# 岩石圈

The tectonic plates of the lithosphere on Earth地球岩石圈的构造板块

Earth cutaway from center to surface, the lithosphere comprising the crust and lithospheric mantle (detail not to scale)地球剖面示意图，岩石圈由地壳和岩石圈地幔组成

A lithosphere (模板:Lang-grc [模板:Transl] for "rocky", and 模板:Wikt-lang [模板:Transl] for "sphere") is the rigid,[1] outermost shell of a terrestrial-type planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy. thumb|upright=1.75|The tectonic plates of the lithosphere on Earth

A lithosphere ( [] for "rocky", and [] for "sphere") is the rigid,Skinner, B.J. & Porter, S.C.: Physical Geology, page 17, chapt. The Earth: Inside and Out, 1987, John Wiley & Sons, outermost shell of a terrestrial-type planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy.

## Earth's lithosphere 地球岩石圈

Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the uppermost mantle. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle. The Lithosphere-Asthenosphere boundary is defined by a difference in response to stress: the lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plastic deformation.

Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the uppermost mantle. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle. The Lithosphere-Asthenosphere boundary is defined by a difference in response to stress: the lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plastic deformation.

The thickness of the lithosphere is thus considered to be the depth to the isotherm associated with the transition between brittle and viscous behavior.[2] The temperature at which olivine becomes ductile (~模板:Cvt) is often used to set this isotherm because olivine is generally the weakest mineral in the upper mantle.[3]

The thickness of the lithosphere is thus considered to be the depth to the isotherm associated with the transition between brittle and viscous behavior. The temperature at which olivine becomes ductile (~1,000 °C or 1,830 °F) is often used to set this isotherm because olivine is generally the weakest mineral in the upper mantle.

The lithosphere is subdivided horizontally into tectonic plates, which often include terranes accreted from other plates.

The lithosphere is subdivided horizontally into tectonic plates, which often include terranes accreted from other plates.

### History of the concept 概念由来

The concept of the lithosphere as Earth's strong outer layer was described by A.E.H. Love in his 1911 monograph "Some problems of Geodynamics" and further developed by Joseph Barrell, who wrote a series of papers about the concept and introduced the term "lithosphere".[4][5][6][7] The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong, solid upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere). These ideas were expanded by Reginald Aldworth Daly in 1940 with his seminal work "Strength and Structure of the Earth."[8] They have been broadly accepted by geologists and geophysicists. These concepts of a strong lithosphere resting on a weak asthenosphere are essential to the theory of plate tectonics.

The concept of the lithosphere as Earth's strong outer layer was described by A.E.H. Love in his 1911 monograph "Some problems of Geodynamics" and further developed by Joseph Barrell, who wrote a series of papers about the concept and introduced the term "lithosphere". The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong, solid upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere). These ideas were expanded by Reginald Aldworth Daly in 1940 with his seminal work "Strength and Structure of the Earth."Daly, R. (1940) Strength and structure of the Earth. New York: Prentice-Hall. They have been broadly accepted by geologists and geophysicists. These concepts of a strong lithosphere resting on a weak asthenosphere are essential to the theory of plate tectonics.

1911年，洛夫 A.E.H. Love在他的专著《地球动力学的若干问题》中阐述了岩石圈作为地球的外部坚硬圈层的概念。之后约瑟夫 · 巴雷尔 Joseph Barrell进一步介绍发展了“岩石圈”一词，并撰写了一系列与之相关的论文。[4][5][6][7] 这个概念是基于大陆地壳上存在显著地重力异常，他从中推断，在一个较弱的可流动层(软流圈)之上一定存在一个坚固的圈层(岩石圈)。1940年，雷金纳德 · 奥尔德沃斯 · 戴利 Reginald Aldworth Daly的开创性著作《地球的强度与结构》扩展了这些观点。[8] 至今它们已被地质学家和地球物理学家广泛接受。坚硬岩石圈位于软弱软流圈之上的概念对于板块构造理论 The Theory of Plate Tectonics至关重要。

### Types 岩石圈类型

Different types of lithosphere不同类型的岩石圈

The lithosphere can be divided into oceanic and continental lithosphere. Oceanic lithosphere is associated with oceanic crust (having a mean density of about 模板:Convert) and exists in the ocean basins. Continental lithosphere is associated with continental crust (having a mean density of about 模板:Convert) and underlies the continents and continental shelfs.[9]

The lithosphere can be divided into oceanic and continental lithosphere. Oceanic lithosphere is associated with oceanic crust (having a mean density of about ) and exists in the ocean basins. Continental lithosphere is associated with continental crust (having a mean density of about ) and underlies the continents and continental shelfs.

