Abstract

Detrital zircons with an age of 3.65–3.87 Ga have been found earlier in Jatulian terrigenous rocks from the eastern Fennoscandian Shield, i.e., the Karelian and Kola regions (Kozhevnikov et al., 2010; Smol’kin et al., 2011, 2019), while rocks of this age are not reported in the inferior Sumian–Sariolian complexes and in the Archean basement. To establish the provenance area and composition of the sources, the first study of geochemical composition (rare-earth and trace elements) of detrital zircons from Jatulian red gravelstones of the Luchlompol’skaya Fm., Pechenga structure, quartzites of the Volomskaya syncline, and cement of conglomerates in the western Onega Trough, which are located at considerable distances from each other, has been carried out. The age of detrital zircon grains ranges mainly within 2.70–3.23 Ga. Some of the detrital zircon grains are of igneous type. Grains and outer envelopes of zonal grains having the youngest age (2.70–2.72 Ga) are referred to the metamorphic type. “Porous” zircon that underwent a fluid effect is also present. The main sources of igneous zircon grains were tonalite and trondhjemite gneisses and acid granulites, which are widespread in the vicinities of the studied structures and were revealed in the lower part of the Kola Superdeep Well (VSD-3), as well as gneisses and amphibolites of the Vodlozero block. The source of detrital zircon grains with an age of 3.65–3.87 Ga is the Siurua trondhjemite gneiss (northern Finland). Their erosion and transportation of zircons took place 2.2–2.1 Ga ago along the western margin of the Svecofennian–Pre-Labradorian Ocean that existed at the initial stage of the Columbia Supercontinent assemblage.

中文翻译：

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Fennoscandia Jatulian陆源岩石太古代碎屑锆石的微量元素组成

摘要

早在芬诺斯坎迪亚地盾东部，即卡累利阿和科拉地区的贾图利亚陆源岩中发现了年龄为 3.65-3.87 Ga 的碎屑锆石（Kozhevnikov et al., 2010; Smol'kin et al., 2011, 2019） ，而这个时代的岩石在下苏米亚-萨里奥利亚杂岩和太古宙基底中没有报道。为确定物源区和物源组成，首次研究了 Luchlompol'skaya 组 Jatulian 红色砾岩、Pechenga 构造、Volomskaya 向斜石英岩的碎屑锆石地球化学成分（稀土和微量元素），以及位于奥涅加海槽西部相距相当远的砾岩的水泥已经进行。碎屑锆石晶粒年龄主要在 2.70~3.23 Ga 之间。一些碎屑锆石颗粒属于火成岩类型。年龄最小（2.70-2.72 Ga）的带状晶粒的晶粒和外壳被称为变质类型。还存在具有流体效应的“多孔”锆石。火成岩锆石颗粒的主要来源是云闪岩和长长花岗岩片麻岩和酸性麻粒岩，它们在研究构造附近广泛分布，并在科拉超深井（VSD-3）的下部发现，以及片麻岩和角闪岩Vodlozero 块。年龄为 3.65-3.87 Ga 的碎屑锆石颗粒的来源是 Siurua 长花岩片麻岩（芬兰北部）。他们对锆石的侵蚀和运输发生了 2.2-2。