Search Results (16)

The complex geology of southwestern Mexico results from prolonged interaction between the North American and Farallon plates along an active subduction zone. This process led to crustal growth via oceanic lithosphere consumption, island arc accretion and batholith exhumation, forming great geological features like the Guerrero composite terrane. On the other hand, the Zihuatanejo subterrane, evolved into the Jalisco Block is now bounded by major grabens. Aeromagnetic data from the Mexican Geological Service (1962–2016) were used to map geological structures and contribute to the mineral exploration. Advanced magnetic processing and 3D modeling (VOXI Magnetic Vector Inversion) revealed the Jalisco Block’s complex structure, including Triassic basement, Jurassic–Cretaceous volcanics, and plutonic bodies such as the Puerto Vallarta batholith. Magnetic anomalies are related to intrusive bodies and mineralized zones, notably Peña Colorada (Fe), El Barqueño (Au), and La Huerta. Iron deposits are linked to intrusive volcanic–sedimentary contacts, while gold aligns with intrusive zones and observed magnetic maxima. A notable NW–SE magnetic low at 20 km depth suggests a reactivated back-arc basin and crustal fracture zone. These findings underscore aeromagnetic surveys’ value in both mineral exploration and geological interpretation. Full article

The metallogenic process of gold deposits is typically characterized by multi-stage mineralization and complex tectonic evolution. Precise determination of metallogenic age is thus critical yet challenging for establishing ore-forming models and tectonic evolutionary frameworks. The Koka gold deposit in Eritrea represents the largest gold discovery to date in the area, though its metallogenic age and tectonic evolution remain debated. This study employs in situ micro-analysis techniques to investigate major/trace elements and U-Pb geochronology of hydrothermal monazite coexisting with gold mineralization, providing new constraints on the metallogenic timeline and tectonic setting. Petrographic observations reveal well-crystallized monazite with structural associations to pyrite and native gold, indicating near-contemporaneous formation. Trace element geochemistry shows peak formation temperatures of 270–340 °C for monazite, consistent with fluid inclusion data. Genetic diagrams confirm a hydrothermal origin, enabling metallogenic age determination. Monazite Tera–Wasserburg lower intercept ages and weighted mean ²⁰⁸Pb/²³³Th ages yield 586 ± 8.7 Ma and 589 ± 2.3 Ma, respectively, overlapping error ranges with published sericite ⁴⁰Ar/³⁹Ar ages. This confirms Ediacaran gold mineralization, unrelated to the Koka granite (851 ± 2 Ma). Statistical analysis of reliable age data reveals a three-stage tectonic evolution model: (1) 1000–875 Ma, Rodinia supercontinental rifting, with depleted mantle-derived mafic oceanic crust formation and Mozambique Ocean spreading; (2) 875–630 Ma, subduction-driven crustal accretion and Koka granite emplacement; and (3) 630–570 Ma, post-collision crustal/lithospheric remelting, with mixed metamorphic–magmatic fluids and meteoric water input driving gold precipitation. Full article

The Raohe subduction–accretion complex (RSAC) in the Wandashan Block, NE China, comprises ultramafic rocks, gabbro, mafic volcanic rocks, deep-sea and hemipelagic sediments, and trench–slope turbidites. We investigate the basalts within the RSAC to resolve debates on its origin. Zircon U-Pb dating of pillow basalt from Dadingzi Mountain yields a concordant age of 117.5 ± 2.1 Ma (MSWD = 3.6). Integrating previous studies, we identify three distinct basalt phases. The Late Triassic basalt (210 Ma–230 Ma) is characterized as komatites–melilitite, exhibiting features of island arc basalt, as well as some characteristics of E-MORB. It also contains high-magnesium lava, suggesting that it may be a product of a juvenile arc. The Middle Jurassic basalt (around 159 Ma–172 Ma) consists of a combination of basalt and magnesium andesite, displaying features of oceanic island basalt and mid-ocean ridge basalt. Considering the contemporaneous sedimentary rocks as hemipelagic continental slope deposits, it is inferred that these basalts were formed in an arc environment associated with oceanic subduction, likely as a result of subduction of the young oceanic crust. The Early Cretaceous basalt (around 117 Ma) occurs in pillow structures, exhibiting some characteristics of oceanic island basalt but also showing transitional features towards a continental arc. Considering the regional distribution of the rocks, it is inferred that this basalt likely formed in a back-arc basin. Integrating the formation ages, nature, and tectonic attributes of the various structural units within the RSAC, as well as previous research, it is inferred that subduction of the Paleo-Pacific Ocean had already begun during the Late Triassic and continued into the Early Cretaceous without cessation. Full article

