Paleomagnetism and rock magnetism as tools for volcanology

Lerner, Geoffrey A.; Piispa, E. J.; Bowles, J. A.; Ort, Michael H.

doi:10.1007/s00445-022-01529-9

Cited by 9 publications

(6 citation statements)

References 112 publications

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“…The PDC flow directions are determined from the k3 axis direction (flow direction arrows in Figs. 9a and 10), which corresponds to the fabric imbrication with respect to the basal flow plane of the deposit (e.g., Fisher et al 1993;Le Pennec et al 1998;Giordano et al 2008;LaBerge et al 2009;Cas et al 2011;Gountié Dedzo et al 2011;Lerner et al 2022). In previous studies, the shape of the AMS ellipsoids from ignimbrites is, in most cases, oblate (e.g., Ellwood 1982;Knight et al 1986;Agrò et al 2015;Ort et al 2015;Moncinhatto et al 2019).…”

Section: Pdc Flow Directions and Post-emplacement Processesmentioning

confidence: 94%

Magnetic fabrics of rhyolite ignimbrites reveal complex emplacement dynamics of pyroclastic density currents, an example from the Altenberg–Teplice Caldera, Bohemian Massif

Vitouš¹,

Tomek²,

Petronis³

2022

Preprint

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The anisotropy of magnetic susceptibility (AMS) is commonly used to infer the flow dynamics, source areas, and post-emplacement processes of pyroclastic density currents (PDC) of young calderas (i.e. Cenozoic). At older calderas, the primary record is often obscured by post-emplacement deformation and/or long-term erosion. Here, we focus on the ~314–313 Ma welded ignimbrites inside the Altenberg–Teplice Caldera (ATC; Bohemian Massif). The small-volume, moderately-welded ignimbrites emplaced prior to caldera-forming eruption yield a generally westward flow direction as determined from the imbrication of the magmatic and magnetic foliation plane. Their eruptive vents were located along the eastern margin of the future caldera. The most voluminous high-grade ignimbrites, products of the caldera-forming event, indicate a high degree of welding and rheomorphic ductile folding that obscured the primary flow fabrics. Based on the fabric pattern, published radiometric and field geology data from the ATC, we interpret that these ignimbrites were sourced from a dike swarm along the northwestern caldera rim. The PDCs then flowed across the subsiding caldera towards the south and south-southeast, where extra-caldera ignimbrites are exposed. The final trap-door caldera collapse triggered the emplacement of the microgranite ring dikes. These dikes, along with the post-caldera granites, may have driven a local resurgence along the eastern caldera rim. As exemplified by the ATC, the AMS fabric can be applied successfully to much older caldera ignimbrites including those with a high degree of welding and rheomorphism to interpret flow direction, deposition, emplacement, and post-emplacement dynamics.

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Section: Pdc Flow Directions and Post-emplacement Processesmentioning

confidence: 94%

Magnetic fabrics of rhyolite ignimbrites reveal complex emplacement dynamics of pyroclastic density currents, an example from the Altenberg–Teplice Caldera, Bohemian Massif

Vitouš¹,

Tomek²,

Petronis³

2022

Preprint

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“…In this study, we covered some of the volcanic products from ancient (Old Krakatau) to recent (Anak Krakatau) to identify possible changes in the magma storage conditions within the Krakatau plumbing systems, as this information is required for monitoring and hazard assessment. We used a combination of petrological, geochemical, and rock magnetic analyses, which are standard tools for characterizing volcanic products (Cañón-Tapia and Pinkerton, 2000;Cinku et al, 2009;Ferré et al, 2012;Amor et al, 2019;Haag et al, 2021;Lerner et al, 2022). We also present mineralogical data, phenocryst and matrix glass compositions to reveal the magmatic plumbing systems, including the storage pressures and/or temperatures from the ancient (Old Krakatau) to the most recent (Anak Krakatau) periods.…”

Section: Introductionmentioning

confidence: 99%

“…Magnetic minerals are sensitive to magma composition and differentiation, oxidation state, pressure, and temperature (Buddington and Lindsley, 1964;Haggerty, 1991;Lanza and Meloni, 2006;Mollo et al, 2013;Liao et al, 2016;Anai et al, 2023). Therefore, previous researchers have reported that magnetic mineral characteristics, such as abundance, composition, texture, and grain size can reflect magmatic conditions and processes (Mollo et al, 2013;Lerner et al, 2022;Xu et al, 2022). The characteristics of magnetic minerals can be identified by geochemistry, petrology, and rock magnetic methods.…”

Section: Introductionmentioning

confidence: 99%

Magma storage conditions beneath Krakatau, Indonesia: insight from geochemistry and rock magnetism studies

Pratama,

Nurfiani,

Suryanata

et al. 2023

Front. Earth Sci.

