This blog will be dormant for the next month or so while traveling and doing field work in Patagonia. We have sporadic web access in public internet cafes when we are in town re-supplying, but I can't promise any interesting posts.
In the meantime, check out some of these other geo-related blogs:
Apparent Dip
Highly Allochthonous
Lab Lemming
Southern Exposure
Green Gabbro
¡...Or Something volverá pronto!
The American Association for the Advancement of Science (AAAS) is having its annual meeting here in San Francisco.
The "Triple-A-S" meeting is designed for a broader audience than most science meetings. This year's theme is Science and Technology for Sustainable Well-Being and also has two days worth of events and demonstrations designed for the general public and whole family:
AAAS Family Science Days | |
| Saturday, 17 February | |
| 11:00 AM | "The Mythbusters: Jamie Savage and Adam Hyneman" — The Science Channel |
| Noon | "BioBug: Field to Fuel" — University of Idaho |
| 12:45 PM | "Iron Science" — The Exploratorium |
| 1:30 PM | "Fun with Science and Astronomy" — The Zula Patrol and KQED Kids! |
| 2:15 PM | AAAS/Subaru SB&F Prize for Excellence in Science Books: Awards ceremony |
| 3:15 PM | "Waves in Nature: Lasers to Tsunamis and Beyond" — Lawrence Livermore National Laboratory |
| 4:00 PM | "The Outreach Roadshow" — Women@SCS Outreach Roadshow, Carnegie Mellon University |
Sunday, 18 February | |
| 11:00 AM | "Name that Mammal!" — Platypus Media |
| 11:45 AM | "The Science Hour of Power" — Sikes Science |
| 12:30 PM | "Global Warming Discovery" — ClimateChangeEducation.Org |
| 1:15 PM | "The Science of Yo-Yos" — Yomega Corp. |
| 2:00 PM | "BioBug: Field to Fuel" — The University of Idaho |
| 2:45 PM | "Cloud Nine" — How The Weatherworks™ |
| 3:30 PM | "Robotics: The Next 10 Years" — The Robotics Society of America and San Francisco State University |
| 4:15 PM | "Kinetic City" — AAAS |
I am headed down south again very soon (next Tues) for my last field season in Patagonia...as a student anyway. I've had one other post about wildlife we encounter down there.
The above animal is a guanaco, which is sort of like a cross between a llama and a camel. These things are all over the place. We were able to get close to this particular one because we were in Parque Nacional Torres del Paine, where they are tamer. When we see them in other areas outside of the park, they keep their distance. Typically one of them will stand between us and the rest of the herd...keeping the herd informed on what we are doing. Guanacos make a noise that sounds like a horse whinney combined with a laughing hyena.
Whenever we see them, we wish we could ride them up the mountain...they can get up the hills a lot faster than us.
Okay...I have a hypothesis. I'm never gonna test this because compiling the data would be a ridiculous waste of my time.
I've noticed a general pattern out there on blogs or forums (places where commenting is allowed) such that the level of snarkiness, rudeness, derisiveness, scorn, disdain, etc. increases as the level of knowledge about the one making the comment decreases. The plot below shows sarcasticity on the y-axis vs. profile disclosure level on the x-axis.
Profile disclosure level of the commenter is discussed here in three basic levels: (1) when the real name and full contact information is either readily available through a link, or not too hard to find, (2) when an alias or nickname is used but enough clues are given that one could likely find out the identity of that person if they really tried, and (3) completely anonymous and without a link to any other site; usually using the name 'anonymous' or some other nondescript handle probably never used again.
However, this qualitative relationship has some important caveats:
a) if the commenter and poster know each other reasonably well sarcasticity is more-or-less independent of disclosure level (this is very common)
b) if the commenter is well-known for making rash comments (that's their bag baby) then they will be more likely to do it regardless
The plot above would require a huge amount of data (hundreds of points) and would likely be a pretty rough trendline. A small sample set, especially taken within one kind of blogging community, would probably not produce this result.
