Cretaceous High Arctic large igneous province (HALIP) sub-alkaline magmatic rocks in Canada are mostly evolved (MgO 2–7 wt%), sparsely plagioclase + clinopyroxene ± olivine-phyric tholeiitic basalts. There were two main HALIP continental flood basalt (CFB) eruption episodes: 135–120 Ma (Isachsen Fm.) and 105–90 Ma (Strand Fiord Fm.), both associated with cogenetic doleritic sills and dykes. Building on a large modern database, 16 HALIP tholeiite types are defined and grouped into genetic series using Ce vs Sm/YbNMORB distributions. Comparison with model melting curves implies that higher-Sm/Yb HALIP basalt types record low-degree melting of garnet-bearing mantle sources. More voluminous intermediate- and low-Sm/Yb HALIP basalt types separated from the mantle at shallower levels after further extensive melting in the spinel-peridotite field. Within a given Sm/Yb range, increases in incompatible elements such as Ce are coupled with progressive clockwise rotation of normalized incompatible trace element profiles. Trace element modeling implies this cannot be due to closed-system fractional crystallization but requires progressive and ubiquitous incorporation of a component resembling continental crust. The fractionation models imply that low-Sm/Yb HALIP basalts (∼7 wt% MgO) initially crystallized olivine gabbro assemblages, with lower-MgO basalts successively crystallizing gabbro and ilmenite-gabbro assemblages. In contrast, higher-Sm/Yb basalts fractionated more clinopyroxene and ilmenite, but extensive plagioclase fractionation is still required to explain developing negative Sr–Eu anomalies. Back-fractionation models require about 40 % addition of olivine to bring the most primitive HALIP basalts (∼7 % MgO) into equilibrium with Fo89 mantle. Inverse fractionation–assimilation modeling shrinks the CFB signature, making decontaminated model parental melts more similar to enriched mid-ocean ridge basalt. The progressive increase of the contamination signature within each HALIP tholeiitic differentiation series is not consistent with models involving derivation of HALIP basalts from a mantle source previously enriched by subduction. Strong interaction of basalt with Sverdrup Basin sedimentary rocks may cause localized over-enrichment in K–Rb–Th–U, but cannot explain strong Ba enrichment in the absence of concomitant K–Rb–Th–U enrichment. The localized Ba enrichment could reflect either a Ba-rich lithospheric mantle component that is strongly manifested in the coeval HALIP alkaline suites, or syn- to post-emplacement fluid-mediated transfer from Ba-rich host rocks.

中文翻译：

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来自加拿大的高北极大型火成岩省大陆拉斑矿的地球化学系统学——管道系统中进行性地壳污染的证据

加拿大白垩纪高北极大火成岩省（HALIP）亚碱性岩浆岩多为演化（MgO 2-7 wt%）、稀疏斜长石+单斜辉石±橄榄石-硬质拉斑玄武岩。有两个主要的 HALIP 大陆洪水玄武岩 (CFB) 喷发事件：135-120 Ma (Isachsen Fm.) 和 105-90 Ma (Strand Fiord Fm.)，均与共生玄武岩岩床和岩脉有关。在大型现代数据库的基础上，使用 Ce 与 Sm/YbNMORB 分布定义了 16 种 HALIP 拉斑矿类型并将其分组为遗传系列。与模型熔融曲线的比较表明，较高 Sm/Yb HALIP 玄武岩类型记录了含石榴石地幔源的低度熔融。在尖晶石-橄榄岩领域进一步广泛熔融后，更多体积的中和低 Sm/Yb HALIP 玄武岩类型在较浅的水平与地幔分离。在给定的 Sm/Yb 范围内，不相容元素（例如 Ce）的增加与归一化不相容微量元素分布的渐进顺时针旋转相结合。微量元素建模意味着这不能归因于封闭系统的分级结晶，而是需要逐步和无处不在地结合类似于大陆地壳的成分。分馏模型表明，低 Sm/Yb HALIP 玄武岩（~7 wt% MgO）最初结晶橄榄石辉长岩组合，低 MgO 玄武岩依次结晶辉长岩和钛铁辉长岩组合。相比之下，较高 Sm/Yb 玄武岩分馏更多的单斜辉石和钛铁矿，但仍需要广泛的斜长石分馏来解释发展中的负 Sr-Eu 异常。反分馏模型需要添加约 40% 的橄榄石才能使最原始的 HALIP 玄武岩（~7% MgO）与 Fo89 地幔达到平衡。逆分馏-同化模型缩小了 CFB 特征，使去污染模型亲代熔体更类似于富集的大洋中脊玄武岩。每个 HALIP 拉斑斑岩分化系列中污染特征的逐渐增加与涉及从先前通过俯冲富集的地幔源中推导 HALIP 玄武岩的模型不一致。玄武岩与 Sverdrup 盆地沉积岩的强相互作用可能导致 K-Rb-Th-U 的局部过度富集，但在没有伴随的 K-Rb-Th-U 富集的情况下不能解释强 Ba 富集。