Continental Lower Crust

Annual Review of Earth and Planetary Sciences - Tập 43 Số 1 - Trang 167-205 - 2015
Bradley R. Hacker1, P. B. Kelemen2, M. D. Behn3
1Department of Earth Science, University of California, Santa Barbara, California 93106;
2Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964;
3Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, 02543

Tóm tắt

The composition of much of Earth's lower continental crust is enigmatic. Wavespeeds require that 10–20% of the lower third is mafic, but the available heat-flow and wavespeed constraints can be satisfied if lower continental crust elsewhere contains anywhere from 49 to 62 wt% SiO2. Thus, contrary to common belief, the lower crust in many regions could be relatively felsic, with SiO2 contents similar to andesites and dacites. Most lower crust is less dense than the underlying mantle, but mafic lowermost crust could be unstable and likely delaminates beneath rifts and arcs. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogites and may continue to descend into the mantle, whereas more silica-rich rocks are transformed into felsic gneisses that are less dense than peridotite but more dense than continental upper crust. These more felsic rocks may rise buoyantly, undergo decompression melting and melt extraction, and be relaminated to the base of the crust. As a result of this refining and differentiation process, such relatively felsic rocks could form much of Earth's lower crust.

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Tài liệu tham khảo

10.1016/S0040-1951(98)00133-4

10.1016/0040-1951(89)90154-6

10.1007/BF00690174

10.1016/0301-9268(74)90014-X

Bassin C, 2000, Eos Trans. AGU, 81, F897

10.1029/2002GC000393

10.1029/2006JB004327

10.1038/ngeo1214

10.1029/JZ066i007p02199

10.1130/GSAT01711A.1

10.1007/978-3-540-88558-0_4

10.1016/S0012-821X(99)00277-0

10.1029/JB094iB12p17793

10.1029/95JB03446

10.1029/95JB00259

10.1130/G24098A.1

10.1130/0016-7606(1991)103<0037:HMLABC>2.3.CO;2

10.1029/95JB03452

10.1038/nature00855

Fountain DM, 1992, Continental Lower Crust

10.1016/0012-821X(81)90133-3

10.1016/S0016-7037(98)00121-5

10.1111/j.1525-1314.2010.00904.x

10.1016/j.lithos.2007.09.017

10.1016/S0012-821X(03)00265-6

10.1029/2005GC001075

10.1093/petrology/egl002

10.1016/j.lithos.2010.08.008

10.1016/j.epsl.2011.05.024

10.1029/92JB02276

10.1002/ggge.20079

10.1016/0016-7037(65)90078-5

10.1007/BF01132324

Holbrook WS, Mooney WD, Christensen NI. 1992. The seismic velocity structure of the deep continental crust. See Fountain et al. 1992, pp. 1–42

Holland HD, 2003, Treatise on Geochemistry, 3, 1

Holland HD, 2014, Treatise on Geochemistry, 4, 2

10.1002/ggge.20129

10.1130/B30238.1

10.1038/nature12758

10.1016/j.chemgeo.2011.10.022

Jaupart C, Mareschal JC. 2003. Constraints on crustal heat production from heat flow data. See Holland & Turekian 2003, pp. 65–84

Jordan EK, 2012, CentAm & IBM Geochem Database

10.1029/2000JB900357

10.1029/2002TC001383

10.1016/0016-7037(88)90206-2

10.1007/BF01829365

10.1007/BF00311004

Kelemen P, Behn MD. 2015. Relamination not delamination: Lower continental crust forms via arc magmatism followed by underplating of subducted, buoyant arc lavas and plutons. Nat. Geosci. In press

10.1016/0012-821X(93)90234-Z

Kelemen PB, Hanghøj K, Greene A. 2003a. One view of the geochemistry of subduction-related magmatic arcs, with an emphasis on primitive andesite and lower crust. See Holland & Turekian 2003, pp. 593–659

Kelemen PB, Hanghøj K, Greene A. 2014. One view of the geochemistry of subduction-related magmatic arcs, with an emphasis on primitive andesite and lower crust. See Holland & Turekian 2014, pp. 749–806

Kelemen PB, 2003, AGU Monogr., 138, 293

10.1016/0012-821X(95)00240-D

Kimbrough DL, 2007, Eos Trans. AGU, 88, T11B

10.1029/94TC02905

10.1016/S0009-2541(97)00027-2

10.1016/S0024-4937(68)80033-7

Laske G, 2013, Geophys. Res. Abstr., 15, EGU2013

Lee CTA. 2014. Physics and chemistry of continental crust recycling. See Holland & Turekian 214, pp. 423–56

10.1073/pnas.0711143105

10.1111/j.1525-1314.2010.00906.x

10.1029/2008JB005935

10.1073/pnas.1115671108

10.1130/0091-7613(1986)14<753:EOSAGG>2.0.CO;2

McLennan SM, 2005, Evolution and Differentiation of the Continental Crust, 92

10.1016/j.lithos.2008.05.008

10.1029/94JB00059

10.1029/97JB02122

Morgan P, 1987, Geophys. Res. Abstr., 14, 248

10.1029/96JB03737

10.1016/0040-1951(66)90030-8

10.1029/94JB03376

Percival JA, Fountain DM, Salisbury M. 1992. Exposed crustal cross sections as windows on the lower crust. See Fountain et al. 1992, pp. 317–62

10.1016/0012-821X(89)90111-8

10.1016/0040-1951(66)90009-6

Rudnick RL. 1992. Xenoliths—samples of the lower continental crust. See Fountain et al. 1992, pp. 269–316

10.1029/95RG01302

Rudnick RL, Gao S. 2003. Composition of the continental crust. See Holland & Turekian 2003, pp. 1–64

Rudnick RL, Gao S. 2014. Composition of the continental crust. See Holland & Turekian 2014, pp. 1–51

10.1016/0012-821X(90)90059-7

Rudnick RL, 1990, NATO Sci. Ser. C, 311, 523

10.1130/2007.1200(02)

10.1139/e67-058

10.1029/2005GC000958

10.1029/2006JB004897

10.1029/GL005i009p00749

10.1007/BF00690173

10.1111/j.1365-3121.2004.00589.x

Su YJ. 2002. Mid-ocean ridge basalt trace element systematics: constraints from database management, ICPMS analyses, global data compilation, and petrologic modeling. PhD Thesis, Columbia Univ., New York, NY

10.1093/petrology/egq002

10.1016/0040-1951(67)90056-X

10.1130/0091-7613(1999)027<0923:URATCO>2.3.CO;2

10.1002/ggge.20072

10.1093/petrology/egq056

10.1016/j.epsl.2007.11.025

10.1038/310575a0

10.2747/0020-6814.49.8.681

Yogodzinski GM, Brown ST, Kelemen P, Vervoort J, Portnya M, et al. 2015. The role of subducted basalt in the source of island arc magmas: evidence from seafloor lavas of the western Aleutians. J. Petrol. In press

10.1029/2009GC002625

10.1016/j.gr.2012.06.013

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Thông tin xuất bản

Annual Review of Earth and Planetary Sciences

Tập 43 Số 1

167-205

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