The Sedimentary Structures and Depositional Mechanics of Certain Ordovician Turbidites, Cloridorme Formation, Gaspé Peninsula, Quebec

1975 ◽  
Vol 12 (11) ◽  
pp. 1934-1952 ◽  
Author(s):  
Keith Skipper ◽  
Gerard V. Middleton
Keyword(s):  
Large Scale ◽  
Fine Sand ◽  
Coarse Sand ◽  
Turbidity Currents ◽  
Upstream Migration ◽  
High Concentration ◽  
Sedimentary Structures ◽  
The North ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Turbidites, belonging to the β1, member, Cloridorme Formation, are exposed on the north shore of the Gaspé Peninsula, Quebec. Their structural attitude is such that vertical sections through turbidite beds are exposed on the wave-cut platform and their strike is approximately parallel to the paleocurrent direction, as shown by sole marks on the bases of beds.Certain thick turbidite beds, in a distal position, display a sequence of sedimentary structures which differs from the sequence defined by Bouma. Three broad divisions are recognized: a basal division consists of either limestone or quartz granule to pebble conglomerate (0–4 cm thick) or coarse sand graywacke or calcareous wacke (0–15 cm thick). Basal divisions of calcareous wacke frequently display ripple-lamination, parallel lamination, or upstream-inclined laminae. Where the upstream inclined laminae form a single set, they occur below a sinuous profile (wavelength 40–80 cm, and amplitude 2–5 cm).A second division (0–330 cm thick) consists in most places of spindle- or globular-shaped calcareous nodules scattered in an argillaceous host. In some beds, streaking and lobing of light colored, carbonate bearing material is associated with these nodules. Internal hemi-ellipsoid structures, arranged en echelon and convex towards the base of the bed, are displayed from the second division. The upper division consists of fine grained siltstone and shale.The upstream-inclined laminae in the basal division of calcareous wacke beds are interpreted as being the result of the upstream migration of antidunes. The nodules within the second division developed as 'pseudo-nodules'. The hemi-ellipsoid structures resemble damped, large scale (macroturbulent) eddies associated with the flow of dense grain dispersions.Correlation of these beds has been achieved over a distance of 12 km. Basal divisions of granule and pebble conglomerate persist over this distance and show that coarse particles may be transported by turbidity currents over long distances. The sedimentary structures of the basal divisions of several calcareous wacke beds might be interpreted as the result of either an increase in flow regime downcurrent, or of nonpreservation of structures at up-current localities.The beds were probably deposited from turbidity currents composed largely of mud and fine sand, but containing a zone of coarse grains concentrated near the bed. The basal division was deposited from this lower zone and a period of traction formed rippled, flat, or antidune bed forms. Stratification in the basal division was preserved by the rapid deposition on top of sediment that settled en masse from the subsequent high concentration body of the current. The formation of a succession of 'quick' beds led to the sedimentation of the second division. The flows responsible for the sequence of structures observed and the downcurrent persistence of the beds probably approached closely a state of 'autosuspension'.

The late Wisconsinan olistostrome of the lower Coppermine River valley, Northwest Territories

1986 ◽  
Vol 23 (11) ◽  
pp. 1700-1708 ◽  
Author(s):  
Denis A. St-Onge ◽  
Jean Lajoie
Keyword(s):  
Debris Flows ◽  
Late Quaternary ◽  
Fine Sand ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
River Valley ◽  
Glacial Lake ◽  
The North ◽  
Geologic Record ◽  
Coppermine River

The late Quaternary olistostrome exposed in the lower Coppermine River valley fills a paleovalley that ranges in apparent width from 150 to 400 m and was cut into Precambrian bedrock before the last glaciation. The olistostrome is here named the Sleigh Creek Formation. The coarse fraction of the formation is matrix supported; beds are massive or reversely graded and have sharp, nonerosive contacts. These characteristics suggest deposition of the coarse fraction by debris flows. The olistostrome sequence is bracketed by, and wedged into, a marine rhythmite sequence, which indicates that deposition occurred in a marine environment.About 10 500 years BP glacier ice in the Coronation Gulf lowland dammed the valley to the south, which was occupied by glacial Lake Coppermine. Sediments accumulated in this lake in a 30 m thick, coarsening upward sequence ranging from glaciolacustrine rhythmites of silt and fine sand at the base to coarse sand alluvium, and deltaic gravels at the top. As the Coronation Gulf lowlands became ice free, the Coppermine River reoccupied its former drainage course to the north. The steep south to north gradient and rapid downcutting by the river through the glacial lake sediments produced unstable slope conditions. The resulting debris flows filled a bedrock valley network below the postglacial sea level, forming the diamicton sequence.The interpretation of the Sleigh Creek Formation raises questions concerning silimar diamicton deposits usually defined as "flowtills." More generally, the results of this study indicate that care must be used when attempting paleogeographic reconstructions of "glaciogenic" deposits in marine sequences in any part of the geologic record.

