Monday, September 27, 2010

Landscapes into Rock - Part 3

This post continues my summary of the Landscapes into Rock conference that took place in London, September 21-23, 2010.  Click here for previous posts.

The second theme of the conference – The Dynamics of the Sediment Routing System – was chaired by Alex Densmore (Durham University) and Ruth Robinson (University of St. Andrews), who assembled a very good mix of nine talks and three keynote speakers: James Syvitski (University of Colorado), Greg Tucker (University of Colorado) and Chris Paola (University of Minesota).

Interesting research of the Golo source-to-sink system was presented by Tor Somme (University of Bergen) et al.  One of the interesting conclusions was that channel aggradation may occur both during eustatic highstand and lowstand, and that sediment partitioning along the source to sink continuum may be controlled by internal thresholds rather than external forcing.

 The keynote by Greg Tucker (University of Colorado) on rapidly changing landscapes underscored some interesting points:

  • channel incision rate correlates with characteristic stream power and shear stress;
  • temporal variability in sediment cover is an important control in long-term bedrock river incision.

Chris Paola’s keynote address on mass balance effects in depositional systems was full of insight, discussing many fascinating concepts:

  • fractional sediment extraction and the subsidence-driven depositional mass loss 
  • similarity in fining profiles along depositional trends
  • the use of generalized models/experiments as reference cases of down transport changes, against which field or subsurface cases can be compared
For the benefit of advancing our knowledge and workflows Chris jokingly invoked the need for adhering to the “Republic of Simplicity”, which created a cascade of comments in almost every talk that followed. Others, in return, advocated the “Republic of Complexity” or the “Monarchy of Necesity”, leading to great discussions but also polarized opinions among two camps: those who view the need to approach the Earth’s dynamic systems in all of their complexity, and those who believe that a simplifying approach maybe more appropriate. I certainly subscribe to the simplicity theory, while I choose to remain a citizen of the world and not subscribe to any republic or monarchy :)

Sunday, September 26, 2010

Random fluid dynamics thoughts (and videos)

I was riding my bike this morning along one of the man-made drainage channels in my extended neighborhood.  Couldn't help to watch the water flow patterns and make connections between fluid dynamics and fluid/sediment flow patterns in modern environments.  The short video below shows the fluid dispersal patterns not dissimilar with what one would see in a river reaching a shoreline and changing flow from confined to unconfined on a gently dipping slope.  Note how the fluid dispersal pattern is fan-like, not different from a fan shape in a distributary channel system.  There is a sharp change in slope, about half way through the image.  Note how the dispersal pattern changes from fan-shape to almost parallel stream lines.

video

There was something else that caught my attention.  To the right of the location in this first video, there was a change in slope, where two concrete slabs came together at an angle.  At the same location, water was flowing from two directions, the stream lines joining at almost 90deg angle.

This caused the flow to have its top surface split in two.  Are these standing waves?  What else are they called and what causes their formation?  The change in slope? Flow directions joining at 90deg angle? A combination of both?  Watch the video and let me know.

video

Saturday, September 25, 2010

Landscapes into Rock - Part 2

The Landscapes into Rock conference held in London this past week had four main themes.  For more general information about the event, see my previous posts.

The first conference theme was "The Erosional Engine". The session was chaired by Alex Whittaker (Imperial College London) and Andrew Carter (Birkbeck College London) and focused on geomorphology, erosion, sediment flux, burial/exhumation histories. The theme had eight contributions in the form of presentations and two keynote speakers: Niels Hovius from University of Cambridge and Kelin Whipple from University of Arizona.  Several posters were also on display.

One of the highlights for me was the talk by Paul Bierman et al (University of Vermont) on their synthesis of the ten-year research in erosion and sediment rates using cosmogenic nuclides, with one big takeaway being the fact that bedrock erosion rates (measured from outcrop along ridgelines) are slower than basin-scale erosion rates inferred from fluvial sediment; the latter integrates processes active across the entire landscapes. Interesting also was the positive correlation between tectonic setting/activity and erosion rates and the documentation of using cosmogenic nuclides as tracers to study processes over 10 to 10^5 years timescale.

The keynote address by Niels Hovius on weathering, erosion and sediment transfer in Taiwan, was another highlight, with a valuable insight into the fact that to get a better understanding of weathering and erosion it is more useful to look at the dynamic forces acting upon a landscape (tectonics, erosion, climate), rather than at the static proxies such as topography or landscape.  Both Niels and Paul referred to mountains as being “big piles of sand”, which stirred a big debate during the discussion sessions.

Kelin Whipple’s keynote talk on tectonic and climatic control on erosion rates made some excellent points: at steady state conditions, tectonic is the major control on erosion (not climate). For non-steady state conditions, some generalizations arise regarding the ability to distinguish between the tectonic or climatic forcing, with erosion rates increasing gradually in response to tectonic forcing, versus erosion rates increasing immediately in response to climate forcing.

