Carnets de Geologie published a new "article" (CG2007 A01) on 27/02/2007.
Article 1 [2007]: Environmental changes during marl-limestone formation: evidence from the Gargasian (Middle Aptian) of La Marcouline Quarry (Cassis, SE France), by Catherine BELTRAN, Marc de RAFÉLIS, Maurice RENARD, Michel MOULLADE & Guy TRONCHETTI.- Format [HTML] or [PDF 646 KB]

Un nouvel "Article" (CG2006 A05) est en ligne depuis le 27.02.2007.
Article 1 [2007] : Variations des paramètres de l'environnement au cours de la sédimentation d’alternances marne-calcaire : Exemple de la série gargasienne (Aptien moyen) de la Carrière de La Marcouline (Cassis, SE France), par Catherine BELTRAN, Marc de RAFÉLIS, Maurice RENARD, Michel MOULLADE & Guy TRONCHETTI.- Format [HTML] ou [PDF 646 KB] [Cet article n'est disponible qu'en version anglaise avec résumés bilingues]

Abstract: "Limestone-marl alternations are usually interpreted to reflect cyclic paleoenvironmental fluctuations linked to Milankovitch-scale climate variations. However, the impact of diagenesis on lithological differentiation can be overprinted on the primary signal. In order to evaluate environmental variations during the deposition of the Gargasian hemipelagic limestone-marl alternations from the "La Marcouline" quarry (SE France), we have applied a multi-discipline approach (carbonate geochemistry, micropaleontology and mineralogy). The work uses of a method of granulometric separation of the main carbonate particles which (1) allows the characterization and quantification of the compositions of the carbonate phases of both lithologies and (2) gives access to the geochemical signatures of similar carbonate (bio-) particles in each lithology. (...)"

Résumé: "Il est classiquement admis que les systèmes alternants marne-calcaire reflètent des variations climatiques orbito-dépendantes. Toutefois, des processus diagénétiques conduisant à la différentiation lithologique peuvent avoir masqué ce signal primaire. Afin de caractériser les variations des paramètres environnementaux associés à la formation des alternances marno-calcaires gargasiennes de La Marcouline (SE France), nous avons mené une étude pluridisciplinaire (géochimique, micropaléontologique et minéralogique) basée sur l'utilisation d'une méthode de séparation granulométrique des particules sédimentaires. Cette approche nous a permis, d'une part de caractériser et quantifier les compositions des phases carbonatées des deux types de lithologies et d'autre part de disposer des signatures géochimiques de (bio-) particules carbonatées identiques dans les marnes et les calcaires marneux. (...)"

- posted by Affenhänger @ 2/27/2007 11:57:00 PM 0 comments links to this post

The webcam in Hartlepool marina appears to be working once again. It's going in fits and starts, so I wonder how long it's online for this time. I've quite missed it.

- posted by Affenhänger @ 2/10/2007 01:15:00 AM 0 comments links to this post

The UK this week boasts reaching a windpower milestone. Braes O'Doune wind farm, near Stirling, Scotland started generating electricity, thus putting UK capacity above the 2 GW (gigawatt = 1000 megawatt) mark. This makes the UK only the seventh nation worldwide to achieve this. Not bad, you may think, until you compare those 2 GW to some other nations:

World wind energy leaders:

1. Germany - 20,622MW
2. Spain - 11,615MW
3. USA - 11,273MW
4. India - 6,053MW
5. Denmark - 3,136MW
6. Italy - 2,123MW
7. UK - 2,016MW
8. Netherlands - 1,564MW
(Source: BWEA)

Now compare that to Germany. Germany is larger than the UK, and the population is around 1.2x that of our's, but their wind power production is a slapping 10x that of the UK's meagre efforts. Even Spain, whose population is only around 80% of the UK's, produces well over five times, almost six times, more than we do.

The most recent figures published by the government show that a mere 4.2% of the UK's electricity is generated by renewables, including wind, solar, hydro and biomass. Time the Luddites had a good kicking.

- posted by Affenhänger @ 2/09/2007 10:52:00 PM 0 comments links to this post

The MARS Journal, a new online peer reviewed open access journal, is now open for submission of manuscripts. The MARS Journal will publish scholarly papers in three general categories:

Mars Science: Observations, data, theory, models, and reviews of scientific literature

Mars Technology: Instruments, spacecraft, missions, tools and techniques, and software

Mars Policy: Exploration strategy, economics, planetary protection, history, and commentary

Be among the first to publish (for free) in The MARS Journal.

