Dan Gibson

Simon Fraser University · Department of Earth Sciences

The northernmost part of the Cache Creek terrane lies in south-central Yukon and comprises metavolcanic rocks, hemipelagic chert and shale, newly identified volcaniclastic and clastic rocks (Michie formation, informal), pyroxenite and gabbro intrusive rocks with an arc to back-arc geochemical signature, as well as tectonized and serpentinized ultra...

Uranium-lead (U-Pb) accessory mineral petrochronology has been increasingly used to constrain the timing of tectonometamorphic events. However, because mafic rocks commonly lack minerals with a high-U/Pb ratio, they may be underrepresented in the chronologic record. This study on polymetamorphic mafic granulites from the Archean Rae craton (norther...

A possible Mesozoic-Cenozoic trajectory for the North American craton is outlined from latitude changes of the craton derived from a revised apparent polar wander path, and from westward movement of the craton based on the assumption that Africa has been the least mobile continent geographically since the latest Paleozoic. During each of five time...

Palaeoproterozoic orogenesis within the Archean southeastern Rae craton is related to the initial amalgamation of Laurentia. Characterizing the accompanying tectonic processes during this time has been complicated due to polymetamorphism, which results in the obscuring of the age record of the terranes involved. To improve the knowledge of the tect...

The origin of high-pressure granulites in the south Rae craton and Snowbird tectonic zone (STZ) is highly enigmatic. Current models for their formation and exhumation envisage continental collision at 2.55 Ga and intracratonic orogenesis at 1.9 Ga, or collision and exhu-mation at ca. 1.9 Ga. As an attempt to reconcile these disparate models, we con...

This study characterizes the polyphase tectonometamorphic history of a major shear system in the Rae craton, the Howard Lake shear zone (HLsz), which exhumed high-grade rocks in the distant hinterland of the Paleoproterozoic Trans-Hudson Orogen. Prior work established a Mesoarchean mantle model-age discrepancy in basement rocks across the HLsz, whi...

In the Lower Cretaceous McMurray-Clearwater succession of the intracontinental Alberta Foreland Basin, Canada, detrital zircon U-Pb geochronology samples (referred to herein as DZ samples) have been used to interpret the strata as representing a paleo-continental-scale drainage system. However, the majority of DZ samples are relatively small (n≈90–...

The Nonacho Group comprises six formations of continental clastic rocks that were deposited between 1.91 and 1.83 Ga. The Nonacho Group is part of a broader assemblage of conglomerate and sandstone that was deposited atop the Rae craton in response to the amalgamation of Laurentia and supercontinent Nuna, but the details of its tectonic setting are...

The Paleoproterozoic Snowbird Tectonic Zone (STZ) is a basement structure that was reactivated during the evolution of the Western Canada Sedimentary Basin (WCSB). The STZ is a fault zone in the western Canadian Shield that trends southwest through central Alberta to the Cordilleran deformation front. Brittle faults associated that parallel this ba...

Convergent-margin basins (CMBs) are commonly associated with active arcs, and hence are rich in detrital zircon (DZ) whose ages closely reflect the timing of deposition. Consequently, maximum depositional ages (MDA) from DZ geochronology can be employed to resolve the stratigraphy and evolution of CMBs. Herein, we use DZ to revise the internal arch...

The lower Nanaimo Group was deposited in the (forearc) Georgia Basin, Canada and records the basin's initiation and early depositional evolution. Nanaimo Group strata are subdivided into 11 lithostratigraphic units, which are identified based on lithology, paleontology, texture, and position relative to both the basal nonconformity and to each othe...

We utilized titanite U-Pb dating in a segment of the Snowbird Tectonic Zone , NWT, to determine ages of deformation and exhumation.

A possible Mesozoic-Cenozoic trajectory for the North American craton is outlined from latitude changes of the craton derived from a revised apparent polar wander path, and from westward movement of the craton based on the assumption that Africa has been the least mobile continent geographically since the latest Paleozoic. During each of five time...

We present the first detailed structural analysis of the Yukon River shear zone (YRSZ), which forms an important structural break within the Yukon-Tanana terrane of the Northern Cordillera in Yukon (Canada). The YRSZ is a NW-SE–striking shear zone that juxtaposes Mississippian orthogneiss hanging-wall rocks (Simpson Range suite) against pre-Late De...

