Download International Heat Flow Commission Global Heat Flow Database

IASPEI/IAVCEI/IAGA/IAPSO/IAMAS/IAHS/IAG/IAC
S
http://www.iaspei.org/commissions/IHFC.html
International Heat Flow Commission
Global Heat Flow Database
W. Gosnold - Custodian
Base
http://www.heatflow.und.edu/
Data Base
“You know, for a minute there, I could have sworn I felt Earth’s crust cooling.”
Source: Omni magazine (1980s)
OUTLINE
•Global heat flux •Heat flow compilations
•Heat flow estimates
•IHFC Database
•Heat flow methodology
•Distribution of U, Th, K
•Limitations and precautions on heat flow data
•Hydrologic signals
•Transient signals
•Climate Change
•Microclimate
•46 TW or 31 TW
Global Heat Flow
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•
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Average solar flux at TOA: 1365 W m‐2
Average solar flux at the surface: 400 W m‐2
Global heat flow from Earth’s interior: 92* mW m‐2
Total surface heat flux from Earth’s interior: 47±2TW
Heat flow research has focused on:
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–
–
–
Tectonics
Thermal history of the planet
Thermal history of petroleum source rocks
Geothermal energy
• For geoneutrino research, we should also consider “reduced heat flow.” q = q0 +AD
Heat Flow Compilations
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Lee and Uyeda (1965) Simmons and Horai (1968) Jessop, Hobart, and Sclater (1975)
Pollack, Hurter, and Johnson, 1993
Gosnold and Panda, 2002
The global heat flow database of the IHFC contains > 22,000 observations.
Global distribution of heat flow data.
38,347 data points from Davies and Davies, 2010.
955 Global Reduced Heat Flow Sites: Heat Production
Dark Blue: 0 – 0.6; Light Blue: 0.6 – 1.2; Light Green 1.2 – 2.2; Yellow Green: 2.2 – 3.6; Red: <3.6
Variability in Surface Heat Flow
• Tectonic age
• Transition between heat flow provinces
• Crustal radioactivity
• Long period transients
• Climate change
• Variability due to surface features:
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–
–
–
Microclimate
Topography
Hydrology
Structure
Global Heat Flow Estimates
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•
•
•
Pollack, Hurter, and Johnson (1993) 44.2 TW±1 TW
Hofmeister and Criss (2006) 33.2 TW±1 TW
Jaupart et al. (2007) 46.0 TW ±3 TW
Davies and Davies (2010) * 46.7 TW ±2 TW 1984
Global heat flow map by Pollack and Chapman (1984)
Davies & Davies (2010) GIS approach with 93,030 surface geology polygons
Heat flow in southern hemisphere shields averages approximately 61.4 mWm‐2, but heat flow in northern hemisphere shields averages 37 mWm‐2.
• Brazil 64.8 mW m‐2 (86)
• Africa 52.3 mW m‐2 (145)
• Australia 68.1 mW m‐2 (157)
• N. America 33.1 mW m‐2 (315)
• Fennoscandia and East European Craton 35 ‐
40 mW m‐2 (1,352)
IHFC Database
Continents and Oceans
http://www.heatflow.und.edu/
Africa
csv file Asia
csv file Antarctica
csv file
Australia
csv file
North America Global data csv file
RTF format
Europe
csv file
South Continental North Pacific Indian Ocean Marine Data
America
Data
csv file
csv file
csv file
csv file
csv file
South Pacific
csv file
North Atlantic Ocean
csv file
South Atlantic Ocean csv file Black Sea
csv file
Mediterranean Red Sea
Sea
csv file
csv file
IHFC Database
Countries
North America & South America
http://www.heatflow.und.edu/
Argentina
csv file
Bermuda
csv file
Bolivia
csv file
Brazil
csv file
Canada
csv file
Chile
csv file
Columbia
csv file
Cuba
csv file
Ecuador
csv file
Greenland
csv file
Mexico
csv file
Panama
csv file
Peru
csv file
Puerto Rico
csv file
USA
csv file
IHFC Database
Canada
Data Descriptive
Number
Code
CAN001
B A A
CAN002
B A A
CAN003
B A A
CAN004
B A A
CAN005
B A B
CAN006
B A C
CAN007
B A B
CAN008
B A A
CAN009
B A A
CAN010
B A G
http://www.heatflow.und.edu/
Site
Name
WINNIPEG
COCHRANE
KAPUSKAS
HEARST
JACKFISH
OSKWIN R
MINCHIN
ENGLISH
NIELSEN
L DUFAUL
Latitude
(degrees)
(+N, ‐S)
49.8019
49.1006
49.4167
49.6844
48.8514
51.8181
50.7019
49.635
55.3853
48.35
Longitude
(degrees) Elevation
(+E, ‐W) (meters)
‐97.1192
232
‐80.935
250
‐82.3689
230
‐83.5336
260
‐86.9681
280
‐89.5858
340
‐90.4689
395
‐91.3175
420
‐77.6833
3
‐79.05
300
IHFC Database
Temp.
