The Paleoproterozoic upper Gowganda Formation, Whitefish Falls area, Ontario, Canada: subaqueous deposits of a braid delta

1995 ◽  
Vol 32 (2) ◽  
pp. 197-209 ◽  
Author(s):  
R. M. Junnila ◽  
G. M. Young
Keyword(s):  
Sediment Supply ◽  
Coarse Grained ◽  
Fold Belt ◽  
Delta Front ◽  
North Shore ◽  
The North ◽  
Tectonically Active ◽  
Sediment Deformation ◽  
Sand Sheets ◽  
Marine Basin

The upper Gowganda Formation is part of the Paleoproterozoic Huronian Supergroup (ca. 2.5–2.2 Ga) of the north shore of Lake Huron. The upper Gowganda Formation rests with sharp conformable contact on glaciogenic rocks of the lower Gowganda Formation and is gradational with cross-bedded sandstones of the overlying Lorrain Formation. At the southern margin of the Huronian fold belt, in the Whitefish Falls area, the upper Gowganda Formation is 380–750 m thick, and consists of four coarsening-upward cycles from 30 to 300 m in thickness. Each is comprised of the succession (a) laminated argillite deposited from suspension on the prodelta, (b) argillite and cross-laminated sandstone laid down on the delta front by normal fluvial input and flood episodes, (c) fine-to coarse-grained, cross-bedded sandstone formed as distributary-mouth sand sheets influenced by shallow marine processes. Abundant soft-sediment deformation indicates rapid sedimentation and (or) contemporaneous fault-related seismicity. Erosional contacts between cycles resulted from marine reworking as sediment supply diminished. Each coarsening-upward cycle is interpreted as the subaqueous deposits of a braid delta that prograded into a moderately wave-influenced, tectonically active marine basin. In some respects, the succession of the deltaic deposits is comparable to those formed during the postglacial evolution of the Mississippi delta, but it is likely that the fluvial regime at the time of deposition of the Gowganda Formation was dominantly braided.

Relationships between tectonics and sedimentation on the northeastern margin of the Subpyrenean trough during the late Santonian

2005 ◽  
Vol 176 (5) ◽  
pp. 443-455 ◽  
Author(s):  
Michel Bilotte ◽  
Laurent Koess ◽  
Elie-Jean Debroas
Keyword(s):  
Debris Flows ◽  
Major Change ◽  
Sediment Supply ◽  
Coarse Grained ◽  
Fault System ◽  
The South ◽  
Delta Front ◽  
Eastern Area ◽  
The North ◽  
Sedimentary Evolution

