| 1. |
- Carracedo, Juan-Carlos, et al.
(author)
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Volcanic and structural evolution of Pico do Fogo, Cape Verde
- 2015
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In: Geology Today. - : Wiley. - 0266-6979 .- 1365-2451. ; 31:4, s. 146-152
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Journal article (peer-reviewed)abstract
- In recent months the media have drawn attention to the Cape Verde archipelago, with particular focus on the island of Fogo, the only island presently active and with an eruption that began on 23 November 2014, finally ceasing on 7 February 2015. The Monte Amarelo conical shield forms most of the 476 km2 almost circular island of Fogo. After attaining a critical elevation of about 3500 m, the Monte Amarelo shield volcano was decapitated by a giant landslide that formed a caldera-like depression (Cha das Caldeiras), which was subsequently partially filled by basaltic nested volcanism. This younger eruptive activity culminated in the construction of the 2829 m-high Pico do Fogo stratocone, apparently entirely made of layers of basaltic lapilli. Continued growth of the Pico do Fogo summit eruptions was interrupted in 1750, most likely after the stratocone reached a critical height. Since then, at least eight eruptions have taken place inside the landslide depression at the periphery of the Pico do Fogo cone, including the 2014–2015 eruptive event. Strong geological similarities with the Canary Islands, 1400 km to the north, have been frequently noted, probably as a consequence of a common process of origin and evolution associated with a mantle hot-spot. These similarities are particularly evident when comparing Fogo with the Teide Volcanic Complex on Tenerife, where a lateral collapse of the Las Cañadas stratovolcano also formed a large depression (the Caldera de Las Cañadas), now partially filled with the 3718 m-high Teide stratocone. However, important geological differences also exist and probably relate to the contrasting evolutionary stages of both islands. The Las Cañadas volcano on Tenerife formed at a late post-erosional stage, with predominantly evolved (trachyte and phonolite) magmas, while at Fogo basaltic volcanism is still dominant.
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| 2. |
- Deegan, Frances, et al.
(author)
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The stiff upper LIP : investigating the High Arctic Large Igneous Province
- 2016
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In: Geology Today. - : Wiley. - 0266-6979 .- 1365-2451. ; 32:3, s. 92-98
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Journal article (pop. science, debate, etc.)abstract
- The Canadian Arctic Islands expose a complex network of dykes and sills that belong to the High Arctic Large Igneous Province (HALIP), which intruded volatile-rich sedimentary rocks of the Sverdrup Basin (shale, limestone, sandstone and evaporite) some 130 to 120 million years ago. There is thus great potential in studying the HALIP to learn how volatile-rich sedimentary rocks respond to magmatic heating events during LIP emplacement. The HALIP remains, however, one of the least well known LIPs on the planet due to its remote location, short field season, and harsh climate. A Canadian–Swedish team of geologists set out in summer 2015 to further explore HALIP sills and their sedimentary host rocks, including the sampling of igneous and meta-sedimentary rocks for subsequent geochemical analysis, and high pressure-temperature petrological experiments to help define the actual processes and time-scales of magma–sediment interaction. The research results will advance our understanding of how climate-active volatiles such as CO2, SO2 and CH4 are mobilised during the magma–sediment interaction related to LIP events, a process which is hypothesised to have drastically affected Earth's carbon and sulphur cycles. In addition, assimilation of sulphate evaporites, for example, is anticipated to trigger sulphide immiscibility in the magma bodies and in so doing could promote the formation of Ni-PGE ore bodies. Here we document the joys and challenges of ‘frontier arctic fieldwork’ and discuss some of our initial observations from the High Arctic Large Igneous Province.
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| 3. |
- Troll, Valentin, et al.
(author)
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Nannofossils: the smoking gun for the Canarian hotspot
- 2015
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In: Geology Today. - : Wiley. - 0266-6979 .- 1365-2451. ; 31:4, s. 137-145
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Journal article (peer-reviewed)abstract
- The origin of volcanism in the Canary Islands has been a matter of controversy for several decades. Discussions have hinged on whether the Canaries owe their origin to seafloor fractures associated with the Atlas Mountain range or to an underlying plume or hotspot of superheated mantle material. However, the debate has recently come to a conclusion following the discovery of nannofossils preserved in the products of the 2011–2012 submarine eruption at El Hierro, which tell us about the age and growth history of the western-most island of the archipelago. Light coloured, pumice-like ‘floating rocks’ were found on the sea surface during the first days of the eruption and have been shown to contain fragments of pre-island sedimentary strata. These sedimentary rock fragments were picked up by ascending magma and transported to the surface during the eruption, and remarkably retained specimens of pre-island Upper Cretaceous to Pliocene calcareous nannofossils (e.g. coccolithophores). These marine microorganisms are well known biostratigraphical markers and now provide crucial evidence that the westernmost and youngest island in the Canaries is underlain by the youngest sediment relative to the other islands in the archipelago. This finding supports an age progression for the onset of volcanism at the individual islands of the archipeligo. Importantly, as fracture-related volcanism is known to produce non-systematic age-distributions within volcanic alignments, the now-confirmed age progression corroberates to the relative motion of the African plate over an underlying mantle plume or hotspot as the cause for the present-day Canary volcanism.
