Carl Guilmette

• Ph.D., Eng.
• Professor (Full) at Université Laval

Garnet is a common minor phase in S-type granites and pegmatites, but its petrogenesis remains poorly constrained. Garnet in these systems may have crystallized from the melt or it may represent inherited grains derived from the source or xenocrysts from the wall rocks. Although garnet has the potential to provide unique insights into the magmatic...

The Neoarchean Era is a key period in Earth's history as it witnessed a significant pulse of crustal formation corresponding to the assembly of several cratons, potentially coeval with a transition in the global tectonic regime. Neoarchean metasedimentary subprovinces of the Superior Craton, the largest unreworked Archean craton on Earth, were form...

Recent advances in geochronological techniques now allow the ability to efficiently decipher the timing and duration of geological processes in complex high-grade polymetamorphosed orogenic terranes. This is the case of the Grenville Front Tectonic Zone, which truncates the Superior Craton to the southeast. The zone exposes parautochtonous Archean...

The source of the melt forming rare-metal granitic pegmatites in high-grade metamorphic orogenic belts is debated and is interpreted to be either (i) the product of magmatic differentiation of a large volume of granitic melt or (ii) the anatectic product of local crustal rocks. The Haut-Saint-Maurice region of the Grenville Province, Canada is of s...

Paleogeographic reconstructions of ancient orogenic belts, such as the Paleoproterozoic Trans-Hudson orogen (THO), are crucial for understanding of their tectonic evolution and the recognition of potentially different terranes juxtaposed during convergence. The foreland of the Ungava Orogen (UO, Nunavik, Quebec), a branch of the THO, is characteriz...

Incorporation of rare earth elements (REE) in garnet enables garnet chronology (Sm-Nd, Lu-Hf), and imparts a garnet-stable signature on cogenetic phases, which allows petrochronology and general petrogenetic tracing of gar-net stability in minerals and melts. Constraints on the uptake and redistribution mechanisms, as well as on the diffusive behav...

This short contribution describes the Archean and Proterozoic history of the central Rae Craton in the Tehery Lake-Wager Bay area, Nunavut. The study area comprises six lithotectonic domains separated by large-scale structures: the Gordon Domain, Lunan Domain, Daly Bay complex, Douglas Harbour Domain, Kummel Lake Domain, and Ukkusiksalik Domain. Th...

Accretionary orogens often contain upper crustal nappes derived from subducted continental lithosphere that display (ultra-)high-pressure, low-temperature ((U)HP-LT) metamorphism. Surprisingly, such orogens also contain continent-derived nappes that underwent ‘Barrovian’ (MP-HT) prograde metamorphism instead. Here, we show that these Barrovian napp...

Metamorphic soles found under allochthonous oceanic lithosphere, or ophiolites, are interpreted as derived from lower plate oceanic crust material accreted to upper plate mantle during intraoceanic subduction initiation. Their metamorphic evolution is inferred to reflect the thermal structure at the site of subduction nucleation, with granulite-bea...

Apparent polar wander paths (APWPs) calculated from paleomagnetic data describe the motion of tectonic plates relative to the Earth’s rotation axis through geological time, providing a quantitative paleogeographic framework for studying the evolution of Earth’s interior, surface, and atmosphere. Previous APWPs were typically calculated from collect...

The Cambrian Explosion (540-515 Ma ago) is arguably the most significant evolutionary transition after the origin of life. A variety of environmental perturbations including rising oxygen levels, changes in ocean chemistry and increased bio-essential elements have been correlated to this rapid faunal diversification. Anomalously high weathering flu...

The Bay of Islands complex, Newfoundland, Canada, represents a fossil subduction system that was obducted onto the Laurentian margin during the Taconic Orogeny. We present whole-rock geochemistry and geochronology for the Bay of Islands metamorphic sole from the Table Mountain and North Arm Mountain massifs. The Bay of Islands metamorphic sole can...

