The localization patterns and mechanisms of orebody formation are critical in understanding and exploring for mineral deposits. Skarn ore deposits are especially difficult to study because of their complex features. The Fenghuangshan ore field is a maturely explored skarn copper ore field with many underground workings that reveal the skarn orebodies and related geological context in detail. This situation enables us to use computational modeling to investigate the irregular localization pattern of the skarn orebodies and their origin. Our 3D geometric modeling results show that the skarn orebodies are irregularly localized along the intrusion contact zone and that the irregular localization pattern is closely related to the topography and orientation of the contact zone. The largest orebodies and dominant reserves occur in the western contact zone (WCZ), mainly in the southern segment, where the contact zone is most concave (toward the intrusion). The thicknesses of the major orebodies in the WCZ are correlated with the Gaussian curvature of the contact surface. To investigate the localization mechanism of such irregular orebodies, we use numerical dynamic modeling to study the intrusion cooling process, which is critical for skarn orebody formation. The model consisted of a granodiorite intrusion and carbonate wall rocks, and it was ran on the FLAC^3D platform to test three different scenarios: (1) syn-extensional cooling, which is the likely regional tectonic condition during the mineralization period; (2) syn-compressional cooling; and (3) cooling with no tectonic load. The dynamic modeling results for these three scenarios are distinctly different. Only the first scenario (NE–SW extension) can produce large-scale maximum dilation zones with a distribution pattern similar to that of the orebodies. As the maximum dilation zones are favorable for the formation of skarn ores, we conclude that the tectonic phase is also a critical constraint condition for the irregular localization of skarn orebodies.

中文翻译：

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通过计算模型研究安徽省铜陵市凤凰山矿田中矽卡岩矿体的不规则定位

矿体形成的定位模式和机制对于理解和勘探矿床至关重要。矽卡岩矿床由于其复杂的特征特别难以研究。凤凰山矿田是一种成熟的矽卡岩型铜矿田，具有许多地下作业，可详细揭示矽卡岩矿体和相关的地质背景。这种情况使我们能够使用计算模型来研究矽卡岩矿体的不规则定位模式及其起源。我们的3D几何建模结果表明，矽卡岩矿体沿着侵入接触带不规则地定位，并且不规则定位模式与接触区的形貌和方向密切相关。最大的矿体和主要储量发生在西部接触带（WCZ），主要发生在南部带，该带的接触带最凹（朝着侵入方向）。WCZ中主要矿体的厚度与接触面的高斯曲率相关。为了研究这种不规则矿体的定位机制，我们使用数值动力学模型来研究侵入冷却过程，这对矽卡岩矿体的形成至关重要。该模型由花岗闪长岩和碳酸盐岩围岩组成，并在FLAC上运行 为了研究这种不规则矿体的定位机制，我们使用数值动力学模型来研究侵入冷却过程，这对矽卡岩矿体的形成至关重要。该模型由花岗闪长岩和碳酸盐岩围岩组成，并在FLAC上运行 为了研究这种不规则矿体的定位机制，我们使用数值动力学模型来研究侵入冷却过程，这对矽卡岩矿体的形成至关重要。该模型由花岗闪长岩和碳酸盐岩围岩组成，并在FLAC上运行^3D平台可以测试三种不同的情况：（1）同延伸冷却，这是矿化期间可能的区域构造条件；（2）同压冷却；（3）无构造负荷的冷却。这三种情况的动态建模结果明显不同。只有第一种情况（NE-SW扩展）才能产生大规模的最大扩张带，其分布模式与矿体相似。由于最大的扩张带有利于矽卡岩矿的形成，因此我们得出结论，构造相也是矽卡岩矿体不规则定位的关键制约条件。