scholarly journals Thickness record of varves from glacial Ojibway Lake recovered in sediment cores from Frederick House Lake, northeastern Ontario

2022 ◽  
Author(s):  
G R Brooks
Keyword(s):  
Ct Scan ◽  
Sediment Cores ◽  
Lake Ontario ◽  
Core Sample ◽  
Glacial Lake ◽  
Varve Thickness ◽  
Core Samples ◽  
Visual Comparison ◽  
Original Interpretation ◽  
Lake Ojibway

The thicknesses of 384 rhythmic couplets were measured along a composite sequence of glacial Lake Ojibway glaciolacustrine deposits recovered in two sediment cores from Frederick House Lake, Ontario. The visual comparison of distinctive couplets in the CT-scan radiographs of the Frederick House core samples to photographs of core samples from Reid Lake show a match of ±1 varve number from v1656-v1902, and ±5 varve numbers between v1903-v2010, relative to the regional numbering of the Timiskaming varve series. There are two interpretations for the post-v2010 couplets that fall within the Connaught varve sequence of the regional series. In the first, the interpreted numbering spans from v2066-v2115, which produces a gap of 55 missing varves equivalent to v2011-v2065, and corresponds to the original interpretation of the Connaught varve numbering. The second spans v2011a-v2060a, and represents alternative (a) numbering for the same varves. Varve thickness data are listed in spreadsheet files (.xlsx and .csv formats), and CT-Scan radiograph images of core samples are laid out on a mosaic poster showing the interpreted varve numbering and between-core sample correlations of the varve couplets.

Insights into the Connaught sequence of the Timiskaming varve series from Frederick House Lake, northeastern Ontario

2021 ◽  
Author(s):  
Gregory R. Brooks
Keyword(s):  
Mass Transport ◽  
Lake Ontario ◽  
Circumstantial Evidence ◽  
Glacial Lake ◽  
Core Samples ◽  
Acoustic Profile ◽  
Lake Ojibway

A sub-bottom acoustic profile survey encountered a mass transport deposit (MTD) bed, 5-7 m thick, interbedded within glaciolacustrine deposits of glacial Lake Ojibway at Frederick House Lake, Ontario. Analysis of the thickness patterns of rhythmic couplets in recovered core samples revealed that the Connaught sequence, the youngest of the Timiskaming varve series, immediately under- and overlie the MTD. Comparison to regional published varve series reveals two possible interpretations for the varve numbering. One, varve(v) 2066 to v2115, requires the inference of a 55 varve year (vyr) disconformity just below the Connaught sequence, while alternative numbering, <i>v2011a</i> to <i>v2060a</i> (<i>a</i> – alternative), extends continuously from older varves. Circumstantial evidence supporting the alternative numbering is: i) the uncertainty of applying a common 55 vyr disconformity to three varve series located up to 23 km apart and which otherwise exhibit closely matching thickness plots; ii) the lack of evidence of an erosive unconformity in the sub-bottom acoustic profiles from Frederick House Lake; and iii) the uncertain varve count within a key part of the Matagami series, located abut 300 km away and from which the 55 vyr disconformity is extrapolated. At Frederick House Lake, the alternative numbering indicates that the maximum position of the Cochrane ice advance and the Connaught varves may be, in effect, contemporary in age. More broadly, the alternative numbering indicates that the youngest known varve that formed before the terminal drainage of glacial Lake Ojibway is <i>v2074a</i> rather than v2129 in the original numbering.

