Tertiary Fumaroles on the Island of Raasay, Inverness-shire

1966 ◽  
Vol 103 (6) ◽  
pp. 558-564 ◽  
Author(s):  
R. C. Selley
Keyword(s):  
Country Rock ◽  
Hydrothermal Solution ◽  
Volcanic Centre ◽  
Downward Movement ◽  
Volcanic Origin ◽  
Volcanic Material ◽  
Fumarole Activity ◽  
Carbonate Material ◽  
Carbonate Matrix ◽  
Stratigraphic Succession

AbstractThree large pipes of brecciated Torridonian sediments set in matrices of calcite and calcareous mudstone occur on the island of Raasay. Previous work has shown that these structures may be due to explosive fumarole activity during the Tertiary volcanic episode. A recent study of the Torridonian stratigraphic succession has made it possible to demonstrate that there was considerable variation in the amount of vertical collapse of the local country rock caused by the explosions. In one vent local fracturing and brecciation took place with no downward movement; in another it is possible to show that Torridonian boulders tumbled at least 350 metres down into the throat of the fumarole. The amount of vertical collapse increases from vent to vent southwards towards the Cuillins volcanic centre.These vents are of particular interest for two reasons. Though clearly of volcanic origin they contain no volcanic material. Secondly, the carbonate matrix of analogous structures is generally believed to be due to the hydrothermal solution of underlying limestone beds. The latter are absent in these examples and the carbonate material seems to be solely of volcanic origin.

scholarly journals Improved SAGE II cloud/aerosol categorization and observations of the Asian tropopause aerosol layer: 1989–2005

2013 ◽  
Vol 13 (9) ◽  
pp. 4605-4616 ◽  
Author(s):  
L. W. Thomason ◽  
J.-P. Vernier
Keyword(s):  
Extinction Coefficient ◽  
Stratospheric Aerosol ◽  
Trace Gas ◽  
Data Sets ◽  
Aerosol Layer ◽  
Volcanic Origin ◽  
New Approach ◽  
Upper Troposphere ◽  
Volcanic Material ◽  
Tropospheric Aerosol

Abstract. We describe the challenges associated with the interpretation of extinction coefficient measurements by the Stratospheric Aerosol and Gas Experiment (SAGE II) in the presence of clouds. In particular, we have found that tropospheric aerosol analyses are highly dependent on a robust method for identifying when clouds affect the measured extinction coefficient. Herein, we describe an improved cloud identification method that appears to capture cloud/aerosol events more effectively than early methods. In addition, we summarize additional challenges to observing the Asian Tropopause Aerosol Layer (ATAL) using SAGE II observations. Using this new approach, we perform analyses of the upper troposphere, focusing on periods in which the UTLS (upper troposphere/lower stratosphere) is relatively free of volcanic material (1989–1990 and after 1996). Of particular interest is the Asian monsoon anticyclone where CALIPSO (Cloud-Aerosol Lidar Pathfinder Satellite Observations) has observed an aerosol enhancement. This enhancement, called the ATAL, has a similar morphology to observed enhancements in long-lived trace gas species like CO. Since the CALIPSO record begins in 2006, the question of how long this aerosol feature has been present requires a new look at the long-lived SAGE II data sets despite significant hurdles to its use in the subtropical upper troposphere. We find that there is no evidence of ATAL in the SAGE II data prior to 1998. After 1998, it is clear that aerosol in the upper troposphere in the ATAL region is substantially enhanced relative to the period before that time. In addition, the data generally supports the presence of the ATAL beginning in 1999 and continuing through the end of the mission, though some years (e.g., 2003) are complicated by the presence of episodic enhancements most likely of volcanic origin.

scholarly journals Measurement and simulation of the 16/17 April 2010 Eyjafjallajökull volcanic ash layer dispersion in the northern Alpine region

2011 ◽  
Vol 11 (6) ◽  
pp. 2689-2701 ◽  
Author(s):  
S. Emeis ◽  
R. Forkel ◽  
W. Junkermann ◽  
K. Schäfer ◽  
H. Flentje ◽  
...  
Keyword(s):  
Spatial Structure ◽  
Numerical Simulations ◽  
Large Scale ◽  
Scale Model ◽  
Network Data ◽  
Aerosol Layer ◽  
Volcanic Origin ◽  
Southern Germany ◽  
Volcanic Material ◽  
Ash Layer

