The evolution of the European Crust – U-Pb, Pb, Hf, and O isotope systematics of detrital zircon, rutile and K-feldspar from the sediments of major European rivers

欧洲地壳的演化 欧洲主要河流沉积物中碎屑锆石、金红石和钾长石的 U-Pb、Pb、Hf 和 O 同位素系统学

• 批准号: 397638449
• 负责人: Professor Dr. Hans Heinrich Bahlburg
• 金额: --
• 依托单位: Institut für Geologie und Paläontologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/397638449?language=en
• 关键词: evolution; European; Crust; Pb; Hf

Large river system drain wide continental areas spanning different geotectonic domains. The detritus accumulating in the lower reaches of such systems ideally reflects the entirety of the lithological spectra constituting the geotectonic domains. Considering sorting and transport effects, river sediments reflect the composition of the respective continental crust and therefore allow for the analysis of its evolution. This analysis rests mainly on minerals that permit the reconstruction of the isotopic and temporal evolution of the crust. We propose a study of 15 major European river systems to study the geochemical evolution of the European continental crust. We will sample the rivers in the lower reaches to obtain U-Pb age dates from zircon and rutile by LA ICPMS. Both minerals are very resilient under weathering and transport conditions. Zircon is derived originally mainly from felsic to intermediate magmatic and metamorphic rocks whereas rutile may be derived also from mafic metamorphic rocks. Therefore rutile allows for the consideration of the role of more mafic lithologies. We will combine these analyses with the study of O and Hf isotopes in zircon by SHRIMP II and LA ICPMS, respectively. Both isotope systems combined allow for the crucial distinction between juvenile and recycled crustal components. Finally, the Pb isotope analysis of K-feldspar by LA ICPMS will be used to evaluate the recycled component in the detrital zircon data and the climatic influence on the detrital compositions as K-feldspar is a common detrital mineral in first-cycle sands.The primary objective of our study is the analysis of the geochemical evolution of the European continental crust in terms of the temporally changing relative contribution of juvenile additions and recycling of older crust. We will assess the evolution of the European continental crust and its relation to the known supercontinent cycles. We will test the alleged bias of the global U-Pb zircon age and supercontinent record towards collisional granitoids of collisional orogens. We will compare our data with the respective record of the Phanerozoic Andes, a long-standing accretionary orogen. The zircon record of the Andes region reflects the same supercontinent cycles as the collisional orogens commonly favored in the definition of such cycles. We will therefore also test our hypothesis that the alleged bias of the zircon and supercontinent record towards granitoids of interior orogens does not universally apply.

大型河流系统流经横跨不同大地构造域的广阔大陆区域。堆积在这些系统下游的碎屑理想地反映了构成大地构造域的整个岩性谱。考虑到分选和搬运效应，河流沉积物反映了各自大陆地壳的组成，因此可以对其演变进行分析。这种分析主要依靠矿物，允许重建的同位素和地壳的时间演变。我们建议对欧洲15个主要河流系统进行研究，以研究欧洲大陆地壳的地球化学演化。我们将在下游的河流中取样，用LA ICPMS获得锆石和金红石的U-Pb年龄。这两种矿物在风化和运输条件下都具有很强的弹性。锆石主要来源于长英质至中质岩浆岩和变质岩，而金红石也可能来源于镁铁质变质岩。因此，金红石允许考虑更多的镁铁质岩性的作用。我们将联合收割机将这些分析与SHRIMP II和LA ICPMS分别对锆石中O和Hf同位素的研究相结合。这两种同位素系统相结合，使年轻和再生地壳成分之间的关键区别。最后，由于钾长石是一种常见的碎屑矿物，利用LA-ICPMS对钾长石进行Pb同位素分析，可以评价碎屑锆石数据中的再循环成分，以及气候对碎屑成分的影响。循环砂。我们研究的主要目的是分析欧洲大陆地壳的地球化学演化，旧地壳的再循环我们将评估欧洲大陆地壳的演化及其与已知超大陆旋回的关系。我们将测试全球锆石U-Pb年龄和超大陆记录对碰撞造山带的碰撞花岗岩类的所谓偏见。我们将把我们的数据与古生代安第斯山脉（一个长期存在的增生造山带）的相应记录进行比较。安第斯山脉地区的锆石记录反映了与碰撞造山带相同的超大陆旋回，这种旋回的定义通常受到青睐。因此，我们也将测试我们的假设，所谓的偏见的锆石和超大陆记录对花岗岩类的内部造山带并不普遍适用。