Geochemical and isotopic imprints of early cretaceous mafic and felsic dyke suites track lithosphere-asthenosphere interaction and craton destruction in the North China Craton
Geochemical and isotopic imprints of early cretaceous mafic and felsic dyke suites track lithosphere-asthenosphere interaction and craton destruction in the North China Craton
复制标题
早白垩世镁铁质和长英质脉岩套的地球化学和同位素印记追踪华北克拉通岩石圈-软流圈相互作用和克拉通破坏
DOI：
10.1016/j.lithos.2018.12.013
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发表时间：
2019
期刊：
影响因子：
3.5
通讯作者：
Yang Fan
中科院分区：
文献类型：
--
作者：
Xue Fei;Santosh M.;Tsunogae T.;Yang Fan
华北克拉通（NCC）在中生代期间经历了严重的岩石圈破坏，尽管与这一过程相关的机制和时间仍然存在争议。与克拉通破坏相关的广泛岩浆活动包括源自岩石圈和软流圈来源的不同成分的岩脉套件。在此，我们对华北克拉通北太行山涞源杂岩体中的煌斑岩、辉绿岩和长英质脉岩套进行了调查。锆石Usingle bondPb测年显示，煌斑岩、辉绿岩和长英质岩脉的加权平均年龄在110-115Ma、117-126Ma和127-130Ma之间，其εHf(t)值分别显示在-17.2至-3.7、-23.3至-14.2和-22.3至-17.2之间，随着时间的推移明显增加，表明镁铁质套件中软流圈成分的输入增加。我们提供了这些岩石的主量、痕量和稀土元素数据，这些数据表明基性岩脉经历了有限的地壳污染，并且以橄榄石和单斜辉石分异结晶为主。涞源镁铁质岩脉是由部分熔融地幔衍生而来，地幔先前被俯冲相关流体富集，在角闪石和石榴石稳定场内，随着时间的推移，软流圈物质的输入不断增加。长英质岩脉表现出埃达克岩特征，岩浆生成是由于富集岩石圈地幔部分熔融产生的板下镁铁质岩浆的热量输入引起的古代基底岩石的改造而产生的。随后，富集的幔源岩浆通过岩石圈断层迁移，并在~117Ma 处就位为辉绿岩脉。软流圈上升流导致了弱区的热机械侵蚀，有限的岩石圈-软流圈相互作用在~115Ma至110Ma期间产生了煌斑岩。我们的数据表明，分层和热机械侵蚀共同导致了早白垩世华北克拉通的克拉通破坏。
The North China Craton (NCC) underwent significant lithospheric destruction during the Mesozoic, although the mechanisms and timings associated with this process remain debated. The extensive magmatism associated with craton destruction includes dyke suites of diverse composition derived from lithospheric and asthenospheric sources. Here we investigate lamprophyre, dolerites and felsic dyke suites from the Laiyuan complex in North Taihang Mountain of the NCC. Zircon Usingle bondPb dating shows weighted mean ages in the range of 110–115 Ma, 117–126 Ma and 127–130 Ma for the lamprophyres, dolerites and felsic dykes and their εHf (t) values show a range of −17.2 to −3.7, −23.3 to −14.2 and − 22.3 to −17.2, respectively, with an evident increase through time suggesting increasing input of asthenospheric components in the mafic suite. We present major, trace and REE data on these rocks which suggest that the mafic dykes experienced limited crustal contamination and were dominated by olivine and clinopyroxene fractional crystallization. The Laiyuan mafic dykes were derived through partial melting mantle previously enriched by subduction-related fluids, within amphibole- and garnet-stability field with increasing input of asthenospheric material through time. The felsic dykes show adakitic feature with magma generation through the reworking of ancient basement rocks induced by heat input from underplated mafic magma which was derived from the partial melting of enriched lithospheric mantle. Subsequently, the enriched mantle-derived magmas migrated through lithospheric faults and were emplaced as dolerite dykes at ~117 Ma. The asthenosphere upwelling contributed to the thermo-mechanical erosion along weak zones, and the limited lithosphere-asthenosphere interaction generated the lamprophyres during ~115 Ma to 110 Ma. Our data suggest that both delamination and thermo-mechanical erosion contributed to the craton destruction of the NCC during Early Cretaceous.