Highly varying radiogenic heat production in Finland, Fennoscandian Shield

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Radiogenic heat production in Finland has been previously studied using airborne gamma-ray surveys and glacial till measurements alike. For the first time, this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country. The dataset of 6465 samples represents mostly Mesoarchean (about 2.7 Ga), Paleoproterozoic (ca. 2.2-1.8 Ga) and Mesoproterozoic (ca. 1.6-1.3 Ga) rocks. Nearly all data are from Precambrian Fennoscandian Shield area, but heat production appears to be highly variable, and above global Archean and Proterozoic averages. Spot readings show an arithmetic average of 1.34 +/- 1.19 mu Wm(-3), and a range from 0.02 to 19.4 mu Wm(-3). The interpolated areal average of the whole area is 1.42 +/- 1.41 mu Wm(-3). The high standard deviation of data is related to the geochemical characteristics of uranium (U), thorium (Th) and potassium (K) resulting in a skewed distribution of heat production. Mesoproterozoic anorogenic rapakivi granites, and late Paleoproterozoic Svecofennian granitoids show the highest heat production values in the range of 3-5 mu Wm(-3). The results show no distinct dependencies of heat production with geological age, metamorphic grade nor seismic P-wave velocity, but an increasing trend of heat production with SiO2 content and decreasing trends of heat production with Fe2O3 content and with rock density are evident. Surface heat flow (44 borehole data values) correlates weakly with heat production (r = 0.35). The general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in Finland and beyond.

Originalspråkengelska
TidskriftTectonophysics
Volym750
Utgåva1
Sidor (från-till)93-116
Antal sidor24
ISSN0040-1951
DOI
StatusPublicerad - 5 jan 2019
MoE-publikationstypA1 Tidskriftsartikel-refererad

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  • 1171 Geovetenskaper

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title = "Highly varying radiogenic heat production in Finland, Fennoscandian Shield",
abstract = "Radiogenic heat production in Finland has been previously studied using airborne gamma-ray surveys and glacial till measurements alike. For the first time, this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country. The dataset of 6465 samples represents mostly Mesoarchean (about 2.7 Ga), Paleoproterozoic (ca. 2.2-1.8 Ga) and Mesoproterozoic (ca. 1.6-1.3 Ga) rocks. Nearly all data are from Precambrian Fennoscandian Shield area, but heat production appears to be highly variable, and above global Archean and Proterozoic averages. Spot readings show an arithmetic average of 1.34 +/- 1.19 mu Wm(-3), and a range from 0.02 to 19.4 mu Wm(-3). The interpolated areal average of the whole area is 1.42 +/- 1.41 mu Wm(-3). The high standard deviation of data is related to the geochemical characteristics of uranium (U), thorium (Th) and potassium (K) resulting in a skewed distribution of heat production. Mesoproterozoic anorogenic rapakivi granites, and late Paleoproterozoic Svecofennian granitoids show the highest heat production values in the range of 3-5 mu Wm(-3). The results show no distinct dependencies of heat production with geological age, metamorphic grade nor seismic P-wave velocity, but an increasing trend of heat production with SiO2 content and decreasing trends of heat production with Fe2O3 content and with rock density are evident. Surface heat flow (44 borehole data values) correlates weakly with heat production (r = 0.35). The general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in Finland and beyond.",
keywords = "1171 Geosciences, Heat production, Radiometric, Uranium, Thorium, Heat flow, Precambrian, PERMIAN GEOLOGICAL PROVINCES, SEISMIC VELOCITY, POLAR PROFILE, VERTICAL-DISTRIBUTION, GRAVITY-ANOMALIES, PRECAMBRIAN CRUST, THERMAL STRUCTURE, NORTHERN FINLAND, FLOW DATA, U-PB",
author = "Veikkolainen, {Toni Henri Kristian} and Kukkonen, {Ilmo Tapio}",
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pages = "93--116",
journal = "Tectonophysics",
issn = "0040-1951",
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Highly varying radiogenic heat production in Finland, Fennoscandian Shield. / Veikkolainen, Toni Henri Kristian; Kukkonen, Ilmo Tapio.

