Plate tectonics conserves angular momentum

C. Bowin

doi:10.5194/ee-5-1-2010

Phase change in subducted lithosphere, impulse, and quantizing Earth surface deformations

Solid Earth ◽

10.5194/se-6-1075-2015 ◽

2015 ◽

Vol 6 (3) ◽

pp. 1075-1085

Author(s):

C. O. Bowin ◽

W. Yi ◽

R. D. Rosson ◽

S. T. Bolmer

Keyword(s):

Angular Momentum ◽

Phase Change ◽

Spherical Harmonic ◽

Plate Tectonics ◽

Phase Changes ◽

Metallic Nickel ◽

Spherical Harmonic Degree ◽

The Pacific ◽

Seamount Chain ◽

Harmonic Degree

Abstract. The new paradigm of plate tectonics began in 1960 with Harry H. Hess's 1960 realization that new ocean floor was being created today and is not everywhere of Precambrian age as previously thought. In the following decades an unprecedented coming together of bathymetric, topographic, magnetic, gravity, seismicity, seismic profiling data occurred, all supporting and building upon the concept of plate tectonics. Most investigators accepted the premise that there was no net torque amongst the plates. Bowin (2010) demonstrated that plates accelerated and decelerated at rates 10−8 times smaller than plate velocities, and that globally angular momentum is conserved by plate tectonic motions, but few appeared to note its existence. Here we first summarize how we separate where different mass sources may lie within the Earth and how we can estimate their mass. The Earth's greatest mass anomalies arise from topography of the boundary between the metallic nickel–iron core and the silicate mantle that dominate the Earth's spherical harmonic degree 2 and 3 potential field coefficients, and overwhelm all other internal mass anomalies. The mass anomalies due to phase changes in olivine and pyroxene in subducted lithosphere are hidden within the spherical harmonic degree 4–10 packet, and are an order of magnitude smaller than those from the core–mantle boundary. Then we explore the geometry of the Emperor and Hawaiian seamount chains and the 60° bend between them that aids in documenting the slow acceleration during both the Pacific Plate's northward motion that formed the Emperor seamount chain and its westward motion that formed the Hawaiian seamount chain, but it decelerated at the time of the bend (46 Myr). Although the 60° change in direction of the Pacific Plate at of the bend, there appears to have been nary a pause in a passive spreading history for the North Atlantic Plate, for example. This, too, supports phase change being the single driver for plate tectonics and conservation of angular momentum. Since mountain building we now know results from changes in momentum, we have calculated an experimental deformation index value (1–1000) based on a world topographic grid at 5 arcmin spacing and displayed those results for viewing.

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Plate tectonics conserves angular momentum

eEarth Discussions ◽

10.5194/eed-4-21-2009 ◽

2009 ◽

Vol 4 (1) ◽

pp. 21-53

Author(s):

C. Bowin

Keyword(s):

Angular Momentum ◽

Plate Tectonics

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Quantizing Earth surface deformations

Solid Earth Discussions ◽

10.5194/sed-7-1059-2015 ◽

2015 ◽

Vol 7 (1) ◽

pp. 1059-1076

Author(s):

C. O. Bowin ◽

W. Yi ◽

R. D. Rosson ◽

T. S. Bolmer ◽

W. J. Sass

Keyword(s):

Angular Momentum ◽

Upper Mantle ◽

Plate Tectonics ◽

Global Analysis ◽

Pacific Plate ◽

Earth Surface ◽

Surface Deformations ◽

The Earth ◽

Analytical Results ◽

Euler Pole

Abstract. The global analysis of Bowin (2010) used the global 14 absolute Euler pole set (62 Myr history) from Gripp and Gordon (1990) and demonstrated that plate tectonics conserves angular momentum. We herein extend that analysis using the more detailed Bird (2003) 52 present-day Euler pole set (relative to a fixed Pacific plate) for the Earth's surface, after conversion to absolute Euler poles. Additionally, new analytical results now provide new details on upper mantle mass anomalies in the outer 200 km of the Earth, as well as an initial quantizing of surface deformations.

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