A Virus Disease and Introduced Parasites as Factors Controlling the European Spruce Sawfly, Diprion hercyniae (Htg.), in Central New Brunswick

1957 ◽  
Vol 89 (8) ◽  
pp. 371-378 ◽  
Author(s):  
F. T. Bird ◽  
D. E. Elgee
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
New Hampshire ◽  
Virus Disease ◽  
Spruce Forests ◽  
North Shore ◽  
The North ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula ◽  
St Lawrence River

An outbreak of the European spruce sawfly, Diprion hercyniae (Htg.), was discovered in the Gaspé Peninsula in 1930. By 1938, heavy infestations had developed west of the Gaspé Peninsula in Quebec, throughout New Brunswick and northern Maine, and in parts of Vermont and New Hampshire. Moderate to light infestations occurred through all other parts of the spruce forests of this region and extended from Nova Scotia, to the north shore of the St. Lawrence River, and west to Ontario.

Nematode communities from the North Sea: environmental controls on species diversity and vertical distribution within the sediment

1999 ◽  
Vol 79 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Maaike Steyaert ◽  
Nelia Garner ◽  
Dirk van Gansbeke ◽  
Magda Vincx
Keyword(s):  
Vertical Distribution ◽  
Fine Particles ◽  
Anthropogenic Impacts ◽  
Fine Sand ◽  
Coarse Sand ◽  
Food Sources ◽  
Fine Sediments ◽  
The North ◽  
Environmental Controls ◽  
Belgian Coast

Nematode assemblages were sampled seasonally at three subtidal stations along the Belgian coast. The stations were characterized by muddy sediments (station 115), fine sand (station 702) and fine to coarse sand (station 790). The forces structuring vertical distribution were investigated by evaluating abundance, species composition, diversity and trophic composition, and relating these to sediment composition, redox state and food sources.The nematode assemblages at the two finer grained stations (115, 702) were dominated by Daptonema tenuispiculum and Sabatieria punctata. For both species, the vertical distribution in the sediment seemed not dependent on the redoxchemistry, as former believed for S. punctata, but primarily influenced by food availability. This feature could also be recognized for Ixonema sordidum and Viscosia langrunensis, the most abundant nematodes at the coarse sandy station (790).In general, nematode diversity was regulated primarily by sediment granulometry. Coarser sediments (station 790) yielded more diverse communities compared to the fine sediments (station 115, 702), however seasonal fluctuations and variations with depth into the sediment were not obvious. At the silty stations, when the sediment column was more oxidized in March, overall diversity was higher and showed a positive relationship to the mud content which varied with depth into the sediment. This positive relation is probably explained by an enhanced deposition of organic matter associated with the accumulation of fine particles near the river-mouths. Furthermore, the higher abundance, the lower diversity and the higher dominance found at the two silty stations of the eastern and the western part of the Belgian coast, pointed to a stressed, organically enriched environment.The results demonstrate that controls on nematode community structure are complex and that information at both species and community level are required to properly evaluate the effects of natural and anthropogenic impacts.

scholarly journals Run-up, inundation, and sediment characteristics of the 22 December 2018 Sunda Strait tsunami, Indonesia

2020 ◽  
Vol 20 (4) ◽  
pp. 933-946 ◽  
Author(s):  
Wahyu Widiyanto ◽  
Shih-Chun Hsiao ◽  
Wei-Bo Chen ◽  
Purwanto B. Santoso ◽  
Rudy T. Imananta ◽  
...  
Keyword(s):  
Average Distance ◽  
Fine Sand ◽  
Coarse Sand ◽  
Sediment Characteristics ◽  
Sediment Samples ◽  
The North ◽  
Sediment Deposits ◽  
Run Up ◽  
Tsunami Run Up ◽  
Krakatau Volcano