One of the favorite arguments used by one type of global warming denialist goes something like this:
The Earth has experienced natural and significant climatic swings in the past; therefore the current climatic swing we are experiencing is likely natural (not human-made); therefore we don't need to take any action.In this view, they accept the results of paleoclimate studies (the source of knowledge of the natural cycles). This argument is typically trotted out by those who are motivated solely by a economic/political paradigm. That is, they predict that the regulation of emissions will result in global economic recession at best or a complete and total economic catastrophe (i.e., the collapse of modern civilization) at worst.
I have to admit, it's nice not trying to produce an actual science post every day. That was a little hectic. Now I can simply link to the latest and greatest until I think of something.
I really hope this info gets out. Napping is not only a great way to spend a half-hour in the middle of the day, not only a way to feel reinvigorated, but apparently napping is good for your health.
So, what's stopping the United States (just because this is where I live) from adopting a siesta culture? Some would say that it would decrease productivity. I wonder if anyone has done a study trying to model the increase in productivity we might gain by a more refreshed workforce? Not even sure how to go about this.
Anyway... this is an equation I can handle: napping = good
above painting found here
No clues. Go.
How does one play 'Where on (Google)Earth?'
And to all you visitors who never play...just bite the bullet and get a dang Blogger account so you can leave comments. Do it here.
Thermochronic is gettin' geochronic over at Apparent Dip with a wonderful post about geochronology that even I can understand.
If you are scientist and have family members or friends asking you to explain how we date rocks then read, bookmark, and re-read that post.
If you are not a scientist and just simply want to know for yourself, I think you'll find it informative and understandable.
Plus, it has M&M's involved in the explanation!
I'm tapped out.
Fortunately, this week fell during a time where I was only really busy instead of super-ultra-crazy busy. But, alas...I have no more 'draft' posts that have been sitting around for weeks/months waiting to be finished. I have no time to create one from scratch for a while.
Here's a run-down of the week's post...a hodge-podge of sedimentary research that i'm either actively engaged in or interested in:
JSW #1: Sediment thickness in the world's oceans
JSW #2: Submarine Geomorphology
JSW #3: Experimental Sedimentary Systems
JSW #4: Learning about sediment dispersal from the age of single grains
JSW #5: Sediment transfer from the continent to the deep sea
The last post was cross-posted over at Deep Sea News...so I would like to thank them. They have a great blog, you should check it out.
These posts are not comprehensive reviews of the topics with extensive lists of references and such. For anyone that is interested in more, feel free to post a comment and I'd be happy to get some more information to you.
Finally, thanks to the folks at Just Science for making this happen.
Visit ...Or Something in the future for ramblings of Earth science stories, commentary and/or rants about science abuse, random nonsense...or something.
This is post #5 for Just Science week.
Today's installment is also cross-posted over at Deep Sea News today.
As we all know, the deep sea contains fantastic records of ancient oceanic conditions. The deep sea also holds clues about the continents. In this case, we can use deep sea sediments to better understand how Earth surface systems respond to climatic fluctuations. The inherent relief between continental and ocean plates drives the transfer of sediment from the shoreline to the deep ocean. A grain of sand lodged from a decomposing rock in the mountains may spend a long time making its way down a river system, or being swashed around at the coast, but ultimately the deep sea is the final resting place. In other words, this is as low as it can go. Combine this with a high volume of sediment over time and the result is an accumulation (sometimes several kilometers thick) for geologists to examine.
Studies of sediment transfer within this context has been coined “source-to-sink” and involve the integration of several Earth science disciplines including sedimentology, geomorphology, hydrology, mineralogy/petrology, geochemistry, marine geophysics, and others. A big chunk of my current research is a collaborative source-to-sink project between Stanford University and the U.S. Geological Survey. We are focused on the sediment records housed in the deep marine basins of the California Continental Borderland region offshore southern
Using multibeam bathymetry, seismic-reflection profiles, and core samples, we can map the distribution and flux of continentally-derived sediment in these basins. The image above is a seismic-reflection profile from the
So, what are we finding out in these studies? A radiocarbon-dated Ocean Drilling Project core in
Ultimately, the record of sediment transfer that is stored in the deep sea (modern or ancient) will tell us a great deal about what was happening on the continent regarding the interactions of tectonism, climate, and Earth surface processes.
