265:. Earth's internal heat flow to the surface is thought to be 80% due to mantle convection, with the remaining heat mostly originating in the Earth's crust, with about 1% due to volcanic activity, earthquakes, and mountain building. Thus, about 99% of Earth's internal heat loss at the surface is by conduction through the crust, and mantle convection is the dominant control on heat transport from deep within the Earth. Most of the heat flow from the thicker continental crust is attributed to internal radiogenic sources; in contrast the thinner oceanic crust has only 2% internal radiogenic heat. The remaining heat flow at the surface would be due to basal heating of the crust from mantle convection. Heat fluxes are negatively correlated with rock age, with the highest heat fluxes from the youngest rock at
287:
178:
625:
22:
735:
165:. As pointed out by John Perry in 1895 a variable conductivity in the Earth's interior could expand the computed age of the Earth to billions of years, as later confirmed by radiometric dating. Contrary to the usual representation of Thomson's argument, the observed thermal gradient of the Earth's crust would not be explained by the addition of radioactivity as a heat source. More significantly,
612:
Primordial heat is the heat lost by the Earth as it continues to cool from its original formation, and this is in contrast to its still actively-produced radiogenic heat. The Earth core's heat flow—heat leaving the core and flowing into the overlying mantle—is thought to be due to primordial heat,
192:
While the total internal Earth heat flow to the surface is well constrained, the relative contribution of the two main sources of Earth's heat, radiogenic and primordial heat, are highly uncertain because their direct measurement is difficult. Chemical and physical models give estimated ranges of
342:, a topic of much debate, and it is thought that the mantle may either have a layered structure with a higher concentration of radioactive heat-producing elements in the lower mantle, or small reservoirs enriched in radioactive elements dispersed throughout the whole mantle.
591:
Geoneutrino detectors can detect the decay of U and Th and thus allow estimation of their contribution to the present radiogenic heat budget, while U and K are not thus detectable. Regardless, K is estimated to contribute 4 TW of heating. However, due to the short
613:
and is estimated at 5–15 TW. Estimates of mantle primordial heat loss range between 7 and 15 TW, which is calculated as the remainder of heat after removal of core heat flow and bulk-Earth radiogenic heat production from the observed surface heat flow.
616:
The early formation of the Earth's dense core could have caused superheating and rapid heat loss, and the heat loss rate would slow once the mantle solidified. Heat flow from the core is necessary for maintaining the convecting outer core and the geodynamo and
337:
studies indicate that it is unlikely to be a significant source of radiogenic heat due to an expected low concentration of radioactive elements partitioning into iron. Radiogenic heat production in the mantle is linked to the structure of
189:). One recent estimate is 47 TW, equivalent to an average heat flux of 91.6 mW/m, and is based on more than 38,000 measurements. The respective mean heat flows of continental and oceanic crust are 70.9 and 105.4 mW/m.
314:. About 50% of the Earth's internal heat originates from radioactive decay. Four radioactive isotopes are responsible for the majority of radiogenic heat because of their enrichment relative to other radioactive isotopes:
656:
Controversy over the exact nature of mantle convection makes the linked evolution of Earth's heat budget and the dynamics and structure of the mantle difficult to unravel. There is evidence that the processes of
241:
in response to heat escaping from Earth's interior, with hotter and more buoyant mantle rising and cooler, and therefore denser, mantle sinking. This convective flow of the mantle drives the movement of Earth's
1321:
Pease, V., Percival, J., Smithies, H., Stevens, G., & Van
Kranendonk, M. (2008). When did plate tectonics begin? Evidence from the orogenic record. When did plate tectonics begin on planet Earth, 199–208.
236:
of a material is proportional to temperature; thus, the solid mantle can still flow on long time scales, as a function of its temperature and therefore as a function of the flow of Earth's internal heat. The
142:
1167:Šrámek, Ondřej; McDonough, William F.; Kite, Edwin S.; Lekić, Vedran; Dye, Stephen T.; Zhong, Shijie (1 January 2013). "Geophysical and geochemical constraints on geoneutrino fluxes from Earth's mantle".
