319:), 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
1309:
20:
268:
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
254:
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
187:
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
263:
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
249:
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
264:
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
182:
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
55:(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
143:
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
250:
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,
211:
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
71:, 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
188:
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).
921:
Murakami, Motohiko; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei (May 2012). "A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data".
152:
660–770 km: A discontinuity in compression wave velocity (6–11%) followed by a steep gradient is indicative of the transformation of the mineral
736:
200:-perovskite). The proportion of each component has been a subject of discussion historically where the bulk composition is suggested to be,
1025:"Effects of the Electronic Spin Transitions of Iron in Lower Mantle Minerals: Implications for Deep Mantle Geophysics and Geochemistry"
456:
Katsura, Tomoo; Yoneda, Akira; Yamazaki, Daisuke; Yoshino, Takashi; Ito, Eiji (2010). "Adiabatic temperature profile in the mantle".
127:. This measurement is estimated from seismic data and high-pressure laboratory experiments. The base of the mesosphere includes the
1146:
837:
Wang, Xianlong; Tsuchiya, Taku; Hase, Atsushi (2015). "Computational support for a pyrolitic lower mantle containing ferric iron".
1289:
1112:
196:
The lower mantle is mainly composed of three components, bridgmanite, ferropericlase, and calcium-silicate perovskite (CaSiO
882:"Is the mantle chemically stratified? Insights from sound velocity modeling and isotope evolution of an early magma ocean"
347:
135:
at approximately 2,700 to 2,890 km (1,678 to 1,796 mi). The base of the lower mantle is about 2700 km.
719:
379:
246:
52:
1338:
1312:
1236:
775:
515:
1139:
1095:
Kumazawa, M; Fukao, Y (1977). "Dual Plate
Tectonics Model". In Manghnani, Murli; Akimoto, Syun-Iti (eds.).
654:"Enhanced convection and fast plumes in the lower mantle induced by the spin transition in ferropericlase"
1155:
39:, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below
1333:
711:
334:, based on a combination of "mesosphere" and "plate", for postulated reference frames in which mantle
613:"Spin transition-induced anomalies in the lower mantle: implications for mid-mantle partial layering"
320:
1256:
1251:
171:
132:
1246:
1241:
1132:
157:
44:
293:
273:
of the lower mantle is currently being investigated and discussed using numerical simulations.
251:
1294:
1218:
1213:
265:
242:
48:
897:
1277:
1036:
989:
930:
893:
846:
787:
778:(2010-01-08). "Iron Partitioning and Density Changes of Pyrolite in Earth's Lower Mantle".
748:
665:
559:
465:
417:
205:
8:
1200:
1184:
235:
112:
64:
1040:
1001:
993:
934:
850:
791:
752:
669:
563:
469:
421:
218:
Chondritic: suggests that the Earth's lower mantle was accreted from the composition of
1104:
1054:
962:
819:
652:
Bower, Dan J.; Gurnis, Michael; Jackson, Jennifer M.; Sturhahn, Wolfgang (2009-05-28).
593:
504:
297:
116:
1282:
1174:
1108:
1074:
1005:
954:
946:
862:
811:
803:
715:
683:
634:
585:
577:
521:
511:
481:
433:
429:
385:
375:
335:
1058:
823:
597:
245:. It was shown that the density profile along the geotherm is in agreement with the
1169:
1100:
1044:
997:
966:
938:
901:
854:
795:
756:
673:
624:
567:
473:
425:
408:
Dziewonski, Adam M.; Anderson, Don L. (1981). "Preliminary reference Earth model".
269:
ferropericlase. The effects of the spin transition on the transport properties and
222:
suggesting a Mg/Si ratio of approximately 1. This infers that bridgmanite and CaSiO
1261:
1208:
316:
304:
906:
881:
880:
Hyung, Eugenia; Huang, Shichun; Petaev, Michail I.; Jacobsen, Stein B. (2016).
