Positive orientation towards the vernacular among the Talysh of Sumgayit

Abstract

The Yao'an and Machangqing alkaline-rich intrusions, lying in east margin of the NW-WNW Ailaoshan-Jinshajiang fault zone, form parts of the Ailaoshan-Jinshajiang alkaline-rich intrusive belt. The Yao'an intrusion consists mainly of syenite porphyry, and the Machangqing intrusion consists mainly of granite porphyry. Chemically these two intrusions are characterized by enrichment in alkaline and potassium. They enrich in LREE and LILE (such as Rb, Sr, Ba, Th, La etc.), deplet HFSE (such as Nb, Ta and Ti etc.), have high Rb/Sr, La/Nb, Ba/Nb and LREE/HREE ratios, and don't show obvious Eu anomalies. The I Sr values of these two intrusions are relatively high, and ε Nd values are relatively low. It is suggested that the intrusions were derived from partial melting of an enriched upper mantle (EMII), a mixture between normal mantle and subducted oceanic crust, in a continental arc of extension tectonic setting. Although these two intrusions share similar characteristics on tectonic setting in the Himalayan period, age and source region, they have some difference on lithology and chemical composition, which was probably related to the difference on physical-chemical condition (such as T, P and fO 2 etc.) during magmatic crystallization, and on different melted degress of source rocks. Au mineralization is considered to be associated with the intrusions of alkaline series while Cu mineralization with the intrusions of alkaline-subalkaline series in Ailaoshan- Jinshajiang alkaline intrusive belt.