330:), asthenosphere, and mesospheric shell. Daly's hypothetical depths to the lithosphere-asthenosphere boundary ranged from 80 to 100 km (50 to 62 mi), and the top of the mesospheric shell (base of the asthenosphere) were from 200 to 480 km (124 to 298 mi). Thus, Daly's asthenosphere was inferred to be 120 to 400 km (75 to 249 mi) thick. According to Daly, the base of the solid Earth mesosphere could extend to the base of the mantle (and, thus, to the top of the
1320:
31:
279:
between ferropericlase and bridgmanite to 10–14 depleting bridgmanite and enriching ferropericlase of Fe. The HS to LS transition are reported to affect the physical properties of the iron bearing minerals. For example, the density and incompressibility was reported to increase from HS to LS state in
265:
studies at relevant pressures and temperatures revealed that a lower mantle composed of greater than 93% bridgmanite phase has corresponding shear-wave velocities to measured seismic velocities. The suggested composition is consistent with a chondritic lower mantle. Thus, the bulk composition of the
198:
as the primary heat transport contribution, while conduction and radiative heat transfer are considered negligible. As a result, the lower mantle's temperature gradient as a function of depth is approximately adiabatic. Calculation of the geothermal gradient observed a decrease from 0.47 kelvins per
274:
The electronic environment of two iron-bearing minerals in the lower mantle (bridgmanite, ferropericlase) transitions from a high-spin (HS) to a low-spin (LS) state. Fe in ferropericlase undergoes the transition between 50–90 GPa. Bridgmanite contains both Fe and Fe in the structure, the Fe occupy
260:
model. The first principle calculation of the density and velocity profile across the lower mantle geotherm of varying bridgmanite and ferropericlase proportion observed a match to the PREM model at an 8:2 proportion. This proportion is consistent with the pyrolitic bulk composition at the lower
275:
the A-site and transition to a LS state at 120 GPa. While Fe occupies both A- and B-sites, the B-site Fe undergoes HS to LS transition at 30–70 GPa while the A-site Fe exchanges with the B-site Al cation and becomes LS. This spin transition of the iron cation results in the increase in
193:
The temperature of the lower mantle ranges from 1,960 K (1,690 °C; 3,070 °F) at the topmost layer to 2,630 K (2,360 °C; 4,270 °F) at a depth of 2,700 kilometres (1,700 mi). Models of the temperature of the lower mantle approximate
66:(PREM) separates the lower mantle into three sections, the uppermost (660–770 km), mid-lower mantle (770–2700 km), and the D layer (2700–2900 km). Pressure and temperature in the lower mantle range from 24–127 GPa and 1900–2600
154:
The lower mantle was initially labelled as the D-layer in Bullen's spherically symmetric model of the Earth. The PREM seismic model of the Earth's interior separated the D-layer into three distinctive layers defined by the discontinuity in
261:
mantle. Furthermore, shear wave velocity calculations of pyrolitic lower mantle compositions considering minor elements resulted in a match with the PREM shear velocity profile within 1%. On the other hand,
222:
suggesting homogeneity between the upper and lower mantle with a Mg/Si ratio of 1.27. This model implies that the lower mantle is composed of 75% bridgmanite, 17% ferropericlase, and 8% CaSiO
82:, and calcium-silicate perovskite. The high pressure in the lower mantle has been shown to induce a spin transition of iron-bearing bridgmanite and ferropericlase, which may affect both
199:
kilometre (0.47 °C/km; 1.4 °F/mi) at the uppermost lower mantle to 0.24 kelvins per kilometre (0.24 °C/km; 0.70 °F/mi) at 2,600 kilometres (1,600 mi).
932:
Murakami, Motohiko; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei (May 2012). "A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data".
163:
660–770 km: A discontinuity in compression wave velocity (6–11%) followed by a steep gradient is indicative of the transformation of the mineral
747:
1157:
1300:
1123:
211:-perovskite). The proportion of each component has been a subject of discussion historically where the bulk composition is suggested to be,
1036:"Effects of the Electronic Spin Transitions of Iron in Lower Mantle Minerals: Implications for Deep Mantle Geophysics and Geochemistry"
358:
467:
Katsura, Tomoo; Yoneda, Akira; Yamazaki, Daisuke; Yoshino, Takashi; Ito, Eiji (2010). "Adiabatic temperature profile in the mantle".
