earth and environmental sciences
Rast-Holbrook Seminar
Trees Behaving Badly
I recently submitted a manuscript to Catena, entitled Hillslope Degradation by Trees in Central Kentucky. The reviews came back generally positive, and requesting minor to moderate revisions. I took care of those revisions, and resubmitted. The paper was then sent to a third referee, who pretty thoroughly trashed it. Catena's editor then rejected it (with option to resubmit). However, I am at an age & stage where I have to pick my battles, and this is not one I choose to fight. But I still think the paper has some worthwhile stuff in it, so I have posted it online. You can get it here.
The abstract is below, but be forwarned that the third reviewer deemed it "quite poorly written", "hard to follow," and a "mishmash of various statements." I don't think it's that bad . . . .
Quo Vadis Physical Geography?
The Canadian Association of Geographers recently held a special session on Changing Priorities in Physical Geography (I did not attend or participate; I was made aware of it by a Canadian colleague). The session description is given here. It got me to thinking about a piece I wrote more than a decade ago in response to a similar mandate, called Laws, Contingencies, and Irreversible Divergence in Physical Geography. I thought I would revisit what I published back in 2004 to see how it holds up. The paper focused on physical geography as science and scholarship, as opposed to the institutional politics of physical geography within geography as a whole, and relative to other disciplines. However, I did predict that physical geography—as geomorphology, climatology, biogeography, soil geography, and geospatial approaches to Earth & environmental sciences—would grow and thrive. However, I also expressed doubt that this work would continue to be called physical geography, and the extent to which it would be conducted under the institutional auspices of geography.
Geomorphology and Graph Theory
Tobias Heckmann, Wolfgang Schwanghart and I recently published the second of our two articles on applications of graph theory in physical geography & geosciences: Graph Theory—Recent Developments of Its Applications in Geomorphology (Geomorphology, v. 243, p. 130-146). The other paper, an overview of graph theory in geosciences, was promoted in this post.
Example of a structural graph, from the article.
Plenty of Peneplains?
In the late 19th and early 20th century, William Morris Davis popularized the concept of the peneplain, an extensive low-relief erosion surface graded to sea level. Peneplains were strongly associated with Davis’ cyclical model of landscape evolution, which fell out of favor with most geomorphologists decades ago. By association, the discussion and study of peneplains also fell out of favor.
But peneplains are making a comeback. This is best illustrated by a report from the Geological Survey of Denmark and Greenland (Green et al., 2013), though the ideas and evidence are also laid out in a number of journal articles by the various co-authors. The report is concerned with development of elevated passive continental margins (think of, e.g., the Great Escarpment of Africa, the eastern Australian highlands, or the main subject of the report, west Greenland). The arguments are strongly dependent on the identification and interpretation of planation surfaces. As these planation surfaces are low-relief, regionally extensive, and are eroded across geological materials of varying resistance, and because the authors present evidence that they were originally graded to sea-level (they were subsequently uplifted), they can be legitimately referred to as peneplains.
Geoscience Metanarratives -- Part 2
This is a continuation of a previous post, and this one will be even less intelligible unless you read that one first.
So, even though we rarely use the term, geoscientists have our metanarratives. Metanarrative is something of a perjorative for postmodern (pomo) critical social theorists, but just because because a metanarrative doesn’t really explain everything, even within its domain, doesn’t make it wrong, useless, or even hubris-y. As long we don’t make claims or insinuations, or have expectations, of a “theory of everything,” overarching theories or explanatory frameworks can be evaluated on their own merits or lack thereof—that is, whether a construct can be considered a metanarrative or not is independent of its utility and value.
Geoscience Metanarratives
At my job I am housed in a building occupied mostly by social science and humanities scholars, many of whom are postmodern, post-structuralist, “critical” social theory oriented. The “critical” is in quotes not to cast aspersions, but because these folks use the term somewhat differently than do scientists, for whom all well-conceived legitimate work is critical in the sense of skepticism, testability, and the potential for falsification. Anyway, my office location ensures that I am exposed to a good deal of the concepts and jargon of that community.
One of those is metanarrative. According to the Sociology Index web site:
Soil Erosion and Climate Change
A lot of us in the geoscience business are concerned these days with interpreting ongoing and past, and predicting future, responses of landforms, soils, and ecosystems to climate change. As one of my interests is rivers, I have noted over the years that in a lot of the literature on paleohydrology the major changes, such as major influxes of sediment, seem to occur at climate transitions, rather than after climate changes or shifts have had a chance to settle in and exert their impacts for awhile.
A related issue is the relationship between precipitation, temperature, runoff, erosion, and vegetation. As climate changes both temperature and precipitation regimes change. And as every physical geography student knows, moisture availability is not just about precipitation, but the balance between precipitation and evapotranspiration (ET). So, if both temperature and precipitation are increasing (as is the case on average on much of the planet now), whether available moisture increases or decreases depends on the relative increases of precipitation and ET.
Soil erosion on cropland.
Strat-and-Transition Models II
This is a continuation of my earlier post on applying state-and-transition models (STM) to stratigraphic information, to account for the missing bits.
Barrell’s (1917) explanation of how oscillatory variations in base level control the timing of deposition. Sedimentation can only occur when base level is actively rising. These short intervals are indicated by the black bars in the top diagram. The resulting stratigraphic column, shown at the left, is full of disconformities, but appears to be the result of continuous sedimentation. Noted sedimentologist Andrew Miall has used this example in several articles to illustrate the problems of gaps in sedimentary & stratigraphic records.