Mafic rocks containing sodic-calcic amphibole in the Green Mountain slice (GMS) and Rowe/Prospect Rock slice (R/PRS), Vermont Appalachians were originally subalkaline basalts emplaced as melts during Neoproterozoic rifting of Rodinia that led to the formation of the Iapetus Ocean basin. Relatively high degrees of partial melting of asthenosphere that was highly depleted in incompatible elements produced R/PRS magma(s), which may have been contaminated locally by continental crust and/or fluids. Trace element chemistry suggests that mafic bodies from different locations in the R/PRS may be fractionated magmatic equivalents. Mafic rocks in the GMS formed from magmas produced by relatively low degrees of partial melting of mantle that was relatively enriched in incompatible elements compared to depleted mantle. These enriched melts may have been derived from a plume and/or enriched lithospheric components, potentially continental crust, embedded in depleted upper mantle. A depleted mantle signature preserved locally in the GMS probably reflects increasing asthenospheric input during crustal thinning, opposed to crustal or fluid contamination. Whole-rock minor and trace element data from the GMS and R/PRS are distinct from analyses of glaucophane schist from the Tillotson Peak Complex in northern Vermont, which may be exhumed Iapetan ocean floor. Exhumed mafic rocks in the GMS and R/PRS were formed as lower plate melts prior to relatively high pressure subduction zone metamorphism, providing evidence for subduction of the Laurentian margin, not subduction erosion. Low pressure greenschist facies mafic rocks that occur structurally between the GMS and R/PRS were sourced from depleted or highly depleted mantle in a supra-subduction zone environment, potentially a forearc or backarc basin; an ophiolitic origin is equivocal. Geochemical and isotopic data and interpretations are compatible with rift-related tectonomagmatic models for the peri-Laurentian realm of the northern Appalachians.

中文翻译：

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镁铁质全岩地球化学和钕同位素，Green Mountain 和 Rowe/Prospect Rock 切片，佛蒙特州阿巴拉契亚山脉

在绿山切片 (GMS) 和 Rowe/Prospect Rock 切片 (R/PRS) 中含有钠钙角闪石的镁铁质岩石，佛蒙特州阿巴拉契亚山脉最初是亚碱性玄武岩，在 Rodinia 的新元古代裂谷期间以熔体的形式出现，导致 Iapetus 海洋的形成盆地。不相容元素高度耗尽的软流圈相对较高程度的部分熔化产生了 R/PRS 岩浆，这些岩浆可能已被大陆地壳和/或流体局部污染。微量元素化学表明，来自 R/PRS 中不同位置的基性体可能是分馏的岩浆等价物。GMS 中的基性岩是由相对较低程度的地幔部分熔融产生的岩浆形成的，与枯竭的地幔相比，不相容元素相对富集。这些富集的熔体可能来自羽流和/或富集的岩石圈成分，可能是大陆地壳，嵌入在枯竭的上地幔中。GMS 局部保留的耗尽地幔特征可能反映了地壳变薄期间软流圈输入的增加，与地壳或流体污染相反。来自 GMS 和 R/PRS 的全岩微量元素和微量元素数据与来自佛蒙特州北部 Tillotson Peak Complex 的蓝闪石片岩的分析不同，后者可能是从 Iapetan 海底挖掘出来的。GMS 和 R/PRS 中挖掘出的基性岩是在相对高压俯冲带变质作用之前作为下部板块熔体形成的，为劳伦边缘俯冲而不是俯冲侵蚀提供了证据。GMS 和 R/PRS 之间的低压绿片岩相基性岩来源于超俯冲带环境中的耗尽或高度耗尽的地幔，可能是弧前或弧后盆地；蛇绿的起源是模棱两可的。地球化学和同位素数据和解释与北阿巴拉契亚山脉 Laurentian 边缘地区的裂谷相关构造岩浆模型兼容。