The geochemical stratigraphy, field relations and temporal variation of the Mull–Morvern Tertiary lava succession, NW Scotland

1995 ◽  
Vol 86 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Andrew Craig Kerr
Keyword(s):  
Sea Level ◽  
Main Part ◽  
Volcanic Ash ◽  
Lava Flows ◽  
Field Observations ◽  
Continuous Section ◽  
Flow Units ◽  
Early Tertiary ◽  
The Uk ◽  
Basaltic Lavas

AbstractThe early Tertiary Mull-Morvern lava succession, NW Scotland, represents the thickest continuous section (1000 m from sea level to the top of Ben More) of Tertiary lavas exposed in the UK. This succession has been sampled and geochemically analysed, on a flow-by-flow basis, throughout the lava succession. Field observations during the course of this sampling suggest that the early lava flows (the Staffa Magma sub-Type) ponded in palaeovalleys along with interlava sediments. In the main part of the Mull lava succession (the Mull Plateau Group) the lava flows are on average ∼ 5 m thick. Most previous Hebridean workers have assumed that the red horizons commonly found between these later lava flows, represent weathered flow tops. However, this study has shown that in some places these red ‘boles’ appear to be a combination of both volcanic ash and weathered basalt.Chemically distinctive units of flows have been found throughout the succession. The two most abundant magma sub-types of the Mull Plateau Group, primitive (>9wt% MgO) basalts with Ba/Nb» 15 and more evolved (<9wt% MgO) basalts-hawaiites with Ba/Nb<15, form packets of flow units which can be up to 200 m thick. These chemically distinctive flow units have been correlated across the lava succession. However, the correlation of individual lava flows has proved difficult. The Mull Plateau Group lavas generally become more evolved and less contaminated with continental crust towards the top of the succession, culminating in the trachytes of the Pale Group on Ben More. Basaltic lavas above the Pale Group have markedly different trace element ratios, and seem to represent shallower, more extensive asthenospheric melting than the Mull Plateau Group.

The palaeoceanographic history of the Celtic Sea since the last deglaciation and its potential for carbon storage

2021 ◽  
Author(s):  
Jacob Noble ◽  
Alix Cage ◽  
Olivia Beavers ◽  
Bradley Sparks ◽  
Mark Furze ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Sea Level ◽  
Carbon Storage ◽  
Benthic Foraminifera ◽  
Future Climate Change ◽  
The Holocene ◽  
Shelf Sea ◽  
Celtic Sea ◽  
The Uk ◽  
Seasonal Stratification

&lt;p&gt;Shelf seas account for around 10-30% of ocean productivity, 30-50% of inorganic carbon burial and up to 80% of organic carbon storage (Sharples et al., 2019); as such, shelf-sea sediments are a potential store of carbon and could play an important role in the &amp;#8216;blue&amp;#8217; carbon cycle, and thus global climate. UK shelf-sea hydrography is dominated by seasonal stratification which drives productivity; however, stratification evolved with sea-level and tidal dynamic changes over the Holocene epoch on the UK shelf, and thus carbon stores will have changed over time. These shallow marine environments are typically seen as erosional environments and have therefore been somewhat overlooked in terms of palaeoenvironments with only a few studies from the UK continental shelf (e.g. Austin and Scourse, 1997). Here we use a core collected from the Celtic Deep, on the UK shelf, to explore environmental change, and the evolution of stratification in this setting and the potential role it plays in the global carbon cycle.&lt;/p&gt;&lt;p&gt;JC106-052PC, a 7.5m long marine sediment core, was recovered in 2018 at a water-depth of 116 m from the Celtic Deep (a relatively deep trough in the Celtic Sea between Britain and Ireland) as part of the BRITICE project. A radiocarbon date of 10,435 &amp;#177;127 years cal BP at 4.1m suggests the core covers the Holocene epoch and preceding deglacial period. Preliminary multiproxy data from this expanded archive (ITRAX XRF, organic content, benthic foraminifera assemblages) points to changing environmental conditions and productivity potentially reflecting the evolution of seasonal stratification in the Celtic Sea over the Holocene. Work currently focuses on increasing the resolution of the benthic foraminifera record of JC106-052PC, extending the record into the deglacial period, and applying a benthic foraminifera transfer function approach to estimate sea-surface temperature of the Celtic Sea during the Holocene and deglacial period.&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;This study aims to increase our understanding of the shelf-sea dynamics and productivity of the Celtic Sea over the last deglacial to Holocene period. By elucidating the response of the Celtic Sea to changing sea level and oceanographic conditions, and its capacity to act as a carbon store, we can better understand the role of other shelf environments, potentially benefiting global studies of palaeoclimate and future climate change.&amp;#160;&lt;/p&gt;

scholarly journals Methods of calculating landslide volume using remote sensing data

