Three measurements of heat flow in Eastern Canada

1968 ◽  
Vol 5 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Alan M. Jessop
Keyword(s):  
Heat Flow ◽  
Superior Province ◽  
Geochemical Analysis ◽  
Eastern Canada ◽  
Flow Measurements ◽  
Grenville Province ◽  
World Average ◽  
Average Value ◽  
The World

Heat flow measurements, with appropriate corrections for the effects of Wisconsin glaciation, from three widely separated locations in eastern Canada are reported. One value in the Grenville rocks of Ontario agrees with earlier published values, but, when corrected for the effects of glaciation, becomes close to the world average value. The heat flow found in the New Quebec part of the Superior Province is significantly lower than is found in the Grenville Province. This can be explained by a hypothesis based on geochemical analysis of the surface rocks.

Some new measurements of heat flow in the Superior Province of the Canadian Shield

1987 ◽  
Vol 24 (7) ◽  
pp. 1486-1489 ◽  
Author(s):  
Malcolm Drury ◽  
Alan Taylor
Keyword(s):  
Standard Deviation ◽  
Heat Flow ◽  
Canadian Shield ◽  
Superior Province ◽  
Flow Measurements ◽  
Radiogenic Heat ◽  
Radiogenic Heat Production ◽  
Climatic Variations ◽  
The Mean ◽  
A Site

Borehole heat-flow measurements are reported from six new sites in the Superior Province of the Canadian Shield. Values adjusted for glaciation effects, but not for Holocene climatic variations, range from 42 to 56 mW/m2. When these new values are combined with 21 previously published borehole values the mean is 42 mW/m2 with a standard deviation of 11 mW/m2. The data for a site on the Lac du Bonnet batholith suggest that the batholith has a thin veneer, less than 3 km, of rock of high radiogenic heat production at the surface.

A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - A review of Red Sea heat flow

1970 ◽  
Vol 267 (1181) ◽  
pp. 191-203 ◽  
Keyword(s):  
Heat Flow ◽  
Red Sea ◽  
High Heat ◽  
Temperature Measurements ◽  
High Heat Flow ◽  
Flow Measurements ◽  
The World ◽  
Brine Pools ◽  
Deep Exploration ◽  
Made In

There are now twelve heat flow measurements in the Red Sea made with heat flow probes from survey ships and several sets of temperature measurements made in deep exploration boreholes. The oceanic measurements are in water depths ranging from 0.94 to 2.70 km and all but one of these measurements give values significantly higher than the world mode of 46 mW m -2 (1.1 ). They include the world record high oceanic measurement of more than 3307 mW m -2 (79.0) in the neighbourhood of the hot brine pools. These measurements show that the deep axial trough of the Red Sea is associated with high heat flow, the values being similar to those found in the mid-Indian Ocean rift, the mid-Atlantic rift and over the crest of the East Pacific rise. It is of considerable interest to see if there is also high heat flow over the Red Sea margins and the main purpose of this paper is to examine temperature data from deep exploration boreholes. The boreholes are drilled mainly in rock salt, sandstones and shales. A discussion is given of the thermal conductivities assumed for these rocks. The boreholes have depths of up to 4 km and in some cases the temperature measurements enable an estimate to be made of the heat flow. These are also found to be high. The significance of the high heat flow to ideas concerning the structure and evolution of the Red Sea is discussed.

New heat flow density and radiogenic heat production data in the Canadian Shield and the Quebec Appalachians

1989 ◽  
Vol 26 (4) ◽  
pp. 845-852 ◽  
Author(s):  
J. C. Mareschal ◽  
C. Pinet ◽  
C. Gariépy ◽  
C. Jaupart ◽  
G. Bienfait ◽  
...  
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Flow Density ◽  
Superior Province ◽  
Heat Flow Density ◽  
Grenville Province ◽  
Radiogenic Heat ◽  
Radiogenic Heat Production ◽  
Sedimentary Sequences ◽  
Reduced Heat Flow