Minimum Maximum Number Gradient
Depth (m) Depth (m) Temps.
Number
(mK m‐1) Conductivities
Conductivity
W m‐1 K‐1
205
610
20
11
56
2.72
300
469
22
15
42
2.51
300
605
41
10
76
2.64
300
654
47
15
89
3.14
150
610
59
14
55
2.91
200
606
52
9
56
2.69
150
605
58
14
58
3
150
612
59
14
60
3.02
120
1042
35
58
IHFC Database
Number of Heat Prod. Heat Flow Number Reference
Year of
mW m‐2 of Sites Number Publication
Heat Prod.
μW m‐3
13
1.4
38
1
1
71
6
1.3
43
1
2
71
10
0.5
33
1
2
71
10
1.8
52
1
2
71
15
1
41
1
3
78
12
0.2
25
1
3
78
17
0.9
42
1
3
78
41
2
40
1
3
78
13
1.3
26
1
1
71
0.6
42
1
4
77
http://www.heatflow.und.edu/
References at end of file
•
“CAN 1 JESSOP,A.M., AND JUDGE, A.S, “ FIVE MEASUREMENTS OF HEAT FLOW IN SOUTHERN CANADA. " CAN. J. EARTH SCI., 8, 711‐716, 1971.”
•
“CAN 2 CERMAK, V., AND JESSOP, A.M.," HEAT FLOW, HEAT GENERATION AND CRUSTAL TEMPERATURE IN THE KAPUSKASING AREA OF THE CANADIAN SHIELD.“ TECTONOPHYSICS, 103, 19‐32, 1971." •
"CAN 3 JESSOP, A.M., AND LEWIS, T.J., " HEAT FLOW AND HEAT GENERATION IN THE SUPERIOR PROVINCE OF THE CANADIAN SHIELD. " TECTONOPHYSICS, 50, 55‐77, 1978." •
"CAN 4 LEWIS, T.J., AND BECK, A.E.," ANALYSIS OF HEAT FLOW DATA‐‐
DETAILED OBSERVATIONS IN MANY HOLES IN A SMALL AREA. " TECTONOPHYSICS, 41, 41‐59, 1977."
Codes
• 1 Geographic area: (A‐F = Continents; N‐S = Oceans)
• 2 Tectonic setting: (Archean, Mesozoic, Cenozoic; Ridge, Trench, Shelf)
• 3 Temperature measurements: (Borehole, Mine, Lake; Probe Type, Ocean Bottom Borehole)
• 4 Conductivity measurements: (Divided bar, Estimated; Needle Probe, Not Specified)
• 5 Corrections: (Climate, Topography; Hydrology, Sedimentation)
• 6 Quality: Author’s comments
Code examples
• BABABA
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North America
Proterozoic
Borehole
Divided Bar
Topographic correction
High quality
• EHACEB
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–
–
–
–
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Europe
Geothermal Area
Borehole
Estimated from literature
Corrected for water circulation
Medium quality
We can calculate heat flow as the product of temperature gradient and thermal conductivity
Fourier’s law of Heat conduction
q = λΓ
A common method for determining heat flow is to use a plot of thermal resistance vs. temperature (Bullard method).
This uses the entire length of the temperature measurements.
2 Ma
66 Ma
251 Ma
570 Ma
Thermal conductivity varies with rock type, composition, grain size, grain orientation, density, porosity, composition of pore fluid, & temperature.
2 Ma
66 Ma
251 Ma
In a conductive environment with constant heat flow, the temperature gradient varies with thermal conductivity.
