Petrology and geochemistry of host rock and gold mineralization at southern part of Ulu Sokor gold deposit, Kelantan, Malaysia / Ahmad Fauzan Yusoff

• Main Author: Ahmad Fauzan , Yusoff
• Format: Thesis
• Published: 2022
• Subjects: Q Science (General); QE Geology
• Online Access: http://studentsrepo.um.edu.my/14716/2/Ahmad_Fauzan.pdf; http://studentsrepo.um.edu.my/14716/1/Ahmad_Fauzan.pdf; http://studentsrepo.um.edu.my/14716/
• Institution: Universiti Malaya

The petrology and geochemistry of host rock and gold mineralization at southern part of Ulu Sokor gold deposit, Kelantan, Malaysia is poorly understood. This study area is located at the Central Belt of Peninsular Malaysia and hosted as an orogenic gold deposit from previous study. Particular deposits in this study area are New Found and New Discovery loads which located at the southern part of the whole Ulu Sokor gold deposit boundary. Two types of host rocks were identified such as phyllite as a metasedimentary rock unit and rhyolite as a volcanic rock unit. Based on the petrological and geochemical data presented, phyllite have been derived from shale and classified as pelitic and felsic source. It was undergone little heavy mineral fractionation and sediment recycling since these samples slightly enriched with Light Rare Earth Elements (LREEs). Some of these samples studied have elevated K2O content that indicate K-metasomatism, which reflects secondary addition of potassium. According to the Chemical Index Alteration (CIA) and Index Compositional Variability (ICV) calculation, it shows that the phyllite are intensely weathered with matured sources. The classifications of depositional conditions are plotted as continental island arc and oceanic island arc. Continental island arc and oceanic island arc are dominated by the development of the subduction process, which synchronic with the tectonic evolution of the Bentong-Raub suture zone. The other type of host rock is rhyolite, which is a typical type of rock that exists in the volcanic arc environment based on the relationship between the collision of Sibumasu and East Malaya blocks. The geochemical features including the enrichment in Large Ion Lithophile Elements (LILEs) relative to High Field Strength Elements (HFSEs), and the restricted calc-alkaline to shoshonitic rocks are indicative of volcanic arc type. The trace and major geochemical elements of volcanic rocks support the evidence of volcanic arc setting. Gold mineralization is primarily hosted in structurally controlled quartz vein, which occurs in various degrees of ductile-brittle environment. Based on the field relationships, ore microscopy, and geochemical data analysis, the main gold mineralization type in the southern part of Ulu Sokor gold deposit is gold (Au)-bismuth (Bi). In terms of mineral exploration and gold prospecting, the significant enrichment in this study area is bismuth. However, some other metals can also be considered as a significant value in this area such as Pb, As, Cu and Zn. From the bulk ore chemistry, the geometric mean values of Au and Bi are 1.8972 ppm (n=23) and 96.3 ppm (n=22) respectively.