References:
1 Perspective image created in GeoMapApp, a fantastic freeware program for exploring the world’s bathymetric database. Download here: http://www.marine-geo.org/geomapapp/
2 Normark, W.R., D.J.W. Piper, and R. Sliter, 2006, Sea-level and tectonic control of middle to late Pleistocene turbidite systems in
3 Bathymetry of the northeastern
4 Barron, J.A., L. Huesser, T. Herbert, and M. Lyle, 2003, High-resolution climatic evolution of coastal northern
4 Romans, B.W. and Normark, W.R., 2006, Distribution and rates of terrigenous sediment accumulation on the Hueneme submarine fan in the late Holocene (4.3 ka – present),
This is post 4 of 5 for Just Science week (Feb 5th-9th).
Earlier posts this week:
Post #1: Sediment thickness in world's oceans
Post #2: Submarine Geomorphology
Post #3: Experimental Sedimentary Systems
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If I could talk to the sand grains in an ancient sedimentary deposit (I guess I already do....so, more accurately, if they could hear me) I would ask: "Where did you come from? Where were you born and where did you grow up? Did you travel a lot before coming here?" If the sand grain could provide answers, we could then start to reconstruct the source areas of ancient sedimentary environments with great accuracy. Mountain belts get eroded...that material ends up as sediment...if you wanna learn something about ancient mountain belts, look at the sediments that they produced.
Zircons can, in some cases, answer some of these questions of provenance (albeit often with a lot of inference and interpretation...but, hey that's what we do).
For example, we can extract these little suckers from a sandstone (which is laborious and tedious process in and of itself....i'll go into that another time) and then determine their age using radiometric dating. I am not even close to an expert on geochronometry ... for this I refer you to another geo-blog, Apparent Dip, which has posts about this subject from time to time.
So, what do you do with the age of a zircon that is in a sedimentary deposit? Typically you date a bunch of grains (50-100) and end up with a distribution of ages. Some are old, some are young. Here's an analogy: let's say you have a few dollars of change in your pocket. Although they are all in your pocket now (the deposit) they probably have different dates on them and are of different morphologies (if they are all the same, that's a pretty special situation).
We end up plotting the ages in a histogram and analyze the different groupings of ages. If we are lucky, we already know something about the potential source area and see if we can make some comparisions (if it hasn't been completely eroded and/or consumed in some way).
Me and some colleagues presented some preliminary data last year at a geology meeting held in Mendoza, Argentina, called "Backbone of the Americas". The figure below is an example of one of these histograms. These plots are preliminary and do not include the requisite error bars, number of grains considered statistically significant, etc. but are posted here as an example of the application (stay tuned for actual interpretations and results in the future).
On the x-axis is age (in millions of years) and relative probability on the y-axis. These four different plots are from different stratigrpahic units within a preserved sedimentary basin (oldest deposits on bottom). A thorough comparison of significant peaks (i.e., lots of grains of similar age) from plot to plot can help us identify trends. One pattern in this particular example is the introduction of younger zircons (the peaks around 80 Ma) in the three upper plots as compared to the bottom one. In this case, the depositional age is very close to the youngest zircons here because the basin was fed by a volcanic arc. So, the younger depositional units were receiving new, baby (or toddler) zircons as sediment.
Anyway....this is just the tip of the iceberg. I'll post again about this and provide links from my fellow geo-bloggers out there who do more of this kind of work are can probably explain it better.
If you want to know the ghory details of this preliminary dataset...you can read the abstract (PDF).
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This is the third post for the Just Science week (Feb 5th-9th). See Monday's and Tuesday's posts.
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On the first post for this week, I said I would stay within a theme of deep-marine sedimentation....well, i'm gonna break from that for this post just because the topic today is just that cool.
For a few years i've been following the work at the St. Anthony Falls Labratory, University of Minnesota, in Minneapolis. And a good friend of mine who works there was kind enough to give us a tour in December. This place does all sorts of cool stuff...like super-cavitation research (!)...but, here i'm gonna show you a few images from their experimental set-ups for studying sedimentation.