548:"Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity"
477:
68:
1327:
1189:
1081:
1009:
950:
866:
807:
687:
638:
581:
485:
437:
389:
799:
572:
547:
525:
1179:
958:
815:
760:
589:
145:
120:
79:
72:
1023:
Lin, Jung-Fu; Speziale, Sergio; Mao, Zhu; Marquardt, Hauke (April 2013).
678:
629:
612:
312:
153:
87:
942:
774:
Irifune, T.; Shinmei, T.; McCammon, C. A.; Miyajima, N.; Rubie, D. C.;
327:
289:
285:
208:
184:
175:
86:
at a depth of 660 kilometers (410 mi). At a depth of 660 km,
1049:
1024:
611:
Shahnas, M.H.; Pysklywec, R.N.; Justo, J.F.; Yuen, D.A. (2017-05-09).
1124:
858:
331:
219:
164:
40:
270:
231:
163:
770–2700 km: A gradual increase in velocity indicative of the
60:
59:. It has been proposed that the composition of the lower mantle is
980:
Badro, James (2014-05-30). "Spin
Transitions in Mantle Minerals".
307:
era, Daly (1940) inferred that the outer Earth consisted of three
300:
156:
to bridgmanite and ferropericlase and the transition between the
83:
653:
308:
128:
56:
19:
773:
204:
Pyrolitic: derived from petrological composition trends from
455:
651:
174:
is considered the transition from the lower mantle to the
920:
610:
879:
1022:
78:
The upper boundary is defined by the sharp increase in
167:
compression of the mineral phases in the lower mantle.
16:
The region from 660 to 2900 km below Earth's surface
737:"The density variation of the earth's central core"
372:
The Earth's lower mantle: composition and structure
255:lower mantle is currently a subject of discussion.
1097:High-Pressure Research: Applications in Geophysics
1073:
503:
407:
369:
230:Laboratory multi-anvil compression experiments of
292:) is derived from "mesospheric shell", coined by
23:Structure of Earth. The mesosphere is labeled as
1325:
836:
741:Bulletin of the Seismological Society of America
708:'Mantle Plumes and Their Record in Earth History
705:
506:Composition and petrology of the earth's mantle
119:. This reaction marks the boundary between the
1140:
1094:
982:Annual Review of Earth and Planetary Sciences
458:Physics of the Earth and Planetary Interiors
410:Physics of the Earth and Planetary Interiors
1147:
1133:
1048:
905:
677:
628:
571:
1088:
701:
699:
697:
501:
18:
258:
1326:
1154:
734:
234:simulated conditions of the adiabatic
138:
1128:
979:
694:
545:
75:dynamics and lower mantle chemistry.
1071:
541:
539:
537:
535:
497:
495:
451:
449:
447:
403:
401:
399:
365:
363:
1076:Strength and Structure of the Earth
1002:10.1146/annurev-earth-042711-105304
886:Earth and Planetary Science Letters
63:, containing three major phases of
13:
1105:10.1016/B978-0-12-468750-9.50014-0
348:Large low-shear-velocity provinces
226:-perovskites are major components.
14:
1350:
617:Geophysical Journal International
532:
492:
444:
396:
360:
53:preliminary reference Earth model
35:, historically also known as the
1308:
1307:
1252:D’’ discontinuity (lower mantle)
1247:660 discontinuity (upper mantle)
1242:410 discontinuity (upper mantle)
1072:Daly, Reginald Aldworth (1940).
1099:. Academic Press. p. 127.
1065:
1016:
973:
914:
873:
830:
767:
238:and measured the density using
131:zone which lies just above the
728:
645:
604:
191:
1:
353:
658:Geophysical Research Letters
502:Ringwood, Alfred E. (1976).
430:10.1016/0031-9201(81)90046-7
7:
370:Kaminsky, Felix V. (2017).