Abstract In the eastern part of the Aquitaine Basin and to the south of the Toulouse high, the Subpyrenean trough is a narrow trench oriented N110°E to N130° E. The deposits on the northeastern side of this depression are preserved in the autochthonous Mesozoic cover of the Variscan Mouthoumet Massif, but also in the parautochthonous or allochthonous tectonic units that fringe to the north (Camps – Peyrepertuse slice, fig. 2) the North Pyrenean frontal thrust. From the Middle Cenomanian to the Lower Santonian included (96 to 85 Ma ago), the sedimentation in the Mouthoumet Massif indicates shallow marine carbonate or mixed (carbonate to terrigenous) conditions. The different facies depend mainly on two parameters : the variations of the accommodation space for sedimentation and the location of the numerous rudist buildups. The deposits are first organized in a homoclinal ramp until the Turonian. From the Coniacian up to the early Santonian, drowned platform patterns prevail. During the late Santonian and more precisely around 85 Ma with an other event around 84 Ma, the Mouthoumet Massif and its cover broke up under tectonic stresses. Positive and negative topographies reactivate the Variscan fault system. Platform – slope/basin morphologies substituted the preceeding ramp and drowned platform morphology. Looking to the south and in the direction N120°E, the distal slope received gravitational and turbiditic sediments called the Grès de Labastide (fig. 7). The sediment supply shifted from north to south and from east to west. To the north of this slope, the platform itself broke up into a mosaic of rhomboedric blocks, leading to a graben and horst morphology. Those units are clearly different according to the character of their sedimentary facies, deltaic or reefal (Montagne des Cornes, Calcaires de Camps – Peyrepertuse). The detailed stratigraphic and sedimentologic studies of some of these systems reveal a tectono-sedimentary evolution involving two successive cycles Ss1 (lower Upper Santonian) and Ss2 (Uppermost Santonian). In the western part of the Mouthoumet Massif this cyclic evolution is recorded from south to north, on the Parahou slope, the Rennes-les-Bains graben and the Bugarach horst. The lower cycle Ss1, located on the Rennes-les-Bains graben, is approximatively 85 Ma to 84 Ma in age. It starts with reworked deposits (lowstand systems tract) made up of sometimes several m3 elements derived from former sedimentary deposits (from Turonian up to Lower Santonian) even when the same deposits are in place on the adjacent horsts (e.g. the eastern horst of Bugarach). Those reworked deposits fill the bottom of the graben, principally in the transit zones (debris-flows of the Conglomerat de la Ferrière), or in the Parahou slope (slumps and debris-flows of the Cascade des Mathieux); then the deltaic complex of Rennes-les-Bains covers the older chaotic deposits; the blue marls and the overlying sandy facies (transgressive and highstand systems tracts) related to prodelta and deltafront deposits represent the infilling of the Rennes-les Bains graben. The upper cycle Ss2 developed probably between 84 Ma to 83,5 Ma; its geographical extension overlaps the limits of the lower cycle (e.g. the Bugarach horst), but its sedimentary organisation is still the same including: on the Parahou slope debris-flow and intrabasinal reworking (Conglomérat des Gascous: lowstand systems tract); on the northern platform transgressive and highstand systems tracts, present in the Montagne des Cornes delta where the Marnes bleues de Sougraigne represent the prodelta deposits, and the terrigenous and rudist buildups of the delta front deposits (fig.7). The final infilling results from the spreading from NE to SW, of the (estuarine ? to) fluvial deposits of the Grès d’Alet Formation at around 83 Ma. In the eastern part of the Mouthoumet Massif, sedimentary development is punctuated by tectonic events. Nevertheless, it is possible to identify in some outcrops the main elements of the two tectono-sedimentary cycles. – The cycle Ss1 is partly preserved in the genetic sequence which links the Calcaires de Camps-Peyrepertuse (shelf margin wedge systems tract) and the Marnes du Pla de Sagnes (transgressive systems tract). The cycle Ss2 is only known through different facies of the Grès de Labastide Formation: reworked deposits on the slope; coarse-grained silicoclastic deposits on the transit zones. – In the cycle Ss1 differences appear between the western and the eastern parts of the Mouthoumet massif. When in the western area deltaic conditions prevailed, in the eastern area a shallow carbonate and buildup facies developed. Such differences disappear in the cycle Ss2 by the general establishment of fore slope deltaic deposits. The geodynamic reconstruction resulting from plate kinematics indicates a major change between the early Coniacian (89 Ma) and the Middle Campanian (79 Ma), when the sinistral/divergent motion of Iberia with respect to stable Europe turned to a dextral/convergent movement. The tectono-sedimentary events presented here took place during this period (85 Ma to 83 Ma). The tectono-sedimentary evolution of the subpyrenean trough and the shift of the European and Iberian plates are thought to be intimately linked. The new chronological and geodynamical data proposed herein show that the genesis and the evolution of the subpyrenean sedimentary processes related to the northern Aquitanian margin of the Subpyrenean trough allow to draw some basic conclusions: – the opening of the Subpyrenean trough occurred in two steps, the first around 85 Ma and the second around 84 Ma; – this caused a change in the sedimentary setting with platform environments replacing the earlier ramp geometry; – the Subpyrenean trough formed and evolved under transtensive tectonic conditions; – during the late Santonian two tectono-eustatic sequences marked the former stages of the eastward opening and infilling of this basin; – the diachronous infilling which began here around 83,5 Ma prograded to the western Plantaurel and Petites-Pyrénées area; – no significant northward shifting of the depositional-axis of the Senonian basins occurred; – only a gradual westward shift of the depositional centers, along the subpyrenean direction of the slope area (N110°E to N130°E) was noticed.