Research this past summer (2022) marked the initiation of a collaborative program between the Geological Survey of Canada, the Geological Survey of Newfoundland and Labrador, and multiple universities (led by Laval University). The program aims to upgrade the geoscientific knowledge of ophiolite complexes throughout Newfoundland, and stimulate mine...

Metamorphic soles found under allochthonous oceanic lithosphere, or ophiolites, are derived from the earliest lower plate oceanic crust accreted to upper plate mantle and are considered diagnostic of intraoceanic subduction initiation. Their metamorphic evolution is inferred to reflect the thermal structure at the site of subduction nucleation, wit...

The immense Central Asian Orogenic Belt (CAOB) records the transition from the Pan‐Rodinian Mirovoi Ocean to the Paleo‐Asian Ocean, but the final closure of the Mirovoi Ocean remains unexplored. Here we document two new eclogite occurrences, located between CAOB microcontinents and the Ediacaran–Cambrian island arc in Mongolia. Pseudosection modeli...

Submittted for peer review to Earth-Science Reviews. Highlights: 1. New paleomagnetic reference frame for the last 320 million years. 2. Global apparent polar wander path computed from site-level data rather than poles. 3. First-order geometry similar to previous models but with smaller uncertainties. 4. Peaks in apparent polar wander may result f...

The Wager shear zone is an ∼450-km long zone of high strain hosted within Proterozoic and Archean rocks of the Rae domain in northwestern Hudson Bay, Nunavut. New field mapping and microstructural analyzes, combined with titanite and apatite geochronology, define the style, kinematics, and timing of Proterozoic ductile deformation. The results indi...

The Ungava Orogen (Nunavik, Quebec) has been interpreted as the result of a Paleoproterozoic arc-continent collision, but its magmatic and tectono-metamorphic evolution, as well as its detailed stratigraphy, remain loosely constrained. The Ungava Orogen (UO) is located in the north-eastern portion of the Trans-Hudson Orogen and formed in response...

Despite a well-developed structural framework, orogenic gold deposits from the Malartic-Val-d’Or Camp (MVC) report ages that span nearly 345 million years (~ 2705–2360 Ma), significantly post-dating the tectono-metamorphic history of the Abitibi-Wawa Orogeny, and are in conflict with the structural setting along the retrograde path of the orogenic...

Atoll garnets are uncommon features that have been recognized in contrasting metamorphic environments worldwide, but their origin remains largely debated. Several models have been proposed to explain their formation, including preferential dissolution of garnet cores by fluid infiltration, polymetamorphism, and the coalescence of subgrains. We repo...

The Cambrian Explosion (541-515 Myr ago) is arguably the most significant evolutionary transition after the origin of life1-2. A variety of environmental perturbations have been correlated to this rapid animal species diversification1-3. Increased weathering fluxes from the continents to the oceans are hypothesized to cause these perturbations4-6,...

The Bangong–Nujiang suture zone (BNSZ), which separates the Gondwana-derived Qiangtang and Lhasa terranes, preserves limited geological records of the Bangong–Nujiang Ocean (BNO). The timing of opening of this ocean has been hotly debated due to the rare and complicated rock records in the suture zones, which span over 100 Ma from Carboniferous–Per...

This study presents a re-examination of historical specimens (DG136 and DG167) from the Monashee complex in the southeastern Canadian Cordillera that are critical to the current understanding of rare earth element (REE) distribution between garnet and monazite (and other accessory minerals) during metamorphism. Nine-hundred and fifty-one new monazi...

The La Pointe gold deposit is hosted by Neoarchean rocks metamorphosed to the amphibolite facies, straddling the boundary between the La Grande and Opinaca subprovinces, in Eeyou Istchee Baie-James (Québec, Canada). The deposit consists of two zones, Zone 25 and Zone 26, which are oriented WNW-ESE (S1) and have been deformed and folded by the main...

The formation of a global network of plate boundaries surrounding a mosaic of lithospheric fragments was a key step in the emergence of Earth’s plate tectonics. So far, propositions for plate boundary formation are regional in nature but how plate boundaries are being created over 1000s of km in short periods of geological time remains elusive. Her...

