Orogenic Fold-Belts and a Hypothesis of Earth Evolution

Dearnley, R.

doi:10.1016/b978-0-08-011465-1.50003-8

Cited by 12 publications

(7 citation statements)

References 239 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reviews of its status have been given by Dearnley (1966), Creer (1967), Carey (1976) and Wesson (1973. Reviews of its status have been given by Dearnley (1966), Creer (1967), Carey (1976) and Wesson (1973.…”

Section: Particle Physics and Cosmologymentioning

confidence: 99%

“…It is consistent with data on the secular accelerations of the Sun and the Moon, since the contraction leads to a small spin-up contribution to the Earth's rotation which tends to help in obtaining agreement between the total spin-down rates as inferred from theory and observation (Lyttleton, 1976). There are good reasons why the phase-change hypothesis has not been accepted by the majority of geophysicists, not the least important of which are the following two: (i) Mountain building does not require contraction but can instead be explained in a more natural way by plate tectonic processes perhaps working together with expansion (the account of the expanding Earth hypothesis by Dearnley (1966) pays particular attention to how expansion relates to mountain building); (ii) The cosmic abundance of iron is consistent with the hypothesis that the Earth's core is mainly metallic iron and not silicate (see Wesson, 1973. Lyttleton's claims that the phase-change hypothesis is superior to the other theories of the cores and interiors of the terrestrial planets (Lyttleton, 1973(Lyttleton, , 1977(Lyttleton, , 1978a are, moreover, meretricious.…”

Section: Particle Physics and Cosmologymentioning

confidence: 99%

See 1 more Smart Citation

Gravity, Particles, and Astrophysics

Wesson¹

1980

Astrophysics and Space Science Library

View full text Add to dashboard Cite

Section: Particle Physics and Cosmologymentioning

confidence: 99%

Section: Particle Physics and Cosmologymentioning

confidence: 99%

Gravity, Particles, and Astrophysics

Wesson¹

1980

Astrophysics and Space Science Library

View full text Add to dashboard Cite

“…Moorbath (1 975) identified 'accretion superevents' lasting 50-1 50 Ma defined by the groupings of rock forming (Rb-Sr, U-Pb) ages, low initial ratios and single stage Pb-Pb models at 3800-3500 and 2800-2500 Ma and representing juvenile additions to the continental crust which cannot be reconciled with remelting of older granitic crust. It is suggested that later Proterozoic peaks at 1900-1600 and 1200-900 Ma also define large accretionary events (see Dearnley 1966 andGlikson 1983); this is supported by 143Nd/ 14Nd ratios for the ca. 1800 Ma events which suggest growth from a homogeneous but previously depleted mantle (De Paolo 198 1).…”

Section: O N S O L I D a T I O N O F T H E C O N T I N E N T A L L mentioning

confidence: 94%

“…The relationship between consolidation and break-up of the continental lithosphere and a tentative assessment of its relationship to inferred modes of mantle convection. Thermal activity in the crust is summarized in terms of the histogram distribution of all radiometric ages after Dearnley (1966) and Rb-Sr isochron ages after Glikson (1983). Note that the 1150-900 Ma mobile episodedoesnot appear in the latter assessment because it is represented predominantly by K-Ar mineral ages.…”

Section: O N S O L I D a T I O N O F T H E C O N T I N E N T A L L mentioning

confidence: 99%

Proterozoic palaeomagne tism and single continent plate tectonics

Piper

1983

Geophysical Journal International

View full text Add to dashboard Cite

Summary. Proterozoic (2700–570 Ma) palaeomagnetic poles from the major shields conform to a single apparent polar wander path on a contiguous reconstruction which brings into alignment, both with each other and with the long axis of the primary continental crust, tectonic and magmatic features ranging from late Archaean (≤ 2900 Ma) to late Proterozoic (1100 Ma) age. This discovery implies that the continental lithosphere behaved on a megatectonic scale as a single coherent plate during this era, subject to internal deformation but not breaking up in a brittle fashion until late Precambrian times. Peripheral parts of the Supercontinent were redistributed over a short interval at ca. 1100 Ma but the continental crust was not dismembered and widely dispersed until 570–530 Ma. This latter episode correlates with the Proterozoic‐Phanerozoic transition and defines the onset of multi‐continent Plate Tectonics. The Proterozoic apw record comprises nine large loops with periods ranging from 270 to 110Ma and averaging 200Ma. Between 2150 and 1000 Ma the loops had a similar signature and their resultant effect was to return the continental lithosphere repeatedly to a stable position with its centre at the geographic pole, probably by the Goldreich‐Toomre mechanism. This periodicity correlates with theoretical and experimental studies of mantle convection predicting avalanche‐type behaviour due to build up of instability in the surface boundary layer with cycles of 50–200 Ma. The consolidation of the continental lithosphere defines several phases in the history of mantle convection: (1) between 3500 and 2800 Ma the sialic scum resulting from differentiation of a thickened and subducting lithosphere was accumulated into the primary body by a large scale mantle convection system; (2) this operated simultaneously with a subcontinental‐lithosphere small‐scale (50–100 km) convection system showing a transition from bimodal to cylindrical roll mode represented by the later greenstone belts (2900–2200 Ma) and straight belts (ca. 2800–2400 Ma); (3) a transition to larger‐scale episodic subcontinental convection is represented by the Proterozoic mobile belts (2200–1100 Ma); (4) a modification of the major suboceanic lithosphere convection is suggested by reorganization of the peripheral shields at 1100 Ma, and (5) a subdivision of this major system resulted in continental dispersal during Lower Cambrian times.

show abstract

“…According to the London geologist Raymond Dearnley, various methods of estimating the growth of Earth "strongly suggest a relatively uniform rate of expansion of the Earth's radius of about 0.65 ± 0.25 mm per year as far back as 4500 Mya" (Dearnley, 1966(Dearnley, , p. 32, 1965. At the 1967 Newcastle meeting on geophysics he repeated the conclusion, noting that the value was almost the same as the cosmological Hubble expansion rate (Dearnley, 1969;MacDougal et al, 1963).…”

Section: Does Expansion Depend On G(t)?mentioning

confidence: 99%

Expanding Earth and declining gravity: a chapter in the recent history of geophysics

Kragh¹

2015

Hist. Geo Space. Sci.

View full text Add to dashboard Cite

Abstract. Although speculative ideas of an expanding Earth can be found before World War II, it was only in the 1950s and 1960s that the theory attracted serious attention among a minority of earth scientists. While some of the proponents of the expanding Earth adopted an empiricist attitude by disregarding the physical cause of the assumed expansion, others argued that the cause, either fully or in part, was of cosmological origin. They referred to the possibility that the gravitational constant was slowly decreasing in time, as first suggested by P. Dirac in 1937. As a result of a stronger gravitation in the past, the ancient Earth would have been smaller than today. The gravitational argument for an expanding Earth was proposed by P. Jordan and L. Egyed in the 1950s and during the next 2 decades it was discussed by several physicists, astronomers and earth scientists. Among those who for a period felt attracted by "gravitational expansionism" were A. Holmes, J. Tuzo Wilson and F. Hoyle. The paper examines the idea of a varying gravitational constant and its impact on geophysics in the period from about 1955 to the mid-1970s.

show abstract

Orogenic Fold-Belts and a Hypothesis of Earth Evolution

Cited by 12 publications

References 239 publications

Gravity, Particles, and Astrophysics

Gravity, Particles, and Astrophysics

Proterozoic palaeomagne tism and single continent plate tectonics

Expanding Earth and declining gravity: a chapter in the recent history of geophysics

Contact Info

Product

Resources

About