type specimens are deposited in GUGC. [ABSTRACT FROM AUTHOR]

Arrenurus is considered one of the most specious genera of water mites. This paper deals with three species of Arrenurus Dugès, 1834 (Acari, Hydrachnidiae, Arrenuridae) from Delingha, Qinghai Province, PR China. Arrenurus (Arrenurus) jaggedis sp. nov. is new to science; Arrenurus (Arrenurus) affinis Koenike, 1887 and Arrenurus (Arrenurus) turgidus Koenike, 1911 are recorded for the first time for the Chinese fauna. Arrenurus (Arrenurus) jaggedis sp. nov. can be distinguished by the petiole with furrows at the end, lateral ridges jagged, dorsal humps well developed, the top sharp and curved towards the front edge of the body. Detailed descriptions and illustrations of the new and newly recorded species are given in this paper. [ABSTRACT FROM AUTHOR]

The Yao'an gold deposit is located in the middle of the Jinshajiang-Ailaoshan alkali-rich metallogenic belt, and this belt hosts many porphyry-type Cu-Au-Mo deposits formed at 46–33 Ma. Yao'an porphyry gold-mineralization is intimately associated with biotite syenite porphyry, whereas the contemporaneous quartz syenite porphyry is barren. In this study, we compared the major and trace elements of apatite and zircon and isotopic compositions of zircon from the biotite syenite porphyry and quartz syenite porphyry, to explore their geochemical differences that may affect their mineralization potential. The results show that both porphyries were derived from the partial melting of the thickened lower crust, which has been modified by slab-derived fluids, but has different mineral crystallization sequences, magma fluid activities, and magma oxidation states, respectively. REE contents in apatite and zircon can be used to reveal the crystallization sequence of minerals. A rapid decrease of (La/Yb)N ratio in apatite from both porphyries may be caused by the crystallization of allanite. Large variation of Cl contents and negative correlation between F/Cl and (La/Yb)N in apatite from fertile porphyry indicate that it has experienced the exsolution of Cl-bearing hydrothermal fluid. Higher Y/Ho and lower Zr/Hf in zircon from fertile porphyry indicate a stronger fluid activity than barren porphyry. The high S, V, As contents, δEu, low δCe in apatite, as well as high Ce4+/Ce3+ and log(fO2) estimated from zircon geochemistry from fertile porphyry, indicate high a oxidation state of fertile porphyry, similar to other fertile porphyries in this metallogenic belt. High fluid activity and fluid exsolution are conducive to the migration and enrichment of metal elements, which are very important for mineralization. High oxygen fugacity inhibits the precipitation of metal in the form of sulfide, thereby enhancing the mineralization potential of rock. Therefore, the exsolution of Cl-bearing hydrothermal fluid and high oxygen fugacity are the key factors promoting mineralization in Yao'an area. [ABSTRACT FROM AUTHOR]

The article focuses on a research paper analyzing the geological characteristics and the genesis of the iron ore metallogenic belt in Tengchong County in Yunnan Province, China. It mentions that the deep-seated magmatic segregation and injection are the internal factors of mineralization. It suggests that mineralization results from the effects of basic?ultra, basic magmatic and arcuate tectonic activities.

This paper deals with five species of Arrenurus Dugs, 1834 from P. R. China. Arrenurus (Truncaturus) linguaus sp. nov., Arrenurus (Arrenurus) pseudodistinctus sp. nov. and Arrenurus (Arrenurus) yanchengensis sp. nov, are new to science; Arrenurus (Arrenurus) crassicaudatus Kramer, 1875 and Arrenurus (Megaluracarus) ussuriensis Sokolow, 1931 are recorded for the first time for the Chinese fauna. Arrenurus (Truncaturus) linguaus sp. nov. can be distinguished by tongue-shaped hyaline petiole, trapezoid hyaline membrane, and more or less triangular acetabular plates. Arrenurus (Arrenurus) pseudodistinctus sp. nov. can be distinguished by the median of petiole enlarged, obviously wider than the front and rear ends; ligulate process well-developed and fishtail-shaped; hyaline membrane trapezoid. Arrenurus (Arrenurus) yanchengensis sp. nov can be distinguished by a short hyaline membrane and extending to the base of the well-developed pygal lobes; petiole lobes have the same length as the petiole. Detailed descriptions and illustrations of the new and newly recorded species are given in this paper.

Three species of the genus Arrenurus Dugs, 1834 are described in detail from China, of which Arrenurus (Arrenurus) ancoralis Zheng Guo sp. nov. and Arrenurus (Arrenurus) unguiculus Zheng Guo sp. nov. are new to science, and Arrenurus (Truncaturus) isikliensis Boyaci zkan, 2004 is recorded for the first time for the Chinese fauna. Arrenurus (A.) ancoralis can be distinguished by D3 on big humps and each with a small protrusion bearing D3 gland; the petiole is well-developed, the middle part contracted, slightly enlarged posteriorly; the ligulate process extending beyond the posterior margin of the petiole and triangle-shaped. Arrenurus (A.) unguiculus can be distinguished by the ligulate process extending beyond the posterior margin for half of petiole length, and nail-shaped. Arrenurus (A.) isikliensis is recorded for the Chinese fauna for the first time. Detailed descriptions and illustrations of the new and the newly recorded species are given in this paper.