I: Tectonophysics, Vol. 750, Nr. 1, 05.01.2019, s. 93-116.

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

TY - JOUR

T1 - Highly varying radiogenic heat production in Finland, Fennoscandian Shield

AU - Veikkolainen, Toni Henri Kristian

AU - Kukkonen, Ilmo Tapio

PY - 2019/1/5

Y1 - 2019/1/5

N2 - Radiogenic heat production in Finland has been previously studied using airborne gamma-ray surveys and glacial till measurements alike. For the first time, this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country. The dataset of 6465 samples represents mostly Mesoarchean (about 2.7 Ga), Paleoproterozoic (ca. 2.2-1.8 Ga) and Mesoproterozoic (ca. 1.6-1.3 Ga) rocks. Nearly all data are from Precambrian Fennoscandian Shield area, but heat production appears to be highly variable, and above global Archean and Proterozoic averages. Spot readings show an arithmetic average of 1.34 +/- 1.19 mu Wm(-3), and a range from 0.02 to 19.4 mu Wm(-3). The interpolated areal average of the whole area is 1.42 +/- 1.41 mu Wm(-3). The high standard deviation of data is related to the geochemical characteristics of uranium (U), thorium (Th) and potassium (K) resulting in a skewed distribution of heat production. Mesoproterozoic anorogenic rapakivi granites, and late Paleoproterozoic Svecofennian granitoids show the highest heat production values in the range of 3-5 mu Wm(-3). The results show no distinct dependencies of heat production with geological age, metamorphic grade nor seismic P-wave velocity, but an increasing trend of heat production with SiO2 content and decreasing trends of heat production with Fe2O3 content and with rock density are evident. Surface heat flow (44 borehole data values) correlates weakly with heat production (r = 0.35). The general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in Finland and beyond.

AB - Radiogenic heat production in Finland has been previously studied using airborne gamma-ray surveys and glacial till measurements alike. For the first time, this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country. The dataset of 6465 samples represents mostly Mesoarchean (about 2.7 Ga), Paleoproterozoic (ca. 2.2-1.8 Ga) and Mesoproterozoic (ca. 1.6-1.3 Ga) rocks. Nearly all data are from Precambrian Fennoscandian Shield area, but heat production appears to be highly variable, and above global Archean and Proterozoic averages. Spot readings show an arithmetic average of 1.34 +/- 1.19 mu Wm(-3), and a range from 0.02 to 19.4 mu Wm(-3). The interpolated areal average of the whole area is 1.42 +/- 1.41 mu Wm(-3). The high standard deviation of data is related to the geochemical characteristics of uranium (U), thorium (Th) and potassium (K) resulting in a skewed distribution of heat production. Mesoproterozoic anorogenic rapakivi granites, and late Paleoproterozoic Svecofennian granitoids show the highest heat production values in the range of 3-5 mu Wm(-3). The results show no distinct dependencies of heat production with geological age, metamorphic grade nor seismic P-wave velocity, but an increasing trend of heat production with SiO2 content and decreasing trends of heat production with Fe2O3 content and with rock density are evident. Surface heat flow (44 borehole data values) correlates weakly with heat production (r = 0.35). The general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in Finland and beyond.

KW - 1171 Geosciences

KW - Heat production

KW - Radiometric

KW - Uranium

KW - Thorium

KW - Heat flow

KW - Precambrian

KW - PERMIAN GEOLOGICAL PROVINCES

KW - SEISMIC VELOCITY

KW - POLAR PROFILE

KW - VERTICAL-DISTRIBUTION

KW - GRAVITY-ANOMALIES

KW - PRECAMBRIAN CRUST

KW - THERMAL STRUCTURE

KW - NORTHERN FINLAND

KW - FLOW DATA

KW - U-PB

U2 - 10.1016/j.tecto.2018.11.006

DO - 10.1016/j.tecto.2018.11.006

M3 - Article

VL - 750

SP - 93

EP - 116

JO - Tectonophysics

JF - Tectonophysics

SN - 0040-1951

IS - 1

ER -