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Reconstruction of the subaerial Holocene volcanic activity through paleomagnetic and 14C dating methods: El Hierro (Canary Islands) (2022)

Risica, Gilda ; Di Roberto, Alessio ; Speranza, Fabio ; [weitere]

Elsevier

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Publikationsdatum: 2022-04-01

Beschreibung: Volcanic hazard assessment relies on the accurate knowledge of the eruptive style and recurrence of volcanic eruptions in the past. At El Hierro (Canary Islands) historical and prehistorical records are still poorly defined, and although the island was the location of one of the most recent eruptions (La Restinga, 2011 CE) of the Canarian archipelago, the recent subaerial volcanism is still poorly studied. Information about the age of Holocene volcanic activity as well as the stratigraphy of the deposits is scarce: few eruptions are dated so far, whereas the others are classified as pre-or Holocene events considering lava flow characteristics along the coast. Here, we report on the dating of eleven (M˜na Chamuscada, M˜na del Tesoro, Orchilla, Las Calcosas, M˜na Negra, Lomo Negro, Below Lomo Negro, Cuchillo del Roque, Malpaso Member, and M˜na del Guanche) Holocene subaerial eruptions, distributed along the three rift zones, combining paleomagnetic and 14C methods. We also provide geochemical analyses for nine of them. Results indicate that M˜na Chamuscada and M˜na del Tesoro occurred more recently than previously considered, setting them within the last two thousand years. Conversely, paleomagnetic and 14C ages found for Lomo Negro eruption are consistent with literature data (Villasante- Marcos and Pav´on-Carrasco, 2014) and constrain the occurrence of this event in the XVI century CE. Finally, for Malpaso Member deposits, the two 14C datings obtained by charcoals found below and above the trachytic layer set the eruption during the Holocene epoch, between ~7300 BCE and ~4700 BCE. For the other eruptions, in two cases (Orchilla and Las Calcosas) many possible time windows during the last 14 ka have been found, whereas a few possible ages have been obtained for the others. On the whole, the resulting chronological reconstruction of the recent activity of El Hierro indicates that eruptions occurred unevenly along the three main rifts, with nine eruptions in the WNW rift, six in the NE rift, and four in the SSE rift. We document at least two periods characterized by high eruptive frequency: an old one, between 8000 BCE and 1000 BCE, with eight eruptions, three of which characterized by more evolved compositions (phonotephrite and trachyte), and a recent one, between 1000 BCE and present day, with at least seven eruptions, mainly showing basanite compositions. The new data yield a significant improvement of Holocene eruption chronology, thus are instrumental for a correct evaluation of the volcanic hazard at El Hierro.

Beschreibung: Published

Beschreibung: 107526

Beschreibung: 1A. Geomagnetismo e Paleomagnetismo

Beschreibung: JCR Journal

Schlagwort(e): Paleomagnetism ; El Hierro ; 04.05. Geomagnetism ; 04.08. Volcanology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Materialart: article

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Aeromagnetism (2022)

Chiappini, Massimo

Elsevier

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Publikationsdatum: 2022-02-10

Beschreibung: The airborne magnetic method was established a few decades ago, as a strong tool in mining and petroleum exploration. Several economically relevant discoveries are often credited to aeromagnetism. Geological reconnaissance and mapping, deep crustal and upper mantle studies, environmental characterization, and national and international security issues can greatly benefit from the aeromagnetic method, as compared with other geophysical prospecting schemes. The rapid rate of coverage and the low cost per unit area explored represent just a few among the many advantages of the technique. Consequently, large-scale airborne magnetic surveys have been carried out in various parts of the globe. The amount of direct discoveries of ore bodies by means of aeromagnetism is impressive. Large magnetic iron deposits found in the early 1960s are in Southern California, Missouri, Nevada, Pennsylvania, Quebec, Ontario, and elsewhere. In the field of petroleum exploration, the method has also been used, although with less direct application. Depth to magnetic basement estimation in sedimentary basins narrows down areas of interest where to conduct exploration surveys in detail by means of more costly methods. The most relevant use of airborne magnetic results is crustal imaging and characterization. Nowadays, geology is interpreted in three dimensions using a digital aeromagnetic map.

Beschreibung: Published

Beschreibung: 675-688

Beschreibung: 1T. Struttura della Terra

Beschreibung: 4T. Sismicità dell'Italia

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: 1V. Storia eruttiva

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Beschreibung: 1A. Geomagnetismo e Paleomagnetismo

Beschreibung: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare

Beschreibung: 5A. Ricerche polari e paleoclima

Beschreibung: 7A. Geofisica per il monitoraggio ambientale

Beschreibung: 1TR. Georisorse

Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale

Beschreibung: 6SR VULCANI – Servizi e ricerca per la società

Beschreibung: 7SR AMBIENTE – Servizi e ricerca per la società

Schlagwort(e): aeromagnetism ; potential fields ; magnetic anomaly ; 04.02. Exploration geophysics ; 04.05. Geomagnetism ; 04.07. Tectonophysics ; 04.08. Volcanology ; 04.06. Seismology