Robert H. Rainbird

Natural Resources Canada | NRCan · Geological Survey of Canada

Mesoproterozoic orogenesis is well established on the western and southern flanks of Laurentia in the well-known Racklan-Forward and Mazatzal Orogens, but its significance within the previously assembled interior of the supercontinent Nuna has not been established. We examine regional isotopic and structural evidence for Mesoproterozoic deformation...

A search for primary evidence of Earth's ancient atmosphere and climate Robert Rainbird, a research scientist working for the Geological Survey of Canada, a division of Natural Resources Canada, looks at the geological evolution of Earth’s ancient atmosphere and climate. What did Earth look like two and a half billion years ago? When did our atmosp...

Geochemical and geochronological data from the Pinguicula Group and unit PR1 of the lower Fifteenmile Group (Yukon, Canada) provide information on sediment provenance and timing of break-up of supercontinent Columbia and seaway development on Laurentia’s northwestern margin. The older unit PR1, in the Coal Creek inlier, has a near-unimodal detrital...

What did Earth look like between one billion and two-and-a-half billion years ago? When did our atmosphere and oceans become oxygen-rich? Did oxygenation occur rapidly or during slow oscillations over hundreds of millions of years? These questions have been debated by scientists for decades because of their implications for the evolution of early l...

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth's thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Frankli...

The Amer Belt, hosting eleven informal formations of the Amer supergroup, is proposed as type area for four regional Paleoproterozoic sequences (Ps1–Ps4) in central Rae Craton, western Churchill Province. The ca. 1.9–1.865 Ga Snowbird orogeny (DP1) affected only Ps1–Ps3, whereas the ca. 1.87–1.81 Ga Hudsonian orogeny (DP2) affected all four. Sequen...

The ∼1.75 to 1.27 Ga Hornby Bay intracontinental basin, exposed in northwestern Canada, northeast of Great Bear Lake, includes the Big Bear, Mountain Lake and Dismal Lakes groups. The Big Bear group comprises mainly immature clastic rocks deposited by high-energy rivers in restricted fault-bounded basins formed during the late-stage assembly of sup...

The Mesoproterozoic Husky Creek Formation is an interlayered redbed and basalt package that overlies a ca. 2.5 km thick, regionally extensive basaltic plateau linked to the 1.27 Ga Mackenzie Large Igneous Province. This succession provides an opportunity to study the interaction between contemporaneous fluvial sedimentation and flood basalt volcani...

Isopachs of Huronian strata of the Elliot and Hough Lake groups in the southern part of the Cobalt Basin can be used to define the geometry of a 4 km wide valley system that directly influenced the location of gravel-bed rivers bearing detrital gold and auriferous pyrite in the Mississagi Formation. Distribution and thickness of these and underlyin...

Significance Earth’s transition from anoxic oceans and atmosphere to a well-oxygenated state led to major changes in nearly every surficial system. However, estimates of surface oxygen levels in the billion years preceding this shift span two orders of magnitude, suggesting a poor understanding of the evolution of the oxygen cycle. We use the isoto...

Grant Young worked extensively on the Paleoproterozoic (ca. 2.45 to 2.22 Ga) Huron(ian) Supergroup, including detailed sedimentological research on both glacial (Coleman member) and non-glacial, deltaic (Firstbrook member) sedimentary rocks of the Gowganda Formation. The outcrop distribution of the Gowganda Fm. and conformably overlying fluvial str...

Tuktut Nogait is a national park located near the western Arctic coast, just east of the hamlet of Paulatuk in the Northwest Territories, Canada. This book features beautiful landscape photographs taken mainly from a helicopter during the summers of 2014 and 2015, when a Geological Survey of Canada field mapping party, led by Robert Rainbird, was c...

The Mesoproterozoic is an important era for the development of eukaryotic organisms in oceans. The earliest unambiguous eukaryotic microfossils are reported in late Paleoproterozoic shales from China and Australia. During the Mesoproterozoic, eukaryotes diversified in taxonomy, metabolism, and ecology, with the advent of eukaryotic photosynthesis,...

Here we present Re-Os geochronological data from two carbonaceous shale units from the Hornby Bay and Amundsen basins that provide important chronological markers for Mesoproterozoic stratigraphic successions within northern Canada. Shale from the basal Escape Rapids Formation yields a robust depositional age of 1067.3 ± 13.5 Ma for the lowermost S...