The Columbia (Nuna) supercontinent existed from approximately 1.9 Ga to 1.3 Ga. Laurentia was part of Columbia, and the western edge of Laurentia (current coordinates) was likely proximal to a large landmass during parts of this interval. Here, we present detrital zircon ages of a Paleoproterozoic sedimentary succession in northern Yukon, Canada, t...

New mapping and sampling in southeastern Northwest Territories (NWT) in the summer of 2015 (GEM2 South Rae project) has resulted in the discovery of a ~300 km long crustal-scale shear zone, herein referred to as the Wholdaia Lake shear zone (WLsz). This report presents detailed SHRIMP (Sensitive High Resolution Ion Microprobe) U-Pb geochronology re...

The pericratonic Yukon-Tanana terrane (YTT) exhibits a complex and enigmatic history of extension, arc magmatism and deformation associated with its separation and re-accretion to the western North American margin by early Mesozoic time. The Yukon River Thrust (YRT) is a suggested compressional ductile shear zone between pre-late Devonian silicicla...

The Paleoproterozoic Wernecke Supergroup of Yukon was deposited when the northwestern margin of Laurentia was undergoing major adjustments related to the assembly of the supercontinent Columbia (Nuna) from 1.75 to 1.60 Ga. U-Pb detrital zircon geochronology coupled with Nd isotope geochemistry and major and trace element geochemistry are used to ch...

The distribution of tectonic superstructure across the Shuswap metamorphic complex of southern British Columbia is explained by east-west– trending corrugations of the Okanagan Valley shear zone detachment. Geological mapping along the southern Okanagan Valley shear zone has identified 100-m-scale to kilometer-scale corrugations parallel to the ext...

Development of amphibolite-facies transposition fabrics in the northern Canadian Cordilleran hinterland occurred diachronously in the Permian-Triassic, Early Jurassic, Middle Jurassic to Early Cretaceous, and Early to mid-Cretaceous. Rocks tectonized in the Permian-Triassic and Early Jurassic were exhumed in the Early Jurassic, while rocks immediat...

The Wernecke Breccia is a set of hydrothermal breccia zones that occur in northern Yukon, Canada. The brecciation has been dated at 1.599 Ga by U-Pb on metasomatic titanite. The host rock is the Wernecke Supergroup, a sedimentary succession deposited on the Laurentian margin between 1.66 and 1.60 Ga. The breccia clasts are dominated by Wernecke Sup...

Mine site characterization often results in the acquisition of geological, geotechnical and hydrogeological data sets that are used in the mine design process but are rarely co-evaluated. For a study site in northern Canada, bivariate and multivariate (hierarchical) statistical techniques are used to evaluate empirical hydraulic conductivity estima...

In situ sensitive high-resolution ion microprobe monazite geochronology and garnet isopleth thermobarometry reveal a previously unrecognized Middle Jurassic to earliest Cretaceous mid-crustal tectono-metamorphic event in the eastern part of the Yukon-Tanana terrane (Finlayson Lake district, southeast Yukon) in the northern Canadian Cordillera. Inte...

Two supercontinents have been proposed for the latter half of the Precambrian: Columbia (or Nuna) from ca. 1.9-1.3 Ga, and Rodinia from ca. 1.1-0.75 Ga. In both supercontinents, Laurentia and Australia are regarded as probable neighbours, although their relative positions are contentious. Here we use detrital zircons ages from unit PR1 of the lower...

The Wernecke igneous clasts consist of blocks of plutonic and volcanic rock that range up to hundreds of metres in size. These clasts occur exclusively within zones of hydrothermal breccia (Wernecke Breccia) which are widespread in central and northern Yukon. The breccia zones are hosted by the Wernecke Supergroup and have been dated by U–Pb titani...

Amphibolite facies metasedimentary schists within the Yukon-Tanana terrane in the northern Canadian Cordillera reveal a two-stage, polymetamorphic garnet growth history. In situ U-Th-Pb Sensitive High Resolution Ion Microprobe dating of monazite provide timing constraints for the late stages of garnet growth, deformation and subsequent decompressio...

Field investigations, including detailed geological and geomorphological mapping have been coupled with stratigraphic and structural studies of the Blais Creek Deep-seated Gravitational Slope Deformations (DsGSD), Monashee Mountains, British Columbia (BC). To reconstruct the DsGSD evolutionary stages and to evaluate its controlling factors, a compl...