The sources of metals enriched in Archean orogenic gold deposits have long been debated. Metasedimentary rocks, which are generally accepted as the main metal source in Phanerozoic deposits, are less abundant in Archean greenstone belts and commonly discounted as a viable metal source for Archean deposits. We report ultralow-detection-limit gold an...

Dating the onset of continental collision is fundamental in defining orogenic cycles and their effects on regional tectonics and geodynamic processes through time. Part of the Paleoproterozoic Trans‐Hudson Orogen, the Southeastern Churchill Province is interpreted to result from the amalgamation of Archean to Paleoproterozoic crustal blocks (amalga...

The formation of a global network of plate boundaries surrounding a mosaic of lithospheric fragments was a key step in the emergence of Earth’s plate tectonics. So far, propositions for plate boundary formation are regional in nature but how plate boundaries are being created over 1000s of km in short periods of geological time remains elusive. Her...

Middle and lower orogenic crust exposed at the Earth's surface represent an exceptional opportunity to investigate accretionary and collisional processes in various tectonic settings. In particular, deciphering their metamorphic history in terms of evolving P-T-t-D paths enables an assessment of lower crustal behavior and the role of granulitic ter...

Secular changes in the architecture, thermal state, and metamorphic style of global orogens are thought to have occurred since the Archean; however, despite widespread research, the driving mechanisms for such changes remain unclear. The Paleoproterozoic may prove to be a key era for investigating secular changes in global orogens, as it marks the...

Ophiolites are widely studied to unravel how new subduction zones form. They may contain crustal and mantle rocks that formed during juvenile stages of intra-oceanic subduction, modifying the pre-existing oceanic lithosphere within which subduction started, and in which a magmatic arc formed upon subduction maturation. Previous geochemical work on...

Strike‐parallel tectonometamorphic discontinuities within the Himalayan metamorphic core are typically interpreted to reflect thrust‐sense movement. However, there is disagreement on the nature and sense of movement across one such structure in central Nepal. Using an integrated approach, this study characterizes multiple structural breaks in the M...

Volcanic rocks in Archean and Paleoproterozoic greenstone belts are abundant and have been suggested as a potential Au source for orogenic Au deposits. The behavior of Au during metamorphism of these rocks is, however, poorly known. We present ultra-low-detection-limit Au analyses from a suite of variably metamorphosed rocks from the Archean La Gra...

Shi et al. (2020) commented on our recent work (Li et al. 2019), which reconstructed the Wilson cycle of the Bangong-Nujiang Tethyan Ocean. They questioned our preferred latest Jurassic-Early Cretaceous Lhasa-Qiangtang initial collision model, and argued that the Bangong-Nujiang Tethyan Ocean did not close until the Late Cretaceous, based on the ex...

Metasedimentary subprovinces within the Superior Province and many Archean cratons worldwide occur as prominent belts separating volcano-plutonic subprovinces. The stages of their development mark major, distinct geodynamic events. Deposition ubiquitously follows a restricted period of voluminous, regional, felsic pluton emplacement. Their geodynam...

Dating the onset of the continental collision and amalgamation of crustal blocks is at the basis of the reconnaissance of orogenic cycles and yields time constraints for the estimate of rates of accretionary processes over the last 4.5 Gyrs. The Paleoproterozoic Southeastern Churchill Province (SECP) represents the easternmost branch of the Trans-H...

The large scale Paleoproterozoic Trans-Hudson Orogen exposed in Canada is recognized to record one of the first complete Wilson cycle. Although it is considered as a prototype of modern accretionary orogen, the strain pattern, thermal state, and architecture in its wedge are still poorly constrained. Part of it, the accretionary New Quebec Orogen (...

Secular changes in the architecture, thermal state, and metamorphic style of global orogens are thought to have occurred since the Archean; however, despite widespread research, the driving mechanisms for such changes remain unclear. The Paleoproterozoic may prove to be a key era for investigating secular changes in global orogens, as it marks the...