2020 ◽  
Vol 149 ◽  
pp. 02009
Author(s):  
Maira Razakova ◽  
Alexandr Kuzmin ◽  
Igor Fedorov ◽  
Rustam Yergaliev ◽  
Zharas Ainakulov
Keyword(s):  
Remote Sensing ◽  
Sea Level ◽  
Remote Sensing Data ◽  
Field Studies ◽  
Aerial Photographs ◽  
Field Observations ◽  
Sensing Data ◽  
Quantitative Estimates ◽  
Landslide Volume ◽  
Engineering Protection

The paper considers the issues of calculating the volume of the landslide from remote sensing data. The main methods of obtaining information during research are field observations. The most important results of field studies are quantitative estimates, such as the volume of the embankment resulting from a landslide, morphometric indicators, etc. The study of a remote and remote object was carried out by remote methods using aerial photographs in the Ile Alatau foothills at 1,600 meters above sea level. The obtained materials from the mudflow survey will be useful in developing solutions to mitigate the effects of disasters and in the design of measures for engineering protection from landslides.

scholarly journals Contributions to 21st century projections of extreme sea-level change around the UK

2019 ◽  
Vol 1 (9) ◽  
pp. 095002 ◽  
Author(s):  
Tom Howard ◽  
Matthew D Palmer ◽  
Lucy M Bricheno
Keyword(s):  
Sea Level ◽  
21St Century ◽  
Sea Level Change ◽  
Level Change ◽  
The Uk

The respiratory toxicity of airborne volcanic ash from the Soufrière Hills volcano, Montserrat

2004 ◽  
Vol 68 (1) ◽  
pp. 47-60 ◽  
Author(s):  
K. A. Bérubé ◽  
T. P. Jones ◽  
D. G. Housley ◽  
R. J. Richards
Keyword(s):  
Volcanic Ash ◽  
Medical Officer ◽  
Intratracheal Instillation ◽  
Airborne Particulate Matter ◽  
Positive Control ◽  
Lung Damage ◽  
Pyroclastic Flows ◽  
Toxicological Studies ◽  
Soufriere Hills ◽  
The Uk

AbstractThe Soufrière Hills stratovolcano on the Caribbean island of Montserrat has been erupting since 18th July 1995. An enormous amount of respirable volcanic ash has been suspended into the atmosphere by the eruptions and wind re-suspension of deposited ash. The large amount of fine, airborne particulate matter, in particular the component 10 μm equivalent aerodynamic diameter (PM10), is a cause of medical concern. Airborne levels have frequently exceeded the UK environmental standard for PM10, (50 μg/m3), although it is noted that this standard was primarily set for urban PM10. The crystalline silica in the ash is mostly cristobalite, at reported levels up to 20%. The UK government’s Chief Medical Officer, referring to Montserrat, has suggested that long-term exposure to high levels of volcanic ash could lead to silicosis. These concerns have prompted government-funded investigations into the potential toxicity of well characterized volcanic ash samples from Montserrat. Given the well established toxicity of cristobalite, particular attention was paid to the amount of this mineral in the ash samples. Three ash samples were tested: (1) a vulcanian eruption ash, (2) ash released in a domecollapse pyroclastic flow, and (3) ash from a major vulcanian explosion that was wind-transported to, and deposited on, the neighbouring island of Antigua. Comparative toxicological studies were carried out on respirable preparations of these three samples together with appropriate control mineral dusts that matched the major components of the Montserrat samples: anorthite, labradorite, cristobalite/ obsidian and cristobalite. Alpha quartz (DQ12) was the positive control. All samples, including the controls, were characterized to establish particle-size distributions, particle morphologies, and to confirm the mineralogy. Rats were challenged with 1 mg via intratracheal instillation, and groups sacrificed at three time points (1, 3 and 9 weeks). Health assessment was made by examining endpoints of increasing lung damage such as inflammation, permeability (oedema), changes in epithelium, and increase in the size of broncho-thoracic lymph nodes. The data indicate that Montserrat respirable ash, derived from dome collapse pyroclastic flows or vulcanian explosions, has minimal acute bioreactivity in the lung. The feldspar standards showed low bioreactivity, in stark contrast to the cristobalite standard that showed progressive increases in lung damage. These results suggest that either the mass of cristobalite present in the Montserrat ash was insufficient to cause an effect in the lung, or the cristobalite in the ash was, for some as yet unknown reason, markedly less bioreactive than our pure cristobalite standard.