The Heilongjiang Complex provides a crucial geological record of the evolutionary history of the Mudanjiang Ocean, making it significant for understanding the accretion process between the Jiamusi Block and the Songliao Block. In this study, we analyzed samples from the Heilongjiang Complex in the Huanan region using zircon U-Pb and ⁴⁰Ar/³⁹Ar isotopic dating. The LA-ICP-MS U-Pb dating results show that the deposition time of the mica quartz schist is Late Triassic (237–207 Ma), while the protolith age of the amphibolite is Middle Triassic (245.5 ± 1.2 Ma). Detrital zircon ages from the mica quartz schist reveal four groups: 155–229 Ma, 237–296 Ma, 485–556 Ma, and 585–2238 Ma. The provenances are related to the magmatic and metamorphic activities at the junction of the Jiamusi Block and Songliao Block. ⁴⁰Ar/³⁹Ar isotopic dating yielded a plateau age of 183.40 ± 1.83 Ma for phengite in the mica quartz schist, with the metamorphic ages obtained from zircon U-Pb dating. We identify three major metamorphic events in the Heilongjiang Complex: (1) ~229 Ma, marking the earliest tectonic thermal disturbance in the complex; (2) 207–202 Ma, corresponding to the metamorphic event related to the collision between the Jiamusi Block and Songliao Block; and (3) ~183 Ma, indicating the closure of the Mudanjiang Ocean. Integrating these new findings with the results of previous research on magmatism and metamorphism, we reconstruct the tectonic evolution of the Mudanjiang Ocean from the Late Paleozoic to the Mesozoic. During the Early Permian, the Mudanjiang Ocean had already opened. Between the Middle Permian and Middle Triassic, bidirectional subduction occurred. In the Late Triassic, the Mudanjiang Ocean entered a subduction dormancy period. By the Early to Middle Jurassic, the Mudanjiang Ocean closed due to continental collision, leading to the final positioning of the Heilongjiang Complex. Full article

The Junggar Basin basement comprises microcontinental blocks amalgamated through successive paleo-oceanic accretion events. Stratigraphic and provenance studies within the basin are crucial for reconstructing its evolution and understanding the closure of paleo-oceanic systems. This study presents an integrated petrographic and geochemical analysis of the Lower Jurassic Badaowan Formation sandstones in the Dongdaohaizi Depression, located in the eastern Junggar Basin. The results reveal a progressive decrease in lithic fragment content and an increase in quartz content from older to younger strata within the Badaowan Formation, indicating an increase in compositional maturity. Provenance analysis indicates that the sandstones are predominantly derived from tuffaceous rocks, granites, basalts, and minor metamorphic rocks. Heavy mineral assemblages, including zircon, chromian spinel, tourmaline, and garnet, suggest parent rocks consisting primarily of intermediate to acidic igneous rocks, mafic igneous rocks, and metamorphic rocks. Integrated petrographic and geochemical data from the surrounding areas of the Dongdaohaizi Depression confirm that the Badaowan Formation sandstones are primarily sourced from the eastern Kelameili Mountain. The continued uplift and migration of the Kelameili Mountain during the Early Jurassic played a dominant role in shaping the sedimentary provenance. LA-ICP-MS analyses reveal that the rare earth element (REE) concentrations in the Lower Jurassic sandstones are slightly lower than the average REE content of the upper continental crust. The sandstones exhibit weak differentiation between light and heavy REEs, reflecting a depositional environment characterized by anoxic reducing conditions. Geochemical results indicate a tectonic setting dominated by a passive continental margin and continental island arc in the source area. Synthesizing these findings with related studies, we propose that the Kelameili Ocean, as part of the Paleo-Asian Ocean, underwent a complex evolution involving multiple oceanic basins and microcontinental subduction–collision systems. From the Middle Ordovician to Late Silurian, the Kelameili region evolved as a passive continental margin. With the onset of subduction during the Middle Devonian to Early Carboniferous, the eastern Junggar Basin transitioned into a continental island arc system. This tectonic transition was likely driven by episodic or bidirectional subduction of the Kelameili Ocean. Full article