596:
the decay of U and K contributed a large fraction of radiogenic heat flux to the early Earth, which was also much hotter than at present. Initial results from measuring the geoneutrino products of
181:
Cross section of the Earth showing its main divisions and their approximate contributions to Earth's total internal heat flow to the surface, and the dominant heat transport mechanisms within Earth
1330:
Stern, R. J. (2008). Modern-style plate tectonics began in
Neoproterozoic time: An alternative interpretation of Earth’s tectonic history. When did plate tectonics begin on planet Earth, 265–280.
246:; thus, an additional reservoir of heat in the lower mantle is critical for the operation of plate tectonics and one possible source is an enrichment of radioactive elements in the lower mantle.
134:, and thus penetrates only a few dozen centimeters on the daily cycle and only a few dozen meters on the annual cycle. This renders solar radiation minimally relevant for processes internal to
330:(K). Due to a lack of rock samples from below 200 km depth, it is difficult to determine precisely the radiogenic heat throughout the whole mantle, although some estimates are available.
1286:
Gando, A., Dwyer, D. A., McKeown, R. D., & Zhang, C. (2011). Partial radiogenic heat model for Earth revealed by geoneutrino measurements. Nature
Geoscience, 4(9), 647–651.
992:
604:
for radiogenic heat, yielded a new estimate of half of the total Earth internal heat source being radiogenic, and this is consistent with previous estimates.
907:
Glatzmaier, Gary A.; Roberts, Paul H. (1995). "A three-dimensional convective dynamo solution with rotating and finitely conducting inner core and mantle".
198:
739:
1105:
of the silicate Earth: Insights into mantle composition, structure and thermal evolution. Earth and
Planetary Science Letters, 278(3), 361–369.
1134:"How much of the heat dissipated into space by Earth is due to radioactive decay of its elements? About half is due to this "radiogenic heat""
872:
Kageyama, Akira; Sato, Tetsuya; the
Complexity Simulation Group (1 January 1995). "Computer simulation of a magnetohydrodynamic dynamo. II".
161:, estimated the age of the Earth at 98 million years, which contrasts with the age of 4.5 billion years obtained in the 20th century by
1141:
1114:
Jaupart, C., & Mareschal, J. C. (2007). Heat flow and thermal structure of the lithosphere. Treatise on
Geophysics, 6, 217–251.
661:
were not active in the Earth before 3.2 billion years ago, and that early Earth's internal heat loss could have been dominated by
1025:
951:
832:
25:
Global map of the flux of heat, in mW/m, from Earth's interior to the surface. The largest values of heat flux coincide with
1123:
Korenaga, J. (2003). Energetics of mantle convection and the fate of fossil heat. Geophysical
Research Letters, 30(8), 1437.
689:
heat transport via enhanced volcanism, while the active plate tectonics of Earth occur with an intermediate heat flow and a
185:
Estimates of the total heat flow from Earth's interior to surface span a range of 43 to 49 terawatts (TW) (a terawatt is 10
114:. This external energy source powers most of the planet's atmospheric, oceanic, and biologic processes. Nevertheless on
1013:
1253:
154:
153:
Based on calculations of Earth's cooling rate, which assumed constant conductivity in the Earth's interior, in 1862
1298:
Lay, T., Hernlund, J., & Buffett, B. A. (2008). Core–mantle boundary heat flow. Nature
Geoscience, 1(1), 25–32.
628:
Earth's tectonic evolution over time from a molten state at 4.5 Ga, to a single-plate lithosphere, to modern
621:; therefore primordial heat from the core enabled Earth's atmosphere and thus helped retain Earth's liquid water.
169:
alters how heat is transported within the Earth, invalidating
Thomson's assumption of purely conductive cooling.
1274:
Korenaga, J. (2008). Urey ratio and the structure and evolution of Earth's mantle. Reviews of
Geophysics, 46(2).
