Structural analysis and vein episode of the Penjom Gold Deposit, Malaysia: Implications for gold mineralisation and tectonic history in the Central Belt of Malaysia

Abstract

Gold mineralisation at the Penjom Gold Deposit, in the Central Belt of Peninsular Malaysia is dominantly hosted in structurally controlled quartz-carbonate veins that display a variable degree of overprinting events under a ductile–brittle regime. Mineralised veins are categorised into two main episodes: fold and thrust-related veins mainly comprised of bedding and Penjom Thrust parallel shear veins and associated extension veins developed during a D2 event. In addition, NE to NNE trending splays and Penjom-Thrust-parallel reverse–dextral and locally NNW to NS reverse-sinistral faults overprint earlier vein events forming a new episode of extensional veins during D3 event, mostly at the fault contacts of intrusives either as shallow-dipping or vertical sheeted, stockwork or brecciated veins. At least two episodes of faulting D4–D5 are evident which postdates the main episodes of veining and mineralisation. This is indicated by a series of late episodes NS trending sinistral and oblique to normal faults which transect and displace the Penjom Thrust and the folded footwall sequence at low angles and responsible for intensive vein deformation along the Penjom Thrust and displacement of ore body. Structural interpretations of mineralised veins suggest that the veins were formed under a compressional to transpressional regime with later post-vein displacement in a transtensional to extensional regime. Vein formation in response to deformation observed at Penjom reflects regional structural deformation within the Central Belt of Peninsular Malaysia and specifically along the Bentong–Raub Suture zone.