Shallow faults, Upper Cretaceous clinoforms, and the Colonsay Collapse, Saskatchewan

2006 ◽  
Vol 43 (12) ◽  
pp. 1859-1875 ◽  
Author(s):  
Don Gendzwill ◽  
Mel Stauffer
Keyword(s):  
Upper Cretaceous ◽  
Late Glacial ◽  
Open Pit ◽  
Normal Faults ◽  
Reflection Seismic ◽  
Horizontal Length ◽  
Vertical Displacements ◽  
Two Stages ◽  
Seismic Reflections ◽  
Glacial Time

Reflection seismic data in the vicinity of the Colonsay potash mine near Saskatoon, Saskatchewan, reveal numerous shallow normal faults with vertical displacements of as much as 25 m. The faults cut the glacial deposits and Upper Cretaceous rocks to a maximum depth of about 400 m. Horizontal length ranges from a few hundred to a few thousand metres. Similar faults are also exposed in several widely separated open-pit coal mines of southern Saskatchewan and may be common elsewhere in the prairies. Such faulting is considered to be a result of Tertiary to Quaternary extensional tectonics and may have been aided in this region by the melting of gas hydrates. The study area includes the east flank of the Colonsay Collapse, a subsidence structure caused by dissolution and removal of salt in the 200 m thick Devonian Prairie Evaporite Formation. Salt was removed in two stages prior to or during early glacial time and in late-glacial time. Subsidence was gradual, with no observable faulting. A complex of clinoform structures about 120 m thick and prograding east-northeast occurs in the Upper Cretaceous Lea Park Formation in the study area and may correlate to the Alderson Member of southern Saskatchewan. Strong seismic reflections within the complex could be due to gas-filled porosity. Where undermined by salt removal in the Colonsay Collapse, the clinoform structures now form drape antiforms.

scholarly journals XIX.—The Bone-Cave in the Valley of Allt nan Uamh (Burn of the Caves), near Inchnadamff, Assynt, Sutherlandshire

1918 ◽  
Vol 37 ◽  
pp. 327-349 ◽  
Author(s):  
B. N. Peach ◽  
J. Horne ◽  
E. T. Newton
Keyword(s):  
Characteristic Feature ◽  
Late Glacial ◽  
Early History ◽  
The Arctic ◽  
Geological History ◽  
Collateral Evidence ◽  
History Of ◽  
Glacial Time

A characteristic feature of the plateau of Cambrian Limestone in the neighbourhood of Inchnadamff is the occurrence in it of swallow-holes, caves, and subterranean channels which are intimately associated with the geological history of the region. The valley of Allt nan Uamh (Burn of the Caves), locally known as the Coldstream Burn, furnishes striking examples of these phenomena. One of the caves in this valley yielded an interesting succession of deposits, from which were collected abundant remains of mammals and birds. The discovery of bones of the Northern Lynx, the Arctic Lemming, and the Northern Vole among these relics, and the collateral evidence of the materials forming some of these layers, seem to link the early history of this bone-cave with late glacial time, or at least with a period before the final disappearance of local glaciers in that region.

Tectonique synsedimentaire d'age cretace superieur en Tunisie nord orientale; blocs bascules et reorganisation des aires de subsidence

2000 ◽  
Vol 171 (4) ◽  
pp. 431-440 ◽  
Author(s):  
Lahcen Boutib ◽  
Fetheddine Melki ◽  
Fouad Zargouni
Keyword(s):  
Structural Analysis ◽  
Upper Cretaceous ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Half Graben ◽  
Combined Movements ◽  
Basin Floor ◽  
Tunisian Atlas ◽  
Facies Variation ◽  
Regional Tectonics

Abstract Structural analysis of late Cretaceous sequences from the northeastern Tunisian Atlas, led to conclude on an active basin floor instability. Regional tectonics resulted in tilted blocks with a subsidence reorganization, since the Campanian time. These structural movements are controlled both by N140 and N100-120 trending faults. The Turonian-Coniacian and Santonian sequences display lateral thickness and facies variation, due to tectonic activity at that time. During Campanian-Maastrichtian, a reorganization of the main subsidence areas occurred, the early Senonian basins, have been sealed and closed and new half graben basins developed on area which constituted previously palaeohigh structures. These syndepositional deformations are characterized by frequent slumps, synsedimentary tilting materials, sealed normal faults and progressive low angle unconformities. These tilted blocks combined to a subsidence axis migration were induced by a NE-SW trending extensional regime. This extension which affects the Tunisian margin during the Upper Cretaceous, is related to the Tethyan and Mesogean rifting phase which resulted from the combined movements of the African and European plates.

