779:
20:
342:
197:
as 'G'. In his 1942 publication of his model, the entire lower mantle was the D layer. In 1949, Bullen found his 'D' layer to actually be two different layers. The upper part of the D layer, about 1,800 km thick, was renamed D′ (D prime) and the lower part (the bottom 200 km) was
168:
The uppermost section of the outer core is thought to be about 500–1,800 K hotter than the overlying mantle, creating a thermal boundary layer. The boundary is thought to harbor topography, much like Earth's surface, that is supported by solid-state convection within the overlying mantle. Variations
214:
A seismic discontinuity occurs within Earth's interior at a depth of about 2,900 km (1,800 mi) below the surface, where there is an abrupt change in the speed of seismic waves (generated by earthquakes or explosions) that travel through Earth. At this depth, primary seismic waves (P waves) decrease
421:
Torsvik, Trond H.; Smethurst, Mark A.; Burke, Kevin; Steinberger, Bernhard (2006). "Large igneous provinces generated from the margins of the large low-velocity provinces in the deep mantle". Geophysical
Journal International. 167 (3): 1447–1460. Bibcode:2006GeoJI.167.1447T.
215:
in velocity while secondary seismic waves (S waves) disappear completely. S waves shear material and cannot transmit through liquids, so it is thought that the unit above the discontinuity is solid, while the unit below is in a liquid or molten form.
198:
named D″. Later it was found that D" is non-spherical. In 1993, Czechowski found that inhomogeneities in D" form structures analogous to continents (i.e. core-continents). They move in time and determine some properties of
149:
do not exist at all in the liquid portion of the core. Recent evidence suggests a distinct boundary layer directly above the CMB possibly made of a novel phase of the basic
394:
Bullen K., Compressibility-pressure hypothesis and the Earth’s interior. Monthly
Notices of the Royal Astronomical Society, Geophysical Supplements, 5, 355–368., 1949
185:("D double-prime" or "D prime prime") and is sometimes included in discussions regarding the core–mantle boundary zone. The D″ name originates from geophysicist
222:, a seismologist who made several important contributions to the study and understanding of the Earth's interior. The CMB has also been referred to as the
341:
WR Peltier (2007). "Mantle
Dynamics and the D" Layer: Impacts of the Post Perovskite Phase". In Kei Hirose; John Brodholt; Thome Lay; David Yuen (eds.).
230:
is most commonly used in reference to a decrease in seismic velocity with depth that is sometimes observed at about 100 km below the Earth's oceans.
434:
573:
616:
585:
169:
in the thermal properties of the CMB may affect how the outer core's iron-rich fluids flow, which are ultimately responsible for
759:
227:
359:
161:
studies have shown significant irregularities within the boundary zone and appear to be dominated by the
African and Pacific
565:
403:
Creager, K.C. and Jordan, T.H. (1986). Asperical structure of the core-mantle boundary. Geophys. Res. Lett. 13, 1497-1500
265:
162:
133:, at a depth of 2,891 km (1,796 mi) below Earth's surface. The boundary is observed via the discontinuity in
553:
226:, the Oldham-Gutenberg discontinuity, or the Wiechert-Gutenberg discontinuity. In modern times, however, the term
808:
782:
239:
189:'s designations for the Earth's layers. His system was to label each layer alphabetically, A through G, with the
706:
263:
Lekic, V.; Cottaar, S.; Dziewonski, A. & Romanowicz, B. (2012). "Cluster analysis of global lower mantle".
194:
609:
181:
An approximately 200 km thick layer of the lower mantle directly above the CMB is referred to as the
625:
477:
Schmerr, N. (2012-03-22). "The
Gutenberg Discontinuity: Melt at the Lithosphere-Asthenosphere Boundary".
412:
Czechowski L. (1993) Geodesy and
Physics of the Earth pp 392-395, The Origin of Hotspots and The D” Layer
351:
170:
94:
381:
716:
711:
602:
244:
223:
570:
764:
688:
683:
130:
127:
84:
73:
274:
747:
486:
443:
307:
270:
8:
803:
670:
654:
432:
Dziewonski, Adam M.; Anderson, Don L. (1981-06-01). "Preliminary reference Earth model".
296:
Lay, Thorne; Hernlund, John; Buffett, Bruce A. (2008). "Core–mantle boundary heat flow".
