Origin and physical and chemical characteristics of glacial overburden in Essex and Kent counties, southwestern Ontario

1997 ◽  
Vol 34 (3) ◽  
pp. 233-246 ◽  
Author(s):  
T. F. Morris ◽  
R. I. Kelly
Keyword(s):  
Coarse Grained ◽  
Glacial Lake ◽  
Silty Clay ◽  
Fine Grained ◽  
The North ◽  
Geochemical Properties ◽  
Clayey Silt ◽  
Kent County ◽  
Stratigraphic Position ◽  
Physical And Chemical

The overburden of Essex and Kent counties, southwestern Ontario, has been described as consisting of a clayey silt to silty clay till overlying a gravelly unit resting on bedrock. Recent Quaternary geology mapping has identified additional materials and redefined the origin of others by determining the stratigraphic position and physical and geochemical properties of materials encountered in a sonic drilling program and field mapping. Catfish Creek Till was deposited on the bedrock surface during the Nissouri Stadial as ice advanced south over the area. As ice retreated during the Erie Interstade, fine-grained glaciolacustrine material was deposited in glacial Lake Leverett and overlay Catfish Creek Till. Tavistock Till was deposited over glacial Lake Leverett material as the Huron lobe readvanced south during the Port Bruce Stadial. As the Huron lobe retreated north, coarse-grained glaciolacustrine materials were deposited in the Leamington area. Ice from the Erie lobe deposited the Port Stanley Till along the north shore of Lake Erie in Kent County and deflected meltwater southward from the Huron lobe in the Blenheim area. A series of recessional moraines were deposited by the Huron lobe as it retreated north. The area is capped by a fine-grained glaciolacustrine deposit.

Deglacial Flood Origin of the Charleston Alluvial Fan, Lower Mississippi Alluvial Valley

1994 ◽  
Vol 41 (3) ◽  
pp. 278-284 ◽  
Author(s):  
Donna A. Porter ◽  
Margaret J. Guccione
Keyword(s):  
Mississippi River ◽  
Alluvial Fan ◽  
Coarse Grained ◽  
Silty Clay ◽  
Mississippi Valley ◽  
Lower Mississippi Valley ◽  
Fine Grained ◽  
The North ◽  
Sand Body ◽  
Braided Stream

AbstractLarge-magnitude flooding of the Mississippi River from proglacial lakes Agassiz and Superior most likely occurred between 11,300 and 10,900 and 9900 and 9500 yr B.P. The Charleston alluvial fan, a depositional remnant of one of these floods, is located at the head of a wide alluvial plain near Charleston, Missouri. The fan is an elongate, convex-up sand body (16 × 24 km) composed of medium- and fine-grained sand at least 8 m thick. This sand contrasts with the older coarse-grained sand of the braided stream surface to the west and south and younger silty clay of the meandering stream level to the north and east. A weakly developed soil separates the underlying braided steam deposits from the alluvial fan. A bulk-soil radiocarbon date of 10,590 ± 200 yr B.P. from the contact between the fan and clays of the meandering stream system indicates that the Charleston fan was deposited near the end of the early interval of flooding from Lake Agassiz about 10,900 yr B.P. If the Charleston fan is the last remnant of deglacial flooding in the lower Mississippi Valley, then deposition of significant quantities of sediment from largemagnitude floods between 10,000 and 9500 yr B.P. did not extend into the lower Mississippi Valley through Thebes Gap.

Origin of glacial ridges (OIS 6) in the Kaskaskia Sublobe, southwestern Illinois, USA

2012 ◽  
Vol 78 (2) ◽  
pp. 341-352 ◽  
Author(s):  
Nathan D. Webb ◽  
David A. Grimley ◽  
Andrew C. Phillips ◽  
Bruce W. Fouke
Keyword(s):  
Debris Flows ◽  
Spatial Arrangement ◽  
Coarse Grained ◽  
Ice Flow ◽  
Glacial Ice ◽  
Distinctive Features ◽  
Fine Grained ◽  
The North ◽  
Till Fabric ◽  
Glacial Landforms