The Origin of Terraces in Buried Valleys in the Northwest of the East European Plain

2021 ◽  
Vol 62 (2) ◽  
pp. 194-206
Author(s):  
N.V. Karpukhina ◽  
S.S. Bricheva ◽  
E.A. Konstantinov ◽  
O.M. Tatarnikov ◽  
A.N. Makkaveev ◽  
...  
Keyword(s):  
Ice Sheet ◽  
East European Plain ◽  
Glacial Erosion ◽  
East European ◽  
Erosion Processes ◽  
Pskov Region ◽  
Object Of Study ◽  
Two Stages ◽  
Glacial Time ◽  
Karst Processes

Abstract —The paper considers the origin of terraces that often complicate the slopes of abnormally deep buried valleys in the northwest of the East European Plain. The Izborsk–Maly valley (Pskov Region, Russia), which is half filled with Quaternary sediments, was chosen as the object of study. Since the upper part of the valley remains unfilled, it is possible to study in detail both geologic and geomorphologic structures of its terraced slopes being of particular interest in the context of the origin of buried valleys and the role of substrate in it. The four denudation-terrace levels that have been identified on the slopes of the Izborsk–Maly valley at absolute elevations of 53, 56–58, 70–72, and 75–77 m formed during the destruction of the preglacial karst landscape under the influence of Pleistocene glaciations. The formation of the terraces was probably linked with several stages of overdeepening of the valley and its expansion by the glacial erosion processes, which corresponded to at least two stages of the ice sheet advance in this area. The last stage may have been the beginning of the Late Valdai (Weichselian) glaciation or the activation of the edge of an ice sheet during its Luga phase (~15.7 cal kyr BP). Results of the study suggest that the Izborsk–Maly valley formed in subglacial conditions. The degree of glacial erosion was determined primarily by the coherence of Devonian carbonate-terrigenous rocks hosting the valley and the degree of the area transformation by karst processes. The cirque shape of slopes is the evidence of karst processes expression in pre-glacial time. Analysis of literature data shows that the origin of denudation terraces in the buried valleys in the northwest of the East European Plain has been paid little attention. The obtained data contribute to the study of this problem and provide insights into the origin of buried valleys.

scholarly journals Aeolian activity during Late Glacial time, with an example from Mongo, Indiana, USA

2019 ◽  
Vol 56 (2) ◽  
pp. 175-182
Author(s):  
Timothy G. Fisher ◽  
Jennifer Horton ◽  
Kenneth Lepper ◽  
Henry Loope
Keyword(s):  
Sand Dunes ◽  
Ice Core ◽  
Late Glacial ◽  
Optically Stimulated Luminescence ◽  
Laurentide Ice Sheet ◽  
Great Lakes Region ◽  
Aeolian Activity ◽  
Minimum Age ◽  
Channel Bottom ◽  
Glacial Time

The last aeolian activity of a significant number of inland sand dunes in the southern Great Lakes region (SGLR) was several thousands of years after deglaciation. At Mongo, Indiana, a field of parabolic sand dunes with a variety of morphologies are within the channel bottom of the Pigeon River meltwater channel, with some dunes having climbed up the channel wall onto the adjacent upland surface. The optically stimulated luminescence (OSL) samples from the channel-bottom dunes have a mean age of 14.2 ± 1.6 ka (n = 2) and the OSL samples from upland dunes have a mean age of 12.3 ± 1.6 ka (n = 4). Dunes and outwash ages and geomorphic setting constrain both the position of the Huron-Erie and Saginaw lobes. The oldest dune age is also a minimum age for cessation of local meltwater flow from the Huron-Erie Lobe of the Laurentide Ice Sheet and formation of the adjacent Sturgis Moraine of the Saginaw Lobe. The final activity of the dunes is coincident with late glacial stadial and interstadial events as recorded in the Greenland ice core records, a similar finding to all other studies of dunes in the SGLR. It is now well recognized that many dunes were last active before, during, and after the Younger Dryas stadial, presumably in response to a climate that was windier and less favorable for vegetation.

scholarly journals Extensional Messinian basins in the Central Mediterranean (Calabria, Italy): new stratigraphic and tectonic insights

2018 ◽  
Vol 73 ◽  
pp. 45 ◽  
Author(s):  
Alfonsa Milia ◽  
Maurizio M. Torrente
Keyword(s):  
Water Environment ◽  
Sedimentary Basins ◽  
Normal Faults ◽  
Seismic Profiles ◽  
Rift Basins ◽  
Central Mediterranean ◽  
Tectonic Events ◽  
Basin Subsidence ◽  
Basement Deformation ◽  
Two Stages

