Relationships between bird communities and vegetation structure in Honghua’erji, northern inner Mongolia

The study of the nesting birds of the coastal riparian zones in Great Kabylia in Algeria, allowed us to identify 45 species of birds, belonging to 12 orders and 26 families. The richest site in terms of species is Takdempt (31 species). The lowest diversity is noted at the level of Boudouaou wadi with 16 species. The values of the Shannon-Weaver diversity index (H') for all sites are quite high (≥3 bits). Concerning the global abundance of avifauna, the site that represents the highest centesimal frequency is that of Takdempt (20.87 %) and this is due to the presence of a colony of Bubulcus ibis (Linnaeus, 1758). The bird communities of the sampled sites are not identical, but the degree of similarity, in general, is quite high (≥ 50 %). The main factors controlling the diversity and the structure of the avifauna of Great Kabylia coastal riparian zones are represented by vertical and horizontal vegetation structure

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Re-Os Geochronology, Whole-Rock and Radiogenic Isotope Geochemistry of the Wulandele Porphyry Molybdenum Deposit in Inner Mongolia, China, and Their Geological Significance

Minerals ◽

10.3390/min10040374 ◽

2020 ◽

Vol 10 (4) ◽

pp. 374

Author(s):

Xiaojun Zhang ◽

Chunliang Yao ◽

David R. Lentz ◽

Ying Qin ◽

Yiwen Wei ◽

...

Keyword(s):

Partial Melting ◽

Continental Crust ◽

Inner Mongolia ◽

Isotope Geochemistry ◽

Minor Component ◽

Depleted Mantle ◽

Molybdenum Deposit ◽

Regional Tectonic ◽

Northern Inner Mongolia ◽

A Minor

The Wulandele molybdenum deposit is a porphyry-type Mo deposit in the Dalaimiao area of northern Inner Mongolia, China. Molybdenite Re-Os dating yields a model age of 134.8 ± 1.9 Ma, with the fine-grained monzogranite most closely related to the mineralization. The lithogeochemical data show that the monzogranite is weakly peraluminous, high-K calc-alkaline series, with reduced to slightly oxidized, highly fractionated I-type granite characteristics. The relatively low initial 87Sr/86Sr (range from 0.705347 to 0.705771), weakly negative εNd(t) (range from −2.0 to −1.3), and crust-mantle mixing of Pb isotopes suggest that the monzogranite originated from the partial melting of mafic juvenile lower continental crust derived from the depleted mantle, with a minor component of ancient continental crust. Combined with the regional tectonic evolution, we argue that the partial melting, then injection, of the monzogranite melt was probably triggered by collapse or delamination of the thickened lithosphere, which was mainly in response to the post-orogenic extensional setting of the Mongol–Okhotsk belt; this is possibly coupled with a back-arc extension related to Paleo-Pacific plate subduction. The extensively fractional crystallization of the monzogranite melt is the crucial enrichment process, resulting in magmatic hydrothermal Mo mineralization in the Wulandele deposit, and the Cretaceous granitoids are generally favorable to form Mo mineralization in the Dalaimiao area.

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