So, basically what we got here are some very sharp scientists who have taken 'playing in a sandbox' to the ultimate level. They have two main experimental tanks that interest me the most: a delta basin and the experimental Earthscape basin, or "Jurassic Tank".
The above image is a deposit growing in the delta basin. Remember this is just a couple meters across. These experiments run for weeks and they photograph at equal time increments so they can make a time-lapse movie at the end to see the evolution of the system. But the real beauty of this is the quantitative information. At other increments during the run time, they scan the deposit with an extremely precise laser and collect data about the topography of the feature. As the deposit is buried by further deposition, they can relate this information to patterns of river avulsion and lobe-switching identified in natural systems.
The image to the right is a plan-view image from "Jurassic Tank", which is an experimental basin a few meters wide by a few meters long. What makes it unique is its ability to create differential subsidence in almost any imaginable pattern. The "basement" of the basin is actually an interlocking framework of numerous plates that each move independently from each other. With this they can run experiments with similar subsidence patterns that are seen in Earth's sedimentary basins.
And, like the delta basin, the progress of the filling is scrutinized and measured. At the end, the entire basin fill is carefully sliced centimeter by centimeter and high-res photos are taken of the cross-section. The goal is to then relate the explicit knowledge of the sedimentation to the resultant stratigraphy. In the "real world" we typically only have the stratigraphy remaining...and it's up to geologists to interpret the processes that generated it.
These experiments are helping us think in different ways regarding what actually controls the patterns we observe and map in stratigraphy.
Check out their web resources:
- St. Anthony Falls Lab (SAFL), is part of
- National Center for Earth Surface Dynamics (NCED)
- NCED Research Projects
- a link to some movies
- data repository for the stratigraphy experiments
This short article from Science in 2000 does a much better job at explaining the goals of particular research projects utilizing these facilities (note: you'll probably need a university or personal license to download).
Science 17 March 2000:
Vol. 287. no. 5460, pp. 1912 - 1915
I had to interrupt the JSW (Just Science week) posts because I wanted to show this quite striking graphic of space junk around our planet from the New York Times.
The red ring of debris is from the recent satellite destruction shenanigans by the Chinese....who's brilliant idea was that?
Click on the above image to see full size and then go here to view the interactive feature at New York Times website.
This is the second post for the Just Science week (Feb 5th-9th) on ...Or Something.
See the first post here.
geomorphic features. The images shown at right and below clearly show beautiful meandering channels that were once on the sea floor (in very deep water) and are now in the subsurface. By analyzing 'slices' within the seismic volume we can map the evolution of the geomorphology through time. These images from a recent paper from Posamentier & Kolla (2003).
For my first post of JSW (Just Science week, Feb 5-9), i'm going to introduce my field of study, sedimentary geology, with an illustration. Much of the rest of this week, I will be discussing more than you've ever wanted to know about the sedimentation along continental margins. Actually, I have no idea what i'll be posting about...that's my guess...you'll have to stay tuned.
The above figure, which can be found here, shows the thickness of sediment in the world's oceans and marginal seas. I love this map...it is really great to get a global view like this. Like many others investigating patterns of nature, it is necessary to look at all scales. This post starts out big....the whole globe. Subsquent posts will zoom in spatially as well as pull back temporally and get a sense of past conditions.
One of the first things to focus on is the continents of North and South America. At this scale the configuration (and history) of the tectonic plates clearly governs the patterns (see map of plate boundaries below). Note the asymmetry of sediment thickness....the eastern margins of the land masses have thick accumuations (the hotter colors) of sediment whereas the western margins do not. The active western margins consist of a subduction margin in South America, transform margin in southern North America, and subduction margin in northern North America at a very large scale. This activity, although it creates a lot of high relief nearshore producing sediment, is not the bes
t place to preserve sediment over long time scales.
The accumulations along the eastern, or "passive" margins, are so thick because they've been piling up for 10s of millions of years. These two strikingly different tectonic settings should be kept in mind.
Another notable pattern on the map of sediment thickness is the Bengal submarine fan. This fan, which sits in the Bay of Bengal between India and southeast Asia is the single largest accumulation of sediment on the planet (extending for nearly 30 degrees of latitude from the margin!).
