Colorado Plateau Uplift: Solved?
In Nature, a team of geologists from four universities has proposed a new model for how the Colorado Plateau rose up over a mile from its surroundings.1 Based on seismic data, they propose a “mantle drip” mechanism by which parts of the lower crust dropped into the mantle, replaced by upwelling magma that condensed and floated, like an inner tube under a table in a swimming pool would cause it to rise.
The Colorado Plateau, covering a 300-mile-wide area in Arizona, Utah, Colorado and New Mexico, is well known for its dramatic landscapes, including the Grand Canyon. Its origin, however, has been mysterious (06/27/2010, “Colorado Plateau Stumps Geologists”). The authors wrote in their abstract, “The origin of these high elevations is unclear because unlike the surrounding provinces, which have undergone significant Cretaceous�Palaeogene compressional deformation followed by Neogene extensional deformation, the Colorado plateau is largely internally undeformed.” It’s as if this 130,000-square-mile province floated up more than a mile without cracking (06/24/2009). Anyone visiting Grand Canyon has probably been struck by the fact that the strata are flat as pancakes for hundreds of miles. And geologists believe this plateau rose and sank multiple times.
In brief, the model proposed by the team led by Anthony Levander [Rice University] concerns movements under the crust that can only be deduced indirectly, from echoes of earthquake waves that change velocity as they encounter crust, mantle, and asthenosphere (lower mantle) regions. Upwelling of mantle material from the asthenosphere would “destabilize continental lithosphere and drive uplift,” they said. The team went far beyond observations of current data, though, to propose multiple “mantle drip” episodes under the Colorado Plateau over 70 million years. Then they suggested that the current one, which had the most effect on the origin of the Grand Canyon, began 6 million years ago – reinforcing younger ages for the famous gorge.
Live Science swallowed the model wholesale without criticism, announcing, “Mystery of Grand Canyon’s Formation Revealed.” In smaller print, it backtracked slightly, saying, “The birth of the Grand Canyon and the Colorado Plateau through which it carved have been a geological mystery. Now a giant anomalous structure discovered on the underside of the plateau could shed light on how it was formed.”
As for Levander et al, “The timing of both Colorado plateau uplift and formation of the Grand Canyon remain unresolved,” the first line of their paper admitted. Their proposal that mantle drip and asthenosphere uplift “delaminates” the lower crust episodically, lifting the Colorado Plateau upward, can only be inferred indirectly, and only for the most recent episode (if there was more than one). “We propose that a series of such events have been removing the lithosphere from the Colorado plateau peripheries since the Farallon slab was removed 20-30 Myr ago, and that we have imaged only the most recent of these,” they ended. “These events are responsible for the uneven, outside-in magmatic invasion of the plateau, as well as uplift of its edges and interior.”
For more on mysteries of the Colorado Plateau, see 06/27/2010, 06/24/2009. For more on the age of Grand Canyon, see 09/16/2005, 11/30/2007, 03/05/2008.
1. Levander et al, “Continuing Colorado plateau uplift by delamination-style convective lithospheric downwelling,” Nature 472 (28 April 2011), pp. 461�465, doi:10.1038/nature10001.
Where are the philosophers of science? They are meekly talking amongst themselves in other parts of the campus, afraid to challenge the priesthood in the science department whom our culture has granted epistemic privilege to declare the way the world is. The timid philosophers are ignored by the science storytellers who run rampant in the journals, announcing their myths as truth to the gullible science media who are only too happy to declare to the peasants what the priesthood has “discovered.”
What are the observations here? Some seismic records in the present. Did these geologists see 70 million years, or even six? Of course not. They can see current landforms, magma outcrops, fault lines, locations of minerals and oil, mountain elevations and other present-day phenomena, and with seismic data can create maps of underground provinces where the echoes speed up or slow down (which they did). That’s about it.
The rest is inference. The word observation occurs only one time in the whole paper: “Petrologic and geochemical observations indicate that late Cretaceous�Palaeogene (~90�40?Myr ago) low-angle subduction hydrated and probably weakened much of the Proterozoic tectospheric mantle beneath the Colorado plateau.” No, it doesn’t indicate any such thing; what they mean is that the empirical observations appear to “fit” with a model or scenario that they find plausible, within the paradigm of long ages and plate tectonics (07/09/2004). Time is orthogonal to their data; there is no time evidence except in their heads.
Making inferences is fine if they can be tested, but who other than God could possibly know what actually happened and when? In contrast to the paltry references to observation, the word “suggests” and its derivatives occur 20 times, as in “The pattern suggests to us….” followed by the word three more times in the next two sentences. the word empirical is entirely absent; evidence appears four times, but only in references to how it “suggests” parts of the story they wish to tell.
Science was supposed to do more than provide suggestions. It was supposed to rely supremely on empirical observations. It has degenerated into a form of divination. The earthquake echoes say nothing about millions of years; the geologists used the echoes like tea leaves or crystal balls to prophesy. The prophecies are required to fit the monolithic paradigms of the Science Temple, where observations are mere props for scenarios that “suggest” unobservable events. These suggestions become plots for stories, handed off to the science reporters who, like court jesters, entertain the public with presumed wisdom from the sages. Choose your sages wisely, then you may become sagacious yourself.