Abundant volcanic rocks in Archean greenstone belts have been suggested as potential sources of metals in Archean orogenic gold deposits. However, the behaviour of gold during the metamorphism of these rocks is poorly known. We present ultra-low detection limit gold analyses from a suite of variably metamorphosed samples from the La Grande subprovi...

The archetypal Semail ophiolite of Oman has inspired much thought on the dynamics of initiation of intra-oceanic subduction zones. Current models invoke subduction initiation at a mid-oceanic ridge located sufficiently close to the Arabian passive margin to allow initiation of continental subduction below the ophiolite within ∼10-15 Myr after the 9...

The Bangong-Nujiang suture zone (BNSZ) separates the Lhasa terrane from the Qiangtang terrane and contains remnants of the Bangong-Nujiang oceanic lithosphere (ophiolites). Despite decades of research, when and how the Bangong-Nujiang ophiolites were emplaced remains enigmatic. In the Gerze area (western segment of the BNSZ), the geochemistry and p...

The New Quebec Orogen consists of a supracrustal belt that was reworked when the Superior craton collided with the Core Zone terrane during the Paleoproterozoic Trans-Hudson Orogeny. Within the New Quebec Orogen, the Kaniapiskau Supergroup can be divided into four terrigenous lithotypes metamorphosed at low-grade: one set with greater compositional...

The Pontiac Subprovince is located in the Superior Province, south of the Abitibi Subprovince. The metasedimentary rocks of the Pontiac Group are characterized by a Barrovian metamorphic gradient increasing from north to south from biotite- through garnet- to staurolite-zone conditions. The Pontiac Subprovince has been interpreted as an accretionar...

Subduction zones are unique to Earth and fundamental in its evolution, yet we still know little about the causes and mechanisms of their initiation. Numerical models show that far-field forcing may cause subduction initiation at weak pre-existing structures, while inferences from modern subduction zones suggest initiation through spontaneous lith...

The Lac Guyer area of the La Grande Subprovince (Superior Province) hosts Mesoarchean east-trending volcano-sedimentary sequences subdivided into 3 stratigraphic units (Mintisch and Rouget Formations and Guyer Group), which were emplaced between 2847 and 2806 Ma on a gneissic-tonalitic basement. These approximately 35 to 175 km-long sequences compr...

Canadian Malartic, with a total endowment of 16.3 Moz Au, is an important example of a large-tonnage, low-grade Archean gold deposit (current reserves of 204 Mt @ 1.08 g/t Au). It is located in the southern Superior Province in contact with, and immediately south of the east-west trending Cadillac-Larder Lake fault zone, which delineates the bounda...

The initiation of subduction is key to the formation and recycling of tectonic plates. To investigate the mechanism of subduction initiation, we explore the history of metamorphic soles, which are metamorphosed oceanic crust and pelagic sediments that are accreted to the mantle section of supra-subduction zone (SSZ) ophiolites. Metamorphic soles ty...

The Bangong-Nujiang suture zone, separating the Lhasa and Qiangtang blocks of the Tibetan Plateau, is marked by remnants of the Bangong-Nujiang oceanic basin. In the Gaize area of central Tibet, Mesozoic sedimentary strata recording the evolution of the basin and subsequent collision between these two blocks include the Upper Triassic-Lower Jurassi...

La Sous-province métasédimentaire de Pontiac est située au sud de la Sous-province de l’Abitibi, au sein de la Province archéenne du Supérieur. La juxtaposition des deux sousprovinces est généralement interprétée comme le résultat d’un processus de subduction. Ce contexte tectonique serait à première vue compatible avec un métamorphisme de type bar...

The New Quebec Orogen (NQO) is the best preserved supracrustal belt of the deeply eroded Paleoproterozoic Trans-Hudson Orogen and thus constitutes an exceptional window to investigate one of the most ancient Wilson cycle sedimentary records within the Manikewan paleo-ocean. It consists of a Paleoproterozoic supracrustal belt that underwent reworkin...

