GeoLog

Tectonics and Structural Geology

Imaggeo on Mondays: Dragon Blood Tree

Imaggeo on Mondays: Dragon Blood Tree

On a small and isolated island in the Indian Ocean you’ll find an endemic population of Dragon Blood Trees (Dracaena cinnabari). Burly, with an interesting umbrella-shaped fractal canopy, these unique trees are a sight to behold.

To see them for yourself, you’ll have to travel to the little known Socotra archipelago. Off the coast of Somalia, but belonging to Yemen, the group of islands boast an impressive assortment of endemic plant life, making them know as the ‘Galapagos of the Middle East’.

Crucial to the uniqueness of the flora and fauna of the archipelago is Socotra’s geographical position and how it came to be there. The African plate extends out from the Horn of Africa, east of the Guardafui graben, in what is known as the Socotra Platform. Here you’ll find four islands, of which Socotra is the largest, as well as two scars of former islands which have been eroded away by wave action.

At in excess of 240 kilometres east of the Horn of Africa and 380 kilometres south of the Arabian Peninsula there is no getting away from the remoteness of the archipelago. Testament to this is the presence of seven endemic bird species on the island.

So how did the strange looking Dragon Blood Tress and other flora and fauna come to populate Socotra and its neighbours?

It is thought that until 43 million years ago, the Socotra archipelago remained largely submerged. Although there were some brief emergence events during the Jurassic/Cretaceous and Cretaceous/Tertiary, given the area was re-submerged after this time, they are considered of little importance.

Subsequently, Socotra Island continued to grow due to uplift. Despite changing sea depths, there are indications that land species could migrate over from mainland African and Arabia via land bridges and stepping stones. With ‘cousin’ species present in Somalia and Arabia, it’s likely the Dragon Blood Trees originated there in the distant past.

From 16,000 years ago onwards, the isolation of the archipelago grew due to a combination of further flooding of low-lying areas, the formation of large basins (namely the Guardafui and Brothers basin) and increasing distance from the mainland. Since then, the species on Socotra and its neighbouring islands have had time to evolve and adapt to their surroundings, become different, albeit sometimes closely related, to their continental counterparts.

It was only around the third century BC that Socotra started to emerge from its isolation after attracting the attention of the young Alexander the Great during one of his war campaigns. The island then became known in the Hellenic World and all the Mediterranean for being one of the main sources of incense, myrrh and dragon’s blood powder resin.

As Socotra commercial importance gradually faded away in the centuries to follow, Dragon’s Blood resin remained one of the main exports of the island. The resin was considered a precious ingredient of dyes, lacquers and varnishes, and the legend has it that Antonio Stradivari – the famous seventeenth century luthier from Cremona – used Socotra’s red resin to varnish his violins.

yemen

The landscape of the Socotra archipelago. Credit: Annalisa Molini via Flickr.

One thing is for sure, as Annalisa Molini’s (Assistant Professor at the Institute Center for Water and Environment, in Abu Dhabi), photographs attest to: Socotra island and it’s Dragon Blood Trees are stunning.

However, the remoteness of the Socotra archipelago and the current armed conflict in Yemen threaten to put at risk the island’s important and unique natural heritage; one that no doubt, should be protected and preserved.

References

M. Culek: Geological and morphological evolution of the Socotra Archipelago (Yemen) from the biogeographical view, Journal of Landscape Ecology, 6, 3, 84–108, DOI: 10.2478/jlecol-2014-0005, 2014

Brown, B.A. Mies, Vegetation Ecology of Socotra, Springer Netherlands, Dordrecht, 2012. doi:10.1007/978-94-007-4141-6.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Velociraptor in the Zagros Mountains

A velociraptor in the Zagros fold and thrust belt. Credit: Stephane Dominguez (distributed via  imaggeo.egu.eu)

A velociraptor in the Zagros fold and thrust belt. Credit: Stephane Dominguez (distributed via imaggeo.egu.eu)

How many times have you turned your head up to the sky and spotted familiar shapes in the clouds? Viewing structures from afar can reveal interesting, common and, sometimes, funny patterns.

Satellite images are often used to map geological terrains. They offer a bird’s eye view of the planet and the opportunity to see broad scale structures, the scale of which would be impossible to grasp from the ground. They can, from time to time, much like when you cloud spot, reveal interesting and unexpected features too!