The blue, green and brown T‐z profiles were measured; the red was calculated.
n
Tz = ∑
i =1
570 Ma
qzi
λi
Resistance reading in KΩ
Light aluminum reel for transport
600 m 4‐conductor shielded cable
Metering wheel for depth measurement
Divided bar thermal conductivity
Copper
Warm end
ΔT1
Lexan
Copper
ΔT3
Core sample
Copper
Lexan
ΔT3
Copper
Cold end
Thermocouples
Radioactive Heat Source
Turcotte & Schubert (1982)
Rate of Heat Production (w m-3)
Conc. kg/kg
Total Heat Production (W)
K
3.58E-09
2.57E-04
5.49E+12
U
2.32E-08
2.57E-08
3.56E+09
Th
2.69E-05
1.03E-07
1.65E+13
2.20E+13
McDonough & Sun (1995)
Rate of Heat Production
Conc. kg/kg
Total Heat Production
K
3.58E-09
2.40E-04
5.13E+12
U
2.32E-08
2.03E-08
2.81E+09
Th
2.69E-05
7.95E-08
1.28E+13
1.79E+13
Lyubetskaya and Korenaga (2007)
Rate of Heat Production
Conc. kg/kg
Total Heat Production
K
3.58E-09
1.90E-04
4.06E+12
U
2.32E-08
1.73E-08
2.40E+09
Th
2.69E-05
6.30E-09
1.01E+12
5.07E+12
Anderson (2007)
Rate of Heat Production
Conc. kg/kg
Total Heat Production
K
3.58E-09
1.51E-04
3.23E+12
U
2.32E-08
1.96E-08
2.71E+09
Th
2.69E-05
7.65E-09
1.23E+12
4.46E+12
Birch et al., (1968) observed a linear relation between heat flow and radioactive heat production with characteristic values of slope and zero intercept for tectono‐
physiographic provinces. The intercept on the heat flow axis ,Q0, is inferred to represent heat flow from the mantle. The IHFC database contains 14,239 continental points. Only 955 have radioactivity data for reduced heat flow calculations.
0
100
km
200
300
Th/U = 3.27±1.86 n = 150
Th/U = 3.27±1.86 n = 150
Total gamma‐ray intensity U, Th, K
Potassium
gamma‐ray
Uranium
gamma‐ray
Thorium
gamma‐ray
“It is not so much the things I don’t know that cause me problems as the things I know that are not so.”
Paraphrased after Mark Twain
A fundamental assumption is that the temperature gradient is vertical and heat flow calculated from the gradient is vertical heat flow.
Topography and complex structure with thermal conductivity contrasts or transient sources and sinks such as water flow invalidate this assumption. AAPG Geothermal Map of North America, Blackwell and Richards, 2004
Climate change &
unknown transients
The effect of a 2 degree
shift in mean annual
surface is shown for
three different periods:
Red curves: one year
Green curves: ten years
Blue curves: 100 years
Three temperature vs. depth observations at a site in North Dakota during the past 23 years show continual warming of the ground surface. The surface energy flux required to heat the subsurface as observed is approximately 40 mW m‐2.
The critical question is what is the source of the surface energy flux. The site is remote, the surface is flat, and land use has not changed. Initial Conditions
q = 60 mW m‐2, λ = 2.5 W m‐1 K‐1, Γ = 24 mK m‐1
Temperature disturbance due to clearing forest 1000 ybp. 2 °C difference from measurements in forest and cleared areas in northern Minnesota, USA.
Temperature disturbance due to clearing forest 1000 ybp. 2 °C difference from measurements in forest and cleared areas in northern Minnesota, USA.
1000 y after forest cleared. Open space is 2 °C warmer. Vertical lines simulate 2 km boreholes for T‐z measurements.
Temperature disturbance due to clearing forest 1000 ybp superimposed on preexisting temperature profile. Surface temperature (MJJA) record based on pollen analyses in upland lakes in southern Manitoba, CA (J. C. Ritchie, 1983) Temperature vs. depth profiles based on diffusion of surface temperature into subsurface at 500 y intervals during past 12,500 y. Temperature vs. depth profiles based on diffusion of surface temperature into subsurface during past 12,500 y. Surface temperature based on pollen analysis from upland lakes in southern Manitoba.
The effect of postglacial warming on the thermal gradient is subtle.
