Imaggeo on Mondays: The perfect overnight stop.

13 Oct

Field camp at a cave. (Credit: Simon Virgo,via imaggeo.egu.eu)

Field camp at a cave. (Credit: Simon Virgo,via imaggeo.egu.eu)

Being an Earth scientist has its perks and camping overnight in a cave under an absolutely stunning unpolluted night sky has to be up there with one of the best! Our Imaggeo on Mondays image is brought to you by Simon Virgo who took the photograph in 2008 during an advanced mapping field course in structural geology in the Batain region of northeastern Oman.

The Batain region extends over an area of approximately 4000 km and is cross cut by a number of east-west trending wadis (valleys that remain dry except during times of heavy rainfall). The Batain Group, consisting of a number of sedimentary and volcanic formations, ranges from Permian to Maastichtian in age. Itis thought to have been deposited in the former ‘Batain Basin’ off eastern Oman and was later destroyed during compressional tectonics from the Group, consisting of a number of sedimentary and volcanic formations, ranges from Permian to Maastichtian in age (299 to 66 million years ago. It is thought to have been deposited in the former ‘Batain Basin’ off eastern Oman and was later destroyed during compressional tectonics during the Cretacous/Paleogene, some 66 million years ago ( boundary (Immenhauser et al.,1998).

ʺThe area is a fantastic playground for structural geologists; it is full of folds (the little cave at which we camped has formed in the hinge of a saddle), small scale faults and large thrust, occasionally associated with megabreccias that show a block size of several meters” explains Simon.

Batain Radiolarites. (Credit: Simon Virgo, via imaggeo.egu.eu)

Batain Radiolarites. (Credit: Simon Virgo, via imaggeo.egu.eu)

The rocks exposed in the region are mostly radiolarites, seen in the picture above, also taken by Simon. Radiolarites are silica rich, chert-like rocks, formed in shallow or deep waters, which mainly consist of the microscopic remains of radiolarians. The units pictured here are 4–20cm thick alternating beds of red and white cherts. The colouring of the red layers results from organic pigments in the units.

The area is not only geologically rich, explains Simon, “other sights include prehistoric tombs with artefacts scattered on top the hills, a fantastic coast with lots of marine and terrestrial wildlife” and let’s not forget absolutely magnificent unpolluted night sky.

 

Some related Literature:

Schreurs, G. and Immenhauser, A. (1999), West-northwest directed obduction of the Batain Group on the eastern Oman continental margin at the Cretaceous-Tertiary boundary, Tectonics, 18, doi: 10.1029/1998TC900020.

Immenhauser, A., et al. (1998), Stratigraphy, sedimentology and depositional environments of the Permian to uppermost Cretaceous Batain Group, eastern-Oman, Eclogae Geologicae Helvetiae, 91.2, 217-235.

DeWever and Baudin (1996). Palaeogeography of radiolarite and organic-rich deposits in Mesozoic Tethys, GR Geologische Rundschau, 85, 310-326.

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

GeoCinema Online: What a difference technology can make.

8 Oct

Advances in technology mean research that was unthinkable some years ago is now possible. For instance, geographically remote areas which were once out of reach have become more accessible through better (not always easier) transportation, so what we understand by ‘remote areas’ has changed significantly over time. The films in this edition of GeoCinema online are fascinating because they showcase how progress in science know-how mean the advancement of our understanding of planet Earth.

A planetary perspective with Landsat and Google Earth engine

Since July 1972, NASA’s Landsat satellites have gathered images over the entire land surface of the Earth. These images, archived at USGS, reveal dynamic changes over time due to human activity (deforestation, urbanization) and natural processes (volcanic eruptions, wildfire). Now, Google Earth Engine allows scientists, researchers and the public to easily view and analyse this treasure trove of planetary data.

Down to the volcano

A team of scientists have set themselves the goal of building an advanced deep ocean laboratory – on the edge of an active submarine volcano, over a mile below the surface. This research certainly pushes the boundaries of what are considered remote areas!

Project Azolla

How a freshwater fern can provide food, feed & biofuel. This video presents the potential of aquatic farming with a special plant: the fresh-water fern Azolla. The new technology showcased in this video highlights how Azolla provides an innovative way of sustainable, renewable farming.