Abstract. A tsunami caused by a flank collapse of the southwest part of the Anak Krakatau volcano occurred on 22 December 2018. The tsunami affected the coastal areas located at the edge of the Sunda Strait, Indonesia. To gain an understanding of the tsunami event, field surveys were conducted a month after the incident. The surveys included measurements of run-up height, inundation distance, tsunami direction, and sediment characteristics at 20 selected sites. The survey results revealed that the run-up height reached 9.2 m in Tanjungjaya and an inundation distance of 286.8 m was found at Cagar Alam, part of Ujung Kulon National Park. The tsunami propagated radially from Anak Krakatau and reached the coastal zone with a direction between 25 and 350∘ from the north. Sediment samples were collected at 27 points in tsunami deposits with a sediment thickness of 1.5–12.7 cm. The average distance from the coast of the area with significant sediment deposits and the deposit limit are 45 % and 73 % of the inundation distance, respectively. Sand sheets were sporadic, highly variable, and highly influenced by topography. Grain sizes in the deposit area were finer than those at their sources. The sizes ranged from fine sand to boulders, with medium sand and coarse sand being dominant. All sediment samples had a well-sorted distribution. An assessment of the boulder movements indicates that the tsunami run-up had minimum velocities of 4.0–4.5 m s−1.

scholarly journals Emergy-Based Sustainability Analysis of an Ecologically Integrated Model with Maize Planting for Silage and Pig-Raising in the North China Plain

2019 ◽  
Vol 11 (22) ◽  
pp. 6485 ◽  
Author(s):  
Lyu Yun ◽  
Jing Li ◽  
Ruixing Hou ◽  
Zhigang Sun ◽  
Peifei Cong ◽  
...  
Keyword(s):  
Large Scale ◽  
North China Plain ◽  
Economic Benefits ◽  
Maize Silage ◽  
High Concentration ◽  
Economic Profit ◽  
Environmental Consequences ◽  
The North ◽  
Loading Ratio ◽  
Emergy Value

The structure of the pig-raising sector in China is changing towards large-scale and intensive systems or ecological pig-raising systems (EPRSs). To choose the best EPRS with high economic benefits and with low environmental consequences, this study combined economic analysis and emergy analysis methods to evaluate several EPRSs. Having a large percentage of maize silage in the feed (max 40%) to replace some maize increased the economic benefit and sustainability of the EPRS and decreased the pressure on the environment. The raising system that consisted of Tuhe black pigs fed feed containing maize silage (EPRS C) performed especially well. The yield-based economic profit and area-based economic profit of EPRS C increased by 37%–54% and 3%–17%, respectively, compared to those of the three-breed crossbred pig-raising systems with or without maize silage added to the feed (EPRS A and EPRS B). Its unit emergy value and emergy loading ratio were 9–22% and 10–15% lower, respectively, than those of EPRS A and EPRS B. Furthermore, its emergy yield ratio and emergy sustainability index were about 2% and 14%–19% higher, respectively, than those of EPRS A and EPRS B. To some extent, the results from EPRS C give some guidelines on improving the performance of the ecological pig-raising sector in China. Moreover, using a high concentration of maize silage in the feed and an optimal local pig type may be beneficial for the sustainability of the ecological pig-raising sector in China.

scholarly journals Sediment transfer in the Rhône River Basin, Switzerland: the role of localized severe Alpine storm events on triggering turbidity currents in Lake Geneva

2021 ◽  
Author(s):  
François Mettra ◽  
Koen Blanckaert ◽  
Ulrich Lemmin ◽  
David Andrew Barry
Keyword(s):  
Large Scale ◽  
River Mouth ◽  
Sediment Concentration ◽  
Turbidity Currents ◽  
Storm Events ◽  
Lake Geneva ◽  
High Concentration ◽  
Low Velocity ◽  
Sediment Transfer

<p>In Lake Geneva, a deep peri-Alpine lake in Switzerland, the sublacustrine Rhône River delta presents a deep canyon, the Rhône Canyon. Previous studies and recent observations show that low-velocity underflows and high-velocity turbidity currents pass frequently in the Rhône Canyon. The former carry little sediment, are long-lasting, slow moving and typically occur in winter when the lake is destratified, whereas the latter are sediment-rich, short-lived and occasionally generate high velocities. In the present study, we revisit three different event types that can trigger turbidity currents in the Rhône Canyon: large-scale floods of the Rhône River, sublacustrine slides on the Rhône delta and short high concentration sediment transport events induced by localized severe storms in the Rhône watershed (~5500 km<sup>2</sup>). Simultaneous observations of hyperconcentrated sediment-laden floods or debris flows in small sub-catchments (as small as 4 km<sup>2</sup>), suspended sediment concentration at the Rhône river mouth, and velocity profiles in the Rhône canyon demonstrate how localized storm events trigger turbidity currents in the canyon. Evidence that these turbidity currents can continue into the deep hypolimnion of Lake Geneva is provided. Preliminary estimations of the frequency of turbidity currents relative to their type of triggering and their contribution to the total sediment load discharged into Lake Geneva are discussed.</p>