Abstract. The spatial structure and the progression speed of the first ash layer from the Icelandic Eyjafjallajökull volcano which reached Germany on 16/17 April is investigated from remote sensing data and numerical simulations. The ceilometer network of the German Meteorological Service was able to follow the progression of the ash layer over the whole of Germany. This first ash layer turned out to be a rather shallow layer of only several hundreds of metres thickness which was oriented slantwise in the middle troposphere and which was brought downward by large-scale sinking motion over Southern Germany and the Alps. Special Raman lidar measurements, trajectory analyses and in-situ observations from mountain observatories helped to confirm the volcanic origin of the detected aerosol layer. Ultralight aircraft measurements permitted the detection of the arrival of a second major flush of volcanic material in Southern Germany. Numerical simulations with the Eulerian meso-scale model MCCM were able to reproduce the temporal and spatial structure of the ash layer. Comparisons of the model results with the ceilometer network data on 17 April and with the ultralight aircraft data on 19 April were satisfying. This is the first example of a model validation study from this ceilometer network data.

scholarly journals Characterization of a volcanic ash episode in southern Finland caused by the Grimsvötn eruption in Iceland in May 2011

2011 ◽  
Vol 11 (9) ◽  
pp. 24933-24968 ◽  
Author(s):  
V.-M. Kerminen ◽  
J. V. Niemi ◽  
H. Timonen ◽  
M. Aurela ◽  
A. Frey ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Dispersion Model ◽  
Volcanic Eruptions ◽  
Particle Analysis ◽  
Satellite Measurements ◽  
Volcanic Origin ◽  
Model Simulations ◽  
Volcanic Material ◽  
Micron Particle ◽  
Mass Concentrations

Abstract. The volcanic eruption of Grimsvötn in Iceland in May 2011, affected surface-layer air quality at several locations in Northern Europe. In Helsinki, Finland, the main pollution episode lasted for more than 8 h around the noon of 25 May. We characterized this episode by relying on detailed physical, chemical and optical aerosol measurements. The analysis was aided by air mass trajectory calculations, satellite measurements, and dispersion model simulations. During the episode, volcanic ash particles were present at sizes from less than 0.5 μm up to sizes >10 μm. The mass mean diameter of ash particles was a few μm in the Helsinki area, and the ash enhanced PM10 mass concentrations up to several tens of μg m−3. Individual particle analysis showed that some ash particles appeared almost non-reacted during the atmospheric transportation, while most of them were mixed with sea salt or other type of particulate matter. Also sulfate of volcanic origin appeared to have been transported to our measurement site, but its contribution to the aerosol mass was minor due the separation of ash-particle and sulfur dioxide plumes shortly after the eruption. The volcanic material had very little effect on PM1 mass concentrations or sub-micron particle number size distributions in the Helsinki area. The aerosol scattering coefficient was increased and visibility was slightly decreased during the episode, but in general changes in aerosol optical properties due to volcanic aerosols seem to be difficult to be distinguished from those induced by other pollutants present in a continental boundary layer. The case investigated here demonstrates clearly the power of combining surface aerosol measurements, dispersion model simulations and satellite measurements in analyzing surface air pollution episodes caused by volcanic eruptions. None of these three approaches alone would be sufficient to forecast, or even to unambiguously identify, such episodes.

scholarly journals Resistance to compression and microstructure of concrete manufactured with supersulfated cements-based materials of volcanic origin exposed to a sulphate environment

2018 ◽  
Vol 9 (1) ◽  
pp. 106-116
Author(s):  
Erick Edgar Maldonado Bandala ◽  
Karina Cabrera Luna ◽  
José Ivan Escalante García ◽  
Demetrio Nieves Mendoza
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Energy Dispersive Spectroscopy ◽  
Energy Dispersive ◽  
Hydration Products ◽  
Volcanic Origin ◽  
Volcanic Material ◽  
Laboratory Conditions ◽  
Scanning Electron

This research presents the results of concretes made with supersulfated cements (SSC) volcanic material bases. The concretes were cured under two regimes one for 24 h at 25 ° C and one for 22 h at 60 ° C and then at 25 ° C. The specimens were exposed to two conditions, dry under laboratory conditions and immersed in a solution with 3.5% CaSO 4 at 25 ° C for up to 180 days. After 180 days, the concrete with a 5% An-10% PC-10% CaO-75% PM cementant exposed to the CaSO4 solution achieved a compressive strength of 46 MPa and 44 MPa dry under conditions of laboratory. The microstructure was analyzed by scanning electron microscopy, energy dispersive spectroscopy and XRD, showing that the main hydration products are C-S-H and ettringite.