822:
141:
Global data on heat-flow density are collected and compiled by the International Heat Flow Commission of the
717:
37:
681:
their internal heat through a single lithospheric plate, and higher heat flows, such as on Jupiter's moon
1365:
1086:
Dye, S. T. (2012). Geoneutrinos and the radioactive power of the Earth. Reviews of Geophysics, 50(3).
1157:
Korenaga, J. (2011). Earth's heat budget: Clairvoyant geoneutrinos. Nature Geoscience, 4(9), 581–582.
712:
618:
100:
1043:"John Perry's neglected critique of Kelvin's age for the Earth: A missed opportunity in geodynamics"
286:
1355:
270:
258:
107:
88:
1360:
1190:
1350:
1233:
1186:
1054:
916:
881:
782:
8:
1137:
1133:
707:
64:
1237:
1058:
920:
885:
786:
1312:
Moore, W. B., & Webb, A. A. G. (2013). Heat-pipe Earth. Nature, 501(7468), 501–505.
1210:
1176:
722:
678:
601:
205:
162:
131:
1249:
1245:
1202:
1021:
947:
928:
828:
702:
690:
597:
339:
299:
254:
250:
238:
213:
166:
106:
Despite its geological significance, Earth's interior heat contributes only 0.03% of
68:
49:
1214:
1241:
1194:
1087:
1062:
924:
889:
790:
637:
221:
135:
858:
847:
Buffett, B. A. (2007). Taking Earth's temperature. Science, 315(5820), 1801–1802.
658:
629:
311:
291:
266:
209:
194:
111:
92:
72:
26:
1345:
1198:
645:
177:
624:
302:
of elements in the Earth's mantle and crust results in production of daughter
1339:
1206:
217:
123:
29:, and the smallest values of heat flux occur in stable continental interiors.
871:
641:
327:
143:
International Association of Seismology and Physics of the Earth's Interior
80:
40:. The flow heat from Earth's interior to the surface is estimated at 47±2
1016:. In Martin J. van Kranendonk; Vickie Bennett; Hugh R.H. Smithies (eds.).
982:
IHFC: International Heat Flow Commission – Homepage. Retrieved 18/09/2019.
1067:
1042:
334:
323:
319:
315:
307:
243:
158:
119:
795:
770:
1018:
Earth's Oldest Rocks (Developments in Precambrian Geology Vol 15, 2007)
229:
225:
127:
57:
1102:
893:
686:
682:
666:
662:
593:
262:
233:
96:
84:
1228:
McDonough, W.F. (2003), "Compositional Model for the Earth's Core",
44:(TW) and comes from two main sources in roughly equal amounts: the
41:
1181:
269:
spreading centers (zones of mantle upwelling), as observed in the
110:
at the surface, which is dominated by 173,000 TW of incoming
21:
820:
303:
76:
734:
1101:
Arevalo Jr, R., McDonough, W. F., & Luong, M. (2009). The
346:
An estimate of the present-day major heat-producing isotopes
979:
674:
670:
186:
115:
148:
1166:
669:. Terrestrial bodies with lower heat flows, such as the
1041:
England, Philip; Molnar, Peter; Richter, Frank (2007).
640:
released by collapsing a large amount of matter into a
1007:
1005:
821:
Donald L. Turcotte; Gerald Schubert (25 March 2002).
1040:
1002:
906:
1337:
1270:
1268:
1266:
1264:
1153:
1151:
1014:"Chapter 2: The Formation Of The Earth And Moon"
651:
67:and powers most geological processes. It drives
769:Davies, J.H.; Davies, D.R. (22 February 2010).
997:Transactions of the Royal Society of Edinburgh
1261:
1148:
856:
632:sometime between 3.2 Ga and 1.0 Ga
52:of isotopes in the mantle and crust, and the
909:Physics of the Earth and Planetary Interiors
768:
764:
762:
760:
758:
756:
754:
172:
1232:, vol. 2, Elsevier, pp. 547–568,
1011:
16:Accounting of heat created within the Earth
1097:
1095:
944:Global Warming: Understanding the Forecast
941:
816:
814:
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806:
1227:
1180:
1066:
794:
751:
1308:
1306:
1304:
1282:
1280:
623:
285:
176:
20:
1108:
1092:
1012:Ross Taylor, Stuart (26 October 2007).
