近日，土耳其比特利斯大学Hakan Coban团队研究了伊斯帕塔角地区（图基耶西南部）硅质碎屑岩的沉积岩石学和地球化学：对物源和构造环境的影响。2025年10月23日出版的《地球化学学报》发表了这项成果。

位于土耳其西南部的伊斯帕塔角内的安塔利亚杂岩体，包含了形成于不同地球动力学背景下的多种岩石类型，蕴藏着揭示东地中海地区地球动力学演化的重要信息。

研究组通过分析不同时代硅质碎屑岩的地球化学特征，对伊斯帕塔角内古沉积盆地的烃源岩及构造环境进行了解读。为此，研究组对新生代浊积砂岩（分别来自伊斯帕塔角北部的始新世伊斯帕塔组和中新世居内杰组）进行了全岩主量元素、微量元素和稀土元素分析，并将其与伊斯帕塔角东部三叠纪页岩及西南部晚白垩世砂岩的现有数据进行了整合。分析结果表明，新生代砂岩样品具有高钙特征（CaO含量为30.54–43.87 wt%，平均37.63 wt%），这一特征与晚白垩世砂岩（CaO平均含量24.92 wt%）及晚三叠世页岩（CaO含量介于11.27–26.71 wt%）具有可比性。

研究组表明，这些样品对多数主要氧化物展现出显著的碳酸盐稀释效应。与成分接近后太古代平均页岩的晚三叠世页岩不同，新生代和晚白垩世与蛇绿岩相关的碎屑沉积物表现出Nb-Ta、Th、Rb、Zr和Hf的显著亏损，以及Ni、Co和Cr的富集特征，指示其源区存在镁铁质-超镁铁质岩类。晚三叠世页岩中Cr（均值80.5 ppm）、V（均值105.5 ppm）、Ni（均值42.3 ppm）和Co（均值13.9 ppm）的显著富集，可归因于源区受到三叠纪类OIB玄武质裂谷岩浆活动的影响。

总体而言，其火成源岩具有混合成因特征：（1）晚三叠世页岩以大陆长英质源岩为主，辅以裂谷相关玄武质镁铁质源岩；（2）晚白垩世砂岩主要来自蛇绿岩质镁铁质-超镁铁质源岩，含少量大陆长英质组分；（3）新生代砂岩则以大陆长英质源岩为主，兼具蛇绿岩质镁铁质-超镁铁质组分。这些推论进一步表明，晚三叠世、晚白垩世和新生代硅质碎屑岩样品独特的母岩组成，分别反映了不同的构造背景：晚三叠世页岩对应于被动裂谷环境，晚白垩世砂岩形成于SSZ（俯冲带）背景，而新生代砂岩则发育于碰撞构造环境。

附：英文原文

Title: Sedimentary petrology and geochemistry of the siliciclastic rocks from the Isparta Angle area (SW Türkiye): Implications for provenance and tectonic settings

Author: oban, Hakan, Elitok, mer, Polat, Sleyman, Caran, emsettin

Issue&Volume: 2025-10-23

Abstract: The Antalya Complex within the Isparta Angle (IA) in the southwest of Türkiye includes various rock types formed in different geodynamic settings and contains important data that shed light on the geodynamic evolution of the Eastern Mediterranean region. In this study, source rocks and tectonic settings of ancient sedimentary basins within the IA have been interpreted using geochemical contents of siliciclastic rocks in different ages. In this regard, whole-rock major, trace and rare earth element (REE) analyses have been conducted on the Cenozoic turbiditic sandstones (from the Eocene Isparta Formation and the Miocene Güneyce Formation in the north of the IA) and integrated with the available data of the Triassic shales from the east and Upper Cretaceous sandstones from the southwest of the IA. The results indicate that Cenozoic sandstone samples are calcium-rich (CaO, 30.54–43.87 wt%, average 37.63 wt%), comparable to those of Upper Cretaceous sandstones (CaO, average 24.92 wt%) and Late Triassic (CaO, range between 11.27–26.71 wt%) shales. They demonstrate an excellent carbonate dilution effect on the majority of major oxides. In contrast to the Late Triassic shales with close affinity to Post-Archean Average Archean Shale (PAAS), Cenozoic and Upper Cretaceous ophiolite-related clastic sediments display strike depletions in Nb–Ta, Th, Rb, Zr and Hf and enrichments in Ni, Co and Cr, suggesting mafic and ultramafic rocks in a source region. Notable enrichments of Cr (average 80.5 ppm), V (average 105.5 ppm), Ni (average 42.3 ppm) and Co (average 13.9 ppm) in Late Triassic shales can be attributed to the influences of Triassic OIB-like basaltic rift magmatism in their source regions. In general, their igneous source rocks were derived from mixed sources, e.g., (1) predominantly continental felsic and lesser rift-related basaltic mafic source rocks for Late Triassic shales, (2) mainly ophiolitic mafic-ultramafic and lesser continental felsic source rocks for Upper Cretaceous sandstones and (3) primarily continental felsic and lesser ophiolitic mafic-ultramafic source rocks for Cenozoic sandstones. These inferences also imply that the distinct parent rock compositions of the Late Triassic, Upper Cretaceous and Cenozoic aged siliciclastic rock samples reflect their distinct tectonic settings such as the passive rift setting of Late Triassic shales, an SSZ setting for the Upper Cretaceous sandstones and a collisional setting of the Cenozoic sandstones, respectively.

DOI: 10.1007/s11631-025-00829-z

Source: https://link.springer.com/article/10.1007/s11631-025-00829-z