730:
390:
257:
138:. This measurement is estimated from seismic data and high-pressure laboratory experiments. The base of the mesosphere includes the
63:
848:
Wang, Xianlong; Tsuchiya, Taku; Hase, Atsushi (2015). "Computational support for a pyrolitic lower mantle containing ferric iron".
1349:
1323:
1247:
786:
526:
207:
The lower mantle is mainly composed of three components, bridgmanite, ferropericlase, and calcium-silicate perovskite (CaSiO
893:"Is the mantle chemically stratified? Insights from sound velocity modeling and isotope evolution of an early magma ocean"
1150:
1166:
146:
at approximately 2,700 to 2,890 km (1,678 to 1,796 mi). The base of the lower mantle is about 2700 km.
1344:
722:
1267:
1262:
182:
143:
1257:
1252:
1143:
168:
55:
1106:
Kumazawa, M; Fukao, Y (1977). "Dual Plate
Tectonics Model". In Manghnani, Murli; Akimoto, Syun-Iti (eds.).
665:"Enhanced convection and fast plumes in the lower mantle induced by the spin transition in ferropericlase"
331:
304:
262:
50:, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below
1305:
276:
253:
1229:
1224:
59:
345:, based on a combination of "mesosphere" and "plate", for postulated reference frames in which mantle
1288:
1047:
1000:
941:
904:
857:
798:
759:
676:
624:"Spin transition-induced anomalies in the lower mantle: implications for mid-mantle partial layering"
570:
476:
428:
216:
1211:
1195:
246:
123:
75:
1065:
973:
830:
604:
308:
127:
284:
of the lower mantle is currently being investigated and discussed using numerical simulations.
1293:
1185:
1119:
1016:
965:
957:
873:
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814:
726:
694:
645:
596:
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532:
522:
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444:
396:
386:
346:
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1111:
1055:
1008:
949:
912:
908:
865:
806:
767:
684:
635:
578:
484:
436:
789:(2010-01-08). "Iron Partitioning and Density Changes of Pyrolite in Earth's Lower Mantle".
327:
315:
1219:
1051:
1012:
1004:
945:
861:
802:
763:
680:
574:
480:
432:
229:
Chondritic: suggests that the Earth's lower mantle was accreted from the composition of
1115:
663:
Bower, Dan J.; Gurnis, Michael; Jackson, Jennifer M.; Sturhahn, Wolfgang (2009-05-28).
515:
79:
1338:
1200:
1092:
1085:
440:
1069:
834:
608:
256:. It was shown that the density profile along the geotherm is in agreement with the
1190:
977:
419:
Dziewonski, Adam M.; Anderson, Don L. (1981). "Preliminary reference Earth model".
280:
ferropericlase. The effects of the spin transition on the transport properties and
233:
suggesting a Mg/Si ratio of approximately 1. This infers that bridgmanite and CaSiO
156:
131:
90:
83:
17:
323:
164:
98:
917:
892:
891:
Hyung, Eugenia; Huang, Shichun; Petaev, Michail I.; Jacobsen, Stein B. (2016).
559:"Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity"
488:
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300:
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195:
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961:
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649:
592:
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448:
400:
810:
583:
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536:
342:
230:
175:
969:
826:
771:
600:
30:
1034:
Lin, Jung-Fu; Speziale, Sergio; Mao, Zhu; Marquardt, Hauke (April 2013).
689:
640:
623:
281:
242:
71:
953:
785:
Irifune, T.; Shinmei, T.; McCammon, C. A.; Miyajima, N.; Rubie, D. C.;
311:
97:
at a depth of 660 kilometers (410 mi). At a depth of 660 km,
94:
1060:
1035:
622:
Shahnas, M.H.; Pysklywec, R.N.; Justo, J.F.; Yuen, D.A. (2017-05-09).
