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Analyses on characteristics of microelement and rare-earth element zone of hadamengou gold deposit, Inner Mongolia
Published in Mohd Johari Mohd Yusof, Junwen Zhang, Advances in Civil Engineering: Structural Seismic Resistance, Monitoring and Detection, 2023
Xin Wang, Xiao Bin Dang, Chuan Yun Yue, Yan Wang, Liang Ming
On the normalized micronutrient of the original mantle (Figure 1), the overall features of the samples are consistent, and the large ion lithophile elements are enriched, especially Rb, Th, K, Pb. The high field strength elements are relatively large, and the ionic lithophile elements are relatively deficient, such as Nb, Ta, Zr, Hf, etc. All samples showed negative anomalies of Be and Ga. Except for samples HD11 and HD10, others show obvious negative anomalies of Ti and Sr. It is generally considered that the negative anomaly of Ti may be related to the separation and crystallization of apatite and ilmenite. The Ta-Nb-Ti negative anomaly is similar to the rock characteristics formed in the “island arc” environment. Most scholars believe that the origin of potassic rocks is related to potassium rich and live metasomatic mantle, and this effect is often accompanied by subduction, such as oceanic island arc, post-collision arc environment, and continental arc. Recent studies also show that in Hadamengou Gold Deposit, the ancient Mongolian ocean crust and Angara ancient land block have moved for many times, such as subduction, collision, and docking; therefore, the characteristics of trace elements in the potassic zone have a certain inheritance to the strata in this area. Generally, the negative anomaly of Sr is related to the crystallization differentiation of plagioclase.
Earthquakes and Associated Landslides in Pakistan
Published in Ramesh P. Singh, Darius Bartlett, Natural Hazards, 2018
Shah F. Khan, Muhammad Asif Khan, Ulrich Kamp, Lewis A. Owen
The Hindu Kush, Karakoram and Pamir Ranges owe their origin to a Middle Jurassic tectonic amalgamation of microcontinents of Gondwana affinity at the southern margin of Eurasia (Şengör 1984; Gaetani et al. 1990; Gaetani 1997; Angiolini et al. 2013). The Neotethys ocean that separated the Karakoram from the Indian plate became a site for two major north dipping subduction zones: one at the immediate southern margin of the Karakoram plate and the other to the south in an intraoceanic setting. Both subduction zones consumed the Neotethys and triggered the Late Cretaceous northward drift of the Indian plate that ultimately collided with the southern margin of the Eurasia plate that was defined by the Karakoram plate (Burg 2011). The Indus suture zone is the main Himalayan structure that demarcates the Indian plate to its south from the subduction complexes and Gondwanaic microcontinents at the southern margin of Eurasia in the north. The deformed northern edge of the Indian plate (including the obliterated lithosphere of the Neotethys) that was emplaced inward onto the Indian plate craton during the Late Palaeocene–Recent India–Eurasia collision and the accompanying Himalayan orogeny define the Himalaya (Figure 14.2). Prior to the Eocene, the northward subduction of the Neotethys resulted in the formation of an Andean-type continental arc also known as Trans-Himalaya, including parts of the southern margin of the Eurasian plate north of the Indus suture zone (Hodges 2000).