The Central Altun orogenic system is a result of the amalgamation of multiple micro-continental blocks and island arcs. This complex system originated from subduction–accretion–collision processes in the Proto-Tethys Ocean during the Early Paleozoic. Research has reported the discovery of several Li-Be granitic pegmatite deposits in the Central Altun Block, including the North Tugeman granitic pegmatite Li-Be deposit, Tugeman granitic pegmatite Be deposit, Tashisayi granitic pegmatite Li deposit, South Washixia granitic pegmatite Li deposit, and Tamuqie granitic pegmatite Li deposit. The Tashidaban granitic pegmatite Li deposit has been newly discovered along the northern margin of the Central Altun Block. Field and geochemical studies of the Tashidaban granitic pegmatite Li deposit indicate: (1) Spodumene pegmatites and elbaite pegmatites, as Li-bearing granitic pegmatites that form the Tashidaban granitic pegmatite Li deposit, intrude into the two-mica schist, and marble of the Muzisayi Formation of the Tashidaban Group. (2) Columbite–tantalite group minerals and zircon U-Pb dating results indicate that the mineralization age of Tashidaban Li granitic pegmatites is 450.2 ± 2.4 Ma with a superimposed magmatic event at around 418–422 Ma later. (3) Whole-rock geochemical results indicate that the Kumudaban rock sequence belongs to the S-type high-K to calc-alkaline granites and the Tashidaban Li granitic pegmatites originated from the extreme differentiation by fractional crystallization of the Kumdaban granite pluton. Full article

The Mugagangri Group (MG), located at the southern margin of the Qiangtang terrane in Tibet, is a crucial research target for understanding the subduction and accretion history of the Meso-Tethys Ocean. Extensional crack-seal veins restricted within sandstone blocks from the broken formation in the MG (Gaize) formed synchronously in the mélange formation. The primary inclusions trapped in the veins recorded multiple pieces of information during the formation of the accretionary wedge. To precisely constrain the MG subduction–accretion processes, we investigated the trapping temperature, salinity, density, and composition of the fluid inclusions within the crack-seal veins derived from the broken formation in the MG (Gaize). The primary inclusions indicate that the crack was sealed at ~151–178 °C. The salinity of the primary inclusions exhibited a well-defined average of 3.3 ± 0.7 wt% NaCl equivalent, slightly lower than the average of seawater (3.5 wt%). There were no nonpolar gases, and only H₂O (low salinity) was detectable in the primary inclusions. These characteristics suggest that the syn-mélange fluids were a type of pore fluid in the shallow subduction zone, with the principal source being pore water from sediments overlying the oceanic crust. Because of mineral dehydration and compaction, the pore fluids became more diluted with H₂O and fluid overpressure owing to a pore fluid pressure that was greater than the hydrostatic pressure. Subsequently, the creation of cracks through hydraulic fracturing provided a novel pathway for the flow of fluids which, in turn, contributed to the décollement step-down and underthrusting processes. These fractures acted as conduits for fluid movement and played a crucial role in facilitating these peculiar occurrences of quartz veins. The depth (~5 km) and temperature estimates of the fluid expulsion align with the conditions of the décollement step-down, thereby leading to the trapping of fluids within the sandstone blocks and their subsequent underplating to the accretionary complex. In our preferred model, such syn-mélange fluids have the potential to provide valuable constraints on the subduction–accretion processes occurring in other accretionary complexes. Full article

Detrital zircons in the matrix of an accretionary complex play an important role in providing evidence to reconstruct oceanic plate subduction and accretion processes. The Nadanhada accretionary complex (NAC) dominated by the Yuejinshan, Raohe and Tongjiang accretionary complexes provides significant geological evidence to better understand the Paleo-Pacific subduction–accretion process. Most previous studies have focused on the Yuejinshan and Raohe accretionary complexes, while those of the Tongjiang accretionary complex on the north side have focused on blocks. In this study, we present zircon U–Pb dating and Hf isotopic data for the matrix of metasedimentary rock in the Tongjiang accretionary complex. The analysis results show that the zircons in the fine silty mudstone, phyllonite and fine argillaceous siltstone define the youngest weighted mean ages (youngest detrital zircon ages) of 261.4 ± 2.9 Ma (247 Ma), 175.2 ± 4.9 Ma (169 Ma) and 168.6 ± 2.1 Ma (162 Ma), respectively, and yield a younging trend of the accretion materials from west to east. Provenance analysis indicates that the matrix was mainly sourced from the neighboring Jiamusi and Xingkai blocks. Based on previous results of the Permian and Late Triassic blocks in the Yuejinshan region, the Permian and Early Jurassic blocks in the Tongjiang region, and the Late Triassic and Early–Middle Jurassic blocks in the Raohe region, as well as the lower limit of the depositional age of the Late Triassic matrix in the Yuejinshan region and the Middle Jurassic and Early Cretaceous matrices in the Raohe region, we propose that the NAC may record the Late Permian–Triassic, Jurassic and Early Cretaceous oceanic accretion events, representing the westward subduction and accretion process of the Paleo–Pacific Ocean Plate. Full article