scholarly journals Using continuous GPS and absolute gravity to separate vertical land movements and changes in sea-level at tide-gauges in the UK

2006 ◽  
Vol 364 (1841) ◽  
pp. 917-930 ◽  
Author(s):  
F.N Teferle ◽  
R.M Bingley ◽  
S.D.P Williams ◽  
T.F Baker ◽  
A.H Dodson
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Tide Gauge ◽  
Absolute Gravity ◽  
Tide Gauges ◽  
Tide Gauge Record ◽  
Vertical Movements ◽  
Movement Component ◽  
The Uk ◽  
Continuous Gps

Researchers investigating climate change have used historical tide-gauge measurements from all over the world to investigate the changes in sea-level that have occurred over the last century or so. However, such estimates are a combination of any true sea-level variations and any vertical movements of the land at the specific tide-gauge. For a tide- gauge record to be used to determine the climate related component of changes in sea-level, it is therefore necessary to correct for the vertical land movement component of the observed change in sea-level. In 1990, the Institute of Engineering Surveying and Space Geodesy and Proudman Oceanographic Laboratory started developing techniques based on the Global Positioning System (GPS) for measuring vertical land movements (VLM) at tide-gauges in the UK. This paper provides brief details of these early developments and shows how they led to the establishment of continuous GPS (CGPS) stations at a number of tide-gauges. The paper then goes on to discuss the use of absolute gravity (AG), as an independent technique for measuring VLM at tide-gauges. The most recent results, from CGPS time-series dating back to 1997 and AG time-series dating back to 1995/1996, are then used to demonstrate the complementarity of these two techniques and their potential for providing site-specific estimates of VLM at tide-gauges in the UK.

Towards a vulnerability assessment of the UK and northern European coasts: the role of regional climate variability

2005 ◽  
Vol 363 (1831) ◽  
pp. 1329-1358 ◽  
Author(s):  
M.N Tsimplis ◽  
D.K Woolf ◽  
T.J Osborn ◽  
S Wakelin ◽  
J Wolf ◽  
...  
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
North Sea ◽  
Positive Response ◽  
Sea Level Change ◽  
Empirical Relationships ◽  
Level Change ◽  
The North ◽  
The North Sea ◽  
The Uk

Within the framework of a Tyndall Centre research project, sea level and wave changes around the UK and in the North Sea have been analysed. This paper integrates the results of this project. Many aspects of the contribution of the North Atlantic Oscillation (NAO) to sea level and wave height have been resolved. The NAO is a major forcing parameter for sea-level variability. Strong positive response to increasing NAO was observed in the shallow parts of the North Sea, while slightly negative response was found in the southwest part of the UK. The cause of the strong positive response is mainly the increased westerly winds. The NAO increase during the last decades has affected both the mean sea level and the extreme sea levels in the North Sea. The derived spatial distribution of the NAO-related variability of sea level allows the development of scenarios for future sea level and wave height in the region. Because the response of sea level to the NAO is found to be variable in time across all frequency bands, there is some inherent uncertainty in the use of the empirical relationships to develop scenarios of future sea level. Nevertheless, as it remains uncertain whether the multi-decadal NAO variability is related to climate change, the use of the empirical relationships in developing scenarios is justified. The resulting scenarios demonstrate: (i) that the use of regional estimates of sea level increase the projected range of sea-level change by 50% and (ii) that the contribution of the NAO to winter sea-level variability increases the range of uncertainty by a further 10–20 cm. On the assumption that the general circulation models have some skill in simulating the future NAO change, then the NAO contribution to sea-level change around the UK is expected to be very small (<4 cm) by 2080. Wave heights are also sensitive to the NAO changes, especially in the western coasts of the UK. Under the same scenarios for future NAO changes, the projected significant wave-height changes in the northeast Atlantic will exceed 0.4 m. In addition, wave-direction changes of around 20° per unit NAO index have been documented for one location. Such changes raise the possibility of consequential alteration of coastal erosion.