The image above is a processed LANDSAT 7 Satellite image. Stephane Dominguez, a researcher at the University of Montpellier, acquired the image to study the Zagros Fold and thrust belt: the result of the collision of the Iranian Plate and the Arabian Plate.

Whilst studying the image, Stephane noticed an uncanny resemblance…who knew the Zagros mountain belt hosts a velociraptor? Stephane modified the image, using Photoshop, to obtain the false colours which highlight the dinosaur shape in the image. A little thumbnail of a velociraptor is included too, for comparison!

The surface morphology of the image is dominated by EW trending folds, with partially eroded cores. Darker/black areas correspond to salt diapirs that reached the surface in the fold cores or along reverse faults bounding the folds. We’ve featured the Zagros Mountains in our Imaggeo on Monday’s posts recently; you can find more details on the geology of the region here.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

The day the Earth trembled: A first-hand account of the 25 April Nepal earthquake

The day the Earth trembled: A first-hand account of the 25 April Nepal earthquake

On the 25th April 2015, Viktor Bruckman, a researcher at the Austrian Academy of Sciences, and a team of his colleagues were a few hours into a hike between the settlements of Lamabagar, in a remote area of northeastern Nepal, and the Lapchi Monastery when a magnitude 7.8 earthquake struck Nepal. Their journey cut short by the trembling Earth, stranded in the heights of the Himalayas, this is their personal experience of the Gorkha earthquake, summarised by EGU Communications Officer Laura Roberts. 

Researching land use in Nepal

Bruckman is part of an international team of researchers, from Austria, Nepal and China, studying the land use and forest resource management in the densely wooded and remote Gaurishankar Conservation Area, in eastern Nepal. Bruckman and his team want to better understand how the local communities are linked to the resources in the area and how their daily life has been affected since the introduction of the Conservation Area. Their research project also aims to explore how the ongoing building of the largest hydropower plant in Nepal: the Upper Tamakoshi Hydropower Project (UTHP) might disrupt the local populations.

The team conducted a set of semi-structured interviews in order to assess land management practices and the impact of new management policies since the Gaurishankar Conservation Area was set up in 2010 (by Dr. Viktor Bruckman).

The team conducted a set of semi-structured interviews to assess land management practices and the impact of new management policies since the Gaurishankar Conservation Area was set up in 2010 (Credit: Dr. Viktor Bruckman).

To answer these questions, Bruckman and his colleagues travelled to Nepal in April to participate in workshops with government and institutional bodies based in Kathmandu, as well as visiting local communities deep within the Gaurishankar Conservation Area to conduct face-to-face interviews.

Beyond the hydropower construction site there are no roads, meaning the team had to hike across the rugged Himalayas to reach the residents of the most remote settlements and the target location for setting up monitoring plots. Their planned route would take them 25 km from Lamabagar, at 2000 m above sea level, reaching Lapchi Monastery, close to the Tibetan border, two days later having climbed to an altitude of 3800 m.

The hike

On the morning of the 25th April, a team composed of Bruckman, his Nepalese colleague Prof. Devkota, Devkota’s student Puskar and Prof. Katzensteiner from the University of Natural Resources and Life Sciences Vienna (BOKU), set off on the trek to Lapchi. They were accompanied, albeit a little later following breakfast, by three porters who carried the bulk of their scientific equipment, some food and other ‘home comforts’ such as sleeping bags and mattresses. Given the physical effort the trek would involve, many of the food supplies were delivered to Lapchi via helicopter, a few days in advance – local porters would meet the team at settlements downstream of the monastery and deliver the provisions over the course of the next few days.

Despite the constant drizzle and strains of the climb, the entire team was stuck by the beauty of the surroundings: steep cliffs of metamorphosed sedimentary series (Tethys Himalaya within the Central Himalayan Domain), diverse mix deciduous forests and glistening streams.

The moment everything changed

At 12:05, not long after having traversed the most challenging section of the hike thus far, walking along the Lapchi River Valley, the ground under the team’s feet started to quiver. The quiver quickly grew to a strong shake dislodging football sized rocks from the surrounding slopes. The realisation hit the researchers that they were experiencing an earthquake and their primary concern was to seek shelter from the ongoing rock fall triggered by the ground shaking.