The relative influence of Laurentide and local ice sheets during the last glacial maximum in the eastern Chic-Chocs Range, northern Gaspé Peninsula, Quebec

2007 ◽  
Vol 44 (11) ◽  
pp. 1603-1625 ◽  
Author(s):  
Pawel Olejczyk ◽  
James T Gray
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Ice Caps ◽  
Ice Cap ◽  
The North ◽  
Gaspe Peninsula ◽  
The Last Glacial Maximum ◽  
Gaspé Peninsula ◽  
The Last Glacial

Geochemical signatures, erratic dispersal, and striae indicate glacial flows in the north-central Gaspé Peninsula exclusively from Appalachian sources, except for the coastal fringe. During the last glacial maximum (LGM), ice from the Monts McGerrigle flowed northward and northwestward over the summits of the eastern Chic-Chocs Range and the coastal plateau to the Gulf of St. Lawrence. Lesser flows also occurred to the north from Mont Albert and the western Chic-Chocs Range. Where intersecting striae were noted, the older flows are associated with a locally developed ice cap. The rare occurrences of striae and erratics, and morphometric and lithological characteristics of summit diamictons, imply limited basal erosion by both local and regional ice caps. This is postulated to result from early protection of rock surfaces by the initial buildup of thin, frozen-based ice in the eastern Chic-Chocs Range. A compact till mantle in the cols and on the coastal plateau and striae parallel to col directions indicate a downslope transition to wet-based ice. Occasional gneiss boulders above the marine limit between Cap-Chat and Sainte-Anne-des-Monts indicate a slight onlap of the Laurentide Ice Sheet (LIS), but the latter was excluded from the interior of the peninsula east of Cap-Chat. Whole-rock geochemistry from three granitoid erratics on Chic-Chocs summits and one in the York River basin indicates a local Devonian rather than a Precambrian Canadian Shield source. The absence of southward downwarping of synchronous postglacial marine limits across the Gaspé Peninsula corroborates this view for the LGM.

A field-scale laboratory to study particulate transport from river source to marine sink: Bute Inlet (Canada)

2021 ◽  
Author(s):  
Sophie Hage ◽  
Sanem Acikalin ◽  
Lewis Bailey ◽  
Matthieu Cartigny ◽  
Michael Clare ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Large Scale ◽  
Sediment Cores ◽  
Past Research ◽  
Transport Processes ◽  
Small Scale ◽  
Turbidity Currents ◽  
Upstream Migration ◽  
Submarine Channel ◽  
The Impact

<p>It is often assumed that particles produced on land (e.g., sediment, pollutants and organic matter) are transported through watersheds to a terminal sediment sink at the seashore. However, terrestrial particles can continue their journey offshore via submarine channels, accumulating in abyssal plains of the oceans. Offshore sediment transport processes are key controls on the burial of organic carbon and the distribution of benthic food, yet they are challenging to study due to the difficulty of capturing usually short duration events within large-scale systems at great ocean depths. Fjords are sufficiently small scale to enable their submarine channel systems to be studied from river source to terminal sink on seafloor fans. Bute Inlet is an up to 650 m deep fjord in British Columbia, Canada. The Homathko and Southgate rivers both feed Bute Inlet with freshwater and terrestrial sediment. A large landslide occurred on 28<sup>th</sup> November 2020, which caused a Glacial-Lake Outburst Flood (GLOF) which breached a moraine-dam and transported huge volumes of material through the Southgate valley and into Bute Inlet. The impact of this recent event on the submarine system in Bute is, for now, poorly constrained but ongoing work is exploring the impact of this major event on the Inlet. Bute Inlet is one of the most studied fjords worldwide, with a range of offshore campaigns that have been conducted during the last seventy years, providing an unprecedented background dataset and thus opportunity to explore what impact a large magnitude, low frequency terrestrial event had on the submarine system. This presentation will provide an overview of the past research conducted on the Bute submarine channel system, under more usual river discharge conditions and compare this background context to the recent GLOF event.</p><p>Previous studies have revealed that the floor of the Inlet is characterized by a 40 km long submarine channel formed by submarine avalanches of sediment (turbidity currents) that can be up to 30 m thick and reach velocities of up to 6.5 m/s. Based on time-lapse bathymetric mapping over 10 years, the evolution of this channel is known to be controlled by the fast (100 to 450 m/yr) upstream migration of 5 to 30 m high steps (called knickpoints) in the channel floor. Sediment cores reveal that the channel floor and proximal lobe are dominated by sand and up to 3 % of total organic carbon in the form of young woody debris. Research in Bute Inlet has thus allowed submarine flow processes, seafloor morphology and deposits to be linked in unprecedented detail. Using those past results as a baseline, new data collected after the GLOF will be crucial for testing the impact of high-magnitude catastrophic events on a marine system and the ultimate sink for the terrestrial material. Understanding what impact the GLOF had on the usual seafloor processes has direct implications for the preservation of benthic communities living in the fjord and for the global carbon cycle.</p>