A review and analysis of varve thickness records from glacial Lake Ojibway (Ontario and Quebec, Canada)

2012 ◽  
Vol 260 ◽  
pp. 43-54 ◽  
Author(s):  
Andy Breckenridge ◽  
Thomas V. Lowell ◽  
Justin S. Stroup ◽  
Gianna Evans
Keyword(s):  
Glacial Lake ◽  
Varve Thickness ◽  
Lake Ojibway

scholarly journals An automated GC-C-GC-IRMS setup to measure palaeoatmospheric δ<sup>13</sup>C-CH<sub>4</sub>, δ<sup>15</sup>N-N<sub>2</sub>O and δ<sup>18</sup>O-N<sub>2</sub>O in one ice core sample

2013 ◽  
Vol 6 (8) ◽  
pp. 2027-2041 ◽  
Author(s):  
P. Sperlich ◽  
C. Buizert ◽  
T. M. Jenk ◽  
C. J. Sapart ◽  
M. Prokopiou ◽  
...  
Keyword(s):  
Ice Core ◽  
Gold Catalyst ◽  
Isotope Ratios ◽  
Core Sample ◽  
Ion Source ◽  
Resolving Power ◽  
Published Data ◽  
Core Samples ◽  
Stable Conditions ◽  
Ch4 And N2o

Abstract. Air bubbles in ice core samples represent the only opportunity to study the mixing ratio and isotopic variability of palaeoatmospheric CH4 and N2O. The highest possible precision in isotope measurements is required to maximize the resolving power for CH4 and N2O sink and source reconstructions. We present a new setup to measure δ13C-CH4, δ15N-N2O and δ18O-N2O isotope ratios in one ice core sample and with one single IRMS instrument, with a precision of 0.09, 0.6 and 0.7‰, respectively, as determined on 0.6–1.6 nmol CH4 and 0.25–0.6 nmol N2O. The isotope ratios are referenced to the VPDB scale (δ13C-CH4), the N2-air scale (δ15N-N2O) and the VSMOW scale (δ18O-N2O). Ice core samples of 200–500 g are melted while the air is constantly extracted to minimize gas dissolution. A helium carrier gas flow transports the sample through the analytical system. We introduce a new gold catalyst to oxidize CO to CO2 in the air sample. CH4 and N2O are then separated from N2, O2, Ar and CO2 before they get pre-concentrated and separated by gas chromatography. A combustion unit is required for δ13C-CH4 analysis, which is equipped with a constant oxygen supply as well as a post-combustion trap and a post-combustion GC column (GC-C-GC-IRMS). The post-combustion trap and the second GC column in the GC-C-GC-IRMS combination prevent Kr and N2O interferences during the isotopic analysis of CH4-derived CO2. These steps increase the time for δ13C-CH4 measurements, which is used to measure δ15N-N2O and δ18O-N2O first and then δ13C-CH4. The analytical time is adjusted to ensure stable conditions in the ion source before each sample gas enters the IRMS, thereby improving the precision achieved for measurements of CH4 and N2O on the same IRMS. The precision of our measurements is comparable to or better than that of recently published systems. Our setup is calibrated by analysing multiple reference gases that were injected over bubble-free ice samples. We show that our measurements of δ13C-CH4 in ice core samples are generally in good agreement with previously published data after the latter have been corrected for krypton interferences.

scholarly journals Hydrodynamic approach to the processing of core sample tests considering microstructural changes

2021 ◽  
Vol 2057 (1) ◽  
pp. 012109
Author(s):  
M N Kravchenko ◽  
M I Ivlev ◽  
N N Dieva
Keyword(s):  
Mathematical Model ◽  
Hydrodynamic Model ◽  
Laboratory Tests ◽  
Gum Arabic ◽  
Porous Matrix ◽  
Core Sample ◽  
Microstructural Changes ◽  
Core Samples ◽  
Hydrodynamic Approach ◽  
The Mathematical Model

Abstract In this paper, authors propose a method to create a complete hydrodynamic model of the polymer displacement process. It is based on the processing of the laboratory tests with core samples, considering the polymer substance properties and microstructural changes occurring in the porous matrix during the adsorption of polymer particles. Based on the adaptation of the mathematical model to the results of tests with polyacrylamide Flopaam and polysaccharide Gum Arabic, calculations of the effectiveness of polymer flooding application on samples of terrigenous deposits are carried out.