 

Have you experienced the trials and tribulations of field work? You aren’t alone! As showcased in our last GeoCinema post. If you missed any of the series so far why not catch up here?

Stay tuned to the blog for more films!

Credits

A planetary perspective with Landsat and Google Earth engine: Denise Zmekhol, http://www.zdfilms.com/A-PLANETARY-PERSPECTIVE

Down to the Volcano: Nancy Penrose and Anne Boucher, https://www.youtube.com/watch?v=PIUKej4_XMU

Project Azolla, from floating fern to renewable resource: Dan Brinkhuis, https://www.youtube.com/watch?v=O34gTsxyDq8&feature=share&list=UU_-wRQieb9Tr5GFfJS8c84A

Imaggeo on Mondays: A mysterious shrinking lake

6 Oct

Air, Fire, Earth and Water. (Credit: Sabrina Matzger via imaggeo.egu.eu)

Air, Fire, Earth and Water. (Credit: Sabrina Matzger via imaggeo.egu.eu)

From this week’s Imaggeo on Mondays image it’s easy to see why Iceland is the setting of so many books, films and TV shows, inspiring and inciting writers and film crews alike. The picture was taken on the shores of Lake Kleifarvatn, in Reykjanes peninsula, approximately 30 km to the west of the country’s capital, Reykjavík.

“The Reykjanes peninsula is unique because it marks theboundary between the North American and Eurasian Plates“, explains Sabrina Metzger, who photographed this stunning landscape. Although her PhD thesis focused on the study of plate-boundary deformation in northern Iceland, Sabrina took the photograph on a rare day off in the south of the island, during a “touristic field trip”.

At 9.1 km² and 97m deep, Lake Kleifarvatn is one of the largest lakes on the Reykjanes peninsula, and one of the deepest in the whole country. It varies considerably in size during the year, controlled mostly by changes in groundwater levels, owing to a small catchment area and its lack of any visible surface drainage.

In the summer of 2001, southern Iceland, including the Reykjanes peninsula, was struck by a series of earthquakes, the largest of which was magnitude 6.6. The effects of the ground motion were widespread and affected the local infrastructure, in addition to the landscape. Following the earthquakes, the water levels in Lake Kleifarvatn began to drop; by 2001 the water level had diminished by 4m. A fissure, approximately 400m long and 30cm wide, observed in the vicinity of the lake, was seen to disappear below its waters. It is thought the fissure is responsible for the draining of the lake between 2000 and 2001. At present water levels have returned back to normal, following years of lake sedimentation which have infilled the fissure.

Kleifarvatn and the surrounding area remain a tourist hotspot, not least because of the incredible landscape but added to by the presence of mudspots, stream holes and other frequent geothermal activity. Perhaps the fact that the best-selling Icelandic author Arnaldur Indriðason used the shrinking of the lake caused by the earthquakes in 2001 as a back drop for his thriller The Draining Lake, adds to the appeal of Kleifarvatn.

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

The known unknowns – the outstanding 49 questions in Earth sciences (Part III)

3 Oct

We continue exploring the biggest conundrums in Earth sciences in this third post of the known unknowns. In the two previous instalments of the series we’ve discovered what the major questions still to be answered about the early days of planet Earth and its inner workings are. We now move onto the planet’s surface. The advent of plate tectonic theory, arguably one of the biggest advancements in the geosciences of the past century, has allowed us to far better understand how continents are built and the hazards associated with moving plates. Nevertheless, there is still much we do not comprehend, opening the door for hugely exciting and innovative research opportunities.

Tectonic-plate motion and deformation

A cross section illustrating the main types of plate boundaries  (Image Source; WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

A cross section illustrating the main types of plate boundaries (Image Source: WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

