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首页> 外文期刊>Contributions to Mineralogy and Petrology >Resubduction of lawsonite eclogite within a serpentinite-filled subduction channel
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Resubduction of lawsonite eclogite within a serpentinite-filled subduction channel

机译：六型型俯冲通道内重新提交律师Eclogite

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Translating burial and exhumation histories from the petrological and geochronological record of high-pressure assemblages in subduction channels is key to understanding subduction channel processes. Convective return flow, either serpentinite or sediment hosted, has been suggested as a potential mechanism to retrieve rocks from significant depths and exhume them. Numerical modelling predicts that during convective flow, subducted material can be cycled within a serpentinite-filled subduction channel. Geochronological and petrological evidences for such cycling during subduction are preserved in lawsonite eclogite from serpentinite melange in the Southern New England Orogen, eastern Australia. Ar-Ar, Rb-Sr phengite and U-Pb titanite geochronology, supported by phase equilibrium forward modelling and mineral zoning, suggest Cambro-Ordovician eclogite underwent two stages of burial separated by a stage of partial exhumation. The initial subduction of the eclogite at ca. 490 Ma formed porphyroblastic prograde-zoned garnet and lawsonite at approximateP-Tconditions of at least 2.9 GPa and 600 degrees C. Partial exhumation to at least 2.0 GPa and 500 degrees C is recorded by garnet dissolution. Reburial of the eclogite resulted in growth of new Mg-rich garnet rims, growth of new prograde-zoned phengite and recrystallization of titanite atP-Tconditions of approximately 2.7 GPa and 590 degrees C. U-Pb titanite, and Ar-Ar and Rb-Sr phengite ages constrain the timing of reburial to ca. 450 Ma. This was followed by a second exhumation event at approximately 1.9 GPa and 520 degrees C. These conditions fall along a cold approximate geotherm of 230 degrees C/GPa. The inferred changes in pressure suggest the lawsonite eclogite underwent depth cycling within the subduction channel. Geochronological data indicate that partial exhumation and reburial occurred over ca. 50 M y., providing some estimation on the timescales of material convective cycling in the subduction channel.
机译：从俯冲渠道中的高压组合的岩石和地理学记录中翻译埋葬和地球谐记录是了解俯冲通道过程的关键。已经提出了对流返回流量，蛇形素或沉积物，被认为是从重要的深度和挖掘它们的潜在机制来检索岩石。数值建模预测，在对流流程期间，底层材料可以循环在串型填充的俯冲通道内。在南部南部南部南部的南部的蛇素酸盐的威尔逊矿石庚池的地位和脑探测器在德森矿石中保存。 AR-AR，RB-SR Phengite和U-PB Titanite地质偶像学由相均衡向前建模和矿物分区支持，建议Cambro-Ordician Eclogite接受了部分挖掘的阶段的两个阶段。 Eclogite在CA的初步俯冲。 490 mA形成的斑骨晶体坐式突出的石榴石和律师在近似的3-Tconition，至少2.9GPa和600摄氏度。的部分呼出到至少2.0GPa和500摄氏度，记录到至少2.0GPa和500摄氏度。 Eclogite的叛乱导致新的MG丰富的石榴石缘，新的植物划分的生长和二氧化钛ATP-TCONDITION的重结晶大约2.7GPa和590摄氏度的RB-TCATAITE和AR-AR和RB- SR Phengite Ages限制了对CA的叛标的时间。 450 mA。这是在大约1.9GPa和520℃下的第二次呼口事件。这些条件沿着230摄氏度的冷近似地热。推断的压力变化表明律兵eClogite在俯冲通道内接受深度循环。地理论系数据表明，偏离和叛转者发生在CA上。 50米y。，对俯冲通道中材料对流循环的时间尺度提供一些估计。

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