Thermodynamic modeling of melt addition to peridotite: Implications for the refertilization of the non-cratonic continental mantle lithosphere
Thermodynamic modeling of melt addition to peridotite: Implications for the refertilization of the non-cratonic continental mantle lithosphere
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橄榄岩熔体添加的热力学模型：对非克拉通大陆地幔岩石圈再肥沃的影响
DOI：
10.1016/j.chemgeo.2022.121050
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发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Reisberg, Laurie
中科院分区：
文献类型：
--
作者：
Pin, Juliette;France, Lydéric;Lambart, Sarah;Reisberg, Laurie
在非克拉通大陆地幔岩石圈演化的经典模式中，黑子岩代表了肥沃地幔高度部分熔融的难熔（<5%斜辉石）残留物，而黑子岩（<5%斜辉石）代表了部分熔融程度较低的残留物。然而，部分熔融并不是唯一可以解释橄榄岩组成变化的过程，橄榄岩的组成变化范围从肥沃的（bbb20 wt% Al2O3, <45 wt% MgO）到耐火的（<2 wt% Al2O3, >45 wt% MgO）。在再成矿过程中，辉锌矿是一种难熔原岩（可能先前由肥沃地幔的部分熔融形成），经过来自下伏软流圈的硅酸盐熔体的反应渗透，导致新一代矿物（主要是斜辉石）的结晶。了解再成矿过程的一个简单但关键的第一步是研究当熔体被添加到橄榄岩中时，模态和主要元素组成是如何演变的。本文采用热力学约束的双组分混合模型，独立评估了压力、温度、氧化还原条件、初始橄榄岩和添加玄武质熔体（以下简称P-T-fO2-Xπ-Xmelt）组成等5个不同参数在熔体添加过程中的作用。我们将结果与观察到的橄榄岩组进行比较。主要观察结果如下：(1)生成的模型与全球橄榄岩数据库基本一致；(2)T、fo2和压力的微小变化对系统演化几乎没有影响。相比之下，渗滤石的矿物学对模态比例的变化有实质性的影响。影响最大的参数是Xmelt，它与地球动力学背景和熔融条件直接相关。该参数直接控制着再成矿反应，从而控制着相比和体岩组成。在熔体阶段优先分配的元素（例如Na）在自然组合中显示出比简单混合模型预测的更强的消耗，这与自然过程发生在开放系统中的事实相一致，并且反应性渗透可能导致相关熔体中不相容元素的富集。我们的研究结果证实了在岩石圈地幔橄榄岩中观测到的大部分成分变化谱可以用原始硅酸盐熔体浸渍在难熔碳酸盐中来解释。
In a classic model of evolution of the non-cratonic continental mantle lithosphere, harzburgites represent the refractory (<5% clinopyroxene) residues of high degrees of partial melting of fertile mantle, while lherzolites (>5% clinopyroxene) represent residues of lesser degrees of partial melting. However, partial melting is not the only process that could explain the peridotite compositional variability that ranges from fertile (>2 wt% Al2O3, <45 wt% MgO) to refractory (<2 wt% Al2O3, >45 wt% MgO). In the refertilization process, harzburgite is a refractory protolith (potentially previously formed by partial melting of a fertile mantle) that undergoes reactive percolation of silicate melts derived from the underlying asthenosphere, resulting in the crystallization of a new generation of minerals (mostly clinopyroxene). A simple but critical first step towards understanding the refertilization process is to examine how modal and major element compositions evolve as melts are added to peridotites. Here we use a thermodynamically-constrained two-component mixing model to independently evaluate the roles of five different parameters: pressure, temperature, redox conditions, and compositions of the initial peridotite and the added basaltic melt (hereafter referred to P-T-fO2-Xπ-Xmelt), during melt addition. We compare the results with observed suites of peridotites. The main observations are as follows: (1) the produced model is consistent with the global peridotite database, and (2) T,fO2and small variations of pressure have almost no impact on the evolution of the system. In contrast, the mineralogy of the percolated harzburgite has a substantial effect on the variation of the modal proportions. The parameter with the most significant impact is Xmelt, which is directly linked to the geodynamic context and melting conditions. This parameter directly controls the refertilization reaction and so, the phase proportions and the bulk-rock composition. Elements that partition preferentially in the melt phase (e.g., Na) display depletions in natural assemblages that are stronger than those predicted from the simple mixing model, consistent with the fact that the natural process occurs in an open system, and that reactive percolation likely results in incompatible element enrichment in the associated melt. Our results corroborate the suggestion that most of the spectrum of compositional variability observed in lithospheric mantle peridotites can be explained by the impregnation of primitive silicate melt in refractory harzburgites.
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DOI：
10.1144/gsl.sp.2003.218.01.05
发表时间：
2003
期刊：
Geological Society, London, Special Publications
影响因子：
--
作者：
O. Müntener;G. B. Piccardo
通讯作者：
O. Müntener;G. B. Piccardo
通过纳米粉末和橄榄石 LA-ICPMS 分析确定再肥沃地幔橄榄岩的元素和同位素特征
影响因子：
3.9
作者：
C. Lawley;D. Pearson;P. Waterton;A. Zagorevski;J. Bédard;S. Jackson;D. Petts;B. Kjarsgaard;Shuangquan Zhang;Donald Wright
通讯作者：
Donald Wright
地幔岩浆作用的不平衡反应输运模型
影响因子：
3.9
作者：
B. Oliveira;J. Afonso;R. Tilhac
通讯作者：
R. Tilhac
东比利牛斯橄榄岩地块的稀土元素和 Sr-Nd 同位素地球化学：大陆岩浆作用改变的次大陆岩石圈地幔
DOI：
--
发表时间：
1991
期刊：
影响因子：
--
作者：
H. Downes;J. Bodinier;M. Thirlwall;J. Lorand;J. Fabriès
通讯作者：
J. Fabriès
使用 U 系列同位素测试海洋玄武岩的辉石岩与橄榄岩来源
影响因子：
3.5
作者：
Elkins, Lynne J.;Bourdon, Bernard;Lambart, Sarah
通讯作者：
Lambart, Sarah