341:
10:
1355:
1237:Mohorovičić (crust–mantle)
907:10.1016/j.epsl.2016.02.001
712:Cambridge University Press
478:10.1016/j.pepi.2010.07.001
276:
160:layer to the lower mantle.
1303:
1270:
1229:
1162:
284:(not to be confused with
1290:Gutenberg (upper mantle)
1271:Regional discontinuities
706:Condie, Kent C. (2001).
546:Badro, J. (2003-04-03).
898:2016E&PSL.440..158H
800:10.1126/science.1181443
573:10.1126/science.1081311
252:Brillouin spectroscopic
170:2700–2900 km: The
1339:Structure of the Earth
1295:Lehmann (upper mantle)
1230:Global discontinuities
761:10.1785/BSSA0320010019
330:, was introduced as a
303:professor. In the pre-
294:Reginald Aldworth Daly
215:-perovskite by volume.
28:
1029:Reviews of Geophysics
735:Bullen, K.E. (1942).
266:partition coefficient
22:
1257:Core–mantle boundary
679:10.1029/2009GL037706
259:Spin transition zone
220:chondritic meteorite
133:mantle–core boundary
1262:Inner-core boundary
1185:Lithospheric mantle
1041:2013RvGeo..51..244L
994:2014AREPS..42..231B
943:10.1038/nature11004
935:2012Natur.485...90M
851:2015NatGe...8..556W
792:2010Sci...327..193I
753:1942BuSSA..32...19B
670:2009GeoRL..3610306B
564:2003Sci...300..789B
470:2010PEPI..183..212K
422:1981PEPI...25..297D
326:A derivative term,
139:Physical properties
1156:Structure of Earth
630:10.1093/gji/ggx198
374:. Cham: Springer.
298:Harvard University
111:) decomposes into
29:
1321:
1320:
1283:continental crust
1114:978-0-12-468750-9
1050:10.1002/rog.20010
839:Nature Geoscience
786:(5962): 193–195.
714:. pp. 3–10.
558:(5620): 789–791.
288:, a layer of the
243:X-ray diffraction
1346:
1311:
1310:
1149:
1142:
1135:
1126:
1125:
1119:
1118:
1092:
1086:
1085:
1079:
1069:
1063:
1062:
1052:
1020:
1014:
1013:
977:
971:
970:
918:
912:
911:
909:
877:
871:
870:
859:10.1038/ngeo2458
834:
828:
827:
771:
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732:
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703:
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681:
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643:
642:
632:
608:
602:
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543:
530:
529:
509:
499:
490:
489:
464:(1–2): 212–218.
453:
442:
441:
405:
394:
393:
367:
113:Mg-Si perovskite
110:
109:
108:
100:
99:
27:in this diagram.
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1323:
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1317:
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1225:
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1153:
1123:
1122:
1115:
1093:
1089:
1070:
1066:
1021:
1017:
978:
974:
929:(7396): 90–94.
919:
915:
878:
874:
835:
831:
772:
768:
733:
729:
722:
704:
695:
650:
646:
609:
605:
544:
533:
518:
510:. McGraw-Hill.
500:
493:
454:
445:
406:
397:
382:
368:
361:
356:
344:
315:(including the
305:plate tectonics
279:
261:
225:
214:
199:
194:
158:transition zone
141:
117:magnesiowĂĽstite
107:
104:
103:
102:
98:
95:
94:
93:
91:
82:velocities and
45:transition zone
41:Earth's surface
17:
12:
11:
5:
1352:
1342:
1341:
1336:
1334:Earth's mantle
1319:
1318:
1316:
1315:
1304:
1301:
1300:
1298:
1297:
1292:
1287:
1286:
1285:
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1233:
1231:
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1223:
1222:
1221:
1216:
1206:
1205:
1204:
1194:
1193:
1192:
1187:
1172:
1166:
1164:
1160:
1159:
1152:
1151:
1144:
1137:
1129:
1121:
1120:
1113:
1087:
1064:
1035:(2): 244–275.
