Parks Rank?

National parks are the best idea we ever had. Absolutely American, absolutely democratic, they reflect us at our best rather than our worst.-Wallace Stegner, 1983

National parks don’t crack the top ten of America’s best ideas.Alan Spears, NPCA

With proposals to hike the admission price to the most popular parks, we are getting a number of turns off of the Stegner quote (like the New York Times’s “Parks of the 1 Percent”). So maybe it would be good to think about this a bit.

Stegner’s over the top characterization of national parks has always seemed a reach (does it really beat out “all men are created equal”? free public schools?), but Spears’s deliberately provocative counter kind of misses the mark too. Spears says there are lots of other better ideas and then cites the 13th and 14th amendments, Civil Rights Act and some other legislative milestones.  But those were not the ideas–those were repair jobs on the imperfectly executed big idea put forth in the Declaration of Independence. So maybe his downgrading of the parks as a big idea was too severe.

Read More…

Where is Real Science Published?

There is a tremendous tension now in science that might not be terribly obvious to those outside the field.  “Publish or perish” is reaching into corners that never should have seen such pressure even as it seems more daunting in places where it was always important, and the response of the community has bifurcated into two misguided directions.

On the one hand, there are the predatory journals that publish anything that accompanies a check. While many seem to operate on deception, using names that closely parallel established peer-review journals, others are pretty clearly their own thing. The amazing insight, as presented in a New York Times piece, is that many scientists who publish in these journals are well aware that they are, in essence, true vanity publishers. Worse, such publications are apparently aiding many in advancing their careers. The existence of many of these journals is not even regarded as a negative by some who advocate for review-free publication of anything anybody wants to call science; the absence of peer-review is a feature, not a bug.

On the other hand there is the quantification of prestige that many want to apply to scientific publications.  The worst application is, without doubt, the financial reward for merely publishing in a journal with a high impact factor. Read More…

War on Science, EPA edition

UPDATE: Science has a piece fully explaining this latest expulsion of academic science from the EPA. And Ars Technica discusses this with a bit of different context.

Some time ago, GG suggested that what many were taking as a “war on science” was more a war on particular parts of science, that the offenders were in fact exploiting science where it was financially remunerative and opposing it where it wasn’t. But actions at the Environmental Protection Agency really look like outright war on science, period.

Consider these actions:

It is hard to look at these actions and see them as anything other than ostrich-like in trying to avoid hearing things some don’t want to hear.  These kind of blanket rules seem designed to stifle scientific participation in any aspect of the EPA’s work.

The Schist-Melt Conundrum

One of the things that has gotten increasingly glaringly obvious is that there is a big problem lurking in the Mojave Desert. The problem, most simply, is that the dates of plutons in the Mojave overlap rather severely with the dates of emplacement of schists in the lower crust. Dating activity reported at the GSA meeting this past week included a bunch of 72-85 Ma intrusive rocks, mostly metaluminous plutonic rocks that seem likely to have had a mantle melt as a primary source, sitting above the area where the Rand Schist was supposedly being emplaced.  Just as bad for mega-flat slab advocates, the extent of these 70-something plutonic rocks is now extensive enough that it seems awfully hard to sneak in a big flat slab through the Mojave–and even if you do, it is coming in way too late to be starting the Laramide orogeny, which was already chunking along at this point.

So two questions: what is going on in the Mojave? and what are the broader implications inland?

Read More…

Dating Stumbles

So Paul Braterman was asking the other day about some advance knowledge of how the new infatuation with detrital zircons and HeFTy plots might be misread in some circles. This is really a question for a real card-carrying geochronologist, but GG will take a swing at it because he’s kind of worried a bit about this and is not staking out any particular terrain.

For the most part both of these are simple variants on classical age-dating techniques (uranium-lead dating and potassium-argon dating), and though rooted in geochronology, most of the applications are elsewhere (e.g., detrital zircons are mainly used as a means of identifying the sources (provenance) of clastic sedimentary rocks, while HeFTy (Helium-Fission Track analysis) is dominantly a means of assessing the thermal or unroofing history of some body of rock through application of multiple geochronometers). But they start pointing at things that could be misleading, so let’s look a bit more….