scholarly journals Stratigraphy and depositional evolution of the uppermost Oligocene –Miocene succession in western Denmark

2004 ◽  
Vol 51 ◽  
pp. 89-109 ◽  
Author(s):  
Erik Skovbjerg Rasmussen
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Depositional Environments ◽  
Sediment Supply ◽  
Coarse Grained ◽  
Sea Level Changes ◽  
Fluvial Systems ◽  
North East ◽  
The North ◽  
Tectonic Movements

The uppermost Oligocene – Miocene succession in Denmark is subdivided into six depositional sequences. The development of the succession was controlled both by tectonic movements and eustatic sea-level changes. Tectonic movements generated a topography, which influenced the depositional pattern especially during low sea level. This resulted in sediment by-pass on elevated areas and the confinement of fluvial systems to structural lows. Structural highs further created restricted depositional environments behind the highs during low sea level. The structural highs were also the locus for sandy spit deposits during transgression and high sea level. Initially sediment supply was from the north and north-east but shifted within the Middle Miocene to an easterly direction indicating a significant basin reorganisation at this time. Eustatic sea-level changes mainly controlledthe timing of sequence boundary development and the overall architecture of the sequences.Consequently, the most coarse-grained sediments were deposited within the forced regressive wedge systems tract, the lowstand systems tract and the early transgressive systems tract. The most distinct progradation occurred in the Aquitanian (Lower Miocene) and was associated with a cold period in central Europe.The subsequent rise of sea level until the Serravallian (Middle Miocene) resulted in an overall back-stepping stacking pattern of the sequences and in decreasing incision.

The origin and significance of convolute lamination and pseudonodules in an ancient deep-marine turbidite system: From deposition to diagenesis

2020 ◽  
Vol 90 (5) ◽  
pp. 480-493
Author(s):  
Omar N. Al-Mufti ◽  
R. William C. Arnott
Keyword(s):  
Isotope Composition ◽  
Coarse Grained ◽  
Intergranular Porosity ◽  
Carbonate Cement ◽  
Windermere Supergroup ◽  
Basin Floor ◽  
Turbidite System ◽  
Sediment Deformation ◽  
General Transport ◽  
Marine Basin

ABSTRACT Soft-sediment deformation structures, like convolute lamination and pseudonodules, are common in deep-marine turbidites, but details of their origin and timing of formation remain a source of debate. Deep-marine basin-floor deposits of the Neoproterozoic Upper Kaza Group (Windermere Supergroup) crop out superbly in the Castle Creek study area and provide an ideal laboratory to investigate these aspects in convolute-laminated pseudonodules, and also how that deformation influenced later diagenesis. Pseudonodules consist of well-sorted, matrix-poor, upper medium- to coarse-grained, planar-stratified or cross-stratified sandstone that are underlain and overlain by comparatively more poorly sorted, matrix-rich, graded sandstone of similar grain size. Deposition of the stratified pseudonodules is interpreted to have occurred during the same event that deposited the graded sandstone, albeit during a period of general transport bypass, whereby isolated, shallow, seafloor depressions became filled with well-sorted, stratified sand. As stratified sand accumulated the depressions slowly subsided until a critical thickness had built up and exceeded the load-bearing capacity of the substrate composed of graded sand. This destabilized the surface separating the two layers and resulted in the stratified unit foundering, and in some cases becoming completely enveloped by, the upward-displaced lower-density substrate. Surprisingly, despite the deformed macroscopic character of the stratified sediment, primary grain fabric, including intergranular porosity up to 40%, was preserved and influenced early diagenesis, which, owing to dispersed phosphate cement and depleted carbon isotope composition of the pervasive carbonate cement, would have begun very near the sediment–water interface. Importantly also, pseudonodules are common in basin-floor deposits but comparatively rare in continental-slope strata. Expanding flow conditions over the basin floor would have promoted grain settling, and in turn development of a more stably (density) stratified flow structure. Ultimately this resulted in higher local rates of sedimentation on the basin floor and the accumulation of a substrate more prone to later liquidization.