The eastern Tiklik belt is mainly composed of meta-sedimentary rocks of the Ailiankate and Sailajiazitage Groups that were previously interpreted as Palaeoproterozoic, Mesoproterozic and Neoproterozoic stratigraphic units, which are part of the Tarim Precambrian basement. Our new detrital (U-Pb) zircon ages yield a dominant single peak with a major range between ca. 700 Ma and 800 Ma for meta-sedimentary rocks from both the Ailiankate and Sailajiazitage Groups, which demonstrates that they were mainly derived from an independent Neoproterozoic terrane. There are several ages of 444–659 Ma, of which, the youngest has an age of 444 ± 6 Ma, indicating that the time of deposition of the meta-sedimentary rocks could have been in the Early Silurian. The porphyritic granite sample has a weighted mean crystallization age of 442 ± 2 Ma. The adakite-like geochemical characteristics of the porphytitic granite suggest derivation from the melting of the oceanic slab and formation in a subduction, arc-related tectonic setting. After integration with relevant published data, our work suggests that the Ailiankate and Sailajiazitage Groups belong to a tectonic mosaic that contains Middle Neoproterozoic extensional and Paleozoic accretionary and collisional complexes, rather than the Paleoproterozoic or Mesoproterozoic basement, as previously regarded. We propose a new tectonic model for the eastern Tiklik belt that started with a Middle Neoproterozoic extension and ended with Paleozoic continuous accretion and collision in a Paleo-Tethys archipelago, which contributed to the considerable continental growth of the southern Tarim Block. Full article

The composite Albian–Eocene orogenic wedge of the northern part of the Inner Western Carpathians (IWC) comprises the European Variscan basement with the Upper Carboniferous–Triassic cover and the Jurassic to Upper Cretaceous sedimentary successions of a large oceanic–continental Atlantic (Alpine) Tethys basin system. This paper presents an updated evolutionary model for principal structural units of the orogenic wedge (i.e., Fatricum, Tatricum and Infratatricum) based on new and published white mica ⁴⁰Ar/³⁹Ar geochronology and P–T estimates by Perple_X modeling and geothermobarometry. The north-directed Cretaceous collision led to closure of the Jurassic–Early Cretaceous basins, and incorporation of their sedimentary infill and a thinned basement into the Albian–Cenomanian/Turonian accretionary wedge. During this compressional D1 stage, the subautochthonous Fatric structural units, including the present-day higher Infratatric nappes, achieved the metamorphic conditions of ca. 250–400 °C and 400–700 MPa. The collapse of the Albian–Cenomanian/Turonian wedge and contemporary southward Penninic oceanic subduction enhanced the extensional exhumation of the low-grade metamorphosed structural complexes (D2 stage) and the opening of a fore-arc basin. This basin hemipelagic Coniacian–Campanian Couches-Rouges type marls (C.R.) spread from the northern Tatric edge, throughout the Infratatric Belice Basin, up to the peri-Pieniny Klippen Belt Kysuca Basin, thus tracing the south-Penninic subduction. The ceasing subduction switched to the compressional regime recorded in the trench-like Belice “flysch” trough formation and the lower anchi-metamorphism of the C.R. at ca. 75–65 Ma (D3 stage). The Belice trough closure was followed by the thrusting of the exhumed low-grade metamorphosed higher Infratatric complexes and the anchi-metamorphosed C.R. over the frontal unmetamorphosed to lowest anchi-metamorphosed Upper Campanian–Maastrichtian “flysch” sediments at ca. 65–50 Ma (D4 stage). Phengite from the Infratatric marble sample SRB-1 and meta-marl sample HC-12 produced apparent ⁴⁰Ar/³⁹Ar step ages clustered around 90 Ma. A mixture interpretation of this age is consistent with the presence of an older metamorphic Ph1 related to the burial (D1) within the Albian–Cenomanian/Turonian accretionary wedge. On the contrary, a younger Ph2 is closely related to the late- to post-Campanian (D3) thrust fault formation over the C.R. Celadonite-enriched muscovite from the subautochthonous Fatric Zobor Nappe meta-quartzite sample ZI-3 yielded a mini-plateau age of 62.21 ± 0.31 Ma which coincides with the closing of the Infratatric foreland Belice “flysch” trough, the accretion of the Infratatricum to the Tatricum, and the formation of the rear subautochthonous Fatricum bivergent structure in the Eocene orogenic wedge. Full article