The recent identification of multiple strike-parallel discontinuities within the exhumed Himalayan metamorphic core has helped revise the understanding of convergence accommodation processes within the former mid-crust exposed in the Himalaya. Whilst the significance of these discontinuities to the overall development of the mountain belt is still...

The structural setting of the Pontiac Subprovince in the vicinity of the world-class Canadian Malartic gold deposit has been revisited by combining and reinterpreting airborne geophysical surveys together with a century of structural observations. Felsic-intermediate intrusive bodies are a key component of this deposit. Defining the regional and lo...

This article expands upon detrital zircon geochronology with a sampling and analysis strategy dating variably tectonized granitoid conglomerate clasts. Its purpose is to elucidate details of the provenance’s tectonomagmatic history from deformation-relative age distributions. The method involves bulk samples of clasts, sorted based on the degree of...

The New Quebec Orogen (NQO) is a Paleo-Proterozoic supra-crustal belt that underwent reworking when the Superior Craton collided with the Core Zone, during the Trans-Hudson Orogeny. Within the NQO, the Labrador Trough regroups greenschist-facies sedimentary and volcanic sequences (Kaniapiskau Supergroup) inferred to represent the rifted margin of t...

Integrated pseudosection modeling and monazite petrochronology of paragneiss from the Kanchenjunga region of northeastern Nepal reveal the presence of cryptic tectonometamorphic discontinuities within the Himalayan metamorphic core. These new data outline a series of thrust-sense structures that juxtapose rocks that generally record a protracted hi...

Analyzing subduction initiation is key for understanding the coupling between plate tectonics and underlying mantle. Here we focus on supra-subduction zone (SSZ) ophiolites and how their formation links to intra-oceanic subduction initiation in an absolute plate motion frame. SSZ ophiolites form the majority of exposed oceanic lithosphere fragments...

Suprasubduction zone ophiolites are relics of oceanic upper plate forearcs and are typically preserved as discontinuous belts with discrete massifs along suture zones. Ophiolites usually contain an incomplete condensed section compared to average modern oceanic lithosphere. The incompleteness and discontinuity of ophiolites are frequently attribute...

The Hongliuhe ophiolite is a fragment of the early Paleozoic oceanic crust situated in a suture zone central to the Beishan orogenic collage, which is a subset to the Central Asian Orogenic Belt in Northwest China. It has lithologic, geochemical and chronological similarities to the Yueyashan–Xichangjing ophiolite 400 km east, along strike, allowin...

The High Himalaya are dominated by the exhumed, former midcrustal rocks that comprise the Himalayan Metamorphic Core (HMC). The processes controlling the evolution of this package of metamorphic rocks has been one of the main focuses of much research along the Himalaya over the past 25 years. Recent research has begun to outline a series of strike-...

The convergence between the Indian plate and the southern margin of the Eurasian continent created an active continental margin from Late Jurassic until about 40 Ma ago, which then evolved to form the Himalaya and the Tibetan Plateau during the continental collision stage. Post-collisional magmatism in southern Tibet, north of the Yarlung Zangbo Su...

The purpose of this first synthesis is to summarize findings on the Yarlung Zangbo Suture Zone (YZSZ) ophiolites in Southern Tibet, and to discuss some of thel remaining scientific problems. The YZSZ ophiolites have been studied for almost 30 years and constitute the youngest of the sutures recognized on the Tibet Plateau. It is now acknowledged th...

Blocks of strongly foliated garnet- and clinopyroxene-bearing amphibolites have recently been discovered in the Saga ophiolitic mélange, South Tibet. The Saga ophiolitic mélange is a sheared serpentinite matrix mélange that crops out along the Yarlung Zangbo Suture Zone (YZSZ), South Tibet. The YZSZ is the youngest and the southernmost of all sutur...