Big deal. So, you may be asking so what...why should we study these accumulations of sediment? I hope to show you with a series of posts why I think it's interesting from a scientific standpoint to figure these things out. From the small-scale processes of transporting/depositing sediment to the spectacular geomorphology present on the sea floor to the implications to studying Earth history.
And, by now, i'm sure most of you may have also noticed the spatial coincidence of some of the thicker accumulations with petroleum provinces. This is no coincidence for sure....where you pile up a bunch of sediment over a long period of time you get the perfect host for our world's (for better or for worse) lifeblood. I'm not going to go too much into this particular application of sedimentary geology...at least not this week. My aim is higher....I want to learn as much as I can from these sediments/rocks. I'm a data junkie...I'll admit it. I want to observe and characterize information about the Earth....i'll take it where I can get it. I've been working on a post about 'peak oil' from a sedimentary geologist's perspective....but not this week. This week, i'll be using this information to tell you something (hopefully) interesting about our planet.
map of tectonic plates found here
I've joined a bunch of science-related bloggers in a week designed to be about Just Science. That is, posts will not be diatribes about the misuse of science by government (not that that's not fun), not rants about intelligent design in public schools (not that that doesn't deserve ranting), not a reference and/or commentary on a mainstream article, etc. ... But a post about some actual science. The goal is at least a post a day.
Good idea!
I'm not sure i'll make a post a day, but i'm sure gonna try.
Here's the feed: http://www.justscience.net/?feed=rss2
See Chris Mooney's blog, The Intersection, for more introduction to this editorial that he and Alan Sokal co-authored in today's LA Times. It's titled Can Washington get smart about science?, and is a nice little piece of writing.
What I like is that Sokal has been known to criticize liberals and Mooney has a book about conservatives in government and their subversion of science. I like to see people team up like this and cut through the partisan crap. It's all too easy for people to stay on "their side", whatever that means. The partisan brain is a funny thing. People with strong partisan tendencies tend to automatically believe, agree, disbelieve, disagree with statements that have yet to be checked for its truthiness.
Sometimes when I stroll about the blogosphere I get severely turned off by ultra-partisan "liberals" spouting complete nonsense. Conservatives do the same, of course....I guess I don't find myself strolling about their internet neighborhoods though.
Anyhow....read Chris and Alan's article, it's good.
The only clue i'm gonna give for this one is that the boundary between shallow water (light blue) and deep water (dark blue) is very sharp.
Good luck!
Keep in mind, this is only one example of this kind of idiocy. Unfortunately, a lot of people get their "information" (opinion) from people like this. For those of you who don't know, Neil Boortz is a Rush Limbaugh-wannabe (sad). Apparently he and another author have written a very thoughtful book about tax reform that I hear good things about. I haven't read it yet, so I can't comment on that but that's not what this is about. This is about someone with a megaphone and a lot of loyal listeners (choir members) spouting stupidity about the recent IPCC report.
I neither have the time nor energy to deconstruct all of this...here's some of my favorite tidbits from his editorial titled "Why I Am Skeptical About Man-Made Global Warming"
A 21-page report from something called the "Intergovernmental Panel On Climate Change" has been released today...in Paris, no less...and as expected, it's predictions are dire.Sweet...right off the bat, we get some anti-French sentiment. Always a crowd-pleaser.
But really, it makes sense that the global warming crowd would come to this conclusion. After all, global warming is a religion. The anti-capitalist enviro-nazis don't ever want the problem to be solved. After all, if global warming were to be solved tomorrow, what would they blame the United States for? They'd have to find some other reason.The underlying motivation for being skeptical about this report is revealed in this introductory section of the editorial. It's not about science at all....it's about the anit-capitalist enviro-nazis...let's call them the ACENs. The ACENs have plotting to take over the world since the first Earth Day I think. This is key to understanding this point of view. By connecting "anti-capitalist" directly to the prefix "enviro" and then throwing in the evil noun "nazi" the stage is set.