Read More…

The Age of Ages

Not so long ago, you would get a date (one) for some igneous unit.  And that was hard enough that you wouldn’t bother with two or three. Dates were so valuable one well-known scientist had an equally well-known safe to keep them in (we still live with a rule at GSA related to this fellow in that recording or photographing presentations is forbidden). Then there was recognition that some systems closed up shop at different temperatures than others.  So maybe you’d see a U-Pb date and a K-Ar date.  A few labs did this work, often under contract; you (the non-geochronologist) might wrap up a sample and send it on to be dated. Dates, while important, were just some numbers that were part of a geologic story.

Now, however, dates are everything (that, and chemical and isotropic analyses at the tiniest levels, which is a related outgrowth). It seems like more than half the talks at GSA involved dating detrital zircons, or dating zoning in zircons, or dating helium diffusing out of zircons. Dates are used to understand erosion, tectonics, stratigraphy, sedimentology, volcanology, paleoearthquakes, glacial action and more. Arguably this ability is utterly changing geomorphology and sedimentology and it seeps into other fields more slowly.

If you haven’t seen a pdf (probability distribution function, not portable document format) or a HEFTY thermal evolution-o-gram, you haven’t been in a geological talk in some time now.

And so it is about time for the revenge of the grumps.  Not GG so much as others.  For the broad application of these new techniques has excited most geologists, but history tells us that there will be a reckoning.  As GG watched lots of folks who have not themselves sat in front of an LA-ICPMS machine in their lives display plot ofter plot of geochronology-derived stuff, you sense that something will come along to threaten this grand promise.

This has always been the way of new techniques.  They appear, they are exciting and new, they are applied everywhere, and then discrepancies emerge. Look back in olden days and see how potassium-argon dating started; it took awhile for practitioners to recognize that sometimes crystals would lose argon and they got dates that were too young, or that certain materials would introduce an excess of argon from other minerals and a date would be too old. Some early results were discarded, the community identified situations when problems were likely to arise, and early over interpretations were scaled back.

There are hints of this already.  Conflicts between U-Th/He dating and some classic geologic constraints hints at some problems in some places. Some work in the past few years indicated that fission-track thermal histories relying on track length distributions were dependent on specific laboratory practices that are not uniform. Puzzling results are emerging in some sedimentological studies where things that simply cannot be seem to be. On occasion, dates seem backwards, with younger dates from systems that should have closed well before materials yielding older dates.

None of this is really a worry. It is the shake-out that is needed.  And as long as you keep in mind that there might be some landmines out there, the hazards are manageable. It is a kind of “trust, but verify” environment. But there will be reverses ahead, and some promising studies might turn out to be chimera. Don’t be surprised to see some papers saying that a certain technique is wrong when applied under certain conditions. But in the end, we will still come out with a host of tools well suited to consider geologic problems. The age of ages is upon us, like it or not.

How flat is your slab?

Somehow that doesn’t sound good…but it helps to illustrate the problem with “the flat slab” in the western U.S.  If you are interested in the emplacement of the Pelona/Rand/Orocopia Schists, your slab is shallow at shallow depths: basically, it eats into the crust.  It certainly was NOT flat in the crust: there was a definite dip as these schists only go so far inland. You may not care if it is flat or shallowly dipping or anything else farther inland.

If you want your arc to die like the arcs in the Andes have died, you want your slab flat somewhere near 100 km depth.  It doesn’t have to be unusually shallow near the trench, but you need it to go flat for some distance to prevent asthenosphere from creeping in and making volcanoes.

If you want a flat slab to make mountains far inland, the stakes get higher. The most common and physically defensible means of doing this is by imparting a basal shear stress to the continental lithosphere, which carries some consequences.

You could have a subduction system with all these–but there arguably is no such example today (the inland mountains best hope are the Sierras Pampeanas, where the shallow part of the subduction system is pretty normal; if you want the erode the continental lithosphere, Alaska might be your best game).

Things could be pretty complicated.  For instance, subducting some amazingly thick piece of ocean floor under the Mojave Desert makes a lot of sense–but such material will plummet into the deep mantle once the thick pile of basalts gets deep enough to become a thick pile of eclogite.  The Mojave’s flat slab might become a steep slab not very much farther inland. It is even possible that such a scenario would generate a more long-lived flat slab, as it is possible that you have to be disconnected from the deeper parts of a subducting slab for a slab to become shallow and track along the base of the continent. So you might have a “flat slab” in the Mojave 10 or 20 million years before subduction becomes “flat” for purposes of places far inboard.

The point? Say what you mean; “flat slab” is too generic a term to be useful.