• 作者： 譚立平；陳憲照；羅天文
• 作者服務機構： 國立臺灣大學地質學系
• 中文摘要： 豐田地區近年閃玉（軟玉）之?量超過全世界之一半。但由於已知之儲量剩餘不多，因而自1975年起，產量銳減。構 造控制，包括帶狀分布、'構造趨向、褶縐、斷層與節理，?已知之探?閃玉最有效方法。閃玉?在帶狀構造之中心，而滑 石則分布在邊緣。主要之構造趨向?北北東，但西北西之趨向則在某些地區亦甚重要。在第四次褶縐期造成的開?，曲滑 與呈西北西趨向之同斜型褶縐軸部之蛇紋岩上磐，與蛇紋岩下磐和呈西北走向的剪理斷層之接觸處，均?閃玉發育之良好 地點。閃玉一般?在片理傾斜小於15°至25°之地區。呈西北西走向之閃玉礦體部分被第五次褶縐期之開?，曲滑，與呈北 北東向之褶縐所彎曲及碎裂。距離較密之節理破壞閃玉，距離??之節理則有助於生?免用炸藥因而減少破裂之閃玉。
• 英文摘要： More than 50 percent of the world's nephrite jade has been produced in the Fengtien area in recent years but the production has decreased since 1975. Structural controls are the best exploration guides and the important structural features include zonal distribution, structural trends, folds, faults and joints. Nephrite occurs in the center of a zoning system, whereas talc occurs mostly on the periphery. The main structural trend is nne, but the wnw trend is important in some districts. The hanging wall of serpentinite near the hinge of the open, flexure-slip, wnw-trending synform of the fourth fold-generation and the contact between the footwall of the serpentinite and the nw-striking faults in the serpentinite are the most favorable loci for nephrite deposits. Nephrite generally occurs where the schistosity dips less than 15 to 25?. The wnw-striking nephrite orebodies are partly bent and broken by the open, flexure-slip, and nne-trending folds of the fifth generation. Closely spaced joints destroy the nephrite, but widely spaced joints may be of help to nephrite mining where the mineral has not been fractured by dynamite blasting.
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