Geothermal measurements in five small lakes of northwest Ontario

1976 ◽  
Vol 13 (7) ◽  
pp. 987-992 ◽  
Author(s):  
R. G. Allis ◽  
G. D. Garland
Keyword(s):  
Heat Flow ◽  
High Heat ◽  
Canadian Shield ◽  
Small Lakes ◽  
Bottom Water Temperature ◽  
Heat Flows ◽  
Small Correction ◽  
Flow Through ◽  
Gradient Measurements ◽  
Lateral Temperature

The heat flow through the floors of five small lakes of known thermal history on the Canadian Shield was measured with a modified Bullard probe. A small correction for seasonal bottom water temperature variations was applied to temperature gradient measurements, and the heat flows are corrected for glaciation, lateral temperature gradients, sedimentation rates, and lateral thermal conductivity changes. Four lakes have an average heat flow of 49 ± 4 mW/m2 (1.2 ± 0.1 μcal/cm2 s). A high heat flow in the fifth lake is thought due to unusual refraction effects. The heat generation–heat flux combination yields a point that falls near accepted lines for the Canadian Shield.

scholarly journals High heat flow in the trans-Hudson Orogen, Central Canadian Shield

1996 ◽  
Vol 23 (21) ◽  
pp. 3027-3030 ◽  
Author(s):  
L. Guillou-Frottier ◽  
C. Jaupart ◽  
J. C. Mareschal ◽  
C. Gariépy ◽  
G. Bienfait ◽  
...  
Keyword(s):  
Heat Flow ◽  
High Heat ◽  
Canadian Shield ◽  
High Heat Flow

Chemical boundary layers of the mantle and core

1989 ◽  
Vol 328 (1599) ◽  
pp. 441-442 ◽  
Keyword(s):  
Boundary Layer ◽  
Heat Flow ◽  
Large Scale ◽  
High Heat ◽  
Mantle Flow ◽  
Sufficient Information ◽  
Deep Interior ◽  
Gravimetric Data ◽  
Flow Through ◽  
The Stability

There is now sufficient information from seismological mapping of the Earth’s deep interior to draw some preliminary conclusions regarding nature of large-scale mantle flow. This paper examines three features of mantle heterogeneity. Seismological studies confirm the existence of a thick (more than 300 km) thermal boundary layer (tbl) beneath the ancient cratonic nuclei. Petrological and gravimetric data imply that the continental tbl is stabilized against convective disruption by a buoyant, viscous, chemical boundary layer (cbl) depleted in Fe and A1 relative to Mg. Geothermal constraints require high heat production within the cbl and low heat flow through its base, indicating that the cbl has been recharged by large-ion lithophile (lil) elements after primary depletion events. Formation of this continental tectosphere cannot be simple conductive cooling, as in the oceans, but must involve several stages characterized by different timescales, terminating with crustal stabilization; the advective thickening of a basalt-depleted, LiL-rich cbl in episodes of compressive orogenesis (e.g. supercontinent assembly) may be an important mechanism for tectospheric consolidation. The stability and low basal heat flow of the cratonic cbl are evidence that the positions of the continents through time are coupled to the upward flow of material from the deep mantle.

Heat flow measurements under some lakes in the Superior Province of the Canadian Shield

1979 ◽  
Vol 16 (10) ◽  
pp. 1951-1964 ◽  
Author(s):  
R. G. Allis ◽  
G. D. Garland
Keyword(s):  
Heat Flow ◽  
High Heat ◽  
Flow Measurements ◽  
Average Heat ◽  
Heat Flows ◽  
Climatic Variations ◽  
Northwestern Ontario ◽  
Flow Heat ◽  
Lateral Heat ◽  
Made In

Six heat flow values have been obtained from measurements made in the sediments of thermally-stable lakes in four major structural belts of northwestern Ontario. Each heat flow is the average of measurements from 3–6 neighbouring lakes. Corrections for the thermal history, lateral heat flow, sedimentation, and refraction effects have been applied. High heat flows which were measured in the Quetico gneiss superbelt (77 mW/m2) and on the Indian Lake intrusion in the Wabigoon superbelt (64 mW/m2) are related to above-average heat productivities at these locations, but the extent in depth of the sources is shown to be very different in the two cases. The consistency of the lake results with borehole measurements, on a heat flow – heat productivity plot, strongly suggests that the former are not perturbed by recent climatic variations.

Estimates of terrestrial heat flow in offshore eastern Canada

1985 ◽  
Vol 22 (10) ◽  
pp. 1503-1517 ◽  
Author(s):  
Marshall Reiter ◽  
Alan M. Jessop
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Newfoundland And Labrador ◽  
High Heat ◽  
Magmatic Activity ◽  
Shelf Edge ◽  
Eastern Canada ◽  
Heat Flows ◽  
Bottom Hole ◽  
Outer Half

From available bottom-hole temperatures and conductivities estimated from lithologic descriptions, heat-flow estimates are calculated for 72 sites on the Canadian Atlantic Shelf. The resulting data suggest a pattern of low heat flow (~055 mW/m2) within the Paleozoic basins in proximity to land areas and generally intermediate heat flow (~60–80 mW/m2) along the outer half of the continental shelf. Higher heat flows (~90 mW/m2) are estimated along the shelf edge in some areas, e.g., the southwestern Scotian Shelf and the eastern Newfoundland and Labrador shelves. Radioactive heat generation in sediments that thicken seawards probably does not account for the observed increase in heat flow. The possibility that higher heat flows in some areas may arise because of fluid movement from depth is suggested. Various other causes for the high heat flows, e.g., tectonic or magmatic activity, are considered less likely.