Because the sun is warmer .. and all of these scientists don't seem to be willing to credit a warmer sun with any of the blame for global warming.Hmmm....reference? Of course, an editorialist can't be bothered with citing. This claim, however, does not fall under opinion. To say something like this requires some backing. But, I will say this...at least he doesn't discredit the actual warming. There aren't many of those left. It's mostly about cause now.
It wasn't all that long ago that these very same scientists were warning us about "global cooling" and another approaching ice age?The very same scientists. Who are they? He, of course, doesn't provide a list. He wants his followers to picture a small group that meet in undergound lairs (sensu Dr. Evil) plotting to take over the world. Here in reality, we know that this report is the summation of hundreds of scientists from around the world and across disciplines.
How much has the earth warmed up in the last 100 years? One degree. Now that's frightening.What an idiot. When the global average temperature was 5-6 degrees colder than now there was an ice sheet a mile thick sitting over my hometown in New York state
Because that famous "hockey stick" graph that purports to show a sudden warming of the earth in the last few decades is a fraud. It ignored previous warming periods ... left them off the graph altogether.Please demonstrate the errors in this. Oh wait....all you have to do is assert that, I forgot. See this summary of the hockey stick graph debate.
Because global warming "activists" and scientists seek to punish those who have different viewpoints. If you are sure of your science you have no need to shout down or seek to punish those who disagree.Seek to punish. Seek to punish?
What happened to the Medieval Warm Period? In 1996 the United Nations Intergovernmental Panel on Climate Change issued a chart showing climatic change over a period of 1000 years. This graph showed a Medieval warming period in which global temperatures were higher than they are today. In 2001 the IPCC issued another 1000 year graph in which the Medieval warming period was missing. Why?Oooh...juicy. Conspiracy. More here.
There are about 160,000 glaciers around the world. Most have never been visited or measured by man. The great majority of these glaciers are growing, not melting.The great majority....what is that 70%? Reference? Of course not.
Rising sea levels? The sea levels have been rising since the last ice age ended. That was 12,000 years ago. Estimates are that in that time the sea level has risen by over 300 feet. The rise in our sea levels has been going on long before man started creating anything but natural CO2 emissions.One of my favorite things people like this do is confuse the issue by constantly bringing up facts about the Earth's climatic fluctuations. What about rate of rise instead of magnitude, Mr. Boortz? If you look at the sea-level curves for the last 12,000 years you see the rate of rise slow until about 5,000-6,000 years ago. Since then the rate of rise is very small, hence we've been at a "stillstand" in sea level (see Lambeck & Chappel, 2001).
During the last 20 years -- a period of the highest carbon dioxide levels -- global temperatures have actually decreased. That's right ... decreased.Another assertion with no reference.
Why are global warming proponents insisting that the matter is settled and that no further scientific research is needed? Why are they afraid of additional information?I definitely want to know what scientist ever said they didn't want more data.....that's all we want! We can't get enough of it...give me a break.
Lab Lemming and Highly Allochthonous decided to answer the question: "What do scientists actually do?".
See what they do on a typical day here and here.
For me, not sure this is a typical day...it's Friday and I just finished a draft of a long paper 2 days ago and gave to advisor. But here goes anyway...
8:15-8:50: train ride into office
8:50-9:25: check email and make blog post about French turbidites
9:25-10:00: chat with colleague on phone who just started a tenure-track position this month, discuss possible future collaborations
10:00-11:15: update spreadsheet database and associated plots with new radiocarbon ages for Holocene sediments offshore southern CA; get excited about how well-constrained this basin is temporally
11:15-11:45: chat with colleague on phone about the above; directions to go for writing it up
11:45-12:20: lunch
12:20-2:00: research possible job opening; start application process
2:00-2:15: get information together for rock samples I need to start processing next week
2:15-2:45: look for said rock samples in inefficient and messy storage area in the attic of building i'm in
2:45-2:50: have a little freak out moment when can't find rock samples (they are all the way from South America!)
