Geochemistry and Sr-Nd isotopes were determined in Triassic calcalkaline metalava and metapyroclastic rocks from Attica and Argolida, central Greece, to ascertain their origin, evolution, and emplacement timing. Sample protoliths were lavas, tuffs, and, subordinately, tuffites of basaltic to rhyolitic composition. Despite up to low-grade hydrothermal metamorphism, samples retain primary structures and geochemical characteristics; in particular, relatively high (La/Lu) chondrite-normalized ratios, pronounced negative Eu anomalies, and Large Ion Lithophile Element (LILE) enrichment. Unlike the narrow Nd isotopic range (0.512342-0.512625), the Sr isotopic range is relatively wide (0.705903-0.711739). As Sr and Nd isotopic ratios do not provide concordant geochronological age for rock emplacement, they were corrected at 170 Ma due to geologic and petrographic considerations. Geochemistry and Sr and Nd isotopic ratios provide evidence of subduction metasomatism and crustal contamination affecting the parental magmas of samples. Their Nd model ages resemble those of Enriched Mid-Ocean Ridge Basalts (E–MORB) under the northern Aegean and Triassic-rift mafic rocks from northern Greece. As a whole, the geological and petrological data suggest that samples were formed both onshore and offshore in the transition zone between the Pelagonian microcontinent, moving away from Gondwana’s Apulian promontory, and the newly-formed intracontinental basin of the Neotethyan Pindos Ocean. A short-lived immature subduction of young oceanic crust under Pelagonia gave samples their strong geochemical and geological characteristics of volcanic-arc.

中文翻译：

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希腊中部下中三叠统火山岩成因和地球动力学环境的地球化学和 Sr-Nd 同位素证据：对新特提斯平多斯洋的影响

在希腊中部阿提卡和阿尔戈利达的三叠纪钙碱性金属熔岩和变质碎屑岩中测定了地球化学和 Sr-Nd 同位素，以确定它们的起源、演化和就位时间。样品原岩是熔岩、凝灰岩，以及从属玄武岩至流纹岩组成的凝灰岩。尽管经历了低品位的热液变质作用，样品仍保留了原始结构和地球化学特征；特别是，相对较高的 (La/Lu) 球粒陨石归一化比率、明显的负 Eu 异常和大离子亲石元素 (LILE) 富集。与狭窄的 Nd 同位素范围 (0.512342-0.512625) 不同，Sr 同位素范围相对较宽 (0.705903-0.711739)。由于 Sr 和 Nd 同位素比不能为岩石就位提供一致的地质年代学年龄，由于地质和岩相学方面的考虑，它们在 170 Ma 时被校正。地球化学和 Sr 和 Nd 同位素比率提供了俯冲交代作用和地壳污染影响样品母岩浆的证据。它们的 Nd 模型年龄类似于爱琴海北部和希腊北部三叠纪裂谷基性岩下的富集中洋脊玄武岩 (E-MORB)。总体而言，地质和岩石学数据表明，在远离冈瓦纳的阿普利亚海角的 Pelagonian 微大陆和新形成的新特提斯平多斯洋的陆内盆地之间的过渡带中，在陆上和海上形成了样品。Pelagonia 下年轻洋壳的短暂未成熟俯冲使样品具有火山弧的强烈地球化学和地质特征。