CAJ | 학술논문

在对江西金山金矿控矿韧性剪切带内岩石和矿石的显微构造分析基础上,对剪切带的递进变形与成矿机理进行探讨.研究发现,金山韧性剪切带在韧性-韧脆性递进剪切变形过程中发育3类石英脉透镜体或石香肠构造;剪切压溶和缝合线构造在金山韧性剪切带内强烈发育;扩散蠕变机制是金山韧性剪切带重要的变形机制.大量缝合线构造的形成增强了岩石的孔隙度和渗透率,有利于流体的迁移和沉淀.金山剪切带内变形和成矿作用经历了漫长复杂的地质过程,粗略估算至少跨过了72 Ma.在递进剪切变形过程中经历多种构造变形机制,如经历了以透入性片理为代表的韧性剪切变形机制到以"次级剪切面"构造网络为代表的韧-脆性剪切变形机制的转换.剪切带的递进剪切变形自始至终控制着金的成矿作用过程,没有递进剪切变形也就没有金山金矿的形成.
재대강서금산금광공광인성전절대내암석화광석적현미구조분석기출상,대전절대적체진변형여성광궤리진행탐토.연구발현,금산인성전절대재인성-인취성체진전절변형과정중발육3류석영맥투경체혹석향장구조;전절압용화봉합선구조재금산인성전절대내강렬발육;확산연변궤제시금산인성전절대중요적변형궤제.대량봉합선구조적형성증강료암석적공극도화삼투솔,유리우류체적천이화침정.금산전절대내변형화성광작용경력료만장복잡적지질과정,조략고산지소과과료72 Ma.재체진전절변형과정중경력다충구조변형궤제,여경력료이투입성편리위대표적인성전절변형궤제도이"차급전절면"구조망락위대표적인-취성전절변형궤제적전환.전절대적체진전절변형자시지종공제착금적성광작용과정,몰유체진전절변형야취몰유금산금광적형성.
Microscopic deformation structures observed in deformed rocks and ores from Jinshan auriferous ductile shear zone of Jinshan gold deposit,Jiangxi Province,are examined and analyzed.Gold mineralization process during progressive shear deformation in the ductile shear zone is discussed.Three classes of quartz-vein boudinage are found developed within the ductile shear zone with respect to vein and boudinage characteristics and timing of major-phase mineralization.The discovery covers intensive pressure solution and pressure dissolution structures of stylolites or dissolution seams developed in the ductile shear zone in detail.The extensively and intensively developed stylolites help enhance porosity and permeability of the shear zone rocks,and provide pathways for migration of fluids as well as space for silica precipitation.Their presence indicates that fluids-enhanced diffusion creep or diffusional mass transfer is not only an important deformation mechanism but also a critical component of mineralization mechanism for Jinshan auriferous ductile shear zone.The paper estimates a minimum 72 million years span for the progressive deformation and mineralization process associated with multiple deformation mechanisms,and underwent a significant deformation regime transfer from penetrative schistosity-dominated fabric of ductile deformation to a non-penetrative (at outcrop and microscopic scales) network of "second-order" shear structures of ductile-brittle deformation.It is concluded that the mineralization process was caused by the progressive shear,and that there would be no such a large gold deposit without the prolonged progressive deformation.