The reconstruction of the paleocontinental configuration involving ancestral North America (Laurentia) at the Paleoproterozoic–Mesoproterozoic boundary has been developed in the last 30 years with different scenarios being proposed and different combinations of landmasses assembled together. However, the lack of information for the northwestern sid...

The Okanagan Valley shear zone delineates the SW margin of the Shuswap metamorphic complex, the largest core complex within the North American Cordillera. The Okanagan Valley shear zone is a major Eocene extensional fault zone that facilitated exhumation of the southern Shuswap metamorphic complex during the orogenic collapse of the SE Canadian Cor...

The late Meso or early Neoproterozoic Pinguicula Group, Wernecke Mountains, Yukon, is a siliciclastic and carbonate succession deposited on an angular unconformity developed on the Wernecke Supergroup. The group consists of three units. Unit A consists of a fining-upward conglomerate and sandstone unit overlain by a monotonous siltstone succession....

Terra Nova, 23, 307–313, 2011 New U-Pb zircon dates from gneissic xenoliths in an Early Cambrian lamprophyre point to late Mesoproterozoic metamorphism and magmatism in the crust beneath northern Yukon. The data indicate a previously unrecognized thermal event in Yukon and extend the recognition of widely spaced 1.3–1.0 Ga igneous, metamorphic and...

Thick, deformed and weakly metamorphosed successions of sedimentary rocks deposited during several extensional, basin-forming events between ca. 1.64 Ga and ca. 540 Ma, record Proterozoic tectonism and hydrothermal activity in east-central Yukon. A SHRIMP study of small (20-80 m), complexly zoned zircon grains from 5 xenoliths in an Early Cambrian...

The late Paleoproterozoic history of the Wernecke Basin of northwestern Laurentia was previously thought to involve deposition of a thick clastic-carbonate succession (Wernecke Supergroup), intrusion of small gabbroic to syenitic stocks and dykes at ˜1.71 Ga (Bonnet Plume River Intrusions), deformation and greenschist- grade metamorphism (Racklan O...

The eastward transition from penetrative ductile deformation, metamorphism, and plutonism in the hinterland of the southern Canadian Cordillera to the “thin-skinned” deformation of the foreland represents a significant change in tectonic style and process. The transition is also marked by a zone of structural divergence across which SW vergent hint...

Zircon and monazite from granitic sheets and dikes in the Monashee complex, Canadian Cordillera, were investigated to determine whether igneous crystallization occurred at 1·9 Ga or 50 Ma with 1·9 Ga inherited zircon and monazite. Four of the five samples are weakly deformed to undeformed, despite occurring in a gneiss dome at the structurally deep...

Crustal thickening in excess of 55 km, and high heat flow, suggest that a high-standing plateau region in the Cordilleran hinterland was present in the Late Cretaceous. A low strength middle crust developed beneath the plateau, and parts of this layer were exhumed to upper crustal levels in Late Cretaceous to Eocene time. During Late Cretaceous tim...

In the southern Canadian Cordillera a zone of structural divergence marks the eastward transition from penetrative ductile deformation and metamorphism in the Omineca belt to the more brittle 'thin-skinned' style of deformation typical of the Foreland belt. In the Selkirk Mountains of southern British Columbia, this zone includes a regional-scale s...

Chemical mapping and in situ U–Th–Pb analyses reveal a link between age domains and zones of relative yttrium (Y) depletion or enrichment within monazite crystals and are correlated with metamorphic reactions involving garnet. Conventional, small-fraction isotope dilution thermal ionization mass spectrometry (ID-TIMS) and sensitive high-resolution...

Analogue and computational models principally provide our present understanding of the mechanisms of prograde metamorphism and orogenesis, yet, due to the difficulty of linking prograde age information with the pressure–temperature (P–T) evolution of a rock, these models for the most part remain untested. Here, we describe an approach that allows m...

Monazite is a mineral of choice for dating metamorphism in amphibolite- and granulite-grade metapelites. However, there exist a number of difficulties that complicate the interpretation of monazite geochronological data and prevent its application to many geological problems. The two main obstacles addressed in this contribution are firstly, the mi...

Exhumed middle crustal rocks of the hinterland of the southeastern Canadian Cordillera were deformed and metamorphosed during Mesozoic and Tertiary progressive crustal thickening. High structural levels were transported to the northeast relative to lower levels through a combination of thrusting and ductile non-coaxial flow. Progressive growth of t...

Thesis (Ph.D.)--Carleton University, 2003. Includes bibliographical references.