scholarly journals Spatial structure and dispersion of the 16/17 April 2010 volcanic ash cloud over Germany

2010 ◽  
Vol 10 (11) ◽  
pp. 26117-26155 ◽  
Author(s):  
S. Emeis ◽  
W. Junkermann ◽  
K. Schäfer ◽  
R. Forkel ◽  
P. Suppan ◽  
...  
Keyword(s):  
Spatial Structure ◽  
Numerical Simulations ◽  
Large Scale ◽  
Scale Model ◽  
Network Data ◽  
Aerosol Layer ◽  
Volcanic Origin ◽  
Southern Germany ◽  
Volcanic Material ◽  
Ash Layer

Abstract. The spatial structure and the progression speed of the first ash layer from the Icelandic Eyjafjallajökull volcano which reached Germany on 16/17 April is investigated from remote sensing data and with numerical simulations. The ceilometer network of the German Weather Service was able to follow the progression of the ash layer over the whole of Germany. This first ash layer turned out to be a rather shallow layer of only several hundreds of metres thickness which was oriented slantwise in the middle troposphere and which was brought downward by large-scale sinking motion over Southern Germany and the Alps. Special Raman lidar measurements, trajectory analyses and in-situ observations from mountain observatories helped to confirm the volcanic origin of the detected aerosol layer. Ultralight aircraft measurements permitted the detection of the arrival of a second major flush of volcanic material in Southern Germany. Numerical simulations with the Eulerian meso-scale model MCCM were able to reproduce the temporal and spatial structure of the ash layer. Comparisons with the ceilometer network data on 17 April and with the ultralight aircraft data on 19 April were satisfying. This is the first example of a model validation study from this ceilometer network data.

scholarly journals Identification of a Buried Late Cenozoic Maar-Diatreme Structure (North Moravia, Czech Republic)

2015 ◽  
Vol 65 (5) ◽  
pp. 471-479
Author(s):  
Vojtěch Šešulka ◽  
Iva Sedláková ◽  
OndŘej Bábek ◽  
Antonín PŘichystal
Keyword(s):  
Czech Republic ◽  
Country Rock ◽  
Spatial Association ◽  
Bouguer Anomaly ◽  
Geophysical Methods ◽  
Magnetic Survey ◽  
Limited Information ◽  
Volcanic Origin ◽  
Relative Dating ◽  
The Town

Abstract The maar-diatreme volcanic structure in the vicinity of the village of Lomnice near the town of Bruntál (North Moravia, Czech Republic) has been investigated using a set of geophysical methods including ground magnetometry, gravimetry and electrical resistivity tomography. The structure was detected by an aerial magnetic survey in the second half of the 20th century. Since its discovery only limited information about this buried structure has been available. The coherence of the magnetic anomaly of 190 nT and Bouguer anomaly of -4.7 mGal indicates a volcanic origin of the structure. The funnel-shaped maar-diatreme structure is filled with lacustrine clay and colluvium of Car-boniferous greywacke, which forms the country rock. The surface diameter of the structure is about 600 m, the depth is more than 400 m. The spatial association with other volcanic centers in the surroundings of the town of Bruntál infers the relative dating of the Lomnice maar. The phreatic eruption and maar-diatreme formation could be an indirect conse-quence of effusive activity of the nearby Velký Roudný volcano. The Lomnice structure is the first Plio-Pleistocene maar-diatreme ever described in North Moravia and Silesia.

scholarly journals Characterization of a volcanic ash episode in southern Finland caused by the Grimsvötn eruption in Iceland in May 2011

2011 ◽  
Vol 11 (23) ◽  
pp. 12227-12239 ◽  
Author(s):  
V.-M. Kerminen ◽  
J. V. Niemi ◽  
H. Timonen ◽  
M. Aurela ◽  
A. Frey ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Dispersion Model ◽  
Volcanic Eruptions ◽  
Particle Analysis ◽  
Satellite Measurements ◽  
Volcanic Origin ◽  
Model Simulations ◽  
Volcanic Material ◽  
Micron Particle ◽  
Mass Concentrations