New heat flow density (HFD) measurements were performed at 10 sites in Quebec. For five of the sites located in the Superior Province, the heat flow density varies between 24 and 35 mW/m2 (26 and 37 mW/m2 after adjustment for Pleistocene climatic variations). In the Grenville Province, the values obtained range between 25 and 28 mW/m2 (29 and 31 mW/m2 after adjustment). For two nearby sites in the Gaspé region (Appalachians), the heat flow density is 47 mW/m2 (48 mW/m2 after adjustment). Radiogenic heat production was also measured. At the sites located in the meta-volcano-sedimentary sequences of the Superior Province, the heat production is low (0.1–0.6 μW/m3) and it does not always correlate with the surface heat flow. In the Grenville Province, the HFD is close to (slightly higher than) the reduced heat flow of the Superior. The higher HFD in the Appalachians is partly explained by the higher crustal heat production, and partly by higher deep heat flow.

Heat flow and deep thermal structure near the southeastern edge of the Canadian Shield

2000 ◽  
Vol 37 (2-3) ◽  
pp. 399-414 ◽  
Author(s):  
J C Mareschal ◽  
C Jaupart ◽  
C Gariépy ◽  
L Z Cheng ◽  
L Guillou-Frottier ◽  
...  
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Thermal Structure ◽  
Canadian Shield ◽  
Eastern Canada ◽  
Data Set ◽  
Grenville Province ◽  
Average Heat ◽  
Crustal Composition ◽  
Abitibi Subprovince

Five new heat-flow and heat-production measurements in the Archean Superior Province are presented. These measurements include the first heat-flow values to be reported for the Opatica subprovince and the Otish basin. These new data complete the data set acquired in the eastern Canadian Shield during the Abitibi-Grenville Lithoprobe transect. The data set now available in eastern Canada, covering geological provinces ranging in age from 2700 to 400 Ma, achieves sufficient sampling to define the deep thermal structure of a continent near the edge of the craton. It shows that, for the Canadian Shield, there is no simple relation between heat flow and the age of tectonic provinces. The map of heat flow in eastern Canada demonstrates that there is no significant difference in heat flow between the Abitibi subprovince and the Grenville Province (including the Adirondacks) where the area-weighted average heat flow is the same (39 vs. 38 mW·m-2, respectively). Outside the Abitibi, the Superior Province is characterized by a higher heat flow (45 mW·m-2). Heat-flow and gravity data are used together to determine changes in crustal composition and thickness. The analysis of these data and constraints from seismology support the view that the variations in surface heat flow can be entirely accounted for by changes in crustal composition. Heat-flow variations across the Abitibi subprovince indicate that there are significant differences in crustal composition that reflect the complex assemblages that make up the Archean crust. The heat-flow map shows a sharp transition between the Grenville Province and the Appalachians, where the average heat flow is significantly higher (57 mW·m-2). This difference is due to higher heat production in the Appalachian upper crust with the same mantle heat flow as in the shield (~12 mW·m-2 throughout eastern Canada). Lower crustal and upper mantle temperatures are typically low, which might explain the preservation of irregular crustal thickness over several billion years.

scholarly journals Ecological analysis of heavy metal and radioactivity potential of Holocene sediments in Iznik Lake

Nukleonika ◽  
2019 ◽  
Vol 64 (3) ◽  
pp. 103-109
Author(s):  
Zeki U. Yumun ◽  
Erol Kam
Keyword(s):  
Heavy Metal ◽  
Background Level ◽  
Agricultural Activities ◽  
Anthropogenic Radionuclides ◽  
Ecological Analysis ◽  
World Average ◽  
Average Value ◽  
Measurement Results ◽  
The World