- posted by Affenhänger @ 2/09/2007 10:45:00 PM 0 comments links to this post

Geologists at the University of Illinois at Urbana-Champaign have located a huge chunk of Earth's lithosphere that went missing 15 million years ago. By finding the massive block of errant rock beneath Tibet, the researchers are helping solve a long-standing mystery, and clarifying how continents behave when they collide.

The Tibetan Plateau and adjacent Himalayan Mountains were created by the movements of vast tectonic plates that make up Earth's outermost layer of rocks, the lithosphere. About 55 million years ago, the Indian plate crashed into the Eurasian plate, forcing the land to slowly buckle and rise. Containing nearly one-tenth the area of the continental U.S., and averaging 16,000 feet in elevation, the Tibetan Plateau is the world's largest and highest plateau.

Tectonic models of Tibet vary greatly, including ideas such as subduction of the Eurasian plate, subduction of the Indian plate, and thickening of the Eurasian lithosphere. According to this last model, the thickened lithosphere became unstable, and a piece broke off and sank into the deep mantle.

"While attached, this immense piece of mantle lithosphere under Tibet acted as an anchor, holding the land above in place," said Wang-Ping Chen, a professor of geophysics at the U. of I. "Then, about 15 million years ago, the chain broke and the land rose, further raising the high plateau."

Until recently, this tantalizing theory lacked any clear observation to support it. Then doctoral student Tai-Lin (Ellen) Tseng and Chen found the missing anchor.

"This remnant of detached lithosphere provides key evidence for a direct connection between continental collision near the surface and deep-seated dynamics in the mantle," Tseng said.

"Moreover, mantle dynamics ultimately drives tectonism, so the fate of mantle lithosphere under Tibet is fundamental to understanding the full dynamics of collision."

Through a project called Hi-CLIMB -- an integrated study of the Himalayan-Tibetan Continental Lithosphere during Mountain Building, Tseng analyzed seismic signals collected at a number of permanent stations and at many temporary stations to search for the missing mass.

Hi-CLIMB created a line of seismic monitoring stations that extended from the plains of India, through Nepal, across the Himalayas and into central Tibet. "With more than 200 station deployments, Hi-CLIMB is the largest broadband (high-resolution) seismic experiment conducted to date," said Chen, who is one of the project's two principal investigators.

Using high-resolution seismic profiles recorded at many stations, Tseng precisely measured the velocities of seismic waves traveling beneath the region at depths of 300 to 700 kilometers. Because seismic waves travel faster through colder rock, Tseng was able to discern the positions of detached, cold lithosphere from her data. "We not only found the missing piece of cold lithosphere, but also were able to reconstruct the positions of tectonic plates back to 15 million years ago," Tseng said. "It therefore seems much more likely that instability in the thickening lithosphere was partially responsible for forming the Tibetan Plateau, rather than the wholesale subduction of one of the tectonic plates."

Other evidence, including the age and the distribution of volcanic rocks and extrapolation of current ground motion in Tibet, the researchers say, also indicates the remnant lithosphere detached about 15 million years ago.

Chen and Tseng present their findings in a paper to appear in the Journal of Geophysical Research.

Source: University of Illinois at Urbana-Champaign

This article was originally published on physorg

- posted by Affenhänger @ 2/09/2007 10:41:00 PM 0 comments links to this post

Here are the eight most common elements in the Earth's crust,
by weight and volume percentages:


Weight%          Vol.%

O     46.60      O   ~94

Si    27.72

Al     8.13

Fe     5.00

Ca     3.63      ~6 in total for all others

Na     2.83

K      2.59

Mg     2.09

Total 98.59

These do vary slightly from source to source,
but generally only in the hundredths column.

- posted by Affenhänger @ 2/01/2007 09:51:00 PM 0 comments links to this post

Cars collide, colours clash,

Disaster movie stuff,

For a man with a Fu Manchu moustache,

Revenge is not enough.

I once lived here.

- posted by Affenhänger @ 2/01/2007 09:12:00 PM 0 comments links to this post