186:
150:
582:
490:
447:
311:
518:
369:
158:
138:
16:
Discontinuity where the bottom of the planet's mantle meets the outer layer of the core
752:
644:
522:
510:
502:
459:
455:
355:
323:
298:
203:
199:
123:
54:
32:
545:
639:
494:
451:
315:
278:
190:
731:
678:
589:
577:
154:
262:
282:
219:
538:
797:
659:
506:
463:
327:
43:
498:
666:
649:
514:
145:
velocities are much slower in the outer core than in the deep mantle while
134:
319:
594:
120:
146:
142:
19:
137:
velocities at that depth due to the differences between the
546:"Earth's interior: Redefining the Core–Mantle Boundary"
539:
Earth's Core–Mantle
Boundary Has Core-Rigidity Zone
431:
295:
344:Post-Perovskite: The Last Mantle Phase Transition
795:
543:
141:of the solid mantle and the molten outer core.
610:
435:Physics of the Earth and Planetary Interiors
206:. Later research supported this hypothesis.
617:
603:
340:
23:Schematic view of the interior of Earth.
209:
18:
476:
796:
624:
334:
598:
119:) of Earth lies between the planet's
566:Mineral phase change at the boundary
256:
218:The discontinuity was discovered by
153:mineralogy of the deep mantle named
583:About.com article on the name of D″
266:Earth and Planetary Science Letters
13:
228:Gutenberg discontinuity or the "G"
163:Large low-shear-velocity provinces
14:
820:
554:The American Geological Institute
544:Audrey Slesinger (January 2001),
532:
778:
777:
722:D’’ discontinuity (lower mantle)
717:660 discontinuity (upper mantle)
712:410 discontinuity (upper mantle)
470:
425:
415:
406:
397:
388:
289:
104:outer core–inner core boundary
1:
250:
456:10.1016/0031-9201(81)90046-7
176:
7:
571:Superplumes at the boundary
240:Core–mantle differentiation
233:
10:
825:
707:Mohorovičić (crust–mantle)
352:American Geophysical Union
283:10.1016/j.epsl.2012.09.014
773:
740:
699:
632:
95:Mohorovicic discontinuity
760:Gutenberg (upper mantle)
741:Regional discontinuities
269:. 357–358 (1–3): 68–77.
499:10.1126/science.1215433
275:2012E&PSL.357...68L
245:Ultra low velocity zone
224:Gutenberg discontinuity
809:Structure of the Earth
765:Lehmann (upper mantle)
700:Global discontinuities
171:Earth's magnetic field
108:
210:Seismic discontinuity
193:as 'A' and the inner
22:
727:Core–mantle boundary
354:. pp. 217–227.
320:10.1038/ngeo.2007.44
113:core–mantle boundary
100:core–mantle boundary
732:Inner-core boundary
655:Lithospheric mantle
491:2012Sci...335.1480S
485:(6075): 1480–1483.
448:1981PEPI...25..297D
422:doi:10.1111/j.1365-
312:2008NatGe...1...25L
139:acoustic impedances
626:Structure of Earth
588:2008-10-06 at the
576:2006-02-13 at the
159:Seismic tomography
109:
64: lower mantle
791:
790:
753:continental crust
361:978-0-87590-439-9
299:Nature Geoscience
204:mantle convection
33:continental crust
816:
781:
780:
619:
612:
605:
596:
595:
562:
561:
560:
527:
526:
474:
468:
467:
429:
423:
419:
413:
410:
404:
401:
395:
392:
386:
385:
379:
375:
373:
365:
349:
338:
332:
331:
293:
287:
286:
260:
82:
71:
63:
52:
41:
30:
824:
823:
819:
818:
817:
815:
814:
813:
794:
793:
792:
787:
769:
736:
695:
628:
623:
590:Wayback Machine
578:Wayback Machine
558:
556:
535:
530:
475:
471:
430:
426:
420:
416:
411:
407:
402:
398:
393:
389:
377:
376:
367:
366:
362:
347:
339:
335:
294:
290:
261:
257:
253:
236:
212:
179:
155:post-perovskite
126:and its liquid
107:
90:
87:
80:
76:
69:
65:
61:
57:
50:
46:
39:
35:
28:
17:
12:
11:
5:
822:
812:
811:
806:
789:
788:
786:
785:
774:
771:
770:
768:
767:
762:
757:
756:
755:
744:
742:
738:
737:
735:
734:
729:
724:
719:
714:
709:
703:
701:
697:
696:
694:
693:
692:
691:
686:
676:
675:
674:
664:
663:
662:
657:
642:
636:
634:
630:
629:
622:
621:
614:
607:
599:
593:
592:
580:
568:
563:
541:
534:
533:External links
531:
529:
528:
469:
442:(4): 297–356.