803:
1338:
1294:
1292:
1082:
1080:
1078:
636:Primordial heat energy comes from the
149:Heat and early estimate of Earth's age
1301:
1277:
193:15–41 TW and 12–30 TW for
63:Earth's internal heat travels along
1289:
1169:Earth and Planetary Science Letters
1075:
993:On the secular cooling of the earth
13:
1144:from the original on 25 June 2017.
607:
281:
276:
14:
1377:
728:
733:
220:, solid but plastically flowing
1324:
1315:
1221:
1160:
1126:
1117:
1034:
985:
857:Morgan Bettex (25 March 2010).
249:Earth heat transport occurs by
95:is also theorized to sustain a
1246:10.1016/b0-08-043751-6/02015-6
973:
960:
935:
900:
865:
850:
841:
827:. Cambridge University Press.
130:flows inward only by means of
93:high-temperature metallic core
1:
745:
652:Heat flow and tectonic plates
271:global map of Earth heat flow
1020:. Elsevier. pp. 21–30.
929:10.1016/0031-9201(95)03049-3
740:Earth's internal heat budget
718:Thermal history of the Earth
212:that is composed of thicker
126:absorbed from non-reflected
38:thermal history of the Earth
34:Earth's internal heat budget
7:
771:"Earth's surface heat flux"
696:
108:Earth's total energy budget
10:
1384:
1199:10.1016/j.epsl.2012.11.001
991:Thomson, William. (1864).
968:Fundamentals of geophysics
859:"Explained: Dynamo Theory"
970:. Cambridge: CUP, 2nd ed.
713:Planetary differentiation
600:from within the Earth, a
382:Mean mantle concentration
290:The evolution of Earth's
173:Global internal heat flow
1230:Treatise on Geochemistry
1088:doi:10.1029/2012RG000400
89:Convective heat transfer
1191:2013E&PSL.361..356S
259:hydrothermal convection
995:, read 28 April 1862.
633:
619:Earth's magnetic field
333:For the Earth's core,
295:
182:
101:Earth's magnetic field
36:is fundamental to the
30:
742:at Wikimedia Commons
627:
289:
180:
24:
1068:10.1130/GSAT01701A.1
648:of accreted matter.
310:and heat energy, or
91:within the planet's
65:geothermal gradients
1238:2003TrGeo...2..547M
1138:Stanford University
1059:2007GSAT...17R...4E
966:Lowrie, W. (2007).
942:Archer, D. (2012).
921:1995PEPI...91...63G
886:1995PhPl....2.1421K
796:10.5194/se-1-5-2010
787:2010SolE....1....5D
708:Geothermal gradient
347:
244:lithospheric plates
56:left over from the
874:Physics of Plasmas
723:Anthropogenic heat
634:
345:
296:
206:structure of Earth
183:
163:radiometric dating
132:thermal conduction
58:formation of Earth
31:
1366:Geothermal energy
1027:978-0-08-055247-7
980:www.ihfc-iugg.org
953:978-0-470-94341-0
834:978-0-521-66624-4
738:Media related to
703:Geothermal energy
691:convecting mantle
598:radioactive decay
589:
588:
340:mantle convection
300:radioactive decay
255:mantle convection
214:continental crust
208:is a rigid outer
167:mantle convection
81:rock metamorphism
77:mountain building
69:mantle convection
50:radioactive decay
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894:10.1063/1.871485
880:(5): 1421–1431.
869:
863:
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854:
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766:
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638:potential energy
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201:, respectively.