  1. What is the relative importance of the forces driving plate tectonics: slab pull, slab suction, mantle drag, and ridge push? (e.g., Conrad & Lithgow-Bertelloni,JGR, 2004; Negredo et al., GRL, 2004, vs. van Benthem & Govers, JGR, 2010). What is the force balance and the geochemical cycle in subduction zones? (Emry et al., JGR, 2014) How much water (and how deep) penetrates into the mantle? (Ranero et al., Nature 2003) How much subcontinental erosion takes place under subduction areas? (Ranero et al.,Nature, 2000)
  2. What happens after the collision of two continents? Does continental collision diminish the rate of plate subduction, as suggested by the slab-pull paradigm? (Alvarez, EPSL, 2010)  How frequent are the processes of mantle delamination and slab break-off? What determines their occurrence? (Magni et al., GRL, 2013; Durezt & Gerya, Tectonoph., 2013)
  3. Why are orogens curved when seen from space? (Weil & Sussman, 2004, GSASP 383)
  4. How well do different approaches to establish plate motion compare? How does the long-term deformation derived from paleomagnetism and structural geology link quantitatively to the present-day motions derived from GPS and from neotectonic patterns of crustal deformation? (Calais et al., EPSL, 2003) How do these last two relate to each other? (Wang et al., Nature, 2012) Can we learn from regional structure of the crust/lithosphere from that link (or viceversa)?
  5. Are plate interiors moving in steady-state linear motion? How rigid are these and why/when did they deform? (Davis et al., Nature, 2005, and Wernicke & Davis, Seismological Research Letters, 2010).
  6. How is relative motion between continents accommodated in diffuse plate boundaries? (eg., the Iberian/African plate boundary). What determines the (a)seismicity of a plate contact?
  7. How/when does deformation propagate from the plate boundaries into plate interiors? (e.g., Cloetingh et al.,QSR, 2005)
  8. What is the rheological stratification of the lithosphere: like a jelly sandwich? Or rather like a creme brulée? (Burov & Watts, GSA Today, 2006). Is the lower crust ductile? Is strength concentrated at the uppermost mantle? Or just the other way around? (e.g., McKenzie et al., 2000, JGR; Jackson, GSA Today, Handy & Brun, EPSL, 2004; and a nice blog post).
  9. Does the climate-controlled erosion and surface transport of sediment modify the patterns of tectonic deformation? Does vigorous erosion cause localized deformation in the core of mountain belts and prevent the propagation of tectonic shortening into the undeformed forelands? Does the deposition of sediment on the flank of mountains stop the frontal advance of the orogen? Is there field evidence for these effects predicted from computer models? (Philip Allen’s blog) (Willett, JGR,1999,Whipple, Nature, 2009Garcia-Castellanos, EPSL, 2007)

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

  10. Can earthquakes be predicted? (Heki, 2011, GRLFreed, 2012, Nat.Geosc.). How far away can they be mechanically triggered? (Tibi et al., Nature, 2003). Little is known about how faults form and when do they reactivate, and even worse, there seems to be no clear pathway as to solve this problem in the near future. Unexpected breakthroughs needed.
  11. How can the prediction of volcanic eruptions be improved? What determines the rates of magma accumulation in the chamber and what mechanisms make magmas eruptible? See for example this article on the Yellowstone Caldera  and this paper regarding volcanic uplift.
  12. How much of the Earth’s surface topography is dynamically sustained by the flow in the mantle? In many regions, the elevation of the continents does not match the predictions from the classical principle of isostasy for the Earth’s outer rigid layer (the lithosphere). This deviation is known as dynamic topography, by opposition to isostatic topography. But what are the mechanisms responsible? Can we learn about the mantle dynamics by estimating dynamic topography? (Braun, Nature Geoscience, 2010). Can the hidden loads needed to explain the accumulation of sediment next to orogens (foreland basins) be linked to these dynamic forces? (Busby & Azor, 2012).
  13. How do land-forming processes react to climate change at a variety of scales, ranging from the Milankovitch cycles to the late Cenozoic cooling of the Earth? Is there a feedback from erosion into climate at these time scales, through the Carbon cycle and the weathering of silicates, for example? What is the role of the surface uplift and erosion of Tibet on the drawdown of atmospheric CO2 over the Cenozoic? (Garzione, Geology, 2008)

 

Have you been enjoying the series so far? Let us know what you think in the comments section below, particularly if you think we’ve missed any fundamental questions!

In the second to last post in the series we will outline the top outstanding research questions with regards to the Earth’s surface: Earth’s landscape history and present environment.

By Laura Roberts Artal, EGU Communications Officer, based on the article previously posted on RetosTerricolas by Daniel Garcia-Castellanos, researcher at ICTJA-CSIC, Barcelona

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