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Differential Phanerozoic evolution of cratonic and non-cratonic lithosphere from a thermochronological perspective: São Francisco Craton and marginal orogens (Brazil)
Gondwana Research ( IF 7.2 ) Pub Date : 2021-01-24 , DOI: 10.1016/j.gr.2021.01.006
Ana Carolina Liberal Fonseca , Tiago Amâncio Novo , Simon Nachtergaele , Tobias M.R. Fonte-Boa , Gerben Van Ranst , Johan De Grave

The São Francisco Craton (SFC) and its marginal Araçuaí and Brasília orogens exhibit a significant diversity in their lithospheric architecture. These orogens were shaped during the Neoproterozoic–Cambrian amalgamation of West Gondwana. The rigid cratonic lithosphere of the SFC and the relatively weak lithosphere of the Araçuaí Orogen were disrupted during the Cretaceous opening of the South Atlantic Ocean, whereas the Brasília Orogen remained in the continental hinterland. In earlier research, the thermal effects of the Phanerozoic reactivations in the shallow crust of the Araçuaí Orogen have been revealed by low-temperature thermochronology, mainly by apatite fission track (AFT) analysis. However, analyses from the continental interior are scarce. Here we present new AFT data from forty-three samples from the Brasília Orogen, the SFC and the Araçuaí Orogen, far from the passive margin of the Atlantic coast (~150 to 800 km). Three main periods of basement exhumation were identified: (i) Paleozoic, recorded both by samples from the SFC and Brasília Orogen; (ii) Early Cretaceous to Cenomanian, recorded by samples from the Araçuaí Orogen; and (iii) Late Cretaceous to Paleocene, inferred in samples from all domains. We compare the differential exhumation pattern of the different geotectonic provinces with their lithospheric strengths. We suggest that the SFC likely concentrated the Meso-Cenozoic reactivations in narrow weak zones while the Araçuaí Orogen displayed a far-reaching Meso-Cenozoic deformation. The Brasília Orogen seems to be an example of a stronger orogenic lithosphere, inhibiting reworking, confirmed by our new AFT data. Understanding the role of the lithosphere rigidity may be decisive to comprehend the processes of differential denudation and the tectonic–morphological evolution over Phanerozoic events.



中文翻译:

从热年代学角度看克拉通和非克拉通岩石圈的古生代差异演化:圣弗朗西斯科·克拉顿和边缘造山带(巴西)

圣弗朗西斯科·克拉顿(SFC)及其边缘的Araçuaí和Brasília造山带在岩石圈构造中表现出极大的多样性。这些造山带是在西冈瓦纳的新元古代-寒武纪合并过程中形成的。SFC的刚性克拉通岩石圈和AraçuaíOrogen相对较弱的岩石圈在南大西洋白垩纪开放期间受到破坏,而BrasíliaOrogen仍留在大陆腹地。在较早的研究中,低温热年代学(主要是通过磷灰石裂变径迹(AFT)分析)揭示了Araçuaí造山带浅地壳中生代活动的热效应。但是,从大陆内部进行的分析很少。在这里,我们展示了来自巴西利亚Orogen的43个样品的新AFT数据,SFC和AraçuaíOrogen,远离大西洋沿岸的被动边缘(约150至800公里)。确定了地下采掘的三个主要时期:(i)古生代,由证监会和巴西利亚造山带公司的样品记录;(ii)由阿拉苏阿造山带的样品记录的早白垩纪至新生代;(iii)从所有领域的样品中推断出白垩纪至新世晚期。我们比较了不同地质构造省份的差分挖掘模式及其岩石圈强度。我们建议,SFC可能将中新生代活化作用集中在狭窄的薄弱区域,而阿拉索伊造山带则显示出深远的中新生代变形。巴西利亚造山带似乎是更强的造山岩石圈的一个例子,它抑制了返工,这一点已得到我们新的AFT数据的证实。

更新日期:2021-02-15
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