P‐T‐D histories from quartz: A case study of the application of the TitaniQ thermobarometer to progressive fabric development in metapelites
P‐T‐D histories from quartz: A case study of the application of the TitaniQ thermobarometer to progressive fabric development in metapelites
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石英的 P-T-D 历史：TitaniQ 温压计在超微晶石渐进织物开发中的应用案例研究
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发表时间：
2013
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通讯作者：
Jay B. Thomas
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作者：
K. Ashley;L. Webb;F. Spear;Jay B. Thomas
本研究调查了石英在多变形变质岩石中记录压力-温度-变形（P-T-D）路径片段的能力，以及石英中钛温度压力计（TitaniQ）的相关应用。本研究选择了来自斯特拉福德穹丘（佛蒙特州东部）的变辉岩，因为它们记录了逆冲变质作用期间的渐进式组构发展，并且具有来自先前工作的良好约束的P-T-D历史。本次研究结果与以往的研究结果一致，表明这些样品中的石英记录了P-T-D路径的额外的不同间隔。六个保存下来的石英平衡事件包括：（1）埋藏过程中的早期辉长岩生长;（2）蓝晶石-石英生成反应;（3）等压加热过程中的预拉坪侵位平衡;（4）等压加热过程中的石英平衡。（4）由于溶液迁移，在褶皱解理发育过程中，石英在石英-长石域中沉淀;（5）推覆体侵位后加热过程中的石英生成（析出）反应;（6）硅质流体流入导致的退变质石英过度生长。对石英体积进行建模可以识别P-T空间中的石英生成反应;对Ti相也可以进行同样的建模，以更好地约束再平衡事件期间的活动。阴极发光成像，显微构造和岩相学调查，等化学稳定性建模，热压法的集成允许识别和解释的石英分区模式，以解开历史，否则将无法获得。
This study investigates the ability of quartz to record segments of the pressure‐temperature‐deformation (P‐T‐D) path in poly‐deformed metamorphic terranes and the associated application of the Ti‐in‐quartz thermobarometer (TitaniQ). Metapelites from the Strafford Dome (eastern Vermont) were selected for this study because they record progressive fabric development during prograde metamorphism and have well constrained P‐T‐D histories from previous work. Results of this investigation are in agreement with previous studies and demonstrate that quartz in these samples records additional distinct intervals of the P‐T‐D path. Six preserved quartz equilibration events include: (1) early prograde growth during burial; (2) kyanite‐in quartz‐producing reactions; (3) prenappe emplacement equilibration during isobaric heating; (4) precipitation of quartz in quartz‐feldspar domains during crenulation cleavage development due to solution transfer; (5) quartz‐producing (chlorite‐out) reactions during heating postnappe emplacement; and (6) retrograde quartz overgrowths from an influx of siliceous fluids. Modeling quartz volume allows for the identification of quartz‐producing reactions in P‐T space; the same may be done for Ti‐phases to better constrain activities during reequilibration events. An integration of cathodoluminescence imaging, microstructural and petrographic investigation, isochemical forward stability modeling, and thermobarometry allows identification and interpretation of zoning patterns in quartz to unravel histories that would otherwise not be obtainable.