Reaction-Induced Porosity in an Eclogite-Facies Vein Selvage (Monviso Ophiolite, W. Alps): Textural Evidence and In Situ Trace Elements and Sr Isotopes in Apatite.
Reaction-Induced Porosity in an Eclogite-Facies Vein Selvage (Monviso Ophiolite, W. Alps): Textural Evidence and In Situ Trace Elements and Sr Isotopes in Apatite.
复制标题
榴辉岩相矿脉边缘中反应引起的孔隙度（蒙维索蛇绿岩，西阿尔卑斯山）：结构证据以及磷灰石中的原位微量元素和锶同位素。
DOI：
10.1093/petrology/egac128
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发表时间：
2023
影响因子：
3.9
通讯作者：
Kylander-Clark, Andrew
中科院分区：
文献类型：
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作者：
Hoover, William F;Penniston-Dorland, Sarah;Piccoli, Philip;Kylander-Clark, Andrew
在低渗透高压变质岩中，流体-岩石反应过程中产生的孔隙有利于流体的运移和交代作用。在来自Monviso蛇绿岩（W. Alps）的未变形榴辉化Fe-Ti变长岩中，发现了一个榴辉岩相斜辉石+磷灰石脉，该榴辉岩具有明显的富含石榴石的边缘。脉状流体来源于邻近的变质岩，与寄主岩石发生反应，从衬底中去除Ca和P，添加Fe、REE、Pb和Cr。在交代过程中，衬底-寄主岩石界面和寄主岩石的结构记录了局部反应性和孔隙度的非均质性，这与初始褐煤丰度的变化有关。这些特征反映了一个由普遍到通道化孔隙结构的层次结构，促进了寄主岩石的广泛交代作用。这种针对局部衍生流体的交代系统的发展表明，不需要大规模的外部衍生流体输送来驱动广泛的流体-岩石交换。交代反应过程中孔隙的产生对于促进低渗透率俯冲板块的进一步流体-岩石反应和流体输运具有重要意义。
Porosity generated during fluid–rock reaction can facilitate fluid transport and metasomatism in low permeability high-pressure metamorphic rocks. Evidence for reaction-induced porosity is found in an eclogite-facies clinopyroxene + apatite vein in an undeformed eclogitized Fe–Ti metagabbro from the Monviso Ophiolite (W. Alps) with a distinct garnet-rich selvage. Vein-forming fluids were sourced from adjacent metagabbros and reaction with the host rock removed Ca and P from the selvage and added Fe, REE, Pb and Cr. Textures at the selvage–host rock interface and in the host rock record local heterogeneity in reactivity and porosity during metasomatism linked to variable initial lawsonite abundance. These features reflect a hierarchy of pervasive-to-channelized porosity structures that facilitated widespread metasomatism of the host rock. Development of this metasomatic system in response to locally derived fluids suggests large-scale externally derived fluid transport is not required to drive extensive fluid–rock exchange. The production of porosity during metasomatic reactions could be important in facilitating further fluid–rock reaction and fluid transport in subducting slabs where permeability is low.