The Saglek-Hebron Complex (SHC) located in Northern Labrador, Canada, includes some of the oldest crustal rocks on Earth. This granite-greenstone terrain is dominated by trondhjemite, Mg-rich tonalite, granite, with subordinate granodiorite, and recorded over one billion years of early magmatic history between ∼3900 Ma and ∼2700 Ma. New in-situ U-Pb analyses on zircons from eighteen rock samples, suggest that six distinct magmatic events formed the felsic crust of the SHC, during the Archean Eon. Age deconvolution analysis constrains these magmatic episodes at ca. 3857 Ma, 3744 Ma, 3575 Ma, 3330 Ma, 3224 Ma and 2750 Ma, respectively defined as the Iqaluk, the Uivak I, the Uivak II, the Iluilik, the Lister and the late granite events. The 3330 Ma Iluilik represents a newly defined magmatic event, distinct from the Lister event previously recognized at ∼3200 Ma. Uranium-Pb geochronology, combined with in-situ Hf isotopic data on zircons and geochemistry of the host rocks, reveal a complex and protracted crustal history of the SHC marked by the reworking of mafic and felsic crust over one billion years. Zircons from the oldest Iqaluk and Uivak I samples yield slightly suprachondritic initial εHf values (up to ∼+4), consistent with the involvement of a long-term depleted source in the Eoarchean. The 3330 Ma Iluilik granodiorite exhibits a low initial εHf value of −6, clearly diverging from the near-chondritic Hf isotopic composition of the 3224 Ma Lister tonalites. Considering a mafic crustal precursor (with a ¹⁷⁶Lu/¹⁷⁷Hf ratio of ∼0.02) for trondhjemite-tonalite-granodiorite (TTG) samples, the initial Hf isotopic compositions of the SHC Eoarchean to Paleoarchean zircons would be consistent with the reworking of Hadean mafic crust. The zircon εHf vs. time trend for granite samples corresponds to a ¹⁷⁶Lu/¹⁷⁷Hf ratio of ∼0.01, suggesting that the granitic crust was mainly produced by crustal reworking of the oldest TTG. Similarly to the felsic crust of the Itsaq Gneiss Complex of SW Greenland, the SHC granitoids appear to record a shift to more juvenile compositions at the end of the Paleoarchean. However, contrary to what is observed in SW Greenland, almost no input of juvenile material has been recorded by the SHC Neoarchean felsic crust.

位于加拿大北拉布拉多的萨格勒克-希伯伦综合体（SHC）包括地球上一些最古老的地壳岩石。花岗岩-绿岩地形以天晶石，富含Mg的方钠石，花岗岩以及次要的花岗闪长岩为主，记录了大约3900 Ma至2700 Ma的十亿多年的早期岩浆历史。对来自18个岩石样品的锆石的新的原位U-Pb分析表明，在太古代Eon时期，六种不同的岩浆事件形成了SHC的长英质地壳。年龄反褶积分析将这些岩浆事件限制在大约 3857 Ma，3744 Ma，3575 Ma，3330 Ma，3224 Ma和2750 Ma分别定义为Iqaluk，Uivak I，Uivak II，Iluilik，Lister和晚期花岗岩事件。3330 Ma Iluilik代表了新定义的岩浆事件，与先前在3200 Ma时识别出的李斯特事件不同。铀-铅地球年代学，再结合锆石和宿主岩石地球化学的原位Hf同位素数据，揭示了SHC复杂而漫长的地壳历史，其特征是经过十亿年的镁铁质和长英质壳的再造。来自最古老的伊卡卢克（Iqaluk）和乌瓦克（Uivak）I样品的锆石产生略微的超洪峰初始εHf值（直至〜+ 4），这与欧亚大陆长期消耗资源的参与一致。3330 Ma Iluilik花岗闪长岩的初始εHf值较低，为-6，明显不同于3224 Ma Lister孔雀石的近软骨Hf同位素组成。考虑镁铁质地壳前体（具有 揭示了SHC复杂而漫长的地壳历史，其特征是经过十亿多年的镁铁质和长英质壳的再造。来自最古老的伊卡卢克（Iqaluk）和乌瓦克（Uivak）I样品的锆石产生略微的超洪峰初始εHf值（直至〜+ 4），这与欧亚大陆长期消耗资源的参与一致。3330 Ma Iluilik花岗闪长岩的初始εHf值较低，为-6，明显不同于3224 Ma Lister孔雀石的近软骨Hf同位素组成。考虑镁铁质地壳前体（具有 揭示了SHC复杂而漫长的地壳历史，其特征是经过十亿多年的镁铁质和长英质壳的再造。来自最古老的伊卡卢克（Iqaluk）和乌瓦克（Uivak）I样品的锆石产生略微的超洪峰初始εHf值（直至〜+ 4），这与欧亚大陆长期消耗资源的参与一致。3330 Ma Iluilik花岗闪长岩的初始εHf值较低，为-6，明显不同于3224 Ma李斯特氏膨润土的近软骨Hf同位素组成。考虑镁铁质地壳前体（具有 与Eoarchean中长期耗竭的资源的使用相一致。3330 Ma Iluilik花岗闪长岩的初始εHf值较低，为-6，明显不同于3224 Ma Lister孔雀石的近软骨Hf同位素组成。考虑镁铁质地壳前体（具有 与Eoarchean中长期耗竭的资源的使用相一致。3330 Ma Iluilik花岗闪长岩的初始εHf值较低，为-6，明显不同于3224 Ma Lister孔雀石的近软骨Hf同位素组成。考虑镁铁质地壳前体（具有斜长石-三叠石-花岗岩-闪长闪长岩（TTG）样品的¹⁷⁶ Lu / ¹⁷⁷ Hf比约为0.02），SHC太古宙锆石到古太古代锆石的初始Hf同位素组成与Hadean镁铁质地壳的再造一致。锆石εHf VS。花岗岩样品的时间趋势对应于¹⁷⁶ Lu / ¹⁷⁷Hf比率约为0.01，表明花岗岩地壳主要是通过对最老的TTG进行地壳再造而产生的。与西南格陵兰的Itsaq片麻岩复合体的长英质壳相似，SHC花岗岩类似乎在古古罗马纪末期开始向更幼稚的组成转变。但是，与格陵兰西南部所观察到的情况相反，SHC新archarean的长英质地壳几乎没有记录到任何未成年人的输入。