AbstractThe origin of Illinois Episode (OIS 6) glacial ridges (formerly: ‘Ridged Drift’) in the Kaskaskia Basin of southwestern Illinois is controversial despite a century of research. Two studied ridges, containing mostly fluvial sand (OSL ages: ~ 150 ± 19 ka), with associated debris flows and high-angle reverse faults, are interpreted as ice-walled channels. A third studied ridge, containing mostly fine-grained till, is arcuate and morainal. The spatial arrangement of various ridge types can be explained by a glacial sublobe in the Kaskaskia Basin, with mainly fine-grained ridges along the sublobe margins and coarse-grained glaciofluvial ridges in a paleodrainage network within the sublobe interior. Illinois Episode till fabric and striation data demonstrate southwesterly ice flow that may diverge near the sublobe terminus. The sublobe likely formed as glacial ice thinned and receded from its maximum extent. The Kaskaskia Basin contains some of the best-preserved Illinois Episode constructional glacial landforms in the North American midcontinent. Such distinctive features probably result from ice flow and sedimentation into this former lowland, in addition to minimal postglacial erosion. Other similar OIS 6 glacial landforms may exist in association with previously unrecognized sublobes in the midcontinent, where paleo-lowlands might also have focused glacial sedimentation.

The effects of hydrodynamic sorting on the Ti isotope composition of sediments

2020 ◽  
Author(s):  
Martijn Klaver ◽  
Pieter Vroon ◽  
Marc-Alban Millet
Keyword(s):  
Chemical Weathering ◽  
Isotope Composition ◽  
Eastern Mediterranean ◽  
Hf Isotope ◽  
Passive Margin ◽  
Coarse Grained ◽  
Fine Grained ◽  
Crustal Composition ◽  
Mass Dependent ◽  
Physical And Chemical

<p>Detrital sediments provide a useful tool to investigate the composition of the continental crust through time. Mass-dependent (“stable”) isotope variations in Archaean to present-day sediments (shales, diamictites) have recently received much attention and Ti, in particular, holds significant promise as a novel tracer of crustal composition [1, 2, 3]. This approach is based on i) the contrasting Ti isotope composition of mafic versus felsic rocks as a result of the removal of isotopically light oxides during igneous differentiation; and ii) the chemical behaviour of Ti, a refractory and biologically inert element that should not fractionate during weathering and sedimentation. Hence, current interpretations of the Ti isotope detrital sediment record rely heavily on the assumption that it reflects the integrated composition of the source(s), and thus provides a record of the proportion of felsic to mafic rocks in that source.</p><p>A potential caveat, however, is the hydrodynamic sorting of dense minerals in coarse, more proximal sediments [4]. This effect is well-known for zircon; coarser sediments tend to have higher Zr/Al<sub>2</sub>O<sub>3</sub> and a less radiogenic Hf isotope composition due to the concentration of zircon grains [e.g., 5, 6]. Shales form the complementary zircon-depleted reservoir characterised by lower Zr/Al<sub>2</sub>O<sub>3</sub> and a more radiogenic Hf isotope composition relative to the source. Common Ti-rich phases such as ilmenite and rutile are also resistant against physical and chemical weathering and could be concentrated together with zircon in coarse sediments.</p><p>We examined a suite of Eastern Mediterranean passive margin sediments with well-constrained provenance [7] and found that Ti indeed behaves like Zr. Fine-grained samples have lower TiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> compared to coarser, proximal deposits of identical provenance. The removal of Ti-rich phases with a light Ti isotope composition into coarse-grained sediments could thus bias the Ti isotope composition of shales towards isotopically heavier values. We will report on the δ<sup>49/47</sup>Ti isotope composition of these sediment samples, but a TiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> mass balance suggests that a bias of more than 0.05 ‰ in the δ<sup>49/47</sup>Ti of shales is possible. Understanding the consequences of hydrodynamic sorting for Ti isotopes in sediments is crucial for their use as a quantitative proxy of crustal composition and for reconciling the shale and diamictite Ti isotope records.</p><p>[1] Greber <em>et al.</em> (2017) <em>Science</em> <strong>357</strong> 1271-1274; [2] Deng <em>et al.</em> (2019) <em>PNAS</em> <strong>116-4</strong> 1132-1135; [3] Saji <em>et al.</em> (2019) <em>Goldschmidt abstract</em> <strong>2929</strong>; [4] Greber & Dauphas (2019) <em>GCA</em> <strong>255</strong> 247-264; [5] Patchett <em>et al.</em> (1984) <em>EPSL</em> <strong>69</strong> 365-378; [6] Carpentier <em>et al.</em> (2009) <em>EPSL</em> <strong>287</strong> 86-99; [7] Klaver <em>et al.</em> (2015) <em>GCA</em> <strong>153</strong> 149-168.</p>