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| 4. |
- Troll, Valentin R., et al.
(author)
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Volcanic particles in agriculture and gardening
- 2017
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In: Geology Today. - : Wiley. - 0266-6979 .- 1365-2451. ; 33:4, s. 148-154
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Journal article (peer-reviewed)abstract
- Volcanic pyroclasts of small size, such as lapilli and small pumice stones, are widely used in agriculture, gardening, and for pot plants as natural inorganic mulch. The technique of using pyroclasts to enhance topsoil stems from the eighteenth century, and specifically from the ad 1730–1736 eruption on Lanzarote. Critical observations on plant development during and after the eruption showed that the vegetation died when buried under a thick layer of lapilli, but grew vigorously when covered thinly. While the agriculture of Lanzarote was restricted to cereals before the eruption, it diversified to many kinds of fruit and vegetables afterwards, including the production of the famous MalvasÃa wines in the Canaries. The population of Lanzarote doubled in the years after the eruption, from about 5000 in 1730 to near 10 000 in 1768, predominantly as a result of the higher agricultural productivity. This outcome led to widespread use of lapilli and pumice fragments throughout the islands and eventually the rest of the globe. Lapilli and pumice provide vesicle space for moisture to be retained longer within the planting soil, which can create an environment for micro-bacteria to thrive in. Through this route, nutrients from volcanic matter are transported into the surrounding soil where they become available to plant life. The detailed processes that operate within the pyroclasts are less well understood, such as the breakdown of nutrients from the rock matrix and transport into the soil by biological action. Further studies promise significant potential to optimize future agricultural efforts, particularly in otherwise arid areas of the globe.
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| 5. |
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| 6. |
- Eriksson, Mats E.
(author)
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A fellow Swede is the reference for humanity
- 2016
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In: Geology Today. - : Wiley. - 0266-6979. ; 32:1, s. 27-29
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Journal article (other academic/artistic)abstract
- There is (or should be) an archived specimen, a reference copy if you like, for all living and fossil species that have been described scientifically. These physical specimens, so-called name-bearing type specimens, are housed at museums or academic institutes around the world for researchers to study and perhaps compare with their own material. But what about our own species, Homo sapiens?.
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| 7. |
- Eriksson, Mats E., et al.
(author)
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Half-a-billion-year-old microscopic treasures-the Cambrian 'Orsten' fossils of Sweden
- 2016
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In: Geology Today. - : Wiley. - 0266-6979. ; 32:3, s. 115-120
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Journal article (other academic/artistic)abstract
- The creatures that gaze back at us through the binocular microscope are so uniquely well-preserved and life-like that had we not known better we would have thought that they were modern. Instead they are half-a-billion-year-old arthropods extracted from Cambrian rocks of Sweden. The microscopic fossils, colloquially known as the 'Orsten' fossils, are now world-famous and basking in the light of the research catwalk since their discovery in the 1970s. These fossils have provided significant insight into the long lost Cambrian biotas and early animal evolution.
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| 8. |
- Eriksson, Mats E.
(author)
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Prehistory as sonic inspiration : palaeontological heritage in popular music
- 2016
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In: Geology Today. - : Wiley. - 0266-6979. ; 32:6, s. 222-227
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Journal article (other academic/artistic)abstract
- Apparently palaeontology is deeply rooted in popular music. Just take bands like T. Rex, Mastodon, Dinosaur Jr, The Ammonites, Mammoth, and Novi Fosili (the new fossils), and you get the picture. Digging into this subject matter it turns out that the extinct residents of prehistoric times have inspired not only band names, but also record and song titles and album cover artwork. In this paper I explore fossils as sonic inspiration or, if you wish, music for the extinct.
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| 9. |
- Eriksson, Mats, et al.
(author)
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Fake it till you make it : The uncanny art of forging amber
- 2015
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In: Geology Today. - : Wiley. - 0266-6979. ; 31:1, s. 21-27
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Journal article (pop. science, debate, etc.)abstract
- Amber has fascinated people since the Stone Age and as one of the best means of preservation of fossil organisms, it tickles our senses. The animals that are sometimes trapped in amber, like frozen moments of long‐lost ecosystems, can be so incredibly well preserved that they look modern—which, in some cases, has proven to be just the case. Because fossil‐bearing amber not only has a significant scientific value but is also a desired commodity on the open market, fake amber has unfortunately been around for centuries.
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| 10. |
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