Lidar observations of volcanic aerosol over the UK since June 2019

2020 ◽  
Author(s):  
Geraint Vaughan ◽  
David Wareing ◽  
Hugo Ricketts
Keyword(s):  
Volcanic Ash ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Lidar System ◽  
Elastic Channel ◽  
Enhanced Sensitivity ◽  
Volcanic Cloud ◽  
The Uk ◽  
Lidar Observations

&lt;p&gt;On 22 June 2019, the Raikoke volcano in the Kuril Islands erupted, sending a plume of ask and sulphur dioxide into the stratosphere. A Raman lidar system at Capel Dewi, UK (52.4&amp;#176;N, 4.1&amp;#176;W) has been used to measure the extent and optical depth of the stratospheric aerosol layer following the eruption. The lidar was modified to give it much enhanced sensitivity in the elastic channel, allowing measurements up to 25 km, but the Raman channel is only sensitive to the troposphere. Therefore, backscatter ratio profiles were derived by comparison with aerosol-free profiles derived from nearby radiosondes, corrected for aerosol extinction. Small amounts of stratospheric aerosol were measured prior to the arrival of the volcanic cloud, probably from pyroconvection over Canada. Volcanic ash began to arrive as a thin layer at 14 km late on 3 July, extending over the following month to fill the stratosphere below around 19 km. Aerosol optical depths reached around 0.03 by mid-August and continued at this level for the remainder of the year. The location of peak backscatter varied considerably but was generally around 15 km. However, on one notable occasion on August 25, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.&lt;/p&gt;

Vesicle paleobarometry in the Pongola Supergroup: A cautionary note and guidelines for future studies

2020 ◽  
Vol 123 (1) ◽  
pp. 95-104
Author(s):  
E.A. Goosmann ◽  
R. Buick ◽  
D.C. Catling ◽  
C. Luskin ◽  
N. Nhleko
Keyword(s):  
Sea Level ◽  
Barometric Pressure ◽  
Air Pressure ◽  
Gas Absorption ◽  
Lava Flows ◽  
Pressure Broadening ◽  
Basalt Lava ◽  
Future Studies ◽  
Kwazulu Natal ◽  
X Ray Computed

Abstract Earth’s global barometric pressure, currently 1 bar at sea level, may have changed over its 4.5-billion-year history. Proxy measurements, including N2/36Ar ratios in ~3.5 to 3.0 Ga hydrothermal quartz, ~2.7 Ga raindrop imprints, and ~2.7 Ga vesicle sizes in subaerial basalt lava flows indicate Archean air pressure could have been between 0.1 and 1.2 bar. However, some models argue air pressure in the Archean should have been much higher than now and could allow pressure broadening of greenhouse gas absorption lines to counteract the “Faint Young Sun”. Thus, additional paleobarometric measurements would be useful to further constrain Earth’s atmospheric evolution. We attempted to use vesicle sizes in lavas erupted near sea-level from the ~2.9 Ga Pongola Supergroup from Mahlangatsha and Mooihoek, eSwatini (formerly Swaziland) and the White Mfolozi River gorge of KwaZulu-Natal, South Africa to provide further Archean paleobarometric data. However, reliable results were unobtainable due to small and scarce amygdales, irregular vesicle morphologies and metamorphic mineralogical homogenization preventing the use of X-ray Computed Tomography for accurate vesicle size determination. Researchers attempting paleobarometric analysis using lava vesicle sizes should henceforth avoid these areas of the Pongola Supergroup and instead look at other subaerially emplaced lava flows. With this being only the second time this method has been used on Precambrian rocks, we provide a list of guidelines informed by this study to aid future attempts at vesicular paleobarometry.

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