New Evidence Concerning the Original Order of Deposition of the Longmyndian Rocks

1948 ◽  
Vol 85 (2) ◽  
pp. 107-109 ◽  
Author(s):  
John Challinor
Keyword(s):  
Coarse Grained ◽  
The West ◽  
North West ◽  
The Road ◽  
Fine Grained ◽  
Original Order ◽  
The North ◽  
The Hill ◽  
New Evidence ◽  
The Village

During the war a large new quarry was opened in the Longmyndian rocks of Haughmond Hill, Shropshire. It is near the south-east edge of the hill, to the west of the road running north from Upton Magna and one mile from the village. On the sketch-map in the Shrewsbury Memoir (p. 58) two arrows are shown, at about this locality, recording dips of 50° in a south-easterly direction. I was told that there was a very small quarry here before the large quarry was excavated. The present quarry is even larger than that near Haughmond Abbey (Shrewsbury Memoir, p. 48), on the north-west side of the Pre-Cambrian outcrop, and the two quarries offer extensive and splendidly displayed exposures of Longmyndian rocks, one in the coarse-grained Western Longmyndian and the other in the fine-grained Eastern Longmyndian.

Uncommon preservation of dinosaur footprints in a tidal breccia: Eubrontes giganteus from the Early Jurassic Mongisty tracksite of Aveyron, southern France

2021 ◽  
pp. 1-18
Author(s):  
Jean-David Moreau ◽  
Jacques Sciau ◽  
Georges Gand ◽  
Emmanuel Fara
Keyword(s):  
Scale Up ◽  
Lower Jurassic ◽  
Depositional Environments ◽  
Early Jurassic ◽  
Coarse Grained ◽  
Southern France ◽  
Fine Grained ◽  
The North ◽  
Dinosaur Tracks ◽  
First Time

Abstract A recent excavation yielded 118 large tridactyl footprints in the Lower Jurassic Dolomitic Formation of the Causses Basin, at Mongisty in southern France. Most of the tracks are ascribed to Eubrontes giganteus Hitchcock, 1845. They are preserved on a surface of 53 m2 and form parallel rows with a preferential orientation towards the north. Such an abundance and density of E. giganteus is observed for the first time in the Early Jurassic from the Causses Basin. Sedimentological and ichnotaphonomical analyses show that the footprints were made at different time intervals, thus excluding the passage of a large group. In contrast to all other tracksites from the Dolomitic Formation, where tracks are preserved in fine-grained sediments corresponding to low-energy depositional palaeoenvironments, the tracks from Mongisty are preserved in coarse-grained sediment which is a matrix- to clast-supported breccia. Clasts consist of angular to sub-rounded, millimetric to centimetric-scale (up to 2 cm), poorly sorted, randomly oriented, homogeneous dolostone intraclasts floating in a dolomudstone matrix. Sedimentological analysis shows that the depositional environments of Mongisty varied from subtidal to intertidal/supratidal settings in a large and protected flat marsh. The lithology of the track-bearing surfaces indicates that the mudflat of the Causses Basin was sporadically affected by large mud flows that reworked and redeposited mudstone intraclasts coming from the erosion of upstream, dry and partially lithified mud beds. Throughout the world, this type of preservation of dinosaur tracks in tidal matrix- to clast-supported breccias remains rare.