The boundary between the Gondwana and Yangtze plate is still controversial. In southwest China, the Sanjiang region marks the collision zone which accreted several blocks coming from the northern Gondwana margin. In this region, subduction of the Paleo-Tethys Ocean and associated continental blocks during the Triassic Period led to the formation of an N–S trending complex involving intrusive and volcanic rocks. The intrusive rocks are important for constraining the evolution of the Paleo-Tethyan in southwestern China. This study presents new geochronological, geochemical, and Sr-Nd-Hf isotopic data of granite porphyries from northern Lancangjiang, in order to discuss the origin of these granites and their tectonic significance. Representative samples of the Zengudi and the Tuobake granite porphyries from the Yezhi area yielded weighted mean ²⁰⁶Pb/²³⁸U ages of 247–254 Ma and 246 Ma, respectively. The Zengudi granite porphyries display zircon Ԑ_Hf(t) values of −12.94 to −2.63, Ԑ_Nd(t) values of −14.5 to −9.35, and initial ⁸⁷Sr/⁸⁶Sr ratios of 0.708 to 0.716. The Tuobake granite porphyries have zircon Ԑ_Hf(t) values of −14.06 to −6.55, Ԑ_Nd(t) values of −10.9 to −9.41, and initial ⁸⁷Sr/⁸⁶Sr ratios of 0.716 to 0.731. Both the Zengudi and Tuobake granite porphyries exhibit strongly peraluminous signatures with high A/CNK nAl₂O₃/(K₂O + Na₂O + K₂O) ratios (1.07–1.86 and 0.83–1.33, respectively). These granites are enriched in Rb and Th, and depleted in Ti, Nb, Ta, Sr, and P, with negative Eu anomalies (Eu/Eu* < 0.61). These geochemical and isotopic data indicate that the primary magma of the granite porphyries originated from partial melting of ancient continental crust as a result of basaltic magma underplating and underwent fractionation crystallization during their emplacement. We propose that the Triassic subduction of the Paleo-Tethys Ocean led to crust shortening and thickening in the Sanjiang region, while the northern Lancangjiang area was involved in the continental collision after the subduction of the Paleo-Tethys Ocean before 254 Ma. Full article

Geological, geochemical and ground magnetic techniques are used to characterize the University alkaline-gabbroid pluton and crosscutting N-S trending alkaline dikes, located northeast of the Kuznetsk Alatau ridge, Siberia. Trace element concentrations and isotopic compositions of the igneous units were determined by XRF, ICP-MS and isotope analysis. The Sm-Nd age of subalkaline (melanogabbro, leucogabbro 494–491 Ma) intrusive phases and crosscutting alkaline dikes (plagioclase ijolite, analcime syenite 392–389 Ma) suggests two stages of activity, likely representing separate events. The subalkaline and alkaline rocks are characterized by low silicic acidity (SiO₂ = 41–49 wt %), wide variations in alkalinity (Na₂O + K₂O = 3–19 wt %; Na₂O/K₂O = 1.2–7.2 wt %), high alumina content (Al₂O₃ = 15–28 wt %) and low titanium content (TiO₂ = 0.07–1.59 wt %). The new trace element data for subalkaline rocks (∑REE 69–280 ppm; La/Yb 3.7–10.2) of the University pluton and also the crosscutting younger (390 Ma) alkaline dikes (∑REE 10–1567 ppm; La/Yb 0.7–17.8 ppm) both reflect an intermediate position between oceanic island basalts (OIBs) and island arc basalts (IABs). The presence of a negative Nb–Ta anomaly and the relative enrichment in Rb, Ba, Sr, and U indicate a probable interaction of mantle plume material with the lithospheric mantle beneath previously formed accretion complexes of subduction zones. The isotopic signatures of strontium (ε_Sr(T) +3.13–+28.31) and neodymium (ε_Nd(T) +3.2–+8.7) demonstrate the evolution of parental magmas from a plume source from moderately depleted PREMA mantle, whose derivatives underwent selective crustal contamination. Full article

