Eclogite-facies vein systems in the Marun-Keu complex (Polar Urals, Russia): textural, chemical and thermal constraints for patterns of fluid flow in the lower crust
Eclogite-facies vein systems in the Marun-Keu complex (Polar Urals, Russia): textural, chemical and thermal constraints for patterns of fluid flow in the lower crust
复制标题
DOI：
10.1007/s00410-004-0569-z
复制
发表时间：
2004-03
影响因子：
3.5
通讯作者：
J. Molina;S. Poli;H. Austrheim;J. Glodny;A. Rusin
中科院分区：
文献类型：
--
作者：
J. Molina;S. Poli;H. Austrheim;J. Glodny;A. Rusin
高压变质作用期间，变质角闪岩-榴辉岩序列生长在Marun-Keu杂岩（俄罗斯乌拉尔极地）石英脉的边缘。残留的前交代榴辉岩相组合是目前在围岩层作为不规则的补丁。围岩填隙石英步道躺在一个高角度的反应前沿提供证据，颗粒规模的孔隙通道化，这可能是由平行于石英步道的粒间流体成分梯度。脉围岩规模的不平衡推断围岩矿物的不均匀性和矿物分离的可变的初始Sr同位素比值。残岩和围岩组合之间的质量平衡计算揭示了双向质量传递的开放系统行为所造成的化学不平衡。脉-围岩系统记录了从408-434 °C（残余物）到526-668 °C（脉沉淀物）的迁移历史。脉岩和交代岩组合形成于单一的流体-岩石相互作用过程中，意味着高的加热速率（≥100 °C/Ma），这可能是大规模流体循环的热平流作用的结果。
Metasomatic amphibole-eclogite sequences grew in selvages of quartz veins from the Marun-Keu complex (Polar Urals, Russia) during high-pressure metamorphism. Relicts of a pre-metasomatic eclogite-facies assemblage are present in the wallrock layers as irregular patches. Wallrock interstitial quartz trails lying at a high angle to reaction fronts provide evidence for grain-scale pore channelisation which may be produced by intergranular-fluid compositional gradients parallel to the quartz trails. Disequilibrium at vein-wallrock scale is inferred from wallrock mineral heterogeneity and from variable initial Sr isotope ratios in mineral separates. Mass-balance calculations between relicts and wallrock assemblages reveal chemical imbalances caused by open system-behaviour with two way mass-transfer. The vein-wallrock system registers a prograde history from 408–434 °C (relicts) to 526–668 °C (vein precipitates). Vein and metasomatic assemblages formed during a single fluid-rock interaction process, implying high heating rates (≥100 °C/Ma), which could result from heat advection by large-scale fluid circulation.