Friday, September 24, 2010

Landscapes into Rock - Part 1

Landscape into Rock conference, held in London during 21-23 September, was an extremely insightful event, rich in ideas and very inspiring. The title itself is meant to represent many aspects of sedimentary geology: 
  • the link between surface geologic processes and the resulting rocks; 
  • the source-to-sink continuum of sedimentary processes and depositional systems, and the need to understand and view this continuum with a holistic approach; 
  • the insights that can be captured from short term processes, rates and models and how these insights may be applied to the rock record, which represents a much longer time frame and records controlling factors and rates that may have been very different compared to what we observe today; 
  • what makes stratigraphy and how do we place stratigraphy in the context of Earth’s dynamic systems.

The organizers were Philip Allen (Imperial College London), Paul Bishop (University of Glasgow), Hugh Sinclair (University of Edinburgh) and Robert Gawthorpe (University of Bergen).  Through careful planning at many levels they made this conference a success.  The event was held at the Burlington House on Picadilly Street.
© RomaniaRocks

The conference was held as one plenary session, which for me was great: more focused and less stressful compared to large conferences with many synchronous sessions, which leads to the desire to clone oneself in order to be able to be in several places at once in order to not miss relevant talks.
The talks and posters were grouped in four themes, which took place in succession over the three days.  I will cover each theme in a separate blog post (to come over the next few days).  Needless to say, I was unable to tweet or blog real time, as internet connection costs an arm and a leg in London.
One side note: during the event, Paul Bierman made everyone aware of the digital archive of Earth surface images that is under development at the University of Vermont. This is a NSF-supported, free archive useful for teaching and learning about geomprphology - enjoy!.

Friday, September 17, 2010

Using crowds to communicate and innovate

Three pieces of information came together today, they merged and managed to spark some ideas in my prefrontal cortex.  First, a note from the organizers of "Landscapes into rocks" conference, which I will attend next week, asking for my permission to record the talk and post it online.  This took me by surprise, and of course the first thought was "what a nice and progressive idea".  Followed by the next thought "what if I have a stomach ache and give a lousy talk? It will remain forever posted on the web,  and I will be forever embarrassed!  I better prepare!"
Then, I stumbled upon a blog post by Seth Godin with an insightful title - "Rehearsing is for cowards", where the basic idea is that a well rehearsed talk/presentation will protect  "against the downside, the unpredictable and the embarrassing" but will not allow for a potential leap forward. Seth states in his post:
"A well-rehearsed performance will go without a hitch. An explorer seeks the hitches, because hitches are the fissures and chasms that help us leap forward."
The third and final piece that made my day was a TED talk by Chris Anderson on Crowd accelerated innovation.  This talk emphasized how internet video allows the communication of ideas beyond the audience that attended an event, and also how it creates a cycle of improvement, through the feedback and the recognition a video post receives.

Dinosaurus Geopark - Hateg, Romania

The Dinosaurus Geopark (in Romanian - Geoparcul Dinozaurilor Tara Hategului) is located in central Romania in a beautiful area named "Tara Hategului".
Source: IUCN and UNEP. 2009. The World Database on Protected Areas (WDPA). UNEP-WCMC. Cambridge, UK
The European geopark concept is relatively new, was established by UNESCO in 1999 and is defined as:
A territory with a great geological heritage. A territory developing the "Geoturism" in cooperation with its inhabitants. An experimental territory inside a thematic network (detailed definition here).
 Hateg Dinosaur Geopark was recognized by UNESCO in 2004 through the effort of two great Romanian geologists, Professor Dan Grigorescu and Lecturer Alexandru Andrasanu, both with the Geology Department, University of Bucharest.  Dan Grigorescu was my first stratigraphy professor during my undergraduate studies in Romania; I clearly remember his passion for research, dinosaurs and the Hateg area.  The geopark is located between the vilages of Baru Mare to the east, and Zeicani to the west, and is surrounded by some of my favorite mountains (links to webpages in Romanian): Sureanu, Retezat, Poiana Rusca.
The geopark is famous for the assemblages of dwarf dinosaurs, numerous reptile fossil assemblages, karst cave systems and volcanic rock formations.  More details on some of the fossil sites and the park in general may be found here.  The area is heavy with history, it is indeed the "heart of the Romanian heart", as one historian put it: archeological sites including the Sarmisegetusa Ulpia Traiana fortress, which is the most important Dacian military, political and religious center; some of the oldest churches and monasteries, such as the Densus Church, believed to have been a pagan worship center before becoming a Christian church; medieval and more recent historical sites.

Tuesday, September 7, 2010

Geology, buildings, cities, architecture

Stone buildings are forever linked to geology by the architects that created them.  And through that, the cities and the human culture they represent are forever linked to geology.  I showed in a previous post how the Romanian village of Corbi and its culture is forever linked to geology through the little church carved in stone by the villagers.
During a recent trip to San Antonio, we strolled by the Bexar County Courthouse, a beautiful building designed in 1892 by James Riely Gordon in a Romanesque Revival style.
The courthouse is built from Texas red sandstone (Pecos Sandstone), with a layer of Texas Pink Granite at the base, all shown in the pictures above, which I took during the trip the other week.
There are no outcrops of the sandstone or the granite in the city, but the courthouse reminds the San Antonians and the tourists alike of the strong link between human creativity, the Earth and its rocks.
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