Quaternary sedimentation and marine placers along the North Shore, Gulf of St. Lawrence

1993 ◽  
Vol 30 (3) ◽  
pp. 553-574 ◽  
Author(s):  
Frances J. Hein ◽  
James P. M. Syvitski ◽  
Lynda A. Dredge ◽  
Bernard F. Long
Keyword(s):  
Current System ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Coarse Grained ◽  
Mineral Concentration ◽  
Lawrence Estuary ◽  
North Shore ◽  
The North ◽  
Late Wisconsinan ◽  
Mineral Concentrations

Offshore areas, along the North Shore of the St. Lawrence Estuary, have major lithostratigraphic and seismostratigraphic units that relate to the advance or retreat of the Late Wisconsinan Ice Sheet, subsequent marine transgression or regression, and reworking of postglacial deposits. Glacial diamicton and glaciomarine units (acoustic units 1 and 2) were emplaced between >18 and 14.5 ka, by basal meltout or ice-marginal sedimentation; they reflect ice-proximal sedimentation associated with ice-terminal stillstands. Deep-water muds (acoustic unit 3) represent ice-distal accumulation of glaciomarine sediment from glaciofluvial plumes between 13.5 and 11 ka. After this time exceptionally thick nearshore coarse-grained deltaic and estuarine successions (acoustic unit 4) were deposited. The uppermost postglacial sediment (acoustic unit 5) forms the seabed and reflects a reworking phase concomitant with a lowering sea level and ablating Late Wisconsinan ice sheets.Glacioisostatic rebound, which occurred about 23 ka to the present, uplifted glacial and marine deposits and resulted in extensive reworking and production of modern placers. Heavy-mineral concentrations vary as follows: terrestrial tills, 9–20%; modem storm-berm and delta top deposits, 43–60%; delta slope deposits, 25–55%; and deep (170+ m) offshore sediments, 0–2%. Three stages occurred in marine placer formation: (1) 6700 BP, fluvial discharge was high, and fluvial-dominated deltas were built; marine limit was 30 m asl, with progradation of deltas and delivery of sediments with at most 2% heavy minerals; (2) 5200 BP, fluvial discharge was reduced; marine limit was 15 m asl, deltaic sediments were reworked, increasing heavy mineral concentration to 2–8%; (3) 2800 BP, fluvial input was greatly reduced, waves and tides were more influential, a strong littoral current system developed, causing significant reworking of nearshore sediments, heavy mineral concentrations increased, with values exceeding 20% locally. Mass budget calculations show that the second-cycle reworked sediment (acoustic unit 5) is a potential economic target (1 km3, or 1700 Mt). If 7% (using atomic weights) of this target sediment is ilmenite (FeTiO3). then 27 Mt of titanium may be available.

scholarly journals Stratigraphy of the marine Lower Triassic succession at Kap Stosch, Hold with Hope, North-East Greenland

2017 ◽  
Vol 65 ◽  
pp. 87-123
Author(s):  
Finn Surlyk ◽  
Morten Bjerager ◽  
Stefan Piasecki ◽  
Lars Stemmerik
Keyword(s):  
Arctic Region ◽  
Lower Triassic ◽  
Coarse Grained ◽  
The Arctic ◽  
Delta Front ◽  
East Greenland ◽  
Fine Grained ◽  
North East ◽  
The North ◽  
Shelf Slope