The direction of extension and the architecture of the Messinian basins of the Central Mediterranean region is a controversial issue. By combining original stratigraphic analysis of wells and seismic profiles collected offshore and onshore Calabria, we reassess the tectonic evolution that controlled the sedimentation and basement deformation during Messinian times. Three main deep sedimentary basins in the Calabria area record a Messinian succession formed by two clays/shales-dominated subunits subdivided by a halite-dominated subunit. The correlation with the worldwide recognized stratigraphic features permit to define the chronology of the stratigraphic and tectonic events. Three main rift basins that opened in a N-S direction have been recognized. On the contrary a fourth supradetachment basin opened toward the East. We found that the basin subsidence was controlled by two stages of activity of normal faults and that Messinian rift basins evolve in a deep-water environment. The overall pattern of extensional faults of the Central Mediterranean corresponds to normal faults striking parallel to the trench and normal faults striking at an oblique angle to the trench (Fig. 14). In particular in Campania and Calabria regions are present two rifts parallel to trench and an intervening rift orthogonal to the trench. We maintain that the recognized Messinian rift basins can be interpreted according to the “Double-door saloon tectonics”.

Late Quaternary Vegetation and Climate of Southern Tierra del Fuego

1989 ◽  
Vol 31 (3) ◽  
pp. 396-406 ◽  
Author(s):  
Calvin J. Heusser
Keyword(s):  
Late Quaternary ◽  
Pollen Dispersal ◽  
Late Glacial ◽  
Tierra Del Fuego ◽  
Fossil Pollen ◽  
Radiocarbon Dates ◽  
Modern Pollen ◽  
Open Woodland ◽  
Glacial Time ◽  
Vegetation And Climate

AbstractVegetation and climate over approximately the past 13,000 yr are reconstructed from fossil pollen in a 9.4-m mire section at Caleta Róbalo on Beagle Channel, Isla Navarino (54°56′S, 67°38′W), southern Tierra del Fuego. Fifty surface samples reflecting modern pollen dispersal serve to interpret the record. Chronologically controlled by nine radiocarbon dates, fossil pollen assemblages are: Empetrum-Gramineae-Gunnera-Tubuliflorae (zone 3b, 13,000–11,850 yr B.P.), Gramineae-Empetrum-assorted minor taxa (zone 3a, 11,850-10,000 yr B.P.), Nothofagus-Gramineae-Tubuliflorae-Polypodiaceae (zone 2, 10,000–5000 yr B.P.), Nothofagus-Empetrum (zone 1b, 5000-3000 yr B.P.), and Empetrum-Nothofagus (zone 1a, 3000-0 yr B.P.). Assemblages show tundra under a cold, dry climate (zone 3), followed by open woodland (zone 2), as conditions became warmer and less dry, and later, with greater humidity and lower temperatures, by closed forest and the spread of mires (zone 1). Comparisons drawn with records from Antarctica, New Zealand, Tasmania, and the subantarctic islands demonstrate broadly uniform conditions in the circumpolar Southern Hemisphere. The influences of continental and maritime antarctic air masses were apparently considerable in Tierra del Fuego during cold late-glacial time, whereas Holocene climate was largely regulated by interplay between maritime polar and maritime tropical air.

Delineating the network of brittle structures with geotechnical, structural and reflection seismic data, Kevitsa open pit, northern Finland

GeoResJ ◽  
2017 ◽  
Vol 13 ◽  
pp. 159-174 ◽  
Author(s):  
Teemu Lindqvist ◽  
Pietari Skyttä ◽  
Emilia Koivisto ◽  
Tuulia Häkkinen ◽  
Petteri Somervuori
Keyword(s):  
Seismic Data ◽  
Open Pit ◽  
Reflection Seismic

Late glacial to Recent stratigraphy, paleontology, and sedimentary processes: Newfoundland continental slope and rise

1985 ◽  
Vol 22 (2) ◽  
pp. 266-282 ◽  
Author(s):  
C. T. Schafer ◽  
F. C. Tan ◽  
D. F. Williams ◽  
J. N. Smith
Keyword(s):  
Late Glacial ◽  
Turbidity Current ◽  
Western Boundary ◽  
Sedimentary Processes ◽  
Suspended Particulate ◽  
Labrador Current ◽  
Current Water ◽  
Late Wisconsinan ◽  
Late Glacial And Holocene ◽  
Glacial Time