scholarly journals Occurrence of a Likely Tuff Bed between the Middle and Upper Siwaliks, Taunsa area, Dera Ghazi Khan, Eastern Sulaiman Range, Pakistan

2020 ◽  
Vol 11 (1) ◽  
pp. 24-34
Author(s):  
Rahman Ullah ◽  
Nie Fengjuin ◽  
Zhang Chengyong ◽  
Saqib Izhar ◽  
Idrees Safdar ◽  
...  
Keyword(s):  
Primary Source ◽  
Volcanic Complex ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Fine Grained ◽  
The North ◽  
Kashmir Basin ◽  
Stratigraphic Position ◽  
The Individual ◽  
Fresh Surface

A likely tuff bed lies along the gradational contact of the Middle and Upper Siwaliks in eastern Sulaiman Range, Taunsa area of Dera Ghazi Khan district, Pakistan. This tuffaceous unit is 0.5–3 m thick and extends for 10 km along the north-south strike in the eastern limb of the Zindapir anticline. It is greyish white to white on fresh surface, fine-grained to silty at the bottom and clayey at the top and thus shows a fining upward grain-size grading. The lower part of the ash bed shows a prominent lamination defined by megascopically visible abundant biotite, while the central and upper parts are so fine-grained that the individual minerals cannot be seen in hand sample. Unlike the lower well-laminated part, the central and upper parts are crudely laminated to apparently massive. The bulk samples analysed with X-ray diffraction consist of quartz, feldspar (plagioclase), biotite, clays, calcite and some ore mineral likely spinel, while the clay-size fractions contain illite, chlorite, biotite and probably their mixed-layered varieties. The colour, texture, presence of abundant biotite and stratigraphic position of the Taunsa tuff correlate with those reported from Potwar plateau and from Kashmir basin. However, the apparent absence of smectite from the XRD pattern makes the Taunsa ash bed different from both Potwar and Kashmir tuffs. The present stratigraphic position of the tuff bed corresponds to shallow diagenetic zone, while the absence of smectite in the tuff and crystallinity of illite suggest that the tuff is probably derived upon reworking from a deeper diagenetic zone belonging to a lower stratigraphic level. The Eocene or other older pre-Siwalik units in Pakistan may have or had some primary ashfall deposits as reported in the northwestern Himalayas of India. This older volcanic ash may have been reworked to its present site of occurrence along the gradational contact of the Middle and the Upper Siwaliks in Taunsa area of Dera Ghazi Khan. However, the primary source of the Taunsa tuff may belong more likely to Chagai arc in Pakistan than to Dacht-e-Nawar volcanic complex in Afghanistan.

scholarly journals Occurrence of a Likely Tuff Bed between the Middle and Upper Siwaliks, Taunsa area, Dera Ghazi Khan, Eastern Sulaiman Range, Pakistan

2020 ◽  
Vol 11 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Rahman Ullah ◽  
Nie Fengjuin ◽  
Zhang Chengyong ◽  
Saqib Izhar ◽  
Idrees Safdar ◽  
...  
Keyword(s):  
Primary Source ◽  
Volcanic Complex ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Fine Grained ◽  
The North ◽  
Kashmir Basin ◽  
Stratigraphic Position ◽  
The Individual ◽  
Fresh Surface