“Large rocks, with size equal to small houses, smashed into the river breaking into smaller pieces which where flung in all directions”, describes Bruckman, who by now had found protection, alongside Prof. Devkota, behind a large tree.

A few moments later, the earthquake ended and both emerged from behind the tree unharmed.

Left: Rockfall from the opposite cliffs made our location a highly dangerous place. Right: Seconds after the main tremor was over, everything was changed. The river color turned brown, dust and Sulphur smell was in the air and the path was destroyed by small landslides or rocks (Credit: Prof. Dr. Klaus Katzensteiner).

Left: Rockfall from the opposite cliffs made the researchers’ location a highly dangerous place. Right: Seconds after the main tremor was over, everything was changed. The river color turned brown, dust and Sulphur smell was in the air and the path was destroyed by small landslides or rocks (Credit: Prof. Dr. Klaus Katzensteiner).

They found Prof. Katzensteiner sheltering under a large rock overhang, but there was no sign of Puskar. The three men eyed up a large boulder which had come to rest on the path and feared the worst. Some minutes later, Puskar appeared, unharmed, along the path accompanied by a lama – a Buddhist monk – who’d encouraged the student to run up hill away from the projectiles from the river.

“The lama saved our student’s life; he was almost hit by a large rock which destroyed the water bottle attached to his backpack,” says Bruckman.

A stroke of luck

With their porters some hours trek behind them, almost no food supplies and no other equipment, and worried about potential flash floods as a result of landslides upstream, the group decided to make their way out of the valley and head back towards Lamabagar, only to find that the trail had been wiped out by a massive landslide.

The lama’s knowledge of the local terrain was invaluable as he guided the scientists to a meditation centre, where a group of about 20 lamas kindly took them in, sharing their food, offering tea and a place to sleep.

Having found a place of shelter, Bruckman and his colleagues, knowing how worried their families would be, were desperate to contact them. But amongst the high peaks of the Himalayas, in one of the most remote parts of Nepal, mobile phone signal is hard to come by. Only once, on the morning of the 26th of April, were the group successful in reaching loved ones, but it was enough: they were able to communicate they had survived, but were now trapped in the Lapchi River Valley.

The retreat where lamas provided the scientists with food and shelter (Credit: Prof. Dr. Klaus Katzensteiner).

The retreat where lamas provided the scientists with food and shelter (Credit: Prof. Dr. Klaus Katzensteiner).

Back home, a rescue mission started: The scientists’ families, the officials of their institutions, their countries Foreign Ministries’, Embassies and the local military all rallied to locate and bring home the researchers. Five days after first arriving at the Buddhist meditation centre, the group was rescued by a helicopter, which took them to the safety of military camp Charikot.

Retracing their steps, this time in a helicopter, Bruckman and his colleagues realised the scale of the devastation caused by the earthquake. The first village they’d intended to reach on their hike, Lumnang, was completely destroyed. 80% of the building structures in the valley had disappeared. Landslides has wiped out large sections of the trail, meaning returning to Lamabagar would have been out of the question.

Tragedy

The team’s porters, travelling behind the researchers when the earthquake hit, were far less fortunate. Tragically, one of the team’s porters was killed by a landslide triggered by the earthquake, whilst another was seriously injured. Only one returned safely to Lamabagar. Whilst hiking, the scientists overtook several groups of people also headed towards Lapchi and a team of hydropower experts – they are all reported missing.

The region, already damaged by the April 25th earthquake, was further rocked by a powerful, magnitude 7.3, aftershock. Since then, Bruckman and his colleagues have been unable to reach their contacts in Lamabagar. Reports indicate that hardly any structures were left standing in the village.

A view of Lamabagar prior to the earthquakes. At 2000m a.s.l., the village lies on the flat riverbed of the Upper Tamakoshi River, which developed as a consequence of a massive landslide (probably earthquake-induced) in the past (by Dr. Viktor Bruckman).

A view of Lamabagar prior to the earthquakes. At 2000m a.s.l., the village lies on the flat riverbed of the Upper Tamakoshi River, which developed as a consequence of a massive landslide (probably earthquake-induced) in the past (Credit: Dr. Viktor Bruckman).