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Understanding the evolution of magma storage conditions on volcanoes which have had more than one caldera-forming eruption (CFE) is important to know about past and present conditions, as a key to forecast future potential hazards. Krakatau volcano is characterized by cyclic phases of growth and destruction of the edifice. A volcanostratigraphic study identified three eruptive periods: Old Krakatau, Young Krakatau, and Anak Krakatau. The Old and Young Krakatau periods ended with the first and second CFE respectively. Due to its permanent activity and edifice evolution, Krakatau poses a high risk on the surrounding inhabited islands. In this study, we combined geochemistry, rock magnetic, and petrology to infer the evolution of magma storage conditions from Old to Anak Krakatau periods. This study is the first to report on the chemical and rock magnetic characteristics, as well as storage system conditions of Old Krakatau and its relation to the ongoing evolution of Krakatau. Our data show that: 1) Old and Young Krakatau magma storage regions are shallow (within the upper 3 km), contain more differentiated magmas, from which the Old Krakatau magmas may be less oxidized and had lower temperatures than Young Krakatau; 2) Anak Krakatau magma storage is deeper (up to 26 km), less differentiated, and erupted hotter but more reduced compared to Old and Young Krakatau. The Old and Young Krakatau lavas were the products of pre-CFE and their chemical characteristics are included at maturation phase, whereas the Young Krakatau pumice samples were the product of the second CFE. Lastly, the post-second CFE activity of AK is currently in an incubation phase and represented by mafic products of frequent and small eruptions. Knowing that the volcano has experienced maturation and CFE phases in the past, the current AK may evolve to those phases in the future.

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“…Magnetic analyses of oriented samples may also enable the identification and interpretation of secondary remagnetization processes in a way that would be difficult to do for unoriented samples. Examples include the interpretation of magnetizations associated with lightning strikes (Carporzen et al., 2012; Verrier & Rochette, 2002), the measurement of emplacement temperatures of volcanoclastic rocks by analyzing unidirectional thermally induced magnetization overprints after deposition (Lerner et al., 2022), the timing of formation of pigmentary hematite (Swanson‐Hysell et al., 2019), and the timing of diagenetic alteration (Heij & Elmore, 2020). Experience with terrestrial rocks has shown that essentially all of the above paleomagnetic investigations can be achieved with samples whose orientations are estimated with uncertainties ∼3° (Tauxe, 2018).…”

Section: Introductionmentioning

confidence: 99%

Oriented Bedrock Samples Drilled by the Perseverance Rover on Mars

Weiss,

Mansbach,

Carsten

et al. 2024

Earth and Space Science

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A key objective of the Perseverance rover mission is to acquire samples of Martian rocks for future return to Earth. Eventual laboratory analyses of these samples would address key questions about the evolution of the Martian climate, interior, and habitability. Many such investigations would benefit greatly from samples of Martian bedrock that are oriented in absolute Martian geographic coordinates. However, the Mars 2020 mission was designed without a requirement for orienting the samples. Here we describe a methodology that we developed for orienting rover drill cores in the Martian geographic frame and its application to Perseverance's first 20 rock samples. To orient the cores, three angles were measured: the azimuth and hade of the core pointing vector (i.e., vector oriented along the core axis) and the core roll (i.e., the solid body angle of rotation around the pointing vector). We estimated the core pointing vector from the attitude of the rover's Coring Drill during drilling. To orient the core roll, we used oriented images of asymmetric markings on the bedrock surface acquired with the rover's Wide Angle Topographic Sensor for Operations and eNgineering (WATSON) camera. For most samples, these markings were in the form of natural features on the outcrop, while for four samples they were artificial ablation pits produced by the rover's SuperCam laser. These cores are the first geographically‐oriented (<2.7° 3σ total uncertainty) bedrock samples from another planetary body. This will enable a diversity of paleomagnetic, sedimentological, igneous, tectonic, and astrobiological studies on the returned samples.

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Paleomagnetism and rock magnetism as tools for volcanology

Cited by 9 publications

References 112 publications

Magnetic fabrics of rhyolite ignimbrites reveal complex emplacement dynamics of pyroclastic density currents, an example from the Altenberg–Teplice Caldera, Bohemian Massif

Magnetic fabrics of rhyolite ignimbrites reveal complex emplacement dynamics of pyroclastic density currents, an example from the Altenberg–Teplice Caldera, Bohemian Massif

Magma storage conditions beneath Krakatau, Indonesia: insight from geochemistry and rock magnetism studies

Oriented Bedrock Samples Drilled by the Perseverance Rover on Mars

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