A likely tuff bed lies along the gradational contact of the Middle and Upper Siwaliks in eastern Sulaiman Range, Taunsa area of Dera Ghazi Khan district, Pakistan. This tuffaceous unit is 0.5–3 m thick and extends for 10 km along the north-south strike in the eastern limb of the Zindapir anticline. It is greyish white to white on fresh surface, fine-grained to silty at the bottom and clayey at the top and thus shows a fining upward grain-size grading. The lower part of the ash bed shows a prominent lamination defined by megascopically visible abundant biotite, while the central and upper parts are so fine-grained that the individual minerals cannot be seen in hand sample. Unlike the lower well-laminated part, the central and upper parts are crudely laminated to apparently massive. The bulk samples analysed with X-ray diffraction consist of quartz, feldspar (plagioclase), biotite, clays, calcite and some ore mineral likely spinel, while the clay-size fractions contain illite, chlorite, biotite and probably their mixed-layered varieties. The colour, texture, presence of abundant biotite and stratigraphic position of the Taunsa tuff correlate with those reported from Potwar plateau and from Kashmir basin. However, the apparent absence of smectite from the XRD pattern makes the Taunsa ash bed different from both Potwar and Kashmir tuffs. The present stratigraphic position of the tuff bed corresponds to shallow diagenetic zone, while the absence of smectite in the tuff and crystallinity of illite suggest that the tuff is probably derived upon reworking from a deeper diagenetic zone belonging to a lower stratigraphic level. The Eocene or other older pre-Siwalik units in Pakistan may have or had some primary ashfall deposits as reported in the northwestern Himalayas of India. This older volcanic ash may have been reworked to its present site of occurrence along the gradational contact of the Middle and the Upper Siwaliks in Taunsa area of Dera Ghazi Khan. However, the primary source of the Taunsa tuff may belong more likely to Chagai arc in Pakistan than to Dacht-e-Nawar volcanic complex in Afghanistan.

scholarly journals Pliocene–Pleistocene basin evolution along the Garlock fault zone, Pilot Knob Valley, California

Geosphere ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1208-1224
Author(s):  
William M. Rittase ◽  
J. Douglas Walker ◽  
Joe Andrew ◽  
Eric Kirby ◽  
Elmira Wan
Keyword(s):  
Volcanic Field ◽  
Coarse Grained ◽  
Fine Grained ◽  
Grain Sizes ◽  
The North ◽  
Source Regions ◽  
Provenance Data ◽  
Garlock Fault ◽  
Depositional Patterns ◽  
Fourth Member

Abstract Exposed Pliocene–Pleistocene terrestrial strata provide an archive of the spatial and temporal development of a basin astride the sinistral Garlock fault in California. In the southern Slate Range and Pilot Knob Valley, an ∼2000-m-thick package of Late Cenozoic strata has been uplifted and tilted to the northeast. We name this succession the formation of Pilot Knob Valley and provide new chronologic, stratigraphic, and provenance data for these rocks. The unit is divided into five members that record different source areas and depositional patterns: (1) the lowest exposed strata are conglomeratic rocks derived from Miocene Eagle Crags volcanic field to the south and east across the Garlock fault; (2) the second member consists mostly of fine-grained rocks with coarser material derived from both southern and northern sources; and (3) the upper three members are primarily coarse-grained conglomerates and sandstones derived from the adjacent Slate Range to the north. Tephrochronologic data from four ash samples bracket deposition of the second member to 3.6–3.3 Ma and the fourth member to between 1.1 and 0.6 Ma. A fifth tephrochronologic sample from rocks south of the Garlock fault near Christmas Canyon brackets deposition of a possible equivalent to the second member of the formation of Pilot Knob Valley at ca. 3.1 Ma. Although the age of the base of the lowest member is not directly dated, regional stratigraphic and tectonic associations suggest that the basin started forming ca. 4–5 Ma. By ca. 3.6 Ma, the northward progradation fanglomerate sourced in the Eagle Crags region waned, and subsequent deposition occurred in shallow lacustrine systems. At ca. 3.3 Ma, southward progradation of conglomerates derived from the Slate Range began. Circa 1.1 Ma, continued southward progradation of fanglomerate with Slate Range sources is characterized by a shift to coarser grain sizes, interpreted to reflect uplift of the Slate Range. Overall, basin architecture and the temporal evolution of different source regions were controlled by activity on three regionally important faults—the Garlock, the Marine Gate, and the Searles Valley faults. The timing and style of motions on these faults appear to be directly linked to patterns of basin development.

