Search results for "WATER"

Enhanced volcanic hot-spot detection using MODIS IR data: results from the MIROVA system

2015

Reorganization of the North Atlantic Oscillation during early Holocene deglaciation

2016

Laurentide ice-sheet retreat continued into the mid-Holocene. Speleothem-based precipitation records suggest the cessation of melt led to the establishment of the present precipitation patterns associated with the North Atlantic Oscillation. The North Atlantic Oscillation is the dominant atmospheric pressure mode in the North Atlantic region and affects winter temperature and precipitation in the Mediterranean, northwest Europe, Greenland, and Asia1. The index1 that describes the sea-level pressure difference between Iceland and the Azores is correlated with a dipole precipitation pattern over northwest Europe and northwest Africa. How the North Atlantic Oscillation will develop as the Gree…

The relationship between eruptive activity, flank collapse, and sea level at volcanic islands: A long-term (>1 Ma) record offshore Montserrat, Les…

2016

Hole U1395B, drilled southeast of Montserrat during Integrated Ocean Drilling Program Expedition 340, provides a long (>1 Ma) and detailed record of eruptive and mass-wasting events (>130 discrete events). This record can be used to explore the temporal evolution in volcanic activity and landslides at an arc volcano. Analysis of tephra fall and volcaniclastic turbidite deposits in the drill cores reveals three heightened periods of volcanic activity on the island of Montserrat (∼930 to ∼900 ka, ∼810 to ∼760 ka, and ∼190 to ∼120 ka) that coincide with periods of increased volcano instability and mass-wasting. The youngest of these periods marks the peak in activity at the Soufriere Hills vol…

Characterisation and origin of hydrothermal waters at São Miguel (Azores) inferred by chemical and isotopic composition

2017

Abstract This study focuses on the characterisation and origin of hydrothermal waters discharging from three main active volcanoes (Furnas, Fogo and Sete Cidades) at Sao Miguel, where 33 water with temperatures ranging between 13 and 97 °C, and 5 precipitate samples were collected. The developed conceptual model for this active hydrothermal system reveals that all waters can be classified by Na-HCO 3 , Na-Cl and Na-SO 4 types and are of meteoric origin. This is confirmed by the stable hydrogen and oxygen isotope data that are positioned close to the local meteoric water line (− 4.1‰ ≤ δ 18 O H2O  ≤ 5.2‰; − 17.6‰ ≤ δD H2O  ≤ 20.4‰), except for the Na-Cl type water at Ferraria (Sete Cidades a…

Impact of Holocene tsunamis detected in lagoonal environments on Corfu (Ionian Islands, Greece): Geomorphological, sedimentary and microfaunal eviden…

2016

Abstract In this paper, we present for the first time geomorphological, sedimentary and microfaunal evidence of palaeotsunami impact on Corfu (Ionian Islands, Greece). The island of Corfu is located in an area of exceptional tectonic stress: towards the south, the African oceanic plate is being subducted underneath the Aegean plate, whereas towards the north, the Adriatic and European plates form a continental collision zone. Recent publications provide evidence of earthquake related co-seismic movements that potentially trigger extreme wave events as well as relative sea level fluctuations. In this context, we investigated two selected near-coast geological archives – the Chalikiopoulou La…

On the Mesozoic Ionian Basin

2001

SUMMARY New seismic reflection profiles of the Italian deep crust project CROP provide new insights on the structure of the Ionian sea. In spite of the Apennines and Hellenides Neogene subduction zones, two conjugate passive continental margins are preserved at the margins of the Ionian sea, along the Malta escarpment to the southwest and the Apulian escarpment to the northeast. The Ionian sea is likely to be a remnant of the Mesozoic Tethys Ocean, confined by these two conjugate passive continental margins. The transition from continental to oceanic crust appears sharper to the northeast than to the southwest. The basin between southeast Sicily and southwest Puglia was about 330 km wide an…

The sedimentary and geomorphological imprint of the AD 365 tsunami on the coasts of southwestern Crete (Greece): Examples from Sougia and Palaiochora

2018

Abstract The southwestern coast of Crete, one of the most seismically active regions in Europe, experienced co-seismic crust uplift by 9 m during the Ms = 8.3 mega-earthquake that struck the eastern Mediterranean world on 21 July AD 365. An associated tsunami event caused thousands of fatalities and destroyed many coastal settlements and infrastructure between the Levante in the east and the Adriatic Sea in the northwest. So far, coastal sedimentary archives in southwestern Crete including distinct palaeotsunami fingerprints are rarely investigated. Therefore, a multi-proxy study including sedimentological, geochemical, geochronological, and microfaunal methods was conducted in order to det…

Pathways and fate of REE in the shallow hydrothermal aquifer of Vulcano island (Italy)

2019

Abstract We investigated the geochemical behaviour of major and Rare Earth Elements (REE), together with oxygen and deuterium isotopic composition in the aquifer of Vulcano, the southernmost island of the Aeolian archipelago (Italy). Studied wells, located at different distances from the crater, are characterised by different contributions of the rising volcanic fluids. In particular, those located in the proximity of La Fossa crater are affected by a strong interaction with volcanic-hydrothermal fluids and show REE behaviour similar to that of fresh rocks, suggesting a congruent dissolution of the solid matrix. Samples from the other wells, located in an area where the volcanic deposits ar…

Porites corals from Crete (Greece) open a window into Late Miocene (10Ma) seasonal and interannual climate variability

2006

Variations in the biotic composition of marine shallow water carbonates document global climatic changes. However, a discontinuous stratigraphic record and uncertainties regarding the ages limit the significance of shallow water carbonates as palaeoclimatic archives on geological time-scales. Notwithstanding these deficits, the environmental information stored in the skeleton of reef biota is a unique source of information that resolves seasonal to interannual climate variability in geological time. Application of the method to corals from carbonate rocks is usually restricted to the past 130,000yr, because the aragonite skeleton undergoes rapid diagenetic alteration. Consequently, reconstr…

Joint Methodology for the Identification and Assessment of Groundwater Dependent Terrestrial Ecosystems in Estonia and Latvia

2020

Dynamic interactions between ground- and surface water are widely known, but the role of groundwater in terrestrial and aquatic ecosystems is often poorly understood and documented due to the spatiotemporal complexity. Many countries have not yet completed the assessment of groundwater dependent ecosystems (GDEs). GDEs are valuable ecosystems that depend on groundwater input and can not be considered and assessed separately. Changes in the quantity and chemical composition of groundwater recharge may result in significant and permanent damage on GDE flora and fauna. Aquifers are dynamic systems which are not subject to administrative boundaries and borders, therefore should be managed in cl…