Mineralogy and element geochemistry of salinized lacustrine organic-rich shale in the Middle Permian Santanghu Basin: Implications for paleoenvironment, provenance, tectonic setting and shale oil potential

Pore type and pore size distribution of tight reservoirs in the Permian Lucaogou Formation of the Jimsar Sag, Junggar Basin, NW China

Paleoenvironmental conditions, organic matter accumulation, and unconventional hydrocarbon potential for the Permian Lucaogou Formation organic-rich rocks in Santanghu Basin, NW China

Use of 1-vinyl imidazole based surfmers for preparation of polyacrylamide–SiO2 nanocomposite through aza-Michael addition copolymerization reaction for rock wettability alteration

Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

Characteristics and origin of tuff-type tight oil in Jimusaer sag, Junggar Basin, NW China

A magmatic-hydrothermal lacustrine exhalite from the Permian Lucaogou Formation, Santanghu Basin, NW China – The volcanogenic origin of fine-grained clastic sedimentary rocks

Santanghu area in northeastern Xinjiang region of Northwest China is an important component of the Central Asian Orogenic Belt (CAOB), in which the dynamic mechanism of Permian magmatism is controversial. In Santanghu area is exposed a thick succession of the Middle Permian basalts, including a small amount of picritic basalts and andesites, known as the Tiaohu Formation. The picritic basalts contain cumulate olivine, and have whole-rock Mg# up to 0.68–0.77; the basalts exhibit porphyritic or doleritic textures, and have relatively low Mg# of 0.41–0.54, typical of evolved magmas. The mafic-ultramafic rocks of the Tiaohu Formation are slightly enriched in Light Rare Earth Elements (LREEs), and exhibit negative Nb and Ti anomalies. They also have high TiO2 content, and Nb/Y and Zr/Yb ratios greater than those of island arc volcanic rocks. Relatively low initial Sr isotopic ratios and high positive ɛ
 Nd(t) and ɛ
 Hf(t) values argue against contamination by ancient continental crust, and suggest formation of the Tiaohu Formation by partial melting of relatively refractory depleted lithospheric mantle that underwent metasomatism and extraction by fluid from the subducted slab. In addition, up to 38% olivine in picritic basalts indicates high-degree partial melting of lithospheric mantle, and the underlying Lucaogou Formation contains fragments of ultra-alkaline magmatic rocks that originated in the deep mantle. These observations imply wide-spread underplating in Santanghu area, which may have been associated with a mantle plume.

Geochemical characteristics and tectonic setting of the Middle Permian Tiaohu Formation mafic-ultramafic rocks of Santanghu area, Xinjiang, Northwest China

Santanghu Basin is located between the Armantai and Karamaili suture zone, at the junction of the Siberia, Kazakhstan and Tarim plates (Chen and Jahn, 2004; Xiao et al., 2008). As an important part of the Central Asian Orogenic Belt, large-scale magmatic rocks of Later Carboniferous-Permian are well developed in Santanghu Basin. Thick volcanic rocks appear in Permian Tiaohu Formation of Santanghu Basin, included basalts and a small amount of picritic rocks and andesites. Picritic rocks are ultramafic lava, which usually occurs in large igneous provinces (Zhang et al., 2006). Evidences of large igneous province in Permian have found in Tarim Basin, Tianshan region, NW China, and some scholars believe the dynamic setting is related with the mantle plume (Xia et al., 2006; Zhang et al., 2010a,b). Does mantle plume also results in intensive magmatic activity of Permian in Santanghu Basin? We focus on the petrology, mineralogy and geochemistry of picritic rocks, which is found from drilling cores in the middle of Malang Depression.

Geochemical characteristics and geological significance of picritic rocks in Permian Tiaohu Formation from Santanghu Basin, Xinjiang, NW China

There is a long-term controversy on sedimentary environment of Late Carboniferous-Permian in Santanghu Basin. In this paper, we study on the geochemical characteristics of source rocks from Harjiawu Formation of Upper Carboniferous and Lucaogou Formation of Middle Permian in Santanghu Basin. The results show that the abundance and maturity of organic matter of source rocks in Harjiawu Formation are both high, which shows excellent source rocks. In contrast, the abundance of organic matter from source rocks in Lucaogou Formation is relatively low and the maturity of organic matter is between immature and mature, which suggests good-excellent source rocks. The organic geochemical characteristics indicate the freshwater lacustrine environment of Late Carboniferous, while Lucaogou Formation is the high salinity lacustrine environment. In addition, magmatic-hydrothermal activity may result in the water salinization of Permian.

https://iopscience.iop.org/article/10.1088/1755-1315/108/3/032051/pdf

Yun Nan

Papers

Characteristics and origin of tuff-type tight oil in Jimusaer sag, Junggar Basin, NW China

A magmatic-hydrothermal lacustrine exhalite from the Permian Lucaogou Formation, Santanghu Basin, NW China – The volcanogenic origin of fine-grained clastic sedimentary rocks

Geochemical characteristics and tectonic setting of the Middle Permian Tiaohu Formation mafic-ultramafic rocks of Santanghu area, Xinjiang, Northwest China

Geochemical characteristics and geological significance of picritic rocks in Permian Tiaohu Formation from Santanghu Basin, Xinjiang, NW China

Sedimentary Environment and Geochemical Characteristics of Source Rocks from Later Carboniferous and Middle Permian in Santanghu Basin, NW China