The flow of heat through the floor of the Atlantic Ocean

1954 ◽  
Vol 222 (1150) ◽  
pp. 408-429 ◽  
Keyword(s):  
Heat Flow ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
High Heat ◽  
Unexpected Result ◽  
Heat Flows ◽  
The North ◽  
The Mean ◽  
The Individual

The measurement of the temperature gradient and thermal conductivity in the sediments beneath the floor of the North Atlantic Ocean is described. Measurements were made at five stations. The mean heat flow and conductivity were found to be 0·98 × 10 -6 cal/cm 2 s and 25 × 10 -4 cal/cm °Cs. The heat flows at the individual stations range from 0·58 to 1·42 × 10 -6 cal/cm 2 s. The high heat flow is an unexpected result, and it is difficult to find a source for so much heat.

A discussion concerning the floor of the northwest Indian Ocean - Heat flow in the northwest Indian Ocean and Red Sea

1966 ◽  
Vol 259 (1099) ◽  
pp. 271-278 ◽  
Keyword(s):  
Indian Ocean ◽  
Heat Flow ◽  
Red Sea ◽  
Deep Structure ◽  
Geothermal Gradient ◽  
Mean Value ◽  
Flow Measurements ◽  
Bottom Water Temperature ◽  
The Indian Ocean ◽  
Flow Through

Twenty-four measurements of the heat flow through the ocean floor were made in the Indian Ocean and three in the Red Sea. A critical analysis of the effects of fluctuations of bottom-water temperature on the geothermal gradient in the Red Sea shows that these fluctuations do not invalidate the measurements of heat flow. The mean value for the Gulf of Aden (this includes five previous measurements) is 3.89 + 0.49 /tcal cm -2 s -1 . This high value, combined with the shape of a profile across the Gulf, suggests a region of unusually high temperature at a depth of less than 10 km below the bottom. The seventeen heat flow measurements made by R.R.S. Discovery and R. V. Vema between the African coast and the Seychelles show little variation about a mean value of 1.17 /tcal cm -2 s -1 . The comparison of these observations and the deep structure, as determined by a series of seismic lines, shows a constant heat flow across the continental margin. The author is indebted to Mr R. Belderson of the National Institute of Oceanography for a brief description of the cores taken on the cruise.

Analysis of the Factors Affecting the Realization of Lambda Transition Temperature of 4He

2011 ◽  
Vol 18 (1) ◽  
pp. 13-24 ◽  
Author(s):  
L. Yin ◽  
P. Lin ◽  
J. Zhao ◽  
X. Qi
Keyword(s):  
Transition Temperature ◽  
Heat Flow ◽  
Depression Effect ◽  
Resistance Thermometer ◽  
Factors Affecting ◽  
Heat Flows ◽  
Flow Through ◽  
Lambda Transition ◽  
The Stability ◽  
Temperature Plateau

Analysis of the Factors Affecting the Realization of Lambda Transition Temperature of 4He Owing to the dramatic change in the thermal conductivity of 4He when its temperature crosses the transition of superfluid (HeI) and normalfluid (HeII), a sealed-cell with a capillary is used to realize the lambda transition temperature, Tλ. A small heat flow is controlled through the capillary of the sealed-cell so as to realize the coexistence of HeI and HeII and maintain the stay of HeI/HeII interface in the capillary. A stable and flat lambda transition temperature "plateau" is obtained. Because there is a depression effect of Tλ caused by the heat flow through the capillary, a series of heat flows and several temperature plateaus are made and an extrapolation is applied to determine Tλ with zero heat flow. A rhodium-iron resistance thermometer with series number A34 (RIRT A34) has been used in 24 Tλ -realization experiments to derive Tλ with a standard deviation of 0.022mK, which proves the stability and reproducibility of Tλ.

Heat flow in the Maritime Provinces of Canada

1979 ◽  
Vol 16 (6) ◽  
pp. 1154-1165 ◽  
Author(s):  
R. D. Hyndman ◽  
A. M. Jessop ◽  
A. S. Judge ◽  
D. S. Rankin
Keyword(s):  
Nova Scotia ◽  
Heat Flow ◽  
New Brunswick ◽  
Heat Production ◽  
Prince Edward Island ◽  
High Heat ◽  
Eastern United States ◽  
Maritime Provinces ◽  
Heat Flows ◽  
Maritime Canada

Heat-flow values have been obtained at six new sites in Nova Scotia and New Brunswick. These values and six previously reported for Maritime Canada range from 45 to 79 mW m−2 (1.07 to 1.89 μcal cm−2 s−1) after correction for Pleistocene glaciation. The mean 62 ± 3 mW m−2 (1.48 ± 0.06 μcal cm−2 s−1) after a glacial correction and 54 ± 3 mW m−2 (1.29 ± 0.06 μcal cm−2 s−1) without the correction are in general agreement with the average for Paleozoic orogenic belts. High heat flows in New Brunswick are probably associated with acidic or felsic volcanics with high radioactive heat production. Low heat-flow values are associated with the deep Carboniferous sedimentary basin of Prince Edward Island and northwestern Nova Scotia. Probably the region was uplifted and the surface crystalline rocks with high radioactive heat production were eroded prior to Carboniferous time. During subsequent slow subsidence, low heat production sediments were deposited in the resulting basin. High heat flows in Nova Scotia are associated with the Devonian granites and the older Meguma sediments and metasediments, which have high radioactive heat production. The heat-flow data from Nova Scotia, together with estimates of the radioactive heat production of basement rocks, are consistent with the heat-flow–heat-production relations for the eastern United States, the Canadian Shield, and for other stable areas. The temperature at the base of the crust at 35 km depth is estimated to average about 750 °C.

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