Controls on fluid flow in transpressive orogens, Taiwan and New Zealand
Controls on fluid flow in transpressive orogens, Taiwan and New Zealand
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台湾和新西兰压弯造山带流体流动的控制
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Y. Chen
中科院分区：
文献类型：
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作者：
P. Upton;D. Craw;B. Yu;Y. Chen
摘要台湾和新西兰南阿尔卑斯山都是年轻的逆冲造山带，具有快速隆升和折返、高热流和强烈的地表过程等特征。但两个造山带的热流、热泉和脉体分布不同。台湾具有较高的热流、分布的温泉和局部的脉状构造。南阿尔卑斯山有一个狭窄的热流异常，局部的暖泉和广泛的静脉。两个造山带都有两个以分水岭为中心的流体流动系统。浅地形驱动的大气水被限制在顶部2-4公里。深部流动主要是矿化岩石交换流体。伸展变形发生在两个造山带的分界区。在深部，垂直拉伸产生近水平的矿脉。在较浅的层次，伸展是水平的，静脉是陡峭的。台湾的脉是罕见的，在从变质到近地表条件的折返过程中，强烈的脉纹区域的流动已经局限于一个地点。最初较弱的板岩带岩石的破裂和脉纹化导致流变学变化，增加了拉伸强度，使其更容易破裂，从而使流体集中流入同一地点。在南阿尔卑斯山更均匀的流变性导致分布脉。
Abstract Taiwan and the Southern Alps of New Zealand are both young transpressive orogens characterized by rapid uplift and exhumation, high heat flow and vigorous surface processes. However, the distribution of heat flow, hot springs and veins in the two orogens is different. Taiwan has higher heat flow, distributed hot springs and localized veining. The Southern Alps has a narrow heat-flow anomaly, localized warm springs and widespread veining. Both orogens have two fluid-flow systems centred about the drainage divide. Shallow topographically driven meteoric water is restricted to the top 2–4 km. Deep flow is dominated by mineralizing rock-exchanged fluids. Extensional deformation occurs in the divide region of both orogens. At depth, vertical stretching produces subhorizontal veins. At shallower levels, stretching is horizontal and veins are steep. Veins in Taiwan are rare with zones of intense veining where flow has been localized into one site during exhumation from metamorphic to near-surface conditions. Fracturing and veining of the initially weak Slate Belt rocks causes a rheological change, increasing the tensile strength and making it more prone to fracturing, thus focusing fluid flow into the same locale. More uniform rheology in the Southern Alps leads to distributed veining.