2:50: remember I already put them aside right under my desk...phew
2:50-3:40: search for paper online that i've been meaning to look at; found it and read abstract, intro, and looked at figures
3:40-now: write this blog post
after now-later: go home and go out to dinner with girlfriend and another friend in San Francisco
Pretty easy-going day all in all
Instead of one photo this week, i'm gonna show a series of photos from a trip I took to southeastern France last June. Most of my research is involved with characterizing and understanding the deposits of turbidity currents, or turbidites. Essentially, picture an underwater 'avalanche' of sand and mud. The sediment travels down a slope into the deep water in fast-moving turbulent flows. Additionally, this very outcrop is where, in the late 1950s Arnold Bouma developed what has come to be known as the 'Bouma sequence'.
The photo above and to the right is a succession of alternating sandstone beds and mudstone beds (note trees for scale).
A road snaked its way up this mountain so we were able to look the rocks in more detail in the well-exposed roadcuts.
This photo shows the character of bedding at a scale of a few meters. The thicker sand beds are typically a little coarser-grained and tend to be more resistant and stick out of the cliff. The finer-grained material is commonly in thinner beds and more recessive.
Statistics of bed thickness patterns have been done for many years on turbidites. The variability is so great from place to place that there doesn't seem to be a very systematic pattern. Some workers have documented some interesting relationships (Talling, 2001 has a good summary of this).
A lot of turbidite sequences include intervals of chaotically deformed material. It may look like good ol' tectonic deformation but it is the result of slumping and sliding of material on the sea floor. In steeper areas of the slope leading to the deep sea, material that was deposited may sluff
off as submarine landslides. The blocks can stay
relatively intact in many cases.
Here's a larger-scale view of a famous outcrop called Chalufy (note trees for scale). This face is cool because you can see the sand-rich bodies pinching out into the blue-gray fine-grained rock. If you notice there are two distinct sand intervals that successively pinch out as wedge shapes from left to right.
This represents the edge of the deep-marine basin. A series of sand-laden turbidity currents came down the slope and incrementally deposited material that started filling in this hole. This kind of complex stratigraphy is more the rule than the exception. These are not simple layers. These flows both create and respond to sea-floor morphology with channels, levees, fans...you name it. The challenge is to take a preserved ancient succession like this and interpret the processes and morphology that existed on the sea floor. From there we build up and start to understand how the basin filled, what controlled the patterns, and relate it to the tectonic evolution.
I'll be posting a bunch of web resources for turbidite research soon....still working on that.
This is clearly one the biggest science news stories of the day/week/month/year/decade and there's tons o' hype...so i'm not going to do a lot of commenting until I have a little time to look at it. Not that i'm any sort of authority...but I like to go over things at least a little bit before trying to summarize and/or synthesize.
The actual Intergovernmental Project on Climate Change (IPCC) report can be obtained here today (2/2/07). The last report was in 2001...this is a significant body of work involving hundreds of scientists from around the world. The review process to decide on the final wording was quite rigorous.
The one thing I'd like to remind people is that this, the first report in a series, is the scientific background. The full report about policy is forthcoming (although there is a short summary of that too). It is extremely important to separate these. Yes, of course they are linked...I don't deny that. But, we should emphasize the objective information at this point.
There will be tons of noise about this report from every direction.....don't read mainstream media summaries that try to present "both sides"...and don't read your favorite op-ed columnist's pre-emptive commentary. Just read the dang report!
If you got to the end of this post and are lazy...here's another link to the IPCC website to download the report. Do it.
RealClimate, as usual, has a great post and good discussion going here.
This is great. The quality and amount of data we are collecting these days regarding the movements of the tectonic plates is fantastic. This article in Science Daily talks about a study looking the East African Rift Valley....a proto-mid-ocean ridge.
The most dramatic event came in September 2005, when hundreds of deep crevices appeared within a few weeks, and parts of the ground shifted eight metres, almost overnight. More than two billion cubic metres of rising molten rock -- magma -- had seeped into a crack between the African and Arabian tectonic plates, forcing them further apart.These researchers are going to sample this new rock. Because this process typically occurs at mid-ocean ridges, it is inherently challenging to take samples. The East African rift is in a very early stage of developing into an ocean spreading center. Once the relatively thin and dense oceanic crust begins to form, the basin will eventually fill with the ocean to create a narrow seaway.