Textural and Isotopic Variations in Diagenetic Kaolinite from the Magnus Oilfield Sandstones

Clay Minerals ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 625-639 ◽  
Author(s):  
C. I. Macaulay ◽  
A. E. Fallick ◽  
R. S. Haszeldine
Keyword(s):  
Isotopic Composition ◽  
Meteoric Water ◽  
Upper Jurassic ◽  
Coarse Grained ◽  
Pore Waters ◽  
Burial Diagenesis ◽  
Fine Grained ◽  
The North ◽  
Subaerial Exposure ◽  
The North Sea

AbstractIn Upper Jurassic sandstones of the Magnus Sandstone Member from the Magnus Oilfield in the North Sea, diagenetic kaolinite morphology and isotopic composition vary away from the Late Cimmerian unconformity. Near the unconformity, coarse-grained (15-30 μm) vermiform kaolinite morphology is most common, whereas downdip, 3 km away, fine-grained (∼10 μm) blocky morphology is prevalent. Kaolinite abundances increase downdip, away from the unconformity, and kaolinite near the unconformity has low δ18O (12·5-14·9%o smow) compared to that downdip (15·9−17·5%o). This reflects replacement of marine depositional pore-waters by meteoric water near the erosion surface. However, isotopic temperature estimates suggest that the majority of kaolinite formed at elevated burial temperatures of ~80°C, and not during subaerial exposure of the sandstone. The δD of kaolinite close to the unconformity is also lower than that downdip. Kaolinite morphology and isotopic composition record meteoric water ingress during Late Cimmerian subaerial erosion and retention of meteoric-derived water in the crest of the Magnus structure during burial diagenesis. Kaolinite formation during subaerial exposure is not of significance to the sandstone reservoir quality.

scholarly journals A massive input of coarse-grained siliciclastics in the Pyrenean Basin during the PETM: the missing ingredient in a coeval abrupt change in hydrological regime

2015 ◽  
Vol 11 (12) ◽  
pp. 1653-1672 ◽  
Author(s):  
V. Pujalte ◽  
J. I. Baceta ◽  
B. Schmitz
Keyword(s):  
Organic Carbon ◽  
Deep Sea ◽  
Coarse Grained ◽  
Simultaneous Increase ◽  
Northern Spain ◽  
Wet Season ◽  
Humid Climate ◽  
Fine Grained ◽  
South Central ◽  
Stratigraphic Position

Abstract. The Paleocene–Eocene thermal maximum (PETM) is represented in numerous shallow and deep marine sections of the south–central and western Pyrenees by a 2–4 m thick unit (locally up to 20 m) of clays or marly clays intercalated within a carbonate-dominated succession. This unit records a massive input into the Pyrenean Gulf of fine-grained terrestrial siliciclastics, attributed to an abrupt hydrological change during the PETM. However, the nature of such a change remains controversial. Here we show that, in addition to fine-grained deposits, large volumes of coarse-grained siliciclastics were brought into the basin and were mostly accumulated in incised valleys and in a long-lived deep-sea channel. The occurrence of these coarse-grained deposits has been known for some time, but their correlation with the PETM is reported here for the first time. The bulk of the incised valley deposits in the PETM interval are cross-bedded sands and pebbly sands, almost exclusively made of quartz. The criteria for indicting a relation to the PETM include their stratigraphic position between upper Thanetian and lower Ilerdian marine carbonates, organic carbon isotope data, and a high percentage of kaolinite in the clay matrix. The axially flowing deep-sea channel existed throughout Paleocene times in the Pyrenean Basin, within which coarse-grained calciclastic and siliciclastic turbidites were accumulated. This Paleocene succession is capped by thickly bedded quartz sandstones and pebbly sandstones, probably deposited by hyperpycnal flows, which are here assigned to the PETM based on their stratigraphic position and organic carbon isotopic data. The large and simultaneous increase in coarse- and fine-grained terrestrial siliciclastics delivered to the Pyrenean Gulf during the PETM is attributed to an increased intra-annual humidity gradient. During the PETM a longer and drier summer season facilitated the erosion of landscapes, whereas a dramatic enhancement of precipitation extremes during the wet season led to intensified flood events, with rivers carrying greater volumes of both bed and suspended loads. This scenario argues against the possibility that PETM kaolinites indicate a coeval warm and humid climate in northern Spain. Instead, the kaolinite reflects the erosion of thick Cretaceous lateritic profiles developed on the Hercynian basement.

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