#### Oceanic lithosphere 大洋岩石圈

Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere. Young oceanic lithosphere, found at mid-ocean ridges, is no thicker than the crust, but oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge. The oldest oceanic lithosphere is typically about 模板:Convert thick.[3] This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick and dense with age. In fact, oceanic lithosphere is a thermal boundary layer for the convection[10] in the mantle. The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time.

$\displaystyle{ h\sim 2\sqrt{\kappa t} }$

Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere. Young oceanic lithosphere, found at mid-ocean ridges, is no thicker than the crust, but oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge. The oldest oceanic lithosphere is typically about thick. This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick and dense with age. In fact, oceanic lithosphere is a thermal boundary layer for the convectionDonald L. Turcotte, Gerald Schubert, Geodynamics. Cambridge University Press, 25 mar 2002 - 456 in the mantle. The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time.

h \, \sim \, 2\, \sqrt{ \kappa t }


$\displaystyle{ h\sim 2\sqrt{\kappa t} }$

Here, $\displaystyle{ h }$ is the thickness of the oceanic mantle lithosphere, $\displaystyle{ \kappa }$ is the thermal diffusivity (approximately 模板:Cvt) for silicate rocks, and $\displaystyle{ t }$ is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge, and V is velocity of the lithospheric plate.[11]

Here, h is the thickness of the oceanic mantle lithosphere, \kappa is the thermal diffusivity (approximately ) for silicate rocks, and t is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge, and V is velocity of the lithospheric plate.

Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. While chemically differentiated oceanic crust is lighter than asthenosphere, thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has the effect that at subduction zones, oceanic lithosphere invariably sinks underneath the overriding lithosphere, which can be oceanic or continental. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones. As a result, oceanic lithosphere is much younger than continental lithosphere: the oldest oceanic lithosphere is about 170 million years old, while parts of the continental lithosphere are billions of years old.[12][13]

Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. While chemically differentiated oceanic crust is lighter than asthenosphere, thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has the effect that at subduction zones, oceanic lithosphere invariably sinks underneath the overriding lithosphere, which can be oceanic or continental. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones. As a result, oceanic lithosphere is much younger than continental lithosphere: the oldest oceanic lithosphere is about 170 million years old, while parts of the continental lithosphere are billions of years old.

##### Subducted lithosphere 俯冲岩石圈

Geophysical studies in the early 21st century posit that large pieces of the lithosphere have been subducted into the mantle as deep as 模板:Convert to near the core-mantle boundary,[14] while others "float" in the upper mantle.[15][16] Yet others stick down into the mantle as far as 模板:Convert but remain "attached" to the continental plate above,[13] similar to the extent of the "tectosphere" proposed by Jordan in 1988.[17] Subducting lithosphere remains rigid (as demonstrated by deep earthquakes along Wadati–Benioff zone) to a depth of about 模板:Convert.[18]

Geophysical studies in the early 21st century posit that large pieces of the lithosphere have been subducted into the mantle as deep as to near the core-mantle boundary, while others "float" in the upper mantle. Yet others stick down into the mantle as far as but remain "attached" to the continental plate above, similar to the extent of the "tectosphere" proposed by Jordan in 1988. Subducting lithosphere remains rigid (as demonstrated by deep earthquakes along Wadati–Benioff zone) to a depth of about .

21世纪初的地球物理学研究认为，部分大块岩石圈板片已经俯冲到地幔中接近核-幔边界的位置，[14] 而其他岩石圈“漂浮”在上地幔中。[15][16] 而还有一些则一直在地幔中，仍然“附着”在其上的大陆板块，[13] 类似于约旦 Jordan1988年提出的“构造圈”的范围。[17] 俯冲岩石圈依然保持刚性(从沿着和达-贝尼奥夫带 Wadati–Benioff Zone发生的深部地震可以看出) ，深度约为600公里(370英里)。[18]

#### Continental lithosphere 大陆岩石圈

Continental lithosphere has a range in thickness from about 模板:Convert to perhaps 模板:Convert;[3] the upper approximately 模板:Convert of typical continental lithosphere is crust. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity. The oldest parts of continental lithosphere underlie cratons, and the mantle lithosphere there is thicker and less dense than typical; the relatively low density of such mantle "roots of cratons" helps to stabilize these regions.[12][13]

Continental lithosphere has a range in thickness from about 40 kilometres (25 mi) to perhaps 280 kilometres (170 mi); the upper approximately 30 to 50 kilometres (19 to 31 mi) of typical continental lithosphere is crust. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity. The oldest parts of continental lithosphere underlie cratons, and the mantle lithosphere there is thicker and less dense than typical; the relatively low density of such mantle "roots of cratons" helps to stabilize these regions.