Abstract. The volcanic eruption of Grimsvötn in Iceland in May 2011 affected surface-layer air quality at several locations in Northern Europe. In Helsinki, Finland, the main pollution episode lasted for more than 8 h around the noon of 25 May. We characterized this episode by relying on detailed physical, chemical and optical aerosol measurements. The analysis was aided by air mass trajectory calculations, satellite measurements, and dispersion model simulations. During the episode, volcanic ash particles were present at sizes from less than 0.5 μm up to sizes >10 μm. The mass mean diameter of ash particles was a few μm in the Helsinki area, and the ash enhanced PM10 mass concentrations up to several tens of μg m−3. Individual particle analysis showed that some ash particles appeared almost non-reacted during the atmospheric transportation, while most of them were mixed with sea salt or other type of particulate matter. Also sulfate of volcanic origin appeared to have been transported to our measurement site, but its contribution to the aerosol mass was minor due the separation of ash-particle and sulfur dioxide plumes shortly after the eruption. The volcanic material had very little effect on PM1 mass concentrations or sub-micron particle number size distributions in the Helsinki area. The aerosol scattering coefficient was increased and visibility was slightly decreased during the episode, but in general changes in aerosol optical properties due to volcanic aerosols seem to be difficult to be distinguished from those induced by other pollutants present in a continental boundary layer. The case investigated here demonstrates clearly the power of combining surface aerosol measurements, dispersion model simulations and satellite measurements in analyzing surface air pollution episodes caused by volcanic eruptions. None of these three approaches alone would be sufficient to forecast, or even to unambiguously identify, such episodes.

scholarly journals Lithic Inclusions in the Taupo Pumice Formation

2021 ◽  
Author(s):  
◽  
Tadiwos Chernet
Keyword(s):  
Trace Element ◽  
Pyroclastic Flow ◽  
Country Rock ◽  
Trace Element Content ◽  
Ground Layer ◽  
Lake Basin ◽  
Low Grade ◽  
Volcanic Centre ◽  
Pyroxene Andesite ◽  
Welded Tuff

<p>The Taupo Pumice Formation is a product of the Taupo eruption of about 1800a, and consists of three phreatomagmatic ash deposits, two plinian pumice deposits and a major low-aspect ratio and low grade (unwelded) ignimbrite which covered most part of the central North Island of New Zealand. The vent area for the eruption is located at Horomatangi Reefs in Lake Taupo. Lithics in the phreatoplinian ash deposits are negligible in quantity, but the plinian pumice deposits contain 5-10% lithics by volume in most near-vent sections. Lithics in the plinian pumice deposits are dominantly banded and spherulitic rhyolite with minor welded tuff, dacite and andesite. The ground layer which forms the base of the ignimbrite unit consists of dominantly lithics and crystals and is formed by the gravitational sedimentation of the 'heavies' from the strongly fluidized head of the pyroclastic flow. Lithic blocks in the ground layer are dominantly banded and spherulitic phenocryst-poor rhyolite, welded tuff with minor dacite and andesite. Near-vent exposures of the ground layer contain boulders upto 2 m in diameter. Friable blocks of hydrothermally altered rhyolite, welded tuff and lake sediments are found fractured but are preserved intact after transportation. This shows that the fluid/pyroclastic particle mixture provided enough support to carry such blocks upto a distance of 10 km from the vent. The rhyolite blocks are subdivided into hypersthene rhyolite, hypersthene-hornblende rhyolite and biotite-bearing rhyolite on the basis of the dominant ferromagnesian phenocryst assamblage. Hypersthene is the dominant ferromagnesian phenocryst in most of the rhyolite blocks in the ground layer and forms the major ferromagnesian crystal of the Taupo Sub-group tephra. The rhyolite blocks have similar whole rock chemistry to the Taupo Sub-group tephra and are probably derived from lava extrusions associated with the tephra eruptions from the Taupo Volcanic Centre in the last 10 ka. Older rhyolite domes and flows in the area are probably represented by the intensely hydrothermally altered rhyolite blocks in the ground layer. The dacite blocks contain hypersthene and augite as a major ferromagnesian phenocryst. Whole rock major and trace element analyses shows that the dacite blocks are distinct from the Tauhara dacites and from the dacites of Tongariro Volcanic Centre. The occurrence of dacite inclusions in significant quantity in the Taupo Pumice Formation indicates the presence of other dacite flows near the vent area. Four types of andesite blocks; hornblende andesite, plagioclase-pyroxene andesite, pyroxene andesite and olivine andesite occur as lithic blocks in the ground layer. The andesites are petrographically distinct from those encountered in deep drillholes at Wairakei (Waiora Valley Andesites), and are different from the Rolles Peak andesite in having lower Sr content. The andesite blocks show similar major and trace element content to those from the Tongariro Volcanic Centre. The roundness of the andesite blocks indicates that the blocks were transported as alluvium or lahars in to the lake basin before being incorporated into the pyroclastic flow. Two types of welded ignimbrite blocks are described. The lithic-crystal rich ignimbrite is correlated with a post-Whakamaru Group Ignimbrite (ca. 100 ka ignimbrite erupted from Taupo Volcanic Centre) which crops out to the north of Lake Taupo. The crystal rich ignimbrite is tentatively correlated with the Whakamaru Group Ignimbrites. The lake sediment boulders, pumiceous mudstone and siltstone in the ground layer probably correlate to the Huka Group sediments or younger Holocene sediments in the lake basin. A comparative mineral chemistry study of the lithic blocks was done. A change in chemistry of individual mineral species was found to accompany the variation in wholerock major element constituents in the different types of lithics. The large quantity of lithic blocks in the ground layer suggests extensive vent widening at the begining of the ignimbrite eruption. A simple model of flaring and collapse of the vent area caused by the down ward movement of the fragmentation surface is presented to explain the origin of the lithic blocks in the ground layer. The lithics in the Taupo Pumice Formation are therfore produced by the disruption of the country rock around the vent during the explosion and primary xenoliths from depths of magma generation were not found. Stratigraphic relations suggest that the most important depth of incorporation of lithics is within the post-Whakamaru Group Ignimbrite volcanics and volcaniclastic sedimentary units.</p>