Abstract In this study, the heavy metal and radioactive properties of Iznik Lake were investigated. Concentration values of the first (Ag, Bi, Mo, Sn, Se, Zn, As, B, Cd, Co, Cr, Cu, Ni, Pb, Pt and Sb) and second (Na, Mg, K, Ca, P, S, Fe, Al and Mn) group of elements in borehole 1 (BH-1) drilling did not show much variation from the top to the bottom of the drilling. Concentration values of the first group of elements in borehole 2 (BH-2) drill samples decreased at higher levels of drilling. In addition, natural and anthropogenic radionuclides were measured by gamma spectrometry, and the results of environmental natural radioactivity of Iznik Lake and its surroundings were determined. In the measurement results, Ra-226 was found to be below the world average value at all locations. It is assumed that the determination of K-40 values above the average values was due to agricultural activities carried out intensively in the study area. Th-232 values were found to be below the world average value in drilling samples; Cs-137 values were below the background level in all samples. According to these results, the study area does not contain any unnatural radioactivity.

Natural radioactivity measurements and external dose estimation by car-borne survey in Douala city, Cameroon

2018 ◽  
Vol 53 (4) ◽  
pp. 255-263 ◽  
Author(s):  
S.D. Takoukam Soh ◽  
Saïdou ◽  
M. Hosoda ◽  
J.E. Ndjana Nkoulou II ◽  
N. Akata ◽  
...  
Keyword(s):  
Dose Rate ◽  
Absorbed Dose ◽  
Distribution Map ◽  
Heterogeneous Distribution ◽  
World Average ◽  
Dose Rates ◽  
Average Value ◽  
Activity Concentrations ◽  
The World

A car-borne survey was carried out in Douala, the largest city in Cameroon to make a detailed distribution map of the absorbed dose rate in the city, to locate the high natural radiation areas useful later to carry out indoor radon, thoron, and thoron progeny measurements. Gamma-ray dose rates were measured using 3-in × 3-in NaI(Tl) detector. Activity concentrations of238U,232Th and40K in soil from Douala city were determined by two methods: the first, usingin situgamma spectrometry and the second, at the laboratory using a NaI(Tl) detector. A heterogeneous distribution of absorbed dose rates in air was observed on the dose rate distribution map, and varies from 29 to 86 nGy h−1with an average of 50 nGy h−1, lower than the world average value of 59 nGy h−1. The activity concentrations with NaI(Tl) detector varied from 18 to 47 Bq kg−1for238U, 21 to 54 Bq kg−1for232Th, and 10 to 410 Bq kg−1for40K with averages of 29, 38, and 202 Bq kg−1respectively, forin situmeasurements. They vary between 29–98 Bq kg−1for238U, 29–92 Bq kg−1for232Th, and 40 to 79 Bq kg−1for40K, with averages of 60, 57, and 56 Bq kg−1respectively for soil samples collected at Douala III subdivision. The highest value of the annual effective dose forin situmeasurements by car was observed at Ndogbong and was found to be 0.7 mSv y−1, higher than the world average value of 0.5 mSv y−1.

scholarly journals Natural radioactivity and external dose assessment of surface soils in Bolikhamxay province, Laos

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Loat Bui Van
Keyword(s):  
Activity Concentration ◽  
Natural Radionuclides ◽  
Soil Samples ◽  
Dose Assessment ◽  
World Average ◽  
Average Value ◽  
Activity Concentrations ◽  
Radium Equivalent ◽  
The World ◽  
Average Activity

We have determined activity concentrations in 33 soil samples collected from Bolikhamxay Province, Laos. The activity concentrations of the natural radionuclides 226Ra,232Th and 40K in soil samples were measured by a gamma spectrometer with a HPGe detector. The average activity concentrations of the natural radionuclides 226Ra, 232Th and 40K are 43.8 ± 5.6, 57.0 ± 7.3 and 426.4 ± 23.1 Bq.kg-1, respectively. The average activity concentrations of 226Ra and 232Th in this work are higher than those of the world average values. Meanwhile, the  activity concentration of 40 K is almost the same of the world average value. The estimated average outdoor annual effective dose (E) and radium equivalent actitvity (Raeq) are 0.17 ± 0.02 mSv.yr-1 and 154.8 ± 16.1 Bq.kg-1, respectively.

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