Water Contents of Early Cretaceous Mafic Dikes in the Jiaodong Peninsula, Eastern North China Craton: Insights into an Enriched Lithospheric Mantle Source Metasomatized by Paleo–Pacific Plate Subduction–Related Fluids

Machine Learning for Identification of Primary Water Concentrations in Mantle Pyroxene

“…Although these basaltic intrusive rocks cooled slowly (Liang et al, 2019;, our results suggest that the cpx has not been significantly degassed. This is possibly due to the magma cooling in a closed system environment.…”

“…However, these intrusions display a typical grabbro structure, meaning a relatively slow cooling rate, and thus raising the possibility of H diffusion in early crystallized cpx during cooling. Liang et al (2019) and discovered high water content in the cpx grains, but were unable to provide strong evidence that H 2 O measured in the cpx represents the H 2 O content during crystallization. Our SVM results show that most of the cpx grains are predicted to be positive samples (105 out of 126 and 9 out of 10 for the studies by Liang et al (2019) and , respectively), indicating that most cpx does preserve information regarding the original water content.…”

“…Liang et al (2019) and discovered high water content in the cpx grains, but were unable to provide strong evidence that H 2 O measured in the cpx represents the H 2 O content during crystallization. Our SVM results show that most of the cpx grains are predicted to be positive samples (105 out of 126 and 9 out of 10 for the studies by Liang et al (2019) and , respectively), indicating that most cpx does preserve information regarding the original water content. The high water contents can significantly reduce the viscosity and the mechanical strength of the lithosphere (Hirth & Kohlstedt, 1996).…”

The distribution, characteristics and fluid sources of lode gold deposits: An overview

“…In the Jiaodong district, voluminous lamprophyre dykes formed synchronously or slightly earlier than gold mineralization and are associated with the same secondary extensional structures of the trans-lithospheric Tanlu faults that control lode veins (Deng et al, 2020b). These lamprophyres were originated from the metasomatized SCLM and are characterized by enriched Sr-Nd-Hf isotopic compositions and high H 2 O contents (Liang et al, 2019;. In addition, several asthenospheric mantle-derived lamprophyres with depleted Sr-Nd-Hf isotopic compositions also formed slightly later than gold mineralization (Ma et al, 2014).…”

“…8 Myr earlier than the major stage of gold mineralization . Likewise, auriferous quartz veins of the Wulong deposit were dated to be in the range of 127 to 122 Ma (Feng et al, 2020;Yu et al, 2020), which, however, are hosted in the Jurassic gneissic granitic plutons (155 Ma, Liu et al, 2019) and Early Cretaceous monzogranitic plutons (~130 Ma, Wei et al, 2003). Apparently, granitic plutons were emplaced 5 to 30 Myr earlier than large scale gold mineralization in the Wulong deposit.…”