A Late Pleistocene plant-bearing deposit in Currie Township, near Matheson, Ontario

1979 ◽  
Vol 16 (5) ◽  
pp. 1130-1136 ◽  
Author(s):  
W. E. Brereton ◽  
J. A. Elson
Keyword(s):  
River Basin ◽  
Late Pleistocene ◽  
Glacial Lake ◽  
Fossil Plants ◽  
Fossil Plant ◽  
James Bay ◽  
Plant Detritus ◽  
Lake Ojibway ◽  
Moose River ◽  
James Bay Lowlands

Two overburden test holes drilled to bedrock in Currie Township, southwest of Matheson, Ontario, penetrated stratified beds containing fossil plant detritus resting on an oxidized substrate, which are between two till sheets underlying glacial Lake Ojibway-Barlow varved clays. The fossil plants, chiefly mosses, represent an environment that is common in the region today, and are radiocarbon dated (GSC-2148) as older than 37000 years. The interglacial deposit is tentatively correlated with the Missinaibi Formation in the Moose River basin of the James Bay lowlands, probably of Sangamon age.

Propagation of waves with a wide range of frequencies in digital core samples and dynamic strain anomaly detection: carbonate rock as a case study

2020 ◽  
Vol 224 (1) ◽  
pp. 340-354
Author(s):  
Jun Matsushima ◽  
Mohammed Y Ali ◽  
Fateh Bouchaala
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Local Strain ◽  
Seismic Wave Propagation ◽  
Core Sample ◽  
Laboratory Measurements ◽  
Frequency Range ◽  
Broad Frequency Range ◽  
Core Samples ◽  
Digital Core

SUMMARY Recent advancements in various types of seismic measurement methods, such as sonic logging, vertical seismic profiling (VSP) and surface seismic surveys, have allowed the high-quality measurement of seismic wave propagation over a broad frequency range. To elucidate the relationship between seismic wave propagation captured by various seismic methods at widely different frequencies and in highly heterogeneous zones (e.g. fractures, vuggy zones) developed in carbonate reservoirs, laboratory measurements have been conducted over a broad frequency range. However, existing laboratory methods measure the effective properties over an entire core sample. Furthermore, there are few laboratory measurements of individual fracture stiffnesses. We propose a method to indirectly estimate the local properties caused by local anomalies (e.g. fractures) in a core sample over a broad frequency range from the dynamic elastic properties of a dry core sample using synthetic seismic waveforms generated from a digital volume of the core sample. 3-D numerical simulations were conducted over a broad frequency range using a digital core model produced by X-ray computed tomography. The proposed method was applied to numerical models and two types (fractured and vuggy) of carbonate core plugs acquired in an Abu Dhabi oil field, with the frequency ranging from 200 Hz to 100 kHz in the tests. Local strain anomalies and their frequency dependencies were successfully detected in the fractured core plug. Such frequency-dependent local responses could be associated with the micromechanics of incomplete solid–solid contacts at fractures or the heterogeneity of core samples, and thus with the frequency-dependent fracture stiffness. It was also demonstrated that the heterogeneity-induced local strain in a vuggy core plug may affect the accuracy of existing low-frequency laboratory measurements.

scholarly journals A younger glacial Lake Iroquois in the Lake Ontario basin, Ontario and New York: re-examination of pollen stratigraphy and radiocarbon dating

2020 ◽  
Vol 57 (4) ◽  
pp. 453-463
Author(s):  
C.F.M. Lewis ◽  
T.W. Anderson
Keyword(s):  
New York ◽  
New York State ◽  
Lake Ontario ◽  
Late Glacial ◽  
Glacial Lake ◽  
Lake Basin ◽  
Long Distance ◽  
Small Lake ◽  
Pollen Stratigraphy ◽  
Lake Basins

