Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit

Williams, George E.

doi:10.1029/1999rg900016

Cited by 330 publications

(300 citation statements)

References 71 publications

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“…Both the mantle and core have evolved since then, including secular cooling, supercontinent aggregation and dispersal, probable nucleation of the solid inner core (Labrosse, 2003), and major reductions in the rate of Earth's rotation due to tidal friction (Williams, 2000). In spite of these evolutionary changes to the core-mantle system, the overall pattern of modulation of geomagnetic reversals persists without any clear indication of a trend.…”

Section: Unresolved Issuesmentioning

confidence: 99%

Mantle superplumes induce geomagnetic superchrons

Olson

Amit

2015

Front. Earth Sci.

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We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and partial collapse of the two seismically-imaged lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of average core heat flux normalized by the difference between the present-day core heat flux and the core heat flux at geomagnetic superchron onset. A low-order polynomial fit to the 0-300 Ma Geomagnetic Polarity Time Scale (GPTS) reveals that a decrease in core heat flux relative to present-day of ∼30% can account for the Cretaceous Normal Polarity and Kiaman Reverse Polarity Superchrons, whereas the hyper-reversing periods in the Jurassic require a core heat flux equal to or higher than present-day. Possible links between GPTS transitions, large igneous provinces (LIPs), and the two lower mantle superplumes are explored. Lower mantle superplume growth and collapse induce GPTS transitions by increasing and decreasing core heat flux, respectively. Age clusters of major LIPs postdate transitions from hyper-reversing to superchron geodynamo states by 30-60 Myr, suggesting that superchron onset may be contemporaneous with LIP-forming instabilities produced during collapses of lower mantle superplumes.

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Section: Unresolved Issuesmentioning

confidence: 99%

Mantle superplumes induce geomagnetic superchrons

Olson

Amit

2015

Front. Earth Sci.

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“…"According to current measurements in DORIS, GPS, GRACE, VLBI projects, the radius of the Earth in the XXI century has not been changing (the measurement error does not exceed 0.2 mm per year) [11][12][13]. The paleomagnetic and paleogeologic data suggest that the radius of the Earth has not changed significantly over the last 400-600 million years at least" [14,15].…”

Section: Discussionmentioning

confidence: 99%

Non-Radiometric Dating of the Age of the Earth: Implications From Fossil Coral Evidence

Mazhenov¹,

Shalkarbekov²

2015

Int J Adv Innovat Thoughts Ideas

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Radioisotope dating has revealed that the age of the Earth is 4.54-4.6 billion years, and these results are widely accepted. However, as with all searches for truth in science, facts should be supported by multiple lines of evidence. Thus, determining the age of the Earth with alternative techniques could serve to strengthen the conclusions that have been reached with radioisotope dating methods. In this paper, a different approach to solving the problem is proposed. As is known from studies of 400 million year old fossil corals, Earth years were 400 days in duration in distant times because the Earth rotated faster than it does today. According to calculations based on the fundamental law of rotational motion dynamics involving the moment of inertia of a body, the radius of the ancient Earth 400 million years ago was 553.379 km less than it is today. This brings us to the impressive conclusion that Earth's radius grew on average by 1.3834475 mm per year over the past 400 million years. Let us call this the evolutionary Earth growth constant; it does not take into account the effect of lunar tidal friction. If the present day Earth radius of 6371 km is divided by 1.3834475 mm per year, we can estimate the growth time of the Earth from its beginning to the presentthe growth time is 4.6 billion years, which is consistent with the radioisotope data, i.e., 4.6 billion years equals the age of the Earth! This new method for measuring Earth's age not only confirms outcomes obtained with radiological methods, but it poses new problems and avenues of research for paleogeologists.

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“…Amongst these was the problem of Earth's rotation. If the Earth's radius were increasing at the fast expansion rate, then the changing moment of inertia of the Earth would have led to significant, observable slowing in the Earth's rotation over the last 200 Ma, well beyond the rate of slowing that has actually been observed (Weijermars, 1986;Williams, 2000). The Earth's density and also its surface gravity would also have been much larger in the Palaeozoic than observations appear to allow.…”

Section: Introductionmentioning

confidence: 95%

Indications from space geodesy, gravimetry and seismology for slow Earth expansion at present – comment on “The Earth expansion theory and its transition from scientific hypothesis to pseudoscientific belief” by Sudiro (2014)

Edwards

2016

Hist. Geo Space. Sci.

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Abstract. In a recent article in this journal, Paolo Sudiro (2014) considered the long history of the expanding Earth theory and its recent descent into what he termed "pseudoscientific belief". The expanding Earth theory contends that the radius of the Earth was once one-half to two-thirds of its current value, with the Earth's continents forming a continuous sialic cover over the Earth. The theory has had two main variants: slow expansion at about 0.5 mm yr −1 radial increase since the time of Earth's formation and fast expansion at about 5 mm yr −1 since the Triassic. Focusing on Maxlow's model, Sudiro thoroughly addresses the possibly insurmountable difficulties of the fast version, such as an improbably high density and surface gravity prior to 200 Ma. He omits, however, any discussion of the slow expansion model, which has a longer history and far fewer theoretical difficulties. Moreover, recent evidence from space geodesy, gravimetry and seismology indicates that the Earth at present may be slowly expanding at 0.1-0.4 mm yr −1 . It is concluded that Sudiro's obituary of the expanding Earth theory as a whole must be considered premature at this time.

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Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit

Cited by 330 publications

References 71 publications

Mantle superplumes induce geomagnetic superchrons

Mantle superplumes induce geomagnetic superchrons

Non-Radiometric Dating of the Age of the Earth: Implications From Fossil Coral Evidence

Indications from space geodesy, gravimetry and seismology for slow Earth expansion at present – comment on “The Earth expansion theory and its transition from scientific hypothesis to pseudoscientific belief” by Sudiro (2014)

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