New constraints from U–Pb dating of detrital zircons on the palaeogeographic origin of metasediments in the Talea Ori, central Crete
New constraints from U–Pb dating of detrital zircons on the palaeogeographic origin of metasediments in the Talea Ori, central Crete
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DOI：
10.1017/s0016756819001365
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发表时间：
2020-01
影响因子：
2.3
通讯作者：
L. Seybold;W. Dörr;C. Trepmann;J. Krahl
中科院分区：
文献类型：
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作者：
L. Seybold;W. Dörr;C. Trepmann;J. Krahl
摘要通过野外、显微结构和碎屑锆石U-Pb定年等方法研究了该区千层岩-石英岩单元和塔里奥里组高压低温变质沉积物的古地理成因。百元岩-石英岩单元年龄bb0 ~ 450 Ma的锆石年龄谱严格意义上表明其古地理成因位于东冈瓦纳北缘。塔里奥里组下地层的硅屑岩组显示大量的寒武系至早石炭世的锆石，锆石年龄谱具有与东冈瓦纳的亲和力。锆石年龄对比表明，远端沉积物来源可能为欧亚大陆活动南缘的萨卡里亚带。为了使锆石数据与地质观测结果相一致，我们提出了不同的替代模型，或这些模型的组合，包括从萨卡里亚带和/或西风源向冈瓦纳北缘的沉积物运输，以及萨卡里亚带的地体位移。同时，也不能排除Talea Ori群在欧亚大陆南部活动边缘的古地理起源。然而，这种选择与通常假设的Talea Ori群与platattenkalk单元的联系不一致，该单元以冈瓦纳北缘的古地理起源为特征。
Abstract High-pressure low-temperature metamorphic sediments of the Phyllite–Quartzite unit sensu stricto and the Talea Ori group are investigated in the field, microstructurally and by U–Pb dating of detrital zircons to shed light on their palaeogeographic origin. Zircon age spectra with ages >450 Ma of the Phyllite–Quartzite unit sensu stricto indicate a palaeogeographic origin at the northern margin of East Gondwana. In contrast, the lower stratigraphic, siliciclastic formations of the Talea Ori group show a high number of well-rounded Cambrian to Early Carboniferous aged zircons and a Neoproterozoic zircon age spectrum with East Gondwana affinity. Based on the comparison of zircon age data, a possible distal sediment source is the Sakarya Zone at the southern active margin of Eurasia. To reconcile the zircon data with the geological observations we propose different alternative models, or a combination of these, including sediment transport from the Sakarya Zone and/or a westerly source towards the northern margin of Gondwana as well as terrane-displacement of the Sakarya Zone. Also, a palaeogeographic origin of the Talea Ori group at the southern active margin of Eurasia cannot be excluded. This alternative, however, would not be consistent with the usually assumed association of the Talea Ori group with the Plattenkalk unit characterized by a palaeogeographic origin at the northern margin of Gondwana.