The strong morphological similitude of the block-in-matrix fabric of chaotic rock units (mélanges and broken formations) makes problematic the recognition of their primary forming-processes. We present results of the comparison between magnetic fabric and mesoscale structural investigations of non-metamorphic tectonic, sedimentary, and polygenetic mélanges in the exhumed Late Cretaceous to early Eocene Ligurian accretionary complex and overlying wedge-top basin succession in the Northern Apennines (northwest Italy). Our findings show that the magnetic fabric reveals diagnostic configurations of principal anisotropy of magnetic susceptibility (AMS) axes orientation that are well comparable with the mesoscale block-in-matrix fabric of mélanges formed by different processes. Broken formations and tectonic mélanges show prolate and neutral-to-oblate ellipsoids, respectively, with magnetic fabric elements being consistent with those of the mesoscale anisotropic “structurally ordered” block-in-matrix fabric. Sedimentary mélanges show an oblate ellipsoid with a clear sedimentary magnetic fabric related to downslope gravitational emplacement. Polygenetic mélanges show the occurrence of a cumulative depositional and tectonic magnetic fabric. The comparison of field and laboratory investigations validate the analysis of magnetic features as a diagnostic tool suitable to analytically distinguish the contribution of different mélange forming-processes and their mutual superposition, and to better understand the geodynamic evolution of subduction-accretion complexes. Full article

The geodynamic development of the north–western (Arctic) margin of the Siberian craton is comprehensively analyzed for the first time based on our database as well as on the analysis of published material, from Precambrian-Paleozoic and Mesozoic folded structures to the formation of the Mesozoic-Cenozoic Yenisei-Khatanga sedimentary basin. We identify the main stages of the region’s tectonic evolution related to collision and accretion processes, mainly subduction and rifting. It is demonstrated that the prototype of the Yenisei-Khatanga basin was a wide late Paleozoic foreland basin that extended from Southern Taimyr to the Tunguska syneclise and deepened towards Taimyr. The formation of the Yenisei-Khatanga basin, as well as of the West-Siberian basin, was due to continental rifting in the Permian-Triassic. The study describes the main oil and gas generating deposits of the basin, which are mainly Jurassic and Lower Cretaceous mudstones. It is shown that the Lower Cretaceous deposits contain 90% of known hydrocarbon reserves. These are mostly stacked reservoirs with gas, gas condensate and condensate with rims. The study also presents data on oil and gas reservoirs, plays and seals in the Triassic, Jurassic and Cretaceous complexes. Full article

New whole-rock lead (Pb) isotope analyses are presented in this study for granitoid orthogneisses from the Southwest Grenville Province in Ontario and Western Quebec. These data are used to test the location of a cryptic Archean-Proterozoic suture proposed on the basis of neodymium (Nd) isotope mapping. Immediately south of the inferred suture boundary, Pb isotope results show a crustal component derived solely from a juvenile Paleoproterozoic mantle source. These data are distinctly different from the reworked Archean craton to the northwest and strongly support the boundary derived from Nd isotope data. Pb signatures in the Paleoproterozoic crust suggest a southerly increase in magmatic reworking due to intensive plutonism during the late Paleoproterozoic and early Mesoproterozoic periods. The accretion of a juvenile arc to the Archean margin during the Penokean event (ca. 1.85 Ga) would have triggered subduction-zone reversal and the development of a long-lived ensialic arc on the composite margin. This was expressed as a 1.75 Ga Killarnian magmatic event and subsequent early Mesoproterozoic magmatism. This tectonic model for the Southwest Grenville Province shows that its crustal evolution is consistent with the Paleoproterozoic Makkovik-Ketilidian Orogen of Labrador and Southern Greenland. Hence, the application of whole-rock Pb isotope data in conjunction with Nd model ages provides data useful for mapping the extent of crustal terranes of differing age, which is essential for modeling the tectonic evolution of complex ancient accretionary orogens. Full article