Carbonate successions older than the 800 Ma Bitter Springs isotope anomaly are sparse and this time is consequently poorly understood. The Shaler and Mackenzie Mountains supergroups of northwestern Canada, however, contain thick ca. 1050-750 Ma carbonate successions recording both deep- and shallow-water depositional environments that are interpret...

1:250,000 Bedrock Geology Map

1:250,000 Bedrock geology map

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Fungi are crucial components of modern ecosystems. They may have had an important role in the colonization of land by eukaryotes, and in the appearance and success of land plants and metazoans1–3. Nevertheless, fossils that can unambiguously be identified as fungi are absent from the fossil record until the middle of the Palaeozoic era4,5. Here we...

The Proterozoic Eon spans Earth's middle age during which many important transitions occurred. These transitions include the oxygenation of the atmosphere, emergence of eukaryotic organisms and growth of continents. Since the sulfur and oxygen cycles are intricately linked to most surface biogeochemical processes, these transitions should be record...

We utilized a novel approach to modeling the oceanic sulfur cycle by combining δ ³⁴ S and Δ ³³ S curves from sulfate evaporite minerals in order to investigate redox conditions during the mid-Neoproterozoic. This technique allowed us to estimate the oxidized and reduced proportions of the total oceanic sulfur sink. Isotopic data from the mid-Neopro...

A new, 1:550 000-scale bedrock geological compilation map of the central Rae Craton and eastern Queen Maud Block is presented that covers parts of northern mainland Nunavut and Southampton Island. The accompanying map information document (and accompanying Excel files) provides an overview of the bedrock geology and contains abridged compilations o...

The diversification of acritarchs (organic-walled vesicular microfossils of unknown affinity), filamentous, and multicellular microorganisms, happened during a time of profound environmental, biological, and ecological change. The Mesoproterozoic to Neoproterozoic transition is a key interval, notably for eukaryotic organisms. New assemblages of or...

Lacking evidence for fluvial lateral‐accretion elements in early Palaeozoic systems has been ascribed to an absence of binding by rooted vegetation on subaerial landscapes. Transposing this thesis to earlier geological times, it has been proposed that, likewise, Precambrian landscapes could not have sustained highly sinuous fluvial networks. This p...

Fluvial floodplains established prior to the greening of continents have long been overlooked, despite their relevance for landscape reconstructions in deep time. The record of fluvial overbank sedimentation dates back as far as the Mesoarchean, and mature assemblages of floodplain landforms had already developed at least by the early Palaeoprotero...

The Ottawa graben is a Neoproterozoic intracratonic rift in northeastern North America that was reactivated throughout the Phanerozoic and persists as a modern seismically active zone of lithospheric weakness with extant topography. U-Pb geochronology of detrital zircon grains, paleoflow directions, and stratigraphic data from the Potsdam Group pro...

Although the geological record indicates that eukaryotes evolved by 1.9–1.4 Ga, their early evolution is poorly resolved taxonomically and chronologically. The fossil red alga Bangiomorpha pubescens is the only recognized crown-group eukaryote older than ca. 0.8 Ga and marks the earliest known expression of extant forms of multicellularity and euka...

The Neoproterozoic Bitter Springs Anomaly (BSA; 810-800 Ma) is characterised by an 8 ‰ negative δ¹³C excursion and is coeval with multiple indicators of increasing oxygenation of the ocean and atmosphere. Here, we use carbonate iodine contents to provide the first constraints on the evolution of local upper ocean redox conditions spanning the BSA....

We present detrital zircon U-Pb data from mainly fluvial sandstones of the Mackenzie Mountains Supergroup, Yukon (four samples), and the Shaler Supergroup, Northwest Territories (seven samples). The high similarity of data sets from widely separated units supports long-held stratigraphic correlations between the late Mesoproterozoic Neoproterozoic...

Proterozoic rivers flowed through barren landscapes, and lacked interactions with macroscopic organisms. It is widely held that, in the absence of vegetation, fluvial systems featured barely entrenched channels that promptly widened over floodplains during floods. This hypothesis has never been tested because of an enduring lack of Precambrian fluv...

Supplementary Figures

Geometric data for the Proterozoic channel forms analysed in this study.

Geometric data, compiled from literature, for the Ordovician-Pleistocene channel forms analysed in this study.

Geometric data, compiled from literature, for the modern perennial river cross-sections analysed in this study.