1015:
988:(1): 231–248.
972:
913:
872:
845:(7): 556–559.
829:
766:
727:
720:
693:
644:
623:(2): 765–773.
603:
531:
516:
491:
443:
416:(4): 297–356.
395:
380:
358:
357:
355:
352:
351:
350:
343:
340:
278:
275:
260:
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228:
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212:
197:
193:
190:
180:
179:
168:
161:
140:
137:
105:
96:
69:ferropericlase
43:; between the
25:Stiffer mantle
15:
9:
6:
4:
3:
2:
1351:
1340:
1337:
1335:
1332:
1331:
1329:
1314:
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1234:
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1220:
1217:
1215:
1212:
1211:
1210:
1207:
1202:
1198:
1195:
1191:
1190:Asthenosphere
1188:
1186:
1183:
1182:
1181:
1178:
1177:
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1168:
1167:
1165:
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1136:
1131:
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1127:
1116:
1110:
1106:
1102:
1098:
1091:
1083:
1082:Prentice Hall
1078:
1077:
1068:
1060:
1056:
1051:
1046:
1042:
1038:
1034:
1030:
1026:
1019:
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1007:
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999:
995:
991:
987:
983:
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968:
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952:
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936:
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928:
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917:
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876:
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789:
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746:
742:
738:
731:
723:
721:0-521-01472-7
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519:
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387:
383:
381:9783319556840
377:
373:
366:
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349:
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329:
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89:
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76:
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66:
62:
58:
54:
50:
46:
42:
38:
34:
26:
21:
1197:Lower mantle
1196:
1180:Upper mantle
1096:
1090:
1080:. New York:
1075:
1067:
1032:
1028:
1018:
985:
981:
975:
926:
922:
916:
889:
885:
875:
842:
838:
832:
783:
779:
776:Frost, D. J.
769:
747:(1): 19–29.
744:
740:
730:
707:
661:
657:
647:
620:
616:
606:
555:
551:
505:
461:
457:
413:
409:
371:
325:
281:
280:
262:
239:
229:
206:upper mantle
195:
181:
148:velocities:
146:seismic wave
142:
125:lower mantle
124:
121:upper mantle
80:seismic wave
77:
73:mantle plume
36:
33:lower mantle
32:
30:
24:
892:: 158–168.
313:lithosphere
192:Composition
154:ringwoodite
88:ringwoodite
65:bridgmanite
1328:Categories
1219:Inner core
1214:Outer core
1201:Mesosphere
517:0070529329
354:References
328:mesoplates
290:atmosphere
286:mesosphere
282:Mesosphere
209:peridotite
185:convection
176:outer core
49:outer core
37:mesosphere
1010:0084-6597
951:0028-0836
867:1752-0894
808:0036-8075
688:0094-8276
639:0956-540X
582:0036-8075
486:0031-9201
438:0031-9201
390:988167555
332:heuristic
309:spherical
165:adiabatic
92:Îł-(Mg,Fe)
61:pyrolitic
1313:Category
1059:21661449
959:22552097
824:19243930
816:19965719
598:12208090
590:12677070
526:16375050
342:See also
336:hotspots
311:layers:
271:rheology
236:geotherm
232:pyrolite
47:and the
1037:Bibcode
990:Bibcode
967:4387193
931:Bibcode
894:Bibcode
847:Bibcode
788:Bibcode
780:Science
749:Bibcode
666:Bibcode
560:Bibcode
552:Science
466:Bibcode
418:Bibcode
338:exist.
301:geology
277:History
240:in situ
172:D-layer
84:density
1278:Conrad
1175:Mantle
1163:Shells
1111:
1057:
1008:
965:
957:
949:
923:Nature
865:
822:
814:
806:
718:
686:
664:(10).
637:
596:
588:
580:
524:
514:
484:
436:
388:
378:
51:. The
1199:(aka
1170:Crust
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