Expansion Tectonics: An Overview

Scientific Paper
Title	Expansion Tectonics: An Overview
Read in full	Link to paper
Author(s)	James Maxlow
Keywords	Expansion Tectonics, Plate Tectonics, Expanding Earth, palaeomagnetism, space geodesy
Published	2008
No. of pages	18

Read the full paper here

Abstract

One of the most profound statements the late Professor Sam Warren Carey (Emeritus Professor of Geology from the University of Tasmania) said to me when I first started researching Expansion Tectonics was: If 50 million believe in a fallacy it is still a fallacy. The point he was making was that the validity of any theory does not depend upon the number of people believing it; hence, an accepted theory may still be fundamentally wrong regardless of how many people believe it is correct. The Plate Tectonic interpretation of global data, for instance, is based on the fundamental premise that the Earths radius has remained constant, or near constant, throughout history. As will be outlined in this paper, this contrasts with an Expansion Tectonic interpretation of the same global data which is based on the fundamental premise that the Earths radius has been steadily increasing throughout Earth history.

Overview

James Maxlow presents here a summary of his modelling programme in Expansion Tectonics, the tradition running from Mantovani (1889, 1909) through Lindemann, Hilgenberg, Vogel and Koziar to Samuel Warren Carey, whose remark about fifty million believers and a fallacy opens the paper. Maxlow's central methodological claim is disarmingly simple and worth stating precisely: the geological, geographical and geophysical data used to support Plate Tectonics and Expansion Tectonics are identical. What separates the two accounts is one premise — whether Earth radius has been constant. Remove it, he argues, and the same data reconstruct better.

His concrete contribution is a set of spherical small-Earth models built from the Commission for the Geological Map of the World / UNESCO Bedrock Geological Map of the World (1991), which for the first time dated ocean-floor bedrock against the magnetic striping. Maxlow's procedure is mechanical rather than interpretive: strip off the youngest age-band of ocean crust, rejoin the exposed margins along their common mid-ocean ridge, and let the model radius fall to whatever value makes the join fit. Repeating this back through the striping gives, he reports, a better than 99 per cent plate fit at every stage, without arbitrary continental fragmentation and without subduction. He claims to have carried this to the early Archaean, located the ancient magnetic poles on every model, and derived a formula for radius change that yields exponential growth to a present rate of 22 mm/year.

The argument

The premise, and what removing it does

Plate tectonics requires that new crust generated along ~60,000 km of spreading ridges be destroyed elsewhere; subduction, Maxlow says, "is an artifact of the basic Plate Tectonic requirement for a constant Earth radius." On an expanding Earth the same ridge accretion simply increases surface area, and no disposal is needed. He stresses that the magnetic striping and age-dating that constrain modern reconstructions "was not available when Plate Tectonic theory was first proposed" — it was gathered afterwards, to quantify a history already assumed.

He also frames the epistemic situation: expansion, he says, "is not a theory seeking physical support. It is rather a concept proposed which best fits all existing physical geologic data", comparable to a laboratory observation that existing physics does not explain and which "begs for extended theoretical models".

The models

Eleven spherical models span the early Jurassic to the present. On them, prior to the Triassic — about 200 million years ago — the modern deep oceans do not exist: all continental crust forms a single shell enclosing an Earth of about 3,200 km radius, roughly 52 per cent of present. Continental-margin sediments (white on his figures) then form a global network marking shallow seas on-lapping the ancient lands. The maximum age of exposed sea-floor crust anywhere is early Jurassic, ~165 million years, which Maxlow treats as the key datum: the ocean floors are young everywhere, and on his reading that is because they did not previously exist rather than because older floor was consumed.

Palaeomagnetism

Maxlow treats the palaeomagnetic pole data as his strongest independent check. Plotted on his models, all pole determinations resolve into diametrically opposed north and south poles for each reconstruction — which they need not do if the reconstruction were wrong — allowing ancient equators and climate belts to be drawn. He reports the Precambrian and Palaeozoic North Pole in eastern Mongolia-China and the South Pole in west central Africa, with the apparent polar wander of the standard literature reinterpreted as continental migration during radius increase.

He confronts directly the 1960s-70s palaeomagnetic determinations of ancient radius, which concluded against expansion and which he identifies as the reason opinion consolidated behind plate tectonics. His objection is technical: the pole positions produced by conventional palaeomagnetic formulae are virtual geomagnetic poles, not actual ones, and the earlier workers therefore "made incorrect assumptions regarding application of the ancient latitude and colatitude to determine radius". Using his own pole locations for Africa, he states, the same data "conclusively quantify a Triassic Expansion Tectonic Earth radius."

Space geodesy

The other measurement he must answer is satellite geodesy. Maxlow's account is that when the global ground-station network became dense enough in the early 1990s, the solution showed a global excess in radius of 18 mm/year; that this was judged "extremely high" against expected post-glacial rebound of under 10 mm/year; that the researchers recommended vertical motion be "restricted to zero, because this is closer to the true situation than an average motion of 18 mm/yr"; and that current global solutions are accordingly constrained to zero by construction. He reads the 18 mm/year as real, and notes it is close to the 22 mm/year he derives independently from sea-floor spreading areas.

Geography, biogeography and climate

Maxlow argues the model reconstructions dispose of the large Panthalassa, Tethys and Iapetus oceans, replacing them with shallow seas on or between the ancient continents. Trilobite migration routes simplify, being limited only by deep-marine barriers and climate extremes. Triassic-Cretaceous dinosaurs cluster into three provinces coinciding with ancestral Permian reptile distributions, links disrupted as continents dispersed. He suggests the dinosaur extinction — which he notes "occurred over a period of 8 to 10 million years" — may be linked to rapid sea-level change as separate Mesozoic oceans rifted and merged, rather than to an asteroid impact. Permian Glossopteris straddles his ancient equator across high northern and southern latitudes, implying a tropical to cool-temperate range.

For climate he uses coal, thick sandstone and glacial rocks as wet indicators, evaporites as dry, limestone reefs as equatorial. He makes a point of Precambrian marine glacial deposits found alongside equatorial limestones and iron-rich rocks — "an enigma for Plate Tectonic reconstructions" — which on a small Earth are explained by the short pole-to-equator distance allowing sea ice to drift into equatorial waters. A consistent northward shift in climate zonation through the record he reads as evidence that an inclined rotational axis was established by the early Palaeozoic.

Mechanism, and the questions expansion must answer

Maxlow reviews five proposed causes and Carey's reasons for rejecting four: a pulsating Earth (fails to give exponential expansion; Carey saw no evidence for contractions); meteoric accretion (would give expansion decreasing with time, and explains neither sea-floor spreading nor oceanic crust distribution); constant mass with phase change of a super-dense core (implies unacceptable Precambrian surface gravity and density); and secular reduction of G (unacceptable former surface gravity, too small a magnitude, no exponential form). The fifth — a cosmological secular increase in Earth's mass — he calls the most popular and adopts: new matter condenses from energy within the core, accumulates at the core-mantle interface, swells the mantle, and appears at the surface as extension along the ridges. He describes matter generation as endothermic, so expansion should eventually decay.

Two derived objections are handled the same way. Ocean water: the argument that a small continuous-crust Earth would drown under 6.3 km of water assumes constant water volume; Maxlow has water and atmosphere out-gassed from the mantle at an accelerating rate. Mountain building: extension is said to preclude compression, but as radius grows the surface curvature flattens, so continental crust must "distort, bend, twist and turn", folding basin sediments and raising rifted margins into escarpments — a cyclical process of uplift, planation and erosion.

Assessment

The paper's genuine strength is that its central operation is checkable by anyone. Maxlow does not argue from a mechanism to a prediction; he takes a published, mainstream data product — the CGMW/UNESCO bedrock map — and applies a purely geometric procedure to it. Whether removing successive age-bands of ocean floor and rejoining the margins produces a closed continental shell at ~52 per cent radius is a question with an answer independent of anyone's theory of gravity or matter creation, and Maxlow deserves credit for putting the claim in that testable form. Two of his observations are also real puzzles that deserve better answers than they usually get: no ocean floor anywhere exceeds ~165-200 Ma, which is a striking fact about a supposedly 4.5-billion-year-old planet; and the Precambrian co-occurrence of glacial deposits with equatorial carbonates and banded iron is a long-standing difficulty for palaeogeography, however it is resolved. His candour that the mechanism is "still largely speculative" and that expansion "is not a theory seeking physical support" is more honest than the confident tone of much of the surrounding literature.

Against this, the argument has serious weaknesses, and they cluster around the fit itself. A better-than-99-per-cent fit is not an independent test of the reconstruction, because the model radius at each step is the free parameter chosen to make the fit close. The procedure has no way of failing: any set of margins can be joined on some sphere. What would make the fit evidential is a radius sequence determined independently and then found to produce a good join — which is exactly what the palaeomagnetic and geodetic sections are supposed to supply, and where the paper is at its weakest.

The palaeomagnetic argument is the most troubling, because as presented it is circular. Maxlow's complaint about virtual geomagnetic poles is technically correct — VGPs are not palaeomagnetic poles, and averaging over secular variation matters — but the fix he applies is to substitute "the Expansion Tectonic magnetic pole locations for Africa", that is, pole positions derived on his own reconstructions, and then report that the resulting radius confirms those reconstructions. That is assuming the conclusion. The original method it displaces was designed precisely to avoid this: palaeoradius is estimated from the angular separations of coeval palaeomagnetic directions within a single rigid continental block, a quantity that does not require knowing where the poles were in any global frame. Maxlow does not address that formulation, and the published results using it — including determinations from Australia, Africa and Laurentia — constrain radius change to a small fraction of what his models need.

The geodetic section misstates what the modern measurements are. Maxlow's 18 mm/year comes from an early-1990s network solution and its handling as a nuisance parameter, and his charge that the value was "simply zeroed out" describes the practice of that era. But space-geodetic determination of the mean Earth radius rate has since been done as a target quantity rather than a residual: combined ITRF solutions from VLBI, SLR, GPS and DORIS give a mean radius change of order 0.1 mm/year with uncertainty of a few tenths of a millimetre — statistically indistinguishable from zero and about two hundred times smaller than the 22 mm/year Expansion Tectonics requires. Independently, satellite laser ranging determination of the Earth's gravitational parameter GM and of the dynamic oblateness J₂ shows no secular mass increase at anything approaching the ~10¹⁷ kg/year the model implies. A paper published in 2008 cannot be faulted for missing work that postdates it, but a reader should not take the geodetic section as current.

Finally, the mechanism section concedes rather more than Maxlow acknowledges. Carey's rejections of four of the five candidate causes are all rejections on physical grounds — surface gravity, density, functional form — which means the argument does after all depend on physics, not on geology alone; the fifth option survives only because it is unconstrained. "New matter condenses from energy within the core" specifies no interaction, no energy source, and no reason for the rate to be exponential rather than anything else, and it sits awkwardly with Maxlow's own statement that the reaction is endothermic — endothermic in what, drawing heat from where. The mass required is not a detail: roughly a five-hundred-fold increase in mantle mass since the Archaean would leave a signature in surface gravity, in the Moon's orbit, and in the palaeontological record of animal size and skeletal loading, none of which the paper examines.

The right reading is probably the one Maxlow himself offers: the models are a systematic exploration of what the striping record looks like if one premise is dropped, and that exercise is legitimate and instructive. What the paper does not deliver is the independent measurement that would turn a good geometric fit into evidence.

See also

• James Maxlow
• Expansion Tectonics
• Expanding Earth
• Plate Tectonics
• Samuel Warren Carey
• Stavros T Tassos
• Neal Adams