139:
1135:
869:
319:
67:
174:
770–2700 km: A gradual increase in velocity indicative of the
70:. It has been proposed that the composition of the lower mantle is
991:
Badro, James (2014-05-30). "Spin
Transitions in Mantle Minerals".
318:
era, Daly (1940) inferred that the outer Earth consisted of three
51:
29:
167:
to bridgmanite and ferropericlase and the transition between the
1139:
664:
215:
Pyrolitic: derived from petrological composition trends from
185:
is considered the transition from the lower mantle to the
89:
The upper boundary is defined by the sharp increase in
178:
compression of the mineral phases in the lower mantle.
27:
The region from 660 to 2900 km below Earth's surface
1281:
1240:
1173:
748:"The density variation of the earth's central core"
383:
The Earth's lower mantle: composition and structure
266:lower mantle is currently a subject of discussion.
1108:High-Pressure Research: Applications in Geophysics
1084:
514:
241:Laboratory multi-anvil compression experiments of
303:) is derived from "mesospheric shell", coined by
34:Structure of Earth. The mesosphere is labeled as
752:Bulletin of the Seismological Society of America
719:'Mantle Plumes and Their Record in Earth History
517:Composition and petrology of the earth's mantle
130:. This reaction marks the boundary between the
1151:
993:Annual Review of Earth and Planetary Sciences
8:
469:Physics of the Earth and Planetary Interiors
421:Physics of the Earth and Planetary Interiors
1158:
1144:
1136:
1059:
916:
688:
639:
582:
712:
710:
708:
370:
245:simulated conditions of the adiabatic
86:dynamics and lower mantle chemistry.
7:
552:
550:
548:
546:
508:
506:
462:
460:
458:
414:
412:
410:
376:
374:
1087:Strength and Structure of the Earth
1013:10.1146/annurev-earth-042711-105304
897:Earth and Planetary Science Letters
74:, containing three major phases of
1116:10.1016/B978-0-12-468750-9.50014-0
359:Large low-shear-velocity provinces
237:-perovskites are major components.
25:
628:Geophysical Journal International
64:preliminary reference Earth model
46:, historically also known as the
1319:
1318:
1263:D’’ discontinuity (lower mantle)
1258:660 discontinuity (upper mantle)
1253:410 discontinuity (upper mantle)
1083:Daly, Reginald Aldworth (1940).
1110:. Academic Press. p. 127.
249:and measured the density using
142:zone which lies just above the
1:
669:Geophysical Research Letters
513:Ringwood, Alfred E. (1976).
441:10.1016/0031-9201(81)90046-7
381:Kaminsky, Felix V. (2017).
1366:
1248:Mohorovičić (crust–mantle)
918:10.1016/j.epsl.2016.02.001
723:Cambridge University Press
489:10.1016/j.pepi.2010.07.001
171:layer to the lower mantle.
1314:
295:(not to be confused with
1301:Gutenberg (upper mantle)
1282:Regional discontinuities
717:Condie, Kent C. (2001).
557:Badro, J. (2003-04-03).
909:2016E&PSL.440..158H
811:10.1126/science.1181443
584:10.1126/science.1081311
263:Brillouin spectroscopic
181:2700–2900 km: The
1350:Structure of the Earth
1306:Lehmann (upper mantle)
1241:Global discontinuities
772:10.1785/BSSA0320010019
341:, was introduced as a
314:professor. In the pre-
305:Reginald Aldworth Daly
226:-perovskite by volume.
39:
1040:Reviews of Geophysics
746:Bullen, K.E. (1942).
277:partition coefficient
33:
1268:Core–mantle boundary
690:10.1029/2009GL037706
270:Spin transition zone
231:chondritic meteorite
144:mantle–core boundary
1273:Inner-core boundary
1196:Lithospheric mantle
1052:2013RvGeo..51..244L
1005:2014AREPS..42..231B
954:10.1038/nature11004
946:2012Natur.485...90M
862:2015NatGe...8..556W
803:2010Sci...327..193I
764:1942BuSSA..32...19B
681:2009GeoRL..3610306B
575:2003Sci...300..789B
481:2010PEPI..183..212K
433:1981PEPI...25..297D
337:A derivative term,
150:Physical properties
18:Mesosphere (mantle)
1167:Structure of Earth
641:10.1093/gji/ggx198
385:. Cham: Springer.
