This study is focused on a plagioclase‐bearing spinel lherzolite from Chah Loqeh area in the Neo‐Tethyan Ashin ophiolite. It is exposed along the west of left‐lateral strike‐slip Dorouneh Fault in the northwest of Central‐East Iranian Microcontinent. Mineral chemistry (Mg#^olivine < ~ 90, Cr#^{clinopyroxene} < ~ 0.2, Cr#^spinel < ~ 0.5, Al₂O₃^{orthopyroxene} > ~ 2.5 wt%, Al₂O₃^{clinopyroxene} > ~ 4.5 wt%, Al₂O₃^spinel > ~ 41.5 wt%, Na₂O^{clinopyroxene} > ~ 0.11 wt%, and TiO₂^{clinopyroxene} > ~ 0.04 wt%) confirms Ashin lherzolite was originally a mid‐oceanic ridge peridotite with low degrees of partial melting at spinel‐peridotite facies in a lithospheric mantle level. However, some Ashin lherzolites record mantle upwelling and tectonic exhumation at plagioclase‐peridotite facies during oceanic extension and diapiric motion of mantle along Nain‐Baft suture zone. This mantle upwelling is evidenced by some modifications in the modal composition (i.e. subsolidus recrystallization of plagioclase and olivine between pyroxene and spinel) and mineral chemistry (e.g. increase in TiO₂ and Na₂O of clinopyroxene, and TiO₂ and Cr# of spinel and decrease in Mg# of olivine), as a consequence of decompression during a progressive upwelling of mantle. Previous geochronological and geochemical data and increasing the depth of subsolidus plagioclase formation at plagioclase‐peridotite facies from Nain ophiolite (~ 16 km) to Ashin ophiolite (~ 35 km) suggest a south to north closure for the Nain‐Baft oceanic crust in the northwest of Central‐East Iranian Microcontinent.

中文翻译：

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奈恩巴夫特洋壳北部岩石圈地幔的演化（伊朗中部阿欣的新特提斯蛇绿岩）

这项研究的重点是新特提斯人Ashin蛇绿岩中Chah Loqeh地区的斜长石尖晶石绿岩。它暴露于伊朗中东部微洲西北部的左走向走滑Dorouneh断层的西部。矿物化学（Mg＃^橄榄石 < ^〜90，Cr＃^斜茂铁 <〜0.2，Cr＃^尖晶石 <〜0.5，Al ₂ O ₃^邻苯二酚 >〜2.5 wt％，Al ₂ O ₃^斜茂铁 >〜4.5 wt％，Al ₂ O ₃^尖晶石 >〜41.5 wt％，Na ₂ O^斜py  >> 0.11 wt％，TiO ₂^斜py >〜0.04 wt％）证实Ashin斜纹岩最初是中洋海脊橄榄石，在岩石圈地幔水平上在尖晶石-橄榄岩相中部分熔融程度低。但是，一些Ashin蛇纹岩在沿Nain-Baft缝合线的大洋伸展和地幔的底辟运动期间，在斜长石-橄榄岩的相中记录了地幔上涌和构造掘出。地幔的上升是由模态组成的一些变化（即斜辉石和橄榄石在辉石和尖晶石之间的亚固相重结晶）和矿物化学（例如，斜辉石的TiO ₂和Na ₂ O和TiO _2的增加）证明的。Cr＃和尖晶石的Cr＃以及橄榄石的Mg＃的降低），这是由于在地幔逐渐上升过程中减压所致。以前的地质年代和地球化学数据以及斜长石-橄榄岩相的固结斜长石形成的深度从Nain蛇绿岩（〜16 km）到Ashin蛇绿岩（〜35 km）逐渐增加，这表明西北部Nain-Baft大洋壳由南向北闭合伊朗中东部微洲。