424:
414:
405:
396:
387:
360:
333:
288:
254:
252:
249:
248:
247:
242:
235:
232:
220:Beno Gutenberg
211:
208:
178:
175:
106:
105:
102:
97:
91:
89:
88:
79:
77:
68:
66:
60:
58:
49:
47:
38:
36:
27:
24:
15:
9:
6:
4:
3:
2:
821:
810:
807:
805:
802:
801:
799:
784:
776:
775:
772:
766:
763:
761:
758:
754:
751:
750:
749:
746:
745:
743:
739:
733:
730:
728:
725:
723:
720:
718:
715:
713:
710:
708:
705:
704:
702:
698:
690:
687:
685:
682:
681:
680:
677:
672:
668:
665:
661:
660:Asthenosphere
658:
656:
653:
652:
651:
648:
647:
646:
643:
641:
638:
637:
635:
631:
627:
620:
615:
613:
608:
606:
601:
600:
597:
591:
587:
584:
581:
579:
575:
572:
569:
567:
564:
555:
551:
547:
542:
540:
537:
536:
524:
520:
516:
512:
508:
504:
500:
496:
492:
488:
484:
480:
473:
465:
461:
457:
453:
449:
445:
441:
437:
436:
428:
418:
409:
400:
391:
383:
371:
363:
357:
353:
346:
345:
337:
329:
325:
321:
317:
313:
309:
305:
301:
300:
292:
284:
280:
276:
272:
268:
267:
259:
255:
246:
243:
241:
238:
237:
231:
229:
225:
221:
216:
207:
205:
201:
196:
192:
188:
184:
174:
172:
166:
164:
160:
156:
152:
148:
144:
140:
136:
132:
129:
125:
122:
118:
114:
103:
101:
98:
96:
93:
92:
86:
78:
75:
67:
59:
56:
48:
45:
44:oceanic crust
37:
34:
26:
25:
21:
726:
721:
667:Lower mantle
650:Upper mantle
557:, retrieved
549:
482:
478:
472:
439:
433:
427:
417:
408:
399:
390:
343:
336:
306:(1): 25–32.
303:
297:
291:
264:
258:
217:
213:
187:Keith Bullen
182:
180:
167:
135:seismic wave
116:
112:
110:
99:
53: upper
378:|work=
128:iron–nickel
804:Geophysics
798:Categories
689:Inner core
684:Outer core
671:Mesosphere
559:2011-03-24
251:References
151:perovskite
131:outer core
85:inner core
74:outer core
523:206538202
507:0036-8075
464:0031-9201
380:ignored (
370:cite book
328:1752-0894
183:D″ region
177:D″ region
165:(LLSVP).
783:Category
586:Archived
574:Archived
550:Geotimes
515:22442480
234:See also
200:hotspots
121:silicate
487:Bibcode
479:Science
444:Bibcode
308:Bibcode
271:Bibcode
147:S-waves
748:Conrad
645:Mantle
633:Shells
521:
513:
505:
462:
358:
326:
143:P-wave
124:mantle
83:
81:
72:
70:
62:
55:mantle
51:
42:
40:
31:
29:
669:(aka
640:Crust
519:S2CID
348:(PDF)
191:crust
679:Core
511:PMID
503:ISSN
460:ISSN
382:help
356:ISBN
324:ISSN
202:and
195:core
111:The
495:doi
483:335
452:doi
316:doi
279:doi
117:CMB
800::
552:,
548:,
517:.
509:.
501:.
493:.
481:.
458:.
450:.
440:25
438:.
374::
372:}}
368:{{
350:.
322:.
314:.
302:.
277:.
173:.
157:.
673:)
618:e
611:t
604:v
525:.
497::
489::
466:.
454::
446::
384:)
364:.
330:.
318::
310::
304:1
285:.
281::
273::
115:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
