Cretaceous-Cenozoic growth of the Patagonian broken foreland basin, Argentina: Chronostratigraphic framework and provenance variations during transitions in Andean subduction dynamics
Cretaceous-Cenozoic growth of the Patagonian broken foreland basin, Argentina: Chronostratigraphic framework and provenance variations during transitions in Andean subduction dynamics
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阿根廷巴塔哥尼亚破碎前陆盆地的白垩纪-新生代生长：安第斯俯冲动力学过渡期间的年代地层框架和物源变化
DOI：
10.1016/j.jsames.2019.102242
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发表时间：
2020
影响因子：
1.8
通讯作者：
Fuentes, Facundo
中科院分区：
文献类型：
--
作者：
Butler, Kristina L.;Horton, Brian K.;Echaurren, Andrés;Folguera, Andrés;Fuentes, Facundo
阿根廷北方丘布特省南纬42 - 43 °巴塔哥尼亚破碎前陆盆地系统的新生代-新生代演化与大洋板片俯冲动力学变化过程中褶皱-冲断带缩短、伸展和基底隆升等弧后阶段的变化有关。基底继承和逐渐变浅的东倾俯冲板是前陆分区的重要机制，由预先存在的（前安第斯山脉）的结构架构和forelandward（东）晚白垩世弧岩浆活动的推进。以前认识到的生长地层有助于确定褶皱冲断带缩短和弧后基底参与隆起的时间，但对沉积物路线的精确后果仍然知之甚少，在俯冲板片变浅和重新变尖之前、期间和之后的盆地演化模式存在不确定性。独特的沉积物源区和岩浆历史使得能够利用新的物源结果评价弧后前陆盆地的地层和构造演化，最大沉积年龄、碎屑锆石U-Pb年代学和Lu-Hf地球化学分析的同位素特征。一份已发表的基岩结晶年龄和变质及火成岩基底岩石分布的汇编确定：由安第斯岩浆弧和相关的前安第斯基底界定的西部源区;东部源区由板内岩浆单元和北巴塔哥尼亚地块组成。我们证明，Aptian-Cenomanian弧后盆地充填主要来自东部的基底火山单元和板内火山单元，随后是晚白垩世（Campanian-Maastrichtian）沉积极性的逆转，随后是从安第斯弧和造山带向西的专属衍生。晚白垩世-古新世板片变浅和弧终止之后，始新世-早中新世伸展板片回滚和弧岩浆活动的更新。此后，中新世沉积与安第斯褶皱冲断带的缩短密切相关。在弧后序列中，新的U-Pb年龄提供了早白垩世至中新世地层单位的沉积年龄，最后，除了U-Pb物源和年代地层的制约外，来自碎屑岩记录的锆石Hf同位素特征证实了一个白垩纪-新生代的历史，包括：（1）大陆岩浆弧的初步建立，（2）中性构造体制向挤压构造体制的转变，（3）岩浆弧的形成，（4）岩浆弧的形成，（5）岩浆弧的形成，（6）岩浆弧的形成，（7）岩浆弧的形成，（8）岩浆弧的形成，（9）岩浆弧的形成，（9）岩浆弧的形成，（10）岩浆弧的形成，（10）岩浆弧的形成，（10）岩浆弧的形成，（11）岩浆弧的形成，（11）岩浆弧的形成，（12）岩浆弧的形成，（11）岩浆弧的形成，（11）岩浆弧的形成，（12）岩浆弧的形成，（11）岩浆弧的形成，（12）岩浆弧的形成（3）俯冲板片变浅和弧后基底分异过程中的弧终止;（4）板片回滚过程中的弧退缩和前陆盆地废弃（伴随适度的伸展和地壳减薄）;（5）弧再生过程中的最终更新缩短。
The Cretaceous-Cenozoic evolution of the Patagonian broken foreland basin system at 42–43°S in the northern Chubut province of Argentina is associated with variable retroarc phases of fold-thrust belt shortening, extension, and basement uplift during changes in the dynamics of oceanic slab subduction. Basement inheritance and progressive shallowing of an east-dipping subducting slab are important mechanisms of foreland partitioning, as dictated by the preexisting (pre-Andean) structural architecture and forelandward (eastward) advance of Late Cretaceous arc magmatism. Previously recognized growth strata help define the timing of fold-thrust belt shortening and retroarc basement-involved uplift, but the precise consequences for sediment routing remain poorly understood, with uncertainties in patterns of basin evolution before, during, and after shallowing and resteepening of the subducting slab.In this study, distinctive sediment source regions and magmatic histories enable evaluation of the stratigraphic and tectonic evolution of the retroarc foreland basin using new provenance results, maximum depositional ages, and isotopic signatures from detrital zircon U-Pb geochronology and Lu-Hf geochemical analyses. A compilation of published bedrock crystallization ages and distributions of metamorphic and igneous basement rocks identify: a western source region defined by the Andean magmatic arc and associated pre-Andean basement; and an eastern source region consisting of intraplate magmatic units and the North Patagonian Massif.We demonstrate that Aptian-Cenomanian retroarc basin fill was derived principally from the basement massif and intraplate volcanic units to the east, followed by a Late Cretaceous (Campanian-Maastrichtian) reversal in sedimentary polarity and subsequent exclusive derivation from the Andean arc and orogenic belt to the west. Late Cretaceous-Paleocene slab shallowing and arc cessation was succeeded by late Eocene–earliest Miocene extension during slab rollback and renewal of arc magmatism. Thereafter, Miocene sedimentation was closely linked to shortening in the Andean fold-thrust belt. Within the retroarc succession, new U-Pb ages provide estimates of depositional ages for Lower Cretaceous through Miocene stratigraphic units.Finally, in addition to U-Pb provenance and chronostratigraphic constraints, zircon Hf isotopic signatures from the detrital record provide confirmation of a Cretaceous-Cenozoic history involving: (1) initial establishment of a continental magmatic arc; (2) transition from a neutral to compressive tectonic regime; (3) shallowing of the subducting slab and arc cessation during retroarc basement partitioning; (4) arc retreat and foreland basin abandonment during slab rollback (with modest extension and crustal thinning); and (5) final renewed shortening during arc rejuvenation.
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DOI：
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