Silurian tabulate coral biostratigraphy and biofacies of northern New Brunswick and the southern Gaspé Peninsula

1990 ◽  
Vol 27 (9) ◽  
pp. 1143-1158 ◽  
Author(s):  
Graham A. Young ◽  
James P. A. Noble
Keyword(s):  
New Brunswick ◽  
Relative Abundance ◽  
Large Scale ◽  
The Other ◽  
Region Analysis ◽  
Abundance Data ◽  
Tabulate Coral ◽  
Gaspe Peninsula ◽  
Tabulate Corals ◽  
Gaspé Peninsula

Diverse Early and Late Silurian tabulate coral faunas occur in the Baie des Chaleurs region. Analysis of relative abundance data of tabulate corals from the Limestone Point and La Vieille formations of northern New Brunswick and the Anse à Pierre-Loiselle, La Vieille, and Gascons formations of the southern Gaspé Peninsula allowed the recognition of three recurrent large-scale biofacies: the Propora–Heliolites, Cystihalysites, and Syringopora biofacies. The Syringopora Biofacies lacks the characteristics that would allow a zonation to be produced, but in each of the other biofacies, two zones are erected. These can be applied throughout the Baie des Chaleurs region and may be used for correlation with other areas having faunal affinities with this region.

scholarly journals Geomorphology of an Exhumed Carboniferous Paleosurface in the Southern Gaspé Peninsula, Québec: Paleoenvironmental and Tectonic Implications

2002 ◽  
Vol 53 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Pierre Jutras ◽  
Jacques Schroeder
Keyword(s):  
Lateral Displacement ◽  
River System ◽  
En Bloc ◽  
Planation Surface ◽  
Passive Margins ◽  
The North ◽  
Rock Formations ◽  
Geomorphic Features ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Abstract Carboniferous sedimentation in the southern Gaspé Peninsula has fossilized a paleosurface which is now gradually being exhumed by erosion. Part of the surface was horizontally cut by a major peneplanation event that took place between 290 Ma (Permian) and 200 Ma (Jurassic). Exhumation of the surface below the peneplanation line must also have started by Jurassic time in response to the en bloc uplift of the evolving Atlantic Ocean's passive margins. Some geomorphic features of the exhumed paleosurface bring clues regarding Carboniferous paleoenvironments and tectonics. A planation surface limited by a scarp, which is leading to a higher planation surface occupied by the same rock formations, is here interpreted as a paleo- wave-cut platform (associated to the Windsor transgression) for it cannot be explained by differential erosion, fault movement or "etchplanation". A series of fault scarps cutting through planation surfaces are interpreted as being the result of post-Acadian fault activity. The preservation of limestone hogbacks on the exhumed paleosurface, which are interpreted as having evolved under an arid climate, is believed to be either related to a pre-Windsor clastic fossilization or to post-Windsor lateral displacement. The tightly embanked river system, which is still currently dissecting the Peninsula's main planation surface, and the karstic systems of both that surface and the exhumed paleosurface, are interpreted as having evolved since Jurassic Time, except for a few cases of river antecedence in the north-central highlands which are interpreted as representing even older river routes.

Sign in / Sign up

Export Citation Format

Share Document