40
35
30
Deg C
25
20
Steady-state T-z
3 Deg T-z
5 Deg T-z
10 Deg T-z
15 Deg T-z
15
10
5
0
0
400
800
Depth (m)
1200
1600
•LSQ analyses of 200 m segments of a temperature log from the Williston basin all appear linear.
•The geothermal gradient increases systematically with depth.
•The surface intercept on the temperature scale decreases systematically with depth.
•Does the change in surface temperature show the amount of warming that has occurred at the surface?
•If so, the minimum warming has been at least 12 K.
WDG3
The normal temperature vs. depth profile in a thick clastic sedimentary section has a convex curvature due to the increase in thermal conductivity with depth caused by compaction which reduces porosity.
Porosity varies with depth as
Φ=Φ0e-cz c is a constant and
z is depth
Thermal conductivity, K, varies with porosity and as a function
of the conductivity of the solid rock and water as K = Kr1‐ΦKwΦ
If heat flow is constant, the temperature at depth is calculated as
T = T0 + ΣΓizi where Γi = q/Ki
Diapositiva 62
WDG3
The normal temperature vs. depth profile in a thick clastic sedimentary section is show by the blue curve. Convex curvature in the curve is due
to the increase in thermal conductivity (green curve) with depth caused by compaction which reduces porosisty (red curve)
Will Gosnold; 05/02/2008
Post glacial warming effect on the temperature gradient for 3 deg and 15 deg warming displayed as a percentage . Any temperature gradient taken from a depth less than 1500 m will yield a low estimate of heat flow.
WDG4
Three equilibrium T‐z profiles that penetrate the thick shale section in the Williston Basin show curvature suggesting either a thermal conductivity decrease with depth or a heat flow increase with depth.
Interestingly, calculations of the theoretical T‐z profiles for normal compaction, red curve, and for the effect of 15 degrees of warming since the Pleistocene combine to produce a T‐z profile (Glacx) that matches the observed profiles.
Diapositiva 64
WDG4
All three equilibrium T-z profiles that penetrate the thick shale section in the Williston Basin show curvature suggesting either a thermal
conductivity decrease with depth or a heat flow increase with depth.
Interestingly, calculations of the theoretical T-z profiles for normal compaction and for the effect of 15 degrees of warming since the
Pleistocene combine to produce a T-z profile that matches the observed profiles.
Will Gosnold; 05/02/2008
46 TW or 31 TW?
At issue is the accuracy of models of heat flow vs. age. q = 510 t ‐.5
q = 480 t ‐.5
q = 473 t ‐.5
Heat flow in conductive environments is predictable and the heat flow map of North America demonstrates this predictability on the continents and in the ocean basins.
High heat flow: young crust and recent tectonics
Low heat flow: old thermally stable crust
Variation in conductive heat flow within heat flow provinces on the continents is due to variation in radioactive heat production.
q = q0+ AD
Heat flow within ocean basins correlates with age.
Side‐by‐side comparison of marine and continental heat flow suggests the presence of non‐conductive and transient signals in marine environments and in young tectonic environments.
Bullard’s Law
"Never take a second heat flow measurement within 20 km of the original for fear that it differ from the first by two orders of magnitude."
2‐D finite‐difference heat flow model
• Temperature profile for the ridge crest and intraplate from D.H. Green
• Temperature at base of intraplate lithosphere 1370 C
• Thermal conductivity profile from Hofmeister (1999) and van den Berg, Yuen, and Steinbach (2001)
• Half‐spreading velocities of 1, 2.5, 5,&10 cm y‐1
Surface Temperature 0 C
T = 1370
T = 1410
Base of Lithosphere = 1370 C
Surface Temperature 0 C
T = 1370
T = 1410
Base of Lithosphere = 1370 C
Temperature and heat flow gradient from ridge crest to 19 Ma (474 km @ 2.5 cm y‐1)
0
1400
1300
-20,000
1200
1100
1000
Depth (m)
-40,000
900
800
-60,000
700
600
-80,000
500
400
-100,000
300
200
-120,000
100
0
40000
80000
120000
Age (y/100)
160000
0
46 or 31 TW
Summary
• The amount of data available from the IHFC database will be increased this year
• Use of the database is the responsibility of the user – there are many uncorrected noise signals
• U, Th, K contribute as much as half of surface heat flow on continents
• Surface heat flux is 46 TW ± 2 TW
• Watch for revisions to heat flow in northern hemisphere that could increase total heat flux