99:which generates
48:produced by the
27:mid-ocean ridges
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1356:Plate tectonics
1336:
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819:
804:
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748:
731:
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659:plate tectonics
654:
630:plate tectonics
610:
608:Primordial heat
581:
579:
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366:
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312:radiogenic heat
306:and release of
292:radiogenic heat
284:
282:Radiogenic heat
279:
277:Sources of heat
267:mid-ocean ridge
261:, and volcanic
239:mantle convects
199:primordial heat
195:radiogenic heat
175:
155:William Thomson
151:
112:solar radiation
73:plate tectonics
54:primordial heat
46:radiogenic heat
17:
12:
11:
5:
1381:
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1125:
1116:
1107:
1091:
1074:
1033:
1026:
1001:
999:, 23, 157–170.
984:
972:
959:
952:
934:
915:(1–3): 63–75.
899:
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749:
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729:External links
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685:, result in
655:
642:gravity well
635:
615:
611:
590:
403:Heat release
354:Heat release
332:
328:potassium-40
308:geoneutrinos
297:
248:
216:and thinner
203:
191:
184:
152:
140:
105:
62:
53:
45:
33:
32:
18:
1351:Geodynamics
1175:: 356–366.
861:. MIT News.
824:Geodynamics
781:(1): 5–24.
775:Solid Earth
335:geochemical
324:thorium-232
320:uranium-235
316:uranium-238
224:, a liquid
159:Lord Kelvin
120:ocean floor
118:and at the
1340:Categories
1053:(1): 4–9.
746:References
644:, and the
594:half-lives
389:kg isotope
367:kg isotope
326:(Th), and
251:conduction
230:inner core
226:outer core
128:insolation
1207:0012-821X
1182:1207.0853
1103:K/U ratio
1047:GSA Today
687:advective
667:volcanism
663:advection
416:kg mantle
395:kg mantle
375:Half-life
263:advection
97:geodynamo
85:volcanism
42:terawatts
1215:15284566
1142:Archived
1140:. 2015.
697:See also
351:Isotope
304:isotopes
234:fluidity
157:, later
1234:Bibcode
1187:Bibcode
1055:Bibcode
917:Bibcode
882:Bibcode
783:Bibcode
679:conduct
419:
407:
398:
386:
370:
358:
1252:
1213:
1205:
1024:
950:
831:
232:. The
222:mantle
122:, the
83:, and
1346:Earth
1211:S2CID
1177:arXiv
602:proxy
580:0.125
562:0.704
378:years
322:(U),
318:(U),
210:crust
187:watts
1250:ISBN
1203:ISSN
1022:ISBN
948:ISBN
829:ISBN
675:Mars
673:and
671:Moon
571:0.22
539:1.08
530:36.9
521:1.25
512:29.2
498:2.91
489:30.8
480:4.47
471:94.6
457:3.27
439:14.0
430:26.4
298:The
204:The
197:and
116:land
1242:doi
1195:doi
1173:361
1063:doi
925:doi
890:doi
791:doi
553:569
448:124
426:Th
87:.
1342::
1303:^
1291:^
1279:^
1263:^
1248:,
1240:,
1209:.
1201:.
1193:.
1185:.
1171:.
1150:^
1136:.
1094:^
1077:^
1061:.
1051:17
1049:.
1045:.
1004:^
946:.
923:.
913:91
911:.
888:.
876:.
805:^
789:.
777:.
773:.
753:^
693:.
683:Io
677:,
584:10
575:10
566:10
557:10
549:U
543:10
534:10
525:10
516:10
508:K
502:10
493:10
484:10
475:10
467:U
461:10
452:10
443:10
434:10
273:.
257:,
253:,
145:.
138:.
103:.
79:,
75:,
71:,
60:.
1244::
1236::
1217:.
1197::
1189::
1179::
1071:.
1065::
1057::
1030:.
956:.
931:.
927::
919::
896:.
892::
884::
878:2
837:.
799:.
793::
785::
779:1
582:×
573:×
564:×
555:×
541:×
532:×
523:×
514:×
500:×
491:×
482:×
473:×
459:×
450:×
441:×
432:×
413:/
410:W
392:/
364:/
361:W
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