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Evidence from Late Cretaceous-Paleogene volcanic rocks of the Kyrenia Range, northern Cyprus for the northern, active continental margin of the Southern Neotethys
Lithos ( IF 2.9 ) Pub Date : 2021-01-01 , DOI: 10.1016/j.lithos.2020.105835
Guohui Chen , Alastair H.F. Robertson

Abstract Late Cretaceous felsic and latest Cretaceous-Paleogene basaltic volcanic rocks are exposed throughout the Kyrenia Range, N Cyprus. Field mapping of the key, well-exposed western range indicates that the felsic volcanics are mainly crop out in the southerly, frontal part of the range, separated from the latest Cretaceous-Paleogene basaltic volcanics farther north by a thrust. New U-Pb zircon dating of the felsic volcanics indicates a primary age of c. 74.0 Ma (Late Campanian). The felsic volcanics are characterised by evolved compositions that were probably generated in an extensional subduction-related setting. Their relatively low Nb and Y but high Rb concentrations, together with characteristic Th/Ta ratios (6–20), suggest a mature continental arc setting. The latest Cretaceous-Paleogene basaltic volcanics have mainly within-plate chemical characteristics (in the east), although some have a subordinate subduction influence; e.g. negative Nb (in the west). Sr-Nd-Hf isotopic signatures (i.e. high positive eNd(t) and eHf(t) values) suggest derivation of the basalts from several OIB-like mantle sources, with probable involvement of a crustal (recycled) component (i.e. elevated Nb/Y ratios). Comparisons with SE Turkey, where Late Cretaceous arc-related granitic rocks are widely developed, suggest that the Kyrenia Range igneous rocks may have originated to the south of the Alanya metamorphic massif (N of Cyprus) and correlative continental units in SE Turkey. The latest Cretaceous-Paleogene basaltic volcanics in N Cyprus and SE Turkey (Maden Complex) are interpreted to represent incipient marginal basin formation, possibly in an oblique-convergent setting, prior to Miocene suturing with Arabia. In the light of alternatives, we infer genesis of the N Cyprus Late Cretaceous and Paleogene volcanic rocks related to stages in the development of the northerly active continental margin of the Southern Neotethys.

中文翻译:

来自塞浦路斯北部凯里尼亚山脉晚白垩世-古近纪火山岩的证据,用于确定南新特提斯群岛北部活动大陆边缘

摘要 晚白垩世长英质和晚白垩世-古近纪玄武质火山岩出露在塞浦路斯北部的凯里尼亚山脉。对出露良好的关键西部山脉的实地测绘表明,长英质火山岩主要出现在该山脉的南侧锋面部分,与更靠北的最新白垩纪-古近纪玄武质火山岩被一个逆冲断层隔开。长英质火山岩的新 U-Pb 锆石测年表明主要年龄为 c。74.0 Ma(晚坎帕阶)。长英质火山岩的特征是演化出的成分可能是在与伸展俯冲相关的环境中产生的。它们相对较低的 Nb 和 Y 但较高的 Rb 浓度,以及特征性的 Th/Ta 比率(6-20),表明成熟的大陆弧环境。最新的白垩纪-古近纪玄武质火山岩主要具有板内化学特征(东部),但也有部分具有次要的俯冲作用;例如负 Nb(在西方)。Sr-Nd-Hf 同位素特征(即高正 eNd(t) 和 eHf(t) 值)表明玄武岩来自几个类 OIB 地幔源,可能涉及地壳(再循环)成分(即升高的 Nb/ Y 比率)。与晚白垩世弧相关花岗岩广泛发育的土耳其东南部的比较表明,凯里尼亚山脉火成岩可能起源于阿拉尼亚变质地块(塞浦路斯北部)的南部和土耳其东南部的相关大陆单元。最新的白垩纪-古近纪玄武质火山岩在塞浦路斯北部和土耳其东南部(马登复合体)被解释为代表了早期边缘盆地的形成,可能在中新世与阿拉伯缝合之前处于斜会聚环境中。根据备选方案,我们推断北塞浦路斯晚白垩世和古近纪火山岩的成因与南新特提斯向北活动大陆边缘的发育阶段有关。
更新日期:2021-01-01
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