The classical marine uppermost Permian – Lower Triassic succession exposed on the north-east coast of Hold with Hope in East Greenland, south-east of Kap Stosch, is placed in the Wordie Creek Group. A new lithostratigraphic subdivision of the group is proposed here. The group comprises the revised Kap Stosch Formation overlain by the new Godthåb Golf Formation. The Kap Stosch Formation is dominated by alternating fine- and coarse-grained, cliff-forming units that constitute the basis for the erection of eight new members. They are (from below): 1. The Nebalopok Member, uppermost Permian, Hypophiceras triviale ammonoid zone, and lowermost Triassic, lower Griesbachian, Hypophiceras triviale – H. martini ammonoid zones, composed of basinal and base-of-slope siltstones and turbiditic sandstones. 2. The conglomeratic Immaqa Member (H. martini ammonoid zone), consisting of a thick clinoform-bedded unit commonly overlain by horizontally bedded deposits, representing the foreset and topset, respectively, of a Gilbert-type delta. 3. The fine-grained Fiskeplateau Member (H. martini ammonoid zone), composed of siltstones and fine-grained sandstones, representing basinal and delta front deposits. 4. The conglomerate-dominated Knolden Member (H. martini ammonoid zone), comprising a clinoform-bedded unit overlain by horizontally-bedded deposits, representing foreset and topset, respectively, of a Gilbert-type delta. 5. The fine-grained Pyramiden Member, (lower–upper Griesbachian Metophiceras subdemissum, Ophiceras commune and Wordieoceras decipiens ammonoid zones), composed of variegated siltstones and sandstones deposited in proximal basin and slope environments. 6. The Naasut Member (top Griesbachian, probably Wordieoceras decipiens ammonoid zone), dominated by thick structureless coarse-grained sandstones commonly showing clinoform bedding, deposited in slope, base-of-slope and proximal basin environments. 7. The Falkeryg Member (lowermost Dienerian, Bukkenites rosenkrantzi ammonoid zone), comprising thick, commonly pebbly sandstones deposited in shelf, slope and base-of-slope environments. 8. The Vestplateau Member (lower Dienerian, Bukkenites rosenkrantzi ammonoid zone) composed of siltstones and fine-grained sandstones deposited in basinal environments. The overlying Godthåb Golf Formation (Dienerian, Anodontophora breviformis – A. fassaensis bivalve zones) is dominated by shallow marine sandstones with several coarser grained levels. The rich ammonoid faunas of the Wordie Creek Group allow a biostratigraphic zonation which can be correlated with schemes from other parts of the Arctic region. This zonation is complemented with information on palyno, conodont, fish and isotope stratigraphy.

scholarly journals Large-scale coastal and fluvial models constrain the late Holocene evolution of the Ebro Delta

2017 ◽  
Vol 5 (3) ◽  
pp. 585-603 ◽  
Author(s):  
Jaap H. Nienhuis ◽  
Andrew D. Ashton ◽  
Albert J. Kettner ◽  
Liviu Giosan
Keyword(s):  
Late Holocene ◽  
Large Scale ◽  
Environmental Changes ◽  
Drainage Basin ◽  
Wave Climate ◽  
Sediment Supply ◽  
Ebro Delta ◽  
Coarse Grained ◽  
Plan View ◽  
The North

Abstract. The distinctive plan-view shape of the Ebro Delta coast reveals a rich morphologic history. The degree to which the form and depositional history of the Ebro and other deltas represent autogenic (internal) dynamics or allogenic (external) forcing remains a prominent challenge for paleo-environmental reconstructions. Here we use simple coastal and fluvial morphodynamic models to quantify paleo-environmental changes affecting the Ebro Delta over the late Holocene. Our findings show that these models are able to broadly reproduce the Ebro Delta morphology, with simple fluvial and wave climate histories. Based on numerical model experiments and the preserved and modern shape of the Ebro Delta plain, we estimate that a phase of rapid shoreline progradation began approximately 2100 years BP, requiring approximately a doubling in coarse-grained fluvial sediment supply to the delta. River profile simulations suggest that an instantaneous and sustained increase in coarse-grained sediment supply to the delta requires a combined increase in both flood discharge and sediment supply from the drainage basin. The persistence of rapid delta progradation throughout the last 2100 years suggests an anthropogenic control on sediment supply and flood intensity. Using proxy records of the North Atlantic Oscillation, we do not find evidence that changes in wave climate aided this delta expansion. Our findings highlight how scenario-based investigations of deltaic systems using simple models can assist first-order quantitative paleo-environmental reconstructions, elucidating the effects of past human influence and climate change, and allowing a better understanding of the future of deltaic landforms.