Zircon U–Pb age, whole-rock geochemistry and Nd–Sr–Pb isotope constraints on petrogenesis of the Eocene Zajkan gabbro–monzogranite intrusion, Tarom-Hashtjin magmatic belt, NW Iran
Published in Australian Journal of Earth Sciences, 2022
M. A. A. Mokhtari, H. Kouhestani, K. Z. Qin
During the Eocene to Oligocene–Miocene, igneous activity is widespread in the Central Iranian Zone as well as in the UDMA, AAMB and East Iranian Zone (Asiabanha & Foden, 2012; Chiu et al., 2013; Haghighi Bardineh et al., 2018; Honarmand et al., 2014; Kouhestani, Ghaderi. et al., 2018; Nabatian et al., 2014, 2016; Nouri et al., 2018; Pang et al., 2013; Sarjoughian et al., 2019; Sepidbar et al., 2019; Shahsavari Alavijeh et al., 2017; Verdel et al., 2011). The intrusions are typical of continental arc magmatism including metasomatised mantle-derived magmas and continental crust partial melts. Subduction of Neo-Tethyan oceanic crust beneath Central Iran played an important role in generating such Andean-type arc magmatism before continental collision in the Zagros orogeny. The complex geochemistry of the Eocene Alborz volcanic rocks has been interpreted as partial melting of metasomatised lithospheric mantle typical of arc magmatism (Asiabanha & Foden, 2012; Brunet et al., 2003; Nabatian et al., 2014; Verdel et al., 2011; Vincent et al., 2005). Recent studies demonstrate that the late Eocene high-K and shoshonitic magmas of the AAMB, UDMA and eastern Pontid in Turkey were formed in an extensional post-collision regime (e.g. Aghazadeh et al., 2011; Asiabanha & Foden, 2012; Castro et al., 2013; Haghighi Bardineh et al., 2018; Honarmand et al., 2014; Karsli et al., 2007, 2012; Nabatian et al., 2014, 2016; Nouri et al.,2018).
Mineralogy and character of the Liikavaara Östra Cu-(W-Au) deposit, northern Sweden
Published in GFF, 2020
Mathis Warlo, Christina Wanhainen, Olof Martinsson, Peter Karlsson
Deformed 2.8–2.6 Ga metagranitoids and gneiss form the Archean basement in northern Norrbotten (Bergman et al. 2001). The basement is only exposed in the northern parts of the region. Elsewhere it is unconformably overlain by supracrustal successions of Palaeoproterozoic age (Bergman et al. 2001). Stratigraphically lowest of these supracrustals are rift-related Karelian rocks (2.4–1.96 Ga), which in the Kiruna area are represented by the Kovo Group (2.8–2.3 Ga) and the overlying Kiruna Greenstone Group (2.3–2.0 Ga; Martinsson 1997; Bergman et al. 2001). Terrestrial to shallow water-deposited Svecofennian successions of metasedimentary and metavolcanic rocks are conformably to disconformably overlying the Karelian units. They comprise the Porphyrite Group, the Kurravaara Conglomerate, the Kiirunavaara Group and the Hauki Quartzite in the Kiruna area (Martinsson 2004; Bergman 2018). Metasedimentary sequences have limited extents (Martinsson et al. 2016). In the Gällivare area, the Muorjevaara Group, a lower Svecofennian unit (1.89–1.88 Ga), comprises both calc-alkaline andesitic metavolcanic and clastic metasedimentary rocks (Fig. 1). Different proportions between these rocks and variations in grain sizes and compositions of the sedimentary rocks record rapid facies changes (Martinsson & Wanhainen 2004). The volcanic rocks were likely formed by an early Svecofennian continental arc magmatism during north-east directed subduction at the margin of the Archean craton (Martinsson & Perdahl 1995; Martinsson 2004).
Geophysical and geochemical characteristics of western Xar Moron suture zone
Published in Petroleum Science and Technology, 2019
Xianli Du, Xuanlong Shan, Xiaojuan Dai, Jian Yi, Rongsheng Zhao, Tiantian Du, Jiayi Wu, Xianfang Du, Hongbo Shi, Qingfa Meng
According to geophysical data, the crust structure on both sides of the Xar Moron suture is obviously different, both of which can be divided into upper, middle and lower crust layers. Low density anomaly zones exist in the upper crust to the north of the fault and in the middle crust to the south of the fault.In the southern part of the fault, the disorderly crustal strata are presumed to be caused by the oceanic subduction and plate collision, and the upwelling of the asthenosphere is caused by the strong tectonic movement.The fault on both sides of the magmatic rocks belong to high in potassium calc-alkaline series, belong to island arc tectonic background, continental arc granite and continental collision granites, shows that there may be a mixture of oceanic crust and mantle magma source.