The future

Following the earthquake, the scientists realise that the original research aims are no longer valid and “we would probably not meet the communities’ needs if we stick to the original ideas”, explains Bruckman.

Therefore, the plan is to carefully assess the regions current situation and develop a new research proposal which will focus on supporting the remote villages on a long-term and sustainable basis. In the event of any future field work in the region, the scientist will ensure they carry, at the very least, an Emergency Position Indicating Radio Beacon (EPIRB), if not a satellite phone.

Science aside, their experience in the Nepal means the scientists were deeply touched by the kindness extended to them by the lamas and now seek to support the communities affected by the earthquakes. In particular they want to raise funds for the families of the porters who passed away and were injured while transporting their supplies.

 By Laura Roberts, EGU Communications Officer

A message from Bruckman and his colleagues

Please help us support the affected families.

For the purpose of collecting donations, we opened an account at the University of Natural Resources and Life Sciences Vienna (BOKU). Funds will be collected in a transparent manner and directly used for supporting the porter’s families and the villagers of Lumnang, who have lost everything and they will most likely not receive help from other sources soon. We will facilitate support through the trustworthy Nepalese project partners (including full documentation) and the Lamas of Lapchi monastery and from the retreat where we were able to stay. Please help us to support this remote region; even a small contribution is very much appreciated. Our direct contacts ensure that 100% of the donations reach the target group.

Here are the account details for wire transfer:

Recipient: Universität für Bodenkultur Wien, Spenden IBAN: AT48 3200 0018 0050 0512 BIC: RLNWATWWXXX Payment reference: 7912000003

Payments via Credit Card are also possible (Master Card and Visa). Should you wish to pay per credit card, please send an e-mail containing your name, address, card number, expiry date and security code (3-digits) to c.hofer@boku.ac.at.

We thank you very much for your contribution!

The team after their ordeal. They extend their deepest condolences to the family of the porter that lost his life during our the Prof. Dr. Klaus Katzensteiner).

The team after their ordeal. They extend their deepest condolences to the family of the porter who lost his life during the expedition. (Credit: Prof. Dr. Klaus Katzensteiner).

 

This blog post is a summary of: How a geophysical extreme event dramatically changed fieldwork plans – a personal account of the Gorkha Earthquake, originally posted on the EGU’s Energy, Resources and the Environment Division Blog.

For more information about the 2015 April and May earthquakes, please see the links provided in the original blog post. You can also access more information via this information briefing issued by the EGU.

Imaggeo on Mondays: Scales of fluvial dissection

Imaggeo on Mondays: Scales of fluvial dissection

High peaks, winding river channels and a barren landscape all feature in today’s Imaggeo on Mondays image, brought to you by Katja Laute, a geomorphologist from Norway. 

This photo was taken from an airplane flying over the Zagros Mountains in Iran. The Zagros Mountain range stretches south and west from the borders of Turkey and Russia to the Persian Gulf, and is Iran’s largest mountain range. The mountain range has a total length of 1500 km and stretches from north eastern Iraq, to the Strait of Hormuz. Many peaks are higher than 2900 m. The tallest mountain is Zard-Kuh at an elevation of 4548 m.

The Zagros fold and thrust belt was formed by the collision of the two tectonic plates- the Iranian Plate and the Arabian Plate. The collision resulted in parallel folds, which are seen as broad anticlines forming the high mountain peaks, , and orogenically are the same age as the Alps. The Zagros Mountains are made up primarily of limestone and dolomite – a sedimentary carbonate rock primarily composed of the anhydrous carbonate mineral of the same name.

The region exemplifies the continental variation of the Mediterranean climate pattern, with a snowy, cold winter and mild rainy spring followed by a dry summer and autumn. In winter, low temperatures can often drop below – 25 °C and many mountain peaks exhibit snow even in summer. The most common ecosystems in the Zagros Mountains are the forest and steppe areas which have a semi-arid temperate climate.

The photo gives an amazing impression of different scales of fluvial dissection. The landscape consists of valleys and their included channels organized into a connecting system known as a drainage network. The powder snow enhances nicely the dendritic drainage pattern.

 

By Katja Laute, Geomorphologist, Trondheim, Norway

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

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