Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions

1994 ◽  
Vol 21 (20) ◽  
pp. 2191-2194 ◽  
Author(s):  
Charles DeMets ◽  
Richard G. Gordon ◽  
Donald F. Argus ◽  
Seth Stein
Keyword(s):  
Time Scale ◽  
Geomagnetic Reversal ◽  
Plate Motions ◽  
Reversal Time

scholarly journals Indo-Atlantic plate accelerations around the Cretaceous-Paleogene boundary: A time-scale error, not a plume-push signal

Geology ◽  
2020 ◽  
Vol 48 (12) ◽  
pp. 1169-1173
Author(s):  
L. Pérez-Díaz ◽  
G. Eagles ◽  
K. Sigloch
Keyword(s):  
Time Scale ◽  
Plate Motion ◽  
Plate Tectonic ◽  
Flood Basalts ◽  
African Plate ◽  
Plate Motions ◽  
Motion Models ◽  
Reversal Time ◽  
Scale Error

Abstract It has been suggested that plume arrival at the base of the lithosphere introduces a push force that overwhelms the balance of torques driving plate circuits, leading to plate-tectonic reorganizations. Among the most compelling evidence in support of a “plume-push” mechanism is the apparent coincidence between eruption of the Deccan flood basalts around 67–64 Ma and a short-lived increase in Indian (and decrease in African) plate speed. Using existing and newly calculated high-resolution plate-motion models, we show that plate divergence rates briefly increased throughout the Indo-Atlantic circuit, contrary to the expected effects of plume-push. We propose that this circuit-wide spike in divergence rates is best explained as the artifact of a magnetic reversal time-scale error around the much studied Cretaceous-Tertiary boundary, and that the period spanning chrons C29–C28 lasted 70% longer than currently assumed. Corrected for this error, the residual long-term patterns of Indo-Atlantic plate motions and accompanying plate-tectonic reorganization are explicable in terms of maturation of the circuit’s spreading ridges, without invoking a significant plume-push force.

Plate Tectonics by Jerks

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Pacific Ocean ◽  
Time Scale ◽  
Plate Tectonics ◽  
Plate Motions ◽  
The Pacific ◽  
The Pacific Ocean ◽  
To Come

Anyone living around the Pacific Ocean will be familiar with plate tectonics by jerks. That is, periods of quiescence when nothing much seems to be happening, punctuated by very large, frequently fatal, and so far unpredictable, earth movements on a time scale of seconds. Surprisingly, careful measurements of plate motions over periods of just a few years (using geodetic methods that will be discussed in Part II) show that the plates are in fact moving almost continuously, so that what there is on all but the very shortest timescales is ‘plate tectonics by creeps’. Happily, in this context, jerks and creeps are not mutually exclusive and so, unlike the biologists, there is no need to come to blows.

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