The purpose of this first synthesis is to summarize findings on the Yarlung Zangbo Suture Zone (YZSZ) ophiolites and discuss still remaining problems. The YZSZ studied for almost 30years and is the youngest of the sutures recognized on Tibet Plateau. It is now acknowledged that the YZSZ is a complex assemblage of sedimentary, metamorphic and igneou...

Rare kyanite-bearing anatectic paragneisses are found as boudins within sillimanite-bearing paragneisses of the core of the Namche Barwa Antiform, Tibet. In the present study, we document an occurrence from the NW side of the Yarlung Zangbo River. These rocks mainly consist of the assemblage garnet + K-feldspar + kyanite ± biotite + quartz + rutile...

The Saga and Sangsang ophiolites are located about 600 and 450 km west of Lhasa and represent a western extention of the central portion of the Yarlung Zangbo Suture Zone (YZSZ) ophiolite belt. The Saga massif comprises fresh mantle lherzolite and cpx-harzburgite, an ophiolite mélange (±amphibolite), metamorphosed mafic crustal rocks (meta-gabbro,...

Strongly foliated amphibolite clasts are found embedded within the ophiolitic mélange underlying the Xigaze Ophiolite near Bainang and Angren, Yarlung Zangbo Suture Zone, Southern Tibet. These high-grade amphibolites are interpreted as remnants of a dismembered subophiolitic metamorphic sole that would have formed during the inception of a subducti...

The 473 + 5/− 3 Myr Asbestos ophiolite complex of the Quebec Appalachians was formed in a forearc basin and obducted on a margin of Laurentia ~ 460 Myr ago. The complex together with its sedimentary cover is well exposed at Burbank Hill (~ 130 km SW of Québec City) where eight distinct lithologies have been identified: 1) pyroxenites and wehrlites...

DOI = 10.3126/hjs.v5i7.1265 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.63

DOI = 10.3126/hjs.v5i7.1258 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.56

Blocks of highly foliated amphibolite are locally embedded within a serpentinite mélange underlying the Yarlung Zangbo ophiolites in the Xigaze area of southern Tibet. The ophiolites are remnants of an Early Cretaceous back-arc basin within the Permo-Cretaceous Tethys Ocean, which are exposed along in the Yarlung Zangbo Suture Zone (YZSZ). These am...

The Saga and Sangsang ophiolites belong to the E-W-trending Early Cretaceous ophiolite belt of the Yarlung Zangbo Suture Zone (YZSZ), resulting from the closure of the Neo-Tethys Ocean during the collision between the Indian and Eurasian plates. These ophiolitic massifs crop out west of Xigaze and presumably represent a western extention of the cen...

Metre to decameter-size clasts of amphibolite are found embedded in ophiolitic melanges underlying the Yarlung Zangbo Suture Zone Ophiolites, South Tibet, China. These ophiolites and melanges occur at the limit between Indian and Tibetan-derived rocks and represent remnants of an Early Cretaceous intraoceanic supra-subduction zone domain, the Neo-T...

This paper presents the main results of a research project focused on the Yarlung Zangbo Suture Zone (YZSZ) ophiolites and related mélanges and flysch. Study area is representing a 300 km long and 30 km wide segment. The Cretaceous ophiolites are remnants of Neo-Tethys basin which was almost totally consumed in a northward oriented subduction zone...

The Mesozoic Yamdrock mélange and the Triassic flysch lie immediately south of the Yarlung Zangbo Suture Zone (YZSZ) ophiolitic belt, in southern Tibet. The whole-rock chemical signature of sandstones (mostly greywackes), red shales and black shales of the Yamdrock mélange and flysch units do not present significant variations between the different...

The southern contact of the Yarlung-Zangbo Suture Zone ophiolitic belt is marked by a highly sheared serpentinite mélange containing ultramafic blocks. These peridotites can be divided into three main groups. (1) Lherzolites and Cpx-harzburgites contain brownish spinel with Mg# of 0.7–0.75 and Cr# of 0.15–0.27. They resemble fertile abyssal peridot...