Micropaleontology, pollen, sediment, and δ18O studies point to considerable variation in sedimentary processes and water-mass characteristics on the northeast Newfoundland slope and rise during late glacial and Holocene time. Allochthonous shelf and upper slope foraminiferal species suggestive of turbidity current activity occur relatively frequently in rise sediments during a postglacial interval, dated by extrapolation from a probable 9300 year old ash horizon. A single late glacial turbidity current deposit involved a much larger volume of sediment than that noted for the earlier events and it appears to have originated primarily on the middle slope. In conjunction with a widespread late glacial interval of fecal pellet deposition, this larger event suggests an increased flux of material in the form of suspended particulate matter to the continental margin following the late Wisconsinan glacial maximum. Oceanographic conditions during late glacial time appear to have stimulated the productivity of zooplankton in the waters off northeastern Newfoundland.Within the late Holocene interval of the rise sediments, there is some micropaleontological and sedimentological evidence for an intensification of the Western Boundary Undercurrent that appears to have started about 1000–2000 years BP. Over the same period of time, the surface water circulation seaward of the northeast Newfoundland shelf appears to have changed from a mode that was dominated occasionally by a northern component of relatively warm North Atlantic drift water to one that is dominated today exclusively by Labrador Current water.

Paleoenvironmental Changes and Glacial Stades of the Last 50,000 Years in the Cordillera Central, Colombia

1996 ◽  
Vol 46 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Jean-Claude Thouret ◽  
Thomas Van der Hammen ◽  
Barry Salomons ◽  
Etienne Juvigné
Keyword(s):  
Late Glacial ◽  
Equilibrium Line Altitude ◽  
Cordillera Central ◽  
The Past ◽  
Paleoenvironmental Changes ◽  
Tephra Layers ◽  
Using Data ◽  
Glacial Time ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Using data from glacial geomorphology, tephra-soil stratigraphy and mineralogy, palynology, and radiocarbon dating, a sequence of glacial and bioclimatic stades and interstades has been identified for the past ca. 50,000 yr in the Ruı́z-Tolima massif, Cordillera Central. Six cold stades separated by warmer interstades occurred before 48,000, between 48,000 and 33,000, between 28,000 and 21,000, from ≥16,000 to ca. 14,000, ca. 13,000–12,400, and ca. 11,000–10,000 yr B.P. Although the radiocarbon ages are minimum-limiting ages obtained from tephra layers on top of tills, the tills are not significantly older because most are bracketed by dated tephra sets in measured stratigraphic sections. Two minor moraine stages likely reflect glacier pauses during cold intervals ca. 7400 yr B.P. and slightly earlier. Finally, glaciers readvanced between the 17th and 19th centuries. In contrast to the glacier cover (ca. 34 km2) on volcanoes of the massif during the last glacial maximum (LGM) the ice cover expanded to 1200 km2 and was still 800 km2 during late-glacial time (LGT). Glacier reconstructions based on the moraines suggest depression of the equilibrium line altitude (ELA) by ca. 1100 m during the LGM and 500–600 m during LGT relative to the modern ELA which lies at ca. 5100 m in the Cordillera Central. Glaciers in this region apparently reached their greatest extent when the climate was cold and moist, e.g., during stades corresponding to marine isotope stage 3; glaciers were still expanding during the LGM ca. 28,000–21,000 yr B.P., but they shrank considerably after 21,000 yr B.P. because of greatly reduced precipitation.

Contemporaneous faulting and clastic intrusions in the Quirke Lake Group, Elliot Lake, Ontario

1970 ◽  
Vol 7 (2) ◽  
pp. 215-225 ◽  
Author(s):  
G. H. Eisbacher
Keyword(s):  
Lake Ontario ◽  
Normal Faults ◽  
Glacial Origin ◽  
Vertical Displacements ◽  
Sedimentary Succession

Contemporaneous faults and clastic intrusions near Elliot Lake are common within the Espanola Formation of the Quirke Lake Group. Contemporaneous faults formed in response to differential vertical displacements which controlled regional paleocurrents and basin slope. The normal faults within the sedimentary succession probably channeled the intrusive material of the clastic dikes. Four types of clastic dikes occur in the Espanola Formation: internally sorted conglomerate dikes; internally unsorted conglomerate dikes; thin sand- and siltstone dikes; and discordant sandstone masses with scattered quartz pebbles. Emplacement of the conglomerate masses into the Espanola Formation may represent a sub-permafrost phenomenon, provided the glacial origin for the boulder conglomerates within the Huronian succession is accepted.

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