We present the results of helicopter-and field-based geological mapping of Elu Inlet and Melville Sound, Kitikmeot Region of Nunavut, Arctic Canada. The area includes a ∼150 km-wide belt of Proterozoic sedimentary rocks that unconformably overlie the Archean Slave Province of the Canadian Shield and are cross-cut by Neoproterozoic mafic rocks and c...

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...

Spectacular canyon exposures of the ~ 1 Ga Nelson Head Formation along the modern Brock River, Northwest Territories, provide a rare opportunity to assess the deposits of pre-vegetation, braided to sinuous channelized fluvial systems. We analyze the sedimentology, architecture, and depositional evolution of 16 stacked fluvial-channel belts at this...

Our understanding of the onset and evolution of flood basalt volcanism is rooted in the study of the character and internal architecture of its eruptive products. Neoproterozoic continental flood basalts of the ca. 720 Ma Franklin magmatic event are preserved as the Natkusiak Formation and are exposed within the Minto Inlier on Victoria Island, Nor...

This paper challenges the conventional interpretation of a major, economically important Mesoproterozoic intracratonic rift system as a group of aulacogens, proposing instead that they are rifts that developed in response to far-field stress caused by continent–continent collision (impactogens) during supercontinent assembly. The tectonostratigraph...

The Mesoproterozoic Pinguicula Group (<1.38 Ga) is exposed in the Wernecke and Hart River inliers in northern Yukon, Canada. The Pinguicula Group records deposition of non-cyclic siliciclastic and carbonate strata on low-energy slopes affected by rare high-energy deposits in a tectonically active epicratonic setting. The succession is ∼1.4 km thick...

The repetitive sedimentology of many Precambrian sheet-dominated fluvial sandstones favoured their attribution to unconfined depositional processes. This article presents outcrop evidence for deep channelled drainage in the 1.9 Ga Burnside River Formation of Kilohigok Basin, Arctic Canada. On the ground, sheet-like sandbodies with ubiquitous cross-...

Elu Inlet and Tariyunnuaq (Melville Sound) are located in the Kitikmeot Region of Nunavut (Canada), and are underlain by a succession of Paleo- to Mesoproterozoic sedimentary rocks known as the Elu and Kilohigok basins. This paper focuses on the stratigraphy and gamma-ray spectrometry of the northeastern margin of the Kilohigok Basin, which is expo...

Geoscience Map 103, 1:50,000. Geologic Survey of Canada. Natural Resources Canada. Ottawa.

Intracontinental basins that lack obvious compartmentalization and extensional faults may lie inboard of, and have the same timing as, rifted continental margins. Neoproterozoic successions of northwest Laurentia are an example where rift and intracontinental basins are spatially and temporally related. This study describes Tonian-Cryogenian pre-ri...

The Upper Proterozoic sequence in the southern part of the East Anabar Basin, as throughout the entire framing of the Anabar uplift, has a two-unit terrigenous-carbonate structure. The results of the U-Pb dating of detrital zircons show that there is a difference in stratigraphy of Riphean strata in the north and south of the Anabar Uplift. In the...

Precambrian fluvial deposits have been traditionally described as architecturally simple, forming shallow and wide braidplains with sheet-like geometry. The varied architecture and morphodynamics of the 1.6 Ga Ellice Formation of Elu Basin, Nunavut, Canada, are examined from detailed studies of section and planform exposures along coastal platforms...

This work was part of the Geo-mapping for Energy and Minerals (GEM) Program in the Elu Basin area. It is being co-led by the Geological Survey of Canada (GSC) and the Canada-Nunavut Geoscience Office. The study area comprises National Topographic System map area 77A. The objective of this work is to improve the sedimentological framework within the...

This work was part of the Geo-mapping for Energy and Minerals (GEM) Program in the Elu Basin area. It is being co-led by the Geological Survey of Canada (GSC) and the Canada-Nunavut Geoscience Office. The study area comprises National Topographic System map area 77A. The objective of this work is to improve the sedimentological framework within the...

A new δ13Ccarb curve combined with δ13Corg values is presented for the upper Shaler Supergroup (∼900 to ∼720 Ma), Amundsen Basin, northwestern Canada. The dataset fills gaps in the existing stratigraphic record and makes correlations with adjacent basins more robust. There is a pronounced negative δ13C excursion in the Wynniatt Formation that can b...