scholarly journals Improved SAGE II cloud/aerosol categorization and observations of the asian tropopause aerosol layer: 1989–2005

2012 ◽  
Vol 12 (10) ◽  
pp. 27521-27554 ◽  
Author(s):  
L. W. Thomason ◽  
J.-P. Vernier
Keyword(s):  
Asian Monsoon ◽  
Trace Gas ◽  
Data Sets ◽  
Aerosol Layer ◽  
Robust Method ◽  
Data Set ◽  
Volcanic Origin ◽  
Upper Troposphere ◽  
Volcanic Material ◽  
Identification Method

Abstract. Observations by CALIPSO have recently been used to identify an aerosol enhancement associated with the Asian Monsoon anticyclone. The Asian Tropopause Aerosol Layer (ATAL) is analogous to observed enhancements in long-lived trace gas species like CO. Since the CALIPSO record only begins in 2006, the question of how long this aerosol feature has been present requires a new look at the long-lived SAGE II data sets despite significant hurdles to its use in the subtropical upper troposphere. We found that a new and more robust method for identifying and eliminating cloud effects from the SAGE II data set was required and, herein, we describe a cloud identification method that appears to capture cloud/aerosol events more effectively than early methods. In addition, we summarize additional challenges to observing the ATAL layer using SAGE II observations. Finally, we perform analyses of the upper troposphere, focusing on periods in which the UTLS is relatively free of volcanic material (1989–1990 and after 1996). We find that there is no evidence of ATAL in the SAGE II data prior to 1998. After 1998, it is clear that aerosol in the upper troposphere in the ATAL region is substantially enhanced relative to the period before that time. In addition, the data generally supports the presence of the ATAL layer beginning in 1999 and continuing through the end of the mission though some years (e.g. 2003) are complicated by the presence of episodic enhancements most likely of volcanic origin.

Mineral Compositions and Textures of Jadeite Orebody and its Country Rock in Nammaw, Myanmar

2012 ◽  
Vol 512-515 ◽  
pp. 652-656 ◽  
Author(s):  
Hui Xuan Yang ◽  
Mei An ◽  
Dong Ye ◽  
En Dong Zu
Keyword(s):  
Country Rock ◽  
Hydrothermal Solution ◽  
Thin Sections ◽  
Mineral Compositions ◽  
Hydrothermal Metamorphism ◽  
Rock Specimens

This paper studies the mineral compositions and textures of seven rock specimens from jadeite orebody and its country rock in Nammaw, Myanmar through XRD and observation of hand specimens and thin sections. The jadeite orebody is mainly composed of jadeite and minor zeolite minerals. Phlogopite schist and chromite-bearing amphibolite occur between the orebody and its country rock. The country rock is antigorite serpentinite. Outside of serpentinite is schist consisting of chlorite, hastingsite and polylithionite. The specimens of jadeite orebody show mainly following texture types: radiation texture, inequigranular crystalloblastic texture, granular-prismatic crystalloblastic texture, metasomatic texture and mylonitic texture. These textures indicate that the formation of the orebody is related to the intrusion of some fused mass or hydrothermal solution and then the orebody underwent dynamical metamorphism and hydrothermal metamorphism.

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