Mechanism of Carboniferous-Permian transgression/regression in the east Ordos basin and associated paleoecological variability: Insight from detrital geochronology and palaeontology data

2020 ◽  
Author(s):  
Chao Fu ◽  
Xinghe Yu ◽  
Marc Jolivet ◽  
Shunli Li ◽  
Zixiao Peng ◽  
...  
Keyword(s):  
North China ◽  
Ordos Basin ◽  
Second Order ◽  
Sediment Supply ◽  
Late Carboniferous ◽  
Coarse Grained ◽  
Early Permian ◽  
The South ◽  
The North ◽  
Facies Associations

<p>Developed on the North China Craton, the intra-cratonic Ordos basin contains a complete Paleozoic to Cenozoic sediment record allowing long-term paleo-environmental and climate change investigation. During the Carboniferous-the early Permian period, convergence between the North China block and the paleo-Yangtze plate to the south lead to a general marine regression characterised by a series of second-order transgression/regression cycles diachronous along the eastern margin of the Ordos. However, the detailed mechanisms that induced these cycles, as well as the associated paleoecological changes, are still unknown. In this study, we integrated the description of numerous core samples with electric-log data and 2-D seismic data to reconstruct the sediment facies associations across the first-order regression from the Carboniferous tidal flat depositional system to the early Permian prograding fluvial delta system. δ<sup>18</sup>O, δ<sup>13</sup>C and clay content (w(Illite + Kaolinite)/w(smectite) ratio) stratigraphic variations were then used to reconstruct the paleo-sea level from the late Carboniferous to the early Permian. We conclude that the direction of second-order transgression/regression mainly stroke to the east during the late Carboniferous and switched clockwise towards the north during the early Permian. We suggest that the variability of the second-order cycles, diachronous in space and time was mainly linked to local variations in sediment supply and regional uplift.  Using detrital zircon U-Pb data, major and trace elements content and heavy minerals assemblages (HMA), we estimated the sediment provenance area. The sediment volumes deposited in the basin through time were obtained using 3Dseismic data. During the Carboniferous, the coarse-grained sediments deposited in the eastern Ordos were derived from the uplifting Helan Mountain. By the early Permian, the detrital material became multi-sourced issuing from both the Yinshan range to the north and the Qinling range to the south. During the first stage, regression was controlled by regional uplift, while the sediment supply controlled the second stage. Indeed, based on sediment dispersal volume calculation, we can infer that the sediment supply during the early Permian was more extensive than during the Late Carboniferous – early Permian. We correlate this observation to a more humid climate during the early Permian: multi- paleoecological indexes, including the sporopollenin content and microsomal type assemblage, suggest that glaciation prevailed during the Late Carboniferous – early Permian shallow-marine stage. In contrast, the early Permian alluvial and deltaic series were deposited under a warmer, interglacial climate (Sakmarian). Finally, the typical interglacial coal accumulation pattern occurs earlier than the Pennsylvanian–Permian transition it characterises around the world (Artinskian).</p>

On Riccia marginata and related species (Ricciaceae, Marchantiophyta)

2012 ◽  
Vol 46 ◽  
pp. 298-305 ◽  
Author(s):  
A. D. Potemkin ◽  
T. Ahti
Keyword(s):  
Related Species ◽  
Lake Ladoga ◽  
Leningrad Region ◽  
Sem Images ◽  
North Shore ◽  
The North ◽  
Molecular Studies ◽  
The Future ◽  
The Town

Riccia marginata Lindb. was described by S. O. Lindberg (1877) from the outskirts of the town of Sortavala near the north shore of Lake Ladoga, Republic of Karelia, Russia. The species has been forgotten in most recent liverwort accounts of Europe, including Russia. Lectotypification of R. marginata is provided. R. marginata shares most characters with R. beyrichiana Hampe ex Lehm. It differs from “typical” plants of R. beyrichiana in having smaller spores, with ± distinctly finely areolate to roughly papillose proximal surfaces and a narrower and shorter thallus, as well as in scarcity or absence of marginal hairs. It may represent continental populations of the suboceanic-submediterranean R. beyrichiana, known in Russia from the Leningrad Region and Karelia only. The variability of spore surfaces in R. beyrichiana is discussed and illustrated by SEM images. A comparison with the spores of R. bifurca Hoffm. is provided. The question how distinct R. marginata is from R. beyrichiana needs to be clarified by molecular studies in the future, when adequate material is available. R. marginata is for the time being, provisionally, included in R. beyrichiana.

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