L'estudi del relleu a través d'experiments al laboratori

Les ciències relacionades amb l'estudi del medi requereixen, en bona part, del coneixement in situ del lloc i del fenòmen que en volem estudiar. No obstant, moltes de vegades, per a contrarestar i simplificar l'escala de treball, el laboratori pot ser una perfecte plataforma per a intentar simular, tan bé com sigui possible, els esdeveniments que es donen en situacions naturals i així, experimentar amb distints escenaris per a donar amb els resultats que un està cercant.

Moltes en són les disciplines que, per a complementar el treball de camp com a font d'informació i investigació, utilitzen tècniques de laboratori per abastir de més consistència les seves investigacions. Dins dels molts exemples que es poden trobar, avui comparteixo un vídeo representatiu de com es poden intentar simular, a la perfecció, moviments geològics estructurals i alhora, ajudar a incrementar el funcionament de la geología estructural, per exemple, de les nostres serralades. Esper us agradi!

Miquel Mir Gual

Special Issue "Mallorca: a Mediterranean Benchmark for Quaternary Studies"

Today I share an Special Issue edited by Societat d'Història Natural de les Balears which deals about the new approaches of Quaternary studies in Mallorca (Balearic Islands, Spain). Its contents are structured in 6 chapters written by different authors. It is an interesting book which contributes to better understanding the Quaternary importance on the Balearic Islands, furthermore to increase the knowledge about this interesting topic.

It compiles and updates a number of key topics (i.e., beaches, eolinites, paleontology, phreatic overgrowths on speleothems, etc.) and is designed to reflect the current state of knowledge of Quaternary geology and sea-level changes in Mallorca, integrating classicla descriptions with the new more detailed perspectives developed over the past decades.

Direct link:

http://shnb.org/monografies/monografia18/Mon_Soc_Hist_Nat_Balears_18_2012.pdf

Ginés, A., Ginés, J., Gómez-Pujol, L., Onac, B.P., Fornós, J.J. (2012). "Mallorca: a Mediterranean Benchmark for Quaternary Studies". Monog. Soc. Hist. Nat. Balears, 18: 219 pp. 

Miquel Mir Gual

El grup de recerca de la UIB, BIOGEOMED, de nou en premsa.

El grup de recerca BIOGEOMED, del Departament de Ciències de la Terra de la Universitat de les Illes Balears, de nou en premsa. Una recent línia de recerca oberta, enfocada al estudi de les costes rocoses a la illa de Menorca s'està engendrant des del grup a fi d'incrementar els coneixements sobre aquests sistemes, dinàmics i alhora amb un cert risc quan es tracta de penya-segats amb urbanitzacions associades. 

               Foto: Xisco Roig-Munar

L'estudi, encapçal.lat per Francesc X. Roig-Munar, pretén incrementar el coneixement sobre la fisionomia i el funcionament de els costes rocoses a l'illa de Menorca, al temps que determinar quins són els processos físics i estructurals que es donen en ells. Les primeres aproximacions apunten a que es tracten de sistemes molt més dinàmics del que es pensava, i que amb tot, suposen un risc geològic important, sobretot en aquells punts on hi ha presència d'urbanitzacions associades.

Link de la notícia:

http://www.menorca.info/menorca/465340/penyasegats/els/grans/desconeguts

Miquel Mir Gual

New theory about the age of Grand Canyon

Over the years, scientists have taken a variety of approaches to determine the canyon's age, such as estimating how quickly sediment traveled from one end of the canyon to the other and studying the age of formations within the canyon. Some produced ages as young as 5 million to 6 million years for portions of the canyon, and others ages as old as 17 million years.

Science has recently published online a new theory which deals about a new theory of the age and origin of Grand Canyon in Colorado (Arizona). The study, carried out by Rebecca Flowers (University of Colorado) and Kenneth Farley (California Institute of Technology), has analyzed four rock samples from the western portions of the Grand Canyon and four from the eastern reaches of the gorge. The pattern of helium concentrations in the samples suggests that substantial parts of the western portion of the Grand Canyon were already carved to within a few hundred meters of their current depth by about 70 million years ago and that erosion hasn't increased dramatically in recent eras, the researchers report. That's a far cry from the 5-million-to 6-million-year-old age suggested by previous research, and is about quadruple the oldest previous estimate from other teams for the canyon's age.

Nevertheless, not everyone is convinced by the team's evidence. Karl Karlstrom, a structural geologist at the University of New Mexico, Albuquerque, describes the findings as "out in left field." His team has also analyzed helium concentrations in apatites that were collected just a couple of kilometers downstream from where Flowers and Farley collected their samples in the western Grand Canyon. And their preliminary results, Karlstrom says, bolster the notion of a young gorge. Those soon-to-be-published results suggest that those rocks were still between 50° and 60°C—implying that they were well over 1 kilometer below the surface of Earth's crust—between 15 million and 20 million years ago.

Source and link:

http://news.sciencemag.org/sciencenow/2012/11/a-grand-old-canyon.html

Miquel Mir Gual

Ocean waves and erosion: coastal processes

Coastal erosion is the wearing away of land and the removal of beach or dune sediments by wave action, tidal currents, wave currents, or drainage (see also beach evolution). Waves, generated by storms, wind, or fast moving motor craft, cause coastal erosion, which may take the form of long-term losses of sediment and rocks, or merely the temporary redistribution of coastal sediments; erosion in one location may result in accretion nearby. The study of erosion and sediment redistribution is called 'coastal morphodynamics'. It may be caused by hydraulic action, abrasion, impact and corrosion.

On non-rocky coasts, coastal erosion results in dramatic (or non-dramatic) rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels,bridges, columns, and pillars. Also abrasion commonly happens in areas where there are strong winds,loose sand,and soft rocks.The blowing of millions of sharp sand grains creates a sandblasting effects. This effect helps to erode,smooth and polish rocks.The definition of abrasion is grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.

In this sense, today I share with all of you an interesting video which shows the effect of wave action above the coast, and its consequences for its further evolution. 

Miquel Mir Gual