美国伊利诺伊大学的David Hernández-Uribe和日本东北大学的Tatsuki Tsujimori合作提出洋壳中进行性硬柱石榴辉岩化，以及对俯冲带深部物质转移的意义。这一研究成果于2023年5月19日发表在国际顶尖学术期刊《地质学》上。

研究人员结合典型俯冲带的岩石模拟与地球动力学计算的方法来表明，硬柱石榴辉岩的出现受俯冲带成熟度控制。研究发现硬柱石榴辉岩不形成于幼年俯冲带；除非是在加热之前挖出的岩石，否则随着时间的推移，洋壳中会形成硬钙磷石组合，但前进加热会使硬钙磷石消失。洋壳中的硬柱石-榴辉岩组合仅在成熟和冷俯冲带中形成并经历了前进变质作用，但在折返过程中仍然需要特定的特征来保存硬柱石。

研究还发现，成熟俯冲带中硬柱石的稳定性受镁铁质地壳和上覆地幔楔物质之间的混杂作用的阻碍；相比之下，随着海底强烈的蚀变和钙铝交代作用，硬柱石的比例增加。因此，后面这些过程是加强回收的关键。因此，研究人员认为，在成熟的俯冲带中，硬柱石驱动的向地幔深处的质量循环是非常重要的，但在俯冲带的幼年阶段，硬柱石榴辉岩在将质量带入地球深部的作用是次要的。

据了解，硬柱石榴辉岩是H₂O和微量元素的主要宿主，也因此它是俯冲带长期深部元素循环的关键。现有的循环模式表明，俯冲洋壳转化为硬柱石-榴辉岩组合，然而，岩石记录中，硬柱石榴辉岩的缺乏引发了这样一个问题，即在俯冲过程中，洋壳在多大程度上转化为硬柱石-榴辉岩组合。

附：英文原文

Title: Progressive lawsonite eclogitization of the oceanic crust: Implications for deep mass transfer in subduction zones

Author: David Hernández-Uribe, Tatsuki Tsujimori

Issue&Volume: 2023-05-19

Abstract: Lawsonite eclogites are major hosts of H₂O and trace elements and thus key for long-term deep element cycling in subduction zones. Existing cycling models suggest that the subducting oceanic crust transforms to lawsonite-eclogite assemblages; yet the scarcity of lawsonite eclogites in the rock record questions to what extent the oceanic crust transforms to lawsonite-eclogite assemblages during subduction. Here, we use petrological modeling coupled with geodynamic calculations for a typical subduction zone to show that the occurrence of lawsonite eclogites is controlled by the maturation of the subduction zone. We find that lawsonite eclogite does not form in infant subduction zones; with time, the oceanic crust forms lawsonite assemblages, but prograde heating obliterates lawsonite except in rocks exhumed prior to such heating. Lawsonite-eclogite assemblages in the oceanic crust form and survive prograde metamorphism only in mature and cold subduction zones but still necessitate specific characteristics during exhumation to preserve lawsonite. We show that the stability of lawsonite in mature subduction zones is hindered by hybridization between the mafic crust and the overlying mantle wedge material; by contrast, lawsonite proportion increases with intense seafloor alteration and Ca-Al metasomatism. These latter processes are thus key for enhancing recycling. We argue that lawsonite-driven mass cycling to the deep mantle is important in mature subduction zones, but the role of lawsonite eclogite in carrying mass deep into Earth in the infant stage of a subduction zone is minor.

DOI: 10.1130/G51052.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G51052.1/623576/Progressive-lawsonite-eclogitization-of-the