309:Harvard University
122:) decomposes into
40:
1332:
1331:
1294:continental crust
1125:978-0-12-468750-9
1061:10.1002/rog.20010
850:Nature Geoscience
797:(5962): 193–195.
725:. pp. 3–10.
569:(5620): 789–791.
299:, a layer of the
254:X-ray diffraction
16:(Redirected from
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1322:
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1103:
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870:10.1038/ngeo2458
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475:(1–2): 212–218.
464:
453:
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124:Mg-Si perovskite
121:
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111:
110:
38:in this diagram.
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940:(7396): 90–94.
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521:. McGraw-Hill.
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326:(including the
316:plate tectonics
290:
272:
236:
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210:
205:
169:transition zone
152:
128:magnesiowĂĽstite
118:
115:
114:
113:
109:
106:
105:
104:
102:
93:velocities and
56:transition zone
52:Earth's surface
28:
23:
22:
15:
12:
11:
5:
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1361:
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1345:Earth's mantle
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1162:
1155:
1148:
1140:
1132:
1131:
1124:
1098:
1075:
1046:(2): 244–275.
1026:
999:(1): 231–248.
983:
924:
883:
856:(7): 556–559.
840:
777:
738:
731:
704:
655:
634:(2): 765–773.
614:
542:
527:
502:
454:
427:(4): 297–356.
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80:ferropericlase
54:; between the
36:Stiffer mantle
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1213:
1209:
1206:
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1201:Asthenosphere
1199:
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1192:
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1093:Prentice Hall
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732:0-521-01472-7
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392:9783319556840
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19:
1208:Lower mantle
1207:
1191:Upper mantle
1107:
1101:
1091:. New York:
1086:
1078:
1043:
1039:
1029:
996:
992:
986:
937:
933:
927:
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896:
886:
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787:Frost, D. J.
780:
758:(1): 19–29.
755:
751:
741:
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668:
658:
631:
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617:
566:
562:
516:
472:
468:
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420:
382:
336:
292:
291:
273:
250:
240:
217:upper mantle
206:
192:
159:velocities:
157:seismic wave
153:
136:lower mantle
135:
132:upper mantle
91:seismic wave
88:
84:mantle plume
47:
44:lower mantle
43:
41:
35:
903:: 158–168.
324:lithosphere
203:Composition
165:ringwoodite
99:ringwoodite
76:bridgmanite
1339:Categories
1230:Inner core
1225:Outer core
1212:Mesosphere
528:0070529329
365:References
339:mesoplates
301:atmosphere
297:mesosphere
293:Mesosphere
220:peridotite
196:convection
187:outer core
60:outer core
48:mesosphere
1021:0084-6597
962:0028-0836
878:1752-0894
819:0036-8075
699:0094-8276
650:0956-540X
593:0036-8075
497:0031-9201
449:0031-9201
401:988167555
343:heuristic
320:spherical
176:adiabatic
103:Îł-(Mg,Fe)
72:pyrolitic
1324:Category
1070:21661449
970:22552097
835:19243930
827:19965719
609:12208090
601:12677070
537:16375050
353:See also
347:hotspots
322:layers:
282:rheology
247:geotherm
243:pyrolite
58:and the
1048:Bibcode
1001:Bibcode
978:4387193
942:Bibcode
905:Bibcode
858:Bibcode
799:Bibcode
791:Science
760:Bibcode
677:Bibcode
571:Bibcode
563:Science
477:Bibcode
429:Bibcode
349:exist.
312:geology
288:History
251:in situ
183:D-layer
95:density
1289:Conrad
1186:Mantle
1174:Shells
1122:
1068:
1019:
976:
968:
960:
934:Nature
876:
833:
825:
817:
729:
697:
675:(10).
648:
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