GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2020-2024  (6)
  • 2023  (6)
Document type
Publisher
Years
  • 2020-2024  (6)
Year
  • 1
    facet.materialart.
    Unknown
    Timing and recurrence intervals for voluminous silicic eruptions from Amatitlán caldera (Guatemala) (2023)
    Elsevier
    Details
    Publication Date: 2024-02-07
    Description: Defining a precise timeline for past eruptions from explosive volcanoes in continental arcs is imperative to forecast future hazards and mitigate volcanic disasters in these often densely populated regions. However, establishing reliable ages for Quaternary eruptions in the Central American Volcanic Arc has been challenging due to the common lack or alteration of suitable K-rich phases for 40Ar/39Ar geochronology, but also from their position in time beyond the reach of 14C dating. This especially holds for the active Amatitlán caldera in Guatemala, from which at least six explosive silicic eruptions have produced tephra blanketing neighboring regions that are today inhabited by millions of people. Zircon, a common datable accessory mineral in Amatitlán caldera magmas, is used here to retrieve eruption ages by applying the novel zircon double-dating method (ZDD) that integrates 238U–230Th disequilibrium dating and (U–Th)/He thermochronology. This approach yielded the first-ever radioisotopic ages of 24 ± 3 ka and 48 ± 6 ka (1σ), respectively, of two of Amatitlán caldera's most recent eruptions (J-tephra and E-tephra). Remarkably, both zircon crystallization and ZDD eruption ages for the older and voluminous T-tephra and L-tephra units significantly post-date existing plagioclase 40Ar/39Ar dates by ca. 26 and 70 kyr, respectively. The ZDD eruption age for T-tephra is 93 ± 4 ka, whereas zircon crystallization ages for L-tephra yield a maximum model eruption age of ca. 124 ka. The strong eruption age divergence between ZDD and plagioclase 40Ar/39Ar dating argues for the presence of inherited or xenocrystic plagioclase in Amatitlán caldera eruptive products. Statistical analysis based on the updated eruptive history suggests a recurrence interval of ca. 17 kyr, which is significantly shorter than previously estimated. The new age data, thus, suggest a more frequent eruptive activity of Amatitlán caldera than formerly thought and underscores the necessity to better understand the current underlying magmatic system and to constrain its past eruptive history more precisely.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: archive
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
    facet.materialart.
    Unknown
    Emplacement history of volcaniclastic turbidites around the central Azores volcanic islands: Frequencies of slope landslides and eruptions (2023)
    GSA (Geological Society of America)
    Details
    Publication Date: 2024-02-07
    Description: Volcanic islands export clastic material to their surrounding oceans by explosive eruptions, lava emissions, biogenic production on their shelves, and failure of their slopes, amongst other processes. This raises the question of whether geological events (in particular, eruptions and landslides) can be detected offshore and dated, and whether any relationships (for example, with climate changes) can be revealed using sediment cores. The volcanically active central Azorean islands (Faial, Pico, São Jorge, and Terceira), with their neighboring submarine basins, are potentially good candidates for such an analysis. Here, chronostratigraphies of four gravity cores collected amongst the islands are constructed based on twelve radiocarbon dates and two dates derived by geochemically correlating primary volcaniclastic turbidites with ignimbrites on Faial and Terceira Islands. Age-depth models are built from the hemipelagic intervals to estimate individual turbidite dates. Volumes of turbidites are modeled by multiplying basin areas with bed thickness, allowing for various turbidite thinning rates and directions. The volumes of landslide-generated turbidites are only comparable with the largest volumes of their adjacent upper-slope submarine landslide valleys; therefore, such turbidites in the cores likely derive from these largest landslides. Emplacement intervals between turbidites originating from both landslides and pyroclastic density currents are found to be mostly a few thousand years. Frequencies of landslide-generated turbidites and hemipelagic sedimentation rates were both highest in the past 8 k.y. compared to preceding periods up to 50 k.y. High hemipelagic sedimentation rates are interpreted to be related to sea-level rise, allowing more shelf bioproduction and release of particles by coastal erosion. The coincident increased frequencies of submarine landslides may also be associated with the increased sediment supply from the islands, resulting in a more rapid build-up of unstable sediments on submarine slopes. Notably, the emplacement frequencies of turbidites of pyroclastic density current origins do not suggest the decreased eruption frequency toward the Holocene that has been found elsewhere.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: other
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
    facet.materialart.
    Unknown
    The cenozoic marine tephra record in Indian Ocean deep drill sites (2023)
    Elsevier
    Details
    Publication Date: 2024-02-14
    Description: Provenance studies of widely distributed tephra deposits are important to deduce systematic changes in the source, size, distribution, and temporal variation of regional explosive volcanism. Long-term deep ocean drilling sedimentary records are particularly useful for these kind of studies. In this study, we establish a robust tephrochronostratigraphy for 235 primary marine tephra layers collected during International Ocean Discovery Program Expeditions 353, 354, and 362, complemented by older drill cores from Deep Sea Drilling Program and Ocean Drilling Program Legs 22, 119, 120, 121, and 183. We infer at least two major phases of highly explosive arc volcanism during the Early Miocene to Pleistocene, as well as three episodes related to explosive ocean island volcanism located in the Kerguelen plateau, the Broken Ridge, and close to Réunion reaching back to the Paleogene. Twenty-two widespread arc-derived tephra layers from individual eruptions can be correlated by geochemical fingerprinting between multiple holes. These provide nine Quaternary and 13 Neogene temporal tie points in the sedimentary sequence including four new Usingle bondPb zircon ages. Provenance analysis of the marine tephra layers, which is based on glass composition, assign eleven of these layers to a Toba-like source, ranging from 24 Ma to 75 ka, with the youngest correlative being Young Toba Tuff. Based on distribution pattern, thickness decay, and compositional evidence another eleven tephra layers can be assigned to a northern Sumatran Arc or to an Andaman Arc provenance. First-order minimum eruptive volume estimates for the Neogene tephra layers imply eruptive magnitudes ranging from M = 6.5 to M = 7.5, proving a continuous history of large explosive eruptions from the Sumatran/Andaman Arc since the Neogene, as previously known from the Quaternary.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
    facet.materialart.
    Unknown
    Revisiting the occurrence and distribution of Indian Ocean Tephra: Quaternary marine Toba ash inventory (2023)
    Elsevier
    Details
    Publication Date: 2024-02-14
    Description: The Toba Caldera on Sumatra, Indonesia is the host of the Young Toba eruption (~74 ka), globally one of the largest and most recognized eruptions during the Quaternