notto said:
If you look at the erosion of the chain, the oldest islands as dated by standard dating have eroded to the water line with the youngest islands still being built from the source of new material.
The independent lines of evidence from dating to erosion show us a fairly good picture of the timeline and mechanisms that created the hawaiin islands.
CPT is not one that explains all of the evidence.
How does CPT explain this?
http://www.soest.hawaii.edu/GG/HCV/haw_formation.html
Notice the first picture.
CPT doesn't present a model of island BUILDING that is needed to actually build the hawaiin island chain. It also doesnt present a model of island erosion or plate movement that matches the profile we see there.
You are starting with a preposition. If you would let the evidence lead you to your conclusion, you will find that it cannot explain the hawaiian islands better than the current mainstream model.
It doesn't explain why the 4 independent lines of evidence that we use to figure out the appoximate dating of the islands and pattern of formation all agree, these being
1) standard dating techniques
2) current movement rate of the plates
3) Erosion patterns of the islands down to the water level
4) That the water level has not changed as this erosion happened.
5) That there is no sediment on the islands from any catastrophy.
That all of these lines of evidence match to form a compresensive theory as to the formation of the islands is strong evidence that the model is correct. CPT's failure to address all of them (not to mention the other problems that have been pointed out to you related to your model) are an indication that the CPT model is NOT correct.
A catastrophic plate tectonics model for the formation of seamounts is not difficult to envision. Seamounts, guyots, and island chains are the result of isolated loci of extrusive volcanism. Current consensus supposes that island chains are a direct product of hot spots beneath the lithosphere, however there is a growing consideration of other hypotheses. As the virtue of simplicity in scientific research programs is rather favored it is preferred that there would only be one correct answer to the origin of such instances if local volcanism. IMO, history has shown that the best explanation is probably the combination of competing paradigms. While I think that this may be accurate, I am not going to advocate either answer as correct, but this topic is actively debated in geodynamics today. I think that CPT could potentially unify our understanding of local extrusive volcanism known to produce ocean island chains.
CPT could explain several unobserved expectations associated with the Hawaiian chain. Because conduction is a fair method of observable heat transport on geologic time scales and distance scales of the thickness of the thermal oceanic lithosphere, if the Hawaiian chain were the result of a thermal plume head, anomalously high heat flow would be predicted. This heat flow anomaly is not observed. As noted, because of the timescales involved with typical PT theory, the lack of a heat flow anomaly tends to disconfirm the existance of a hot spot origin. However because of the timescales associated with CPT, a significant heat flow anomaly may not be expected at the surface.
Perhaps CPT can also better explain the variable change in the rate of volcanism over the period of the formation of the chain. As the catastrophic regime of plate tectonics came to an end it might be expected that the higher rate of hot spot volcanism would continue for a brief period, adding mass to the large island.
http://www.mantleplumes.org/images/HawaiiMagRate_500.gif
I know that CPT is not free of problems in the explanation of observations associated with local ocean volcanism, island chains, seamounts, and guyots. Mainstream hypotheses still require development as well to eliminate various inconsistencies, although collectively they may be less abundant or significant. However I do think that CPT can do a considerable job even in its current rather undeveloped state as a hypothesis.
Such volcanism and the formation of seamounts and ocean island chains is explained rather well within CPT as it is in PT. The real topic of debate for CPT is the geomorphological evolution of seamount summits and the origin of guyots.
Their characteristic summit geomorphology consists of a rim of reef facies enclosing layered lagoonal facies with a pelagic cover above an eroded volcanic basement. I have long considered it a vexing mystery and admitted that it is impossible to envision a period of gradual erosion, subsequent atoll formation and pelagic sedimentation. However I recently have formulated and considered a possible solution.
Classical interpretation hypothesizes that seamounts build to exceed sea level and when volcanism deactivates it rides on the underlying plate and subsides gradually with age due to conductive cooling and thickening of the underlying lithosphere.
I have been entertaining different ideas regarding possible processes of heat transfer in the oceanic lithosphere during an event like CPT and had focused my attention on the process of propogating fracturing in the crust and deep lithosphere. I think there are at least two probable mechanisms for fracturing available, corresponding to large-scale and smaller fracturing 'events'. Those mechanisms being tensile stresses on the lithosphere (from fundamental plate motion mechanisms such a basal tractions and slab pull, (consider studies of the lithospheric stress field by Lithgow-Bertelloni and Guynn, 2004) and faulting due to the spherical geometry on which tectonics operates (eg. transformational faulting)) and instantaneous volumetric thermal contraction from hydorthermal penetration (perhaps a combination of both).
Now, considering the mechanism of fracturing, I have thought that large stress-related faulting and fracturing of the crust would occur on a frequency on the order of 10-200+ km on the ocean floor--fracture zones may constitute the largest sinks of rigorous hydrothermal cooling (or not--I have not directly confirmed this hypothesis). If we consider, as I have, that these instances of faulting in the ocean floor are the loci where lithospheric cooling take place, it would be at these large fractures that cooling would take place and thus where the oceanic lithosphere would thicken and cause ocean floor to subside. Adjacent to faults oceanic lithosphere would be relatively thinner, or at least much warmer. These initial thermal variations in the oceanic lithosphere would of course effect surface bathymetry.
Of course, seamounts formed on top of warm lithosphere would have a greater chance to exceed the height of sea level from the ocean floor. Subsequently, conductive heat transfer and further (less active) hydrothermal circulation in the thermally heterogenous lithosphere would bring it towards a thermal equilibrium and isotherms would have less extreme vertical variation (causing present lithospheric thickness and bathymetry to be near-parabolic with distance/age from the ridge). As in conventional theory, seamounts would ride on the ocean floor and subside, however not as a direct result of the age of underlying lithosphere (albeit, presumably over timescales of (presumably) thousands of years).
This makes it much easier to account for seamount wave erosion, atoll growth, lagoonal facies, and post-subsidance pelagic cover.
An illustrative diagram of the thermal Evolution of a fracture from progressive increase in penetration depth:
http://www.veracitystudios.com/other/lithosphere_fracture_thermal.gif
Bathymetry and lithospheric thickness (defined by an isotherm):
http://www.veracitystudios.com/other/lithosphere_thermalequilibrium.gif
Possible evolution of a cool fracture post-CPT:
http://www.veracitystudios.com/other/fracture_isothermal_evolution.gif
Clearly there is a lot of uncertainty in the processes involved in how I have
(and haven't) described them and how the mechanisms might operate. And although inconsistencies are sure to remain, I think that further research here could yield interesting results.
Lithgow-Bertelloni, C., and J. H. Guynn (2004), Origin of the lithospheric stress field, J. Geophys. Res., 109.
-Chris Grose