Because of its relatively low density, continental lithosphere that arrives at a subduction zone cannot subduct much further than about 模板:Cvt before resurfacing. As a result, continental lithosphere is not recycled at subduction zones the way oceanic lithosphere is recycled. Instead, continental lithosphere is a nearly permanent feature of the Earth.[19]模板:Sfn

Because of its relatively low density, continental lithosphere that arrives at a subduction zone cannot subduct much further than about 100 km (62 mi) before resurfacing. As a result, continental lithosphere is not recycled at subduction zones the way oceanic lithosphere is recycled. Instead, continental lithosphere is a nearly permanent feature of the Earth.

## Mantle xenoliths 地幔捕掳体

Geoscientists can directly study the nature of the subcontinental mantle by examining mantle xenoliths[20] brought up in kimberlite, lamproite, and other volcanic pipes. The histories of these xenoliths have been investigated by many methods, including analyses of abundances of isotopes of osmium and rhenium. Such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite the mantle flow that accompanies plate tectonics.[21]

Geoscientists can directly study the nature of the subcontinental mantle by examining mantle xenoliths brought up in kimberlite, lamproite, and other volcanic pipes. The histories of these xenoliths have been investigated by many methods, including analyses of abundances of isotopes of osmium and rhenium. Such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite the mantle flow that accompanies plate tectonics.

## References 参考文献

1. Skinner, B.J. & Porter, S.C.: Physical Geology, page 17, chapt. The Earth: Inside and Out, 1987, John Wiley & Sons,
2. Parsons, B. & McKenzie, D. (1978). "Mantle Convection and the thermal structure of the plates" (PDF). Journal of Geophysical Research. 83 (B9): 4485. Bibcode:1978JGR....83.4485P. CiteSeerX 10.1.1.708.5792. doi:10.1029/JB083iB09p04485.
3. Pasyanos M. E. (2008-05-15). "Lithospheric Thickness Modeled from Long Period Surface Wave Dispersion" (PDF). Retrieved 2014-04-25.
4. Barrell, J (1914). "The strength of the Earth's crust". Journal of Geology. 22 (4): 289–314. Bibcode:1914JG.....22..289B. doi:10.1086/622155. JSTOR 30056401. S2CID 118354240.
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9. Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 2–4, 29. ISBN 9780521880060.
10. Donald L. Turcotte, Gerald Schubert, Geodynamics. Cambridge University Press, 25 mar 2002 - 456
11. Stein, Seth; Stein, Carol A. (1996). "Thermo-Mechanical Evolution of Oceanic Lithosphere: Implications for the Subduction Process and Deep Earthquakes". Subduction. Geophysical Monograph Series. 96: 1–17. Bibcode:1996GMS....96....1S. doi:10.1029/GM096p0001. ISBN 9781118664575.
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14. Burke, Kevin; Torsvik, Trond H. (2004). "Derivation of Large Igneous Provinces of the past 200 million years from long-term heterogeneities in the deep mantle". Earth and Planetary Science Letters. 227 (3–4): 531. Bibcode:2004E&PSL.227..531B. doi:10.1016/j.epsl.2004.09.015.
15. Replumaz, Anne; Kárason, Hrafnkell; Van Der Hilst, Rob D; Besse, Jean; Tapponnier, Paul (2004). "4-D evolution of SE Asia's mantle from geological reconstructions and seismic tomography". Earth and Planetary Science Letters. 221 (1–4): 103–115. Bibcode:2004E&PSL.221..103R. doi:10.1016/S0012-821X(04)00070-6.
16. Li, Chang; Van Der Hilst, Robert D.; Engdahl, E. Robert; Burdick, Scott (2008). "A new global model for P wave speed variations in Earth's mantle". Geochemistry, Geophysics, Geosystems. 9 (5): n/a. Bibcode:2008GGG.....905018L. doi:10.1029/2007GC001806.
17. Jordan, T. H. (1988). "Structure and formation of the continental tectosphere". Journal of Petrology. 29 (1): 11–37. Bibcode:1988JPet...29S..11J. doi:10.1093/petrology/Special_Volume.1.11.
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20. Nixon, P.H. (1987) Mantle xenoliths J. Wiley & Sons, 844 p.
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