The Geological Survey of Canada, under the Remote Predictive Mapping project of the Geo-mapping for Energy and Minerals program, Natural Resources Canada, has the mandate to produce up-to-date geoscience maps of Canada’s territory north of latitude 60°. Over the past three decades, the increased availability of space-borne sensors imaging the Earth...

The early Proterozoic Era between 2.45 and 2.2 Ga is well known for a distinct minima in juvenile magmatism and detrital zircon abundance, an intriguing observation given its coincidence with many fundamental changes in Earth processes. A recent hypothesis seeks to explain this Siderian ‘Quiet Interval’ as the result of a plate tectonic shutdown in...

The oxygenation of Earth’s surface fundamentally altered global biogeochemical cycles and ultimately paved the way for the rise of metazoans at the end of the Proterozoic. However, current estimates for atmospheric oxygen (O2) levels during the billion years leading up to this time vary widely. On the basis of chromium (Cr) isotope data from a suit...

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...

Gabbroic sills of the widespread, ca. 720 Ma Franklin large igneous event intruded sedimentary strata of the Neoproterozoic Shaler Supergroup exposed in the Minto Inlier on Victoria Island in the western Arctic. The mafic magmatism occurred during breakup of the supercontinent Rodinia and preceded Sturtian glaciation. Calc-silicate metamorphic reac...

Annual Report Yukon Exploration and Geology 2013

The Archean nucleus of Laurentia, the Superior province, formed between 2.7 and 2.6 Ga. There is little record of sediment deposition on the craton for 100 m.yr. until deposition of the Huronian clastic sedimentary rocks (4–12 km thick) began along the south-central margin of the Superior province between 2.5 and 2.2 Ga. Huronian detrital zircon ag...

Abstract New Re–Os ages from black shales of the Neoproterozoic Shaler Supergroup from the Minto Inlier, Victoria Island, Arctic Canada, constrain the late Tonian to early Cryogenian depositional history of the Amundsen Basin. The Re–Os ages of 761 ± 41 Ma and 848 ± 49 Ma for the Wynniatt Fm., and 892 ± 13 Ma for the Boot Inlet Fm., along with rece...

Late Paleoproterozoic basins of Canada's north, including the Thelon, Athabasca, and Hornby Bay basins, can be broadly correlated based on similarities in age, sequence stratigraphy, paleocurrents, and detrital zircon provenance, but their detailed evolution is poorly understood and their age and lateral equivalencies are poorly constrained. This s...

A variety of early Paleoproterozoic supercontinents or supercratons have been proposed, including Kenorland, Superia and Vaalbara. Improved geologic knowledge of the Churchill Province, Canadian shield, suggests that the classical Kenorland configuration, with linked Rae and Hearne cratons, is invalid and represents a younger ca. 1.9 Ga Nuna config...

Regional geological mapping of the glaciated surface of northwestern Victoria Island in the western Canadian Arctic revealed an anomalous structure in otherwise flat-lying Neoproterozoic and lower Paleozoic carbonate rocks, located south of Richard Collinson Inlet. The feature is roughly circular in plan view, approximately 25 km in diameter, and c...

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...

Supervised classification (robust classification method) of Landsat-7 and SPOT-5 data was used to analyse the bedrock geology of a part of the western Minto Inlier on Victoria Island, Canada. The robust classification method was used as it provides a series of uncertainty measures for evaluating the classification results. Six bedrock classes inclu...

The Neoproterozoic Franklin large igneous province on Victoria Island, Canada, is characterized by continental flood basalts and a sill-dominated feeder system. Field relationships indicate that fault-guided transfer zones allowed magma to jump up-section to form higher-level intrusions. Where sills connect to dikes and magmas moved up-section, roo...

The Torridonian succession in NW Scotland is a well-exposed sequence of sedimentary rocks that record the early Neoproterozoic geological evolution of Laurentia. An excellent review by Stewart (2002) summarised the observations on the three main 'Torridonian' units: the Stoer, Sleat and Torridon groups. The Torridon Group, deposited between 1000 –...

One of Earth's greatest mountain-building episodes, the Grenvillian orogeny, occurred with the assembly of the supercontinent Rodinia at the end of the Mesoproterozoic era, about 1.2-1.0 billion years ago. Weathering and erosion of the Grenvillian mountain chain, the roots of which can be traced today for nearly 12,000 km, produced huge volumes of...

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....