Revision of palynochronologic and radiocarbon age estimates for the termination of glacial Lake Iroquois, mainly based on a currently accepted younger determination of the key Picea–Pinus pollen transition, shows agreement with recently established constraints for this late glacial event in the Lake Ontario basin at 13 000 cal years BP. The date of emergence or isolation of small lake basins reflects the termination of inundation by glacial lake waters. The increasing upward presence of plant detritus and the onset of organic sedimentation marks the isolation level in the sediments of a small lake basin. The upward relative decline and cessation of pollen from trees such as Pinus, Quercus, and other thermophilous hardwoods that were wind transported long distances from southern areas also mark the isolation of inundated small lake basins by the declining water level of Lake Iroquois as local vegetation grew and local pollen overwhelmed long-distance-transported pollen. Re-examination of data in small lake basins north of Lake Ontario using the above criteria shows that the age range for the termination of Lake Iroquois derived from these data overlaps other age constraints. These constraints are based on a varve-estimated duration of post-Iroquois phases before incursion of the Champlain Sea, a newly discovered late ice advance into northern New York State, and the age of a mastodon at Cohoes, New York. The new age (13 000 cal years BP) for Lake Iroquois termination is significantly younger than the previous estimate of 11 800 14C (13 600 cal) years BP.

Chronology of glacial Lake Agassiz meltwater routed to the Gulf of Mexico

2003 ◽  
Vol 59 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Timothy G. Fisher
Keyword(s):  
Gulf Of Mexico ◽  
Sediment Cores ◽  
Glacial Lake ◽  
Mississippi Valley ◽  
Lake Agassiz ◽  
Radiocarbon Dates ◽  
Glacial Lake Agassiz ◽  
Radiocarbon Chronology

AbstractSediment cores with new radiocarbon dates from the southern outlet of glacial Lake Agassiz indicate that meltwater delivery to the Mississippi valley was disrupted at 10,800 14C yr B.P. and the outlet was abandoned by 9400 14C yr B.P. These findings confirm the timing of generally accepted terminations of the Lockhart and Emerson Phases of Lake Agassiz. Additionally, the radiocarbon chronology indicates that the spillway was fully formed by 10,800 14C yr B.P. and that the occupancy in late-Emerson time was likely short-lived with minimal spillway erosion.

Sediment Record of Biogeochemical Responses to Anthropogenic Perturbations of Nutrient Cycles in Lake Ontario

1988 ◽  
Vol 45 (7) ◽  
pp. 1291-1303 ◽  
Author(s):  
Claire L. Schelske ◽  
John A. Robbins ◽  
Wayne S. Gardner ◽  
Daniel J. Conley ◽  
Richard A. Bourbonniere
Keyword(s):  
Sediment Cores ◽  
Lake Ontario ◽  
Inorganic Phosphorus ◽  
Relative Increase ◽  
Stratigraphic Correlation ◽  
Sediment Record ◽  
Calcite Precipitation ◽  
Order Of Magnitude ◽  
Recent Sediments ◽  
Secondary Consequence

Two sediment cores collected from the Rochester basin of Lake Ontario were dated with 210Pb and stratigraphic correlation and analyzed to determine whether nutrient accumulation with time was consistent with previous computer-simulated total phosphorus (TP) loadings. Relative increases in TP and nonapatite inorganic phosphorus (NAIP) accumulation were less than the fivefold increase in TP loading from 1800 to 1950 predicted independently from Chapra's simulation model. In addition, increases in TP accumulation occurred mainly after 1940 and the proportion of NAIP relative to TP increased in one core and decreased in the other. Of the nutrients studied, only increases in organic carbon (OC) paralleled the increases in modelled TP loadings. The relative increase in inorganic carbon (IC) was greatest, with accumulation increasing an order of magnitude after 1940 in one core. This large increase in IC, amounting to 20% calcite in recent sediments, was attributed to biologically induced calcite precipitation, a secondary consequence of increased planktonic photosynthetic removal of carbon dioxide that resulted from accelerated eutrophication after 1940 when modelled TP concentrations increased rapidly. Biogenic silica (BSi) accumulation, an indicator of increased diatom production, peaked between 1850 and 1870 when increases in TP and NAIP fluxes were minimal. Results provide evidence that historic biogeochemical responses inferred from OC, IC, and BSi accumulation in the sediment record provide stronger signals of phosphorus enrichment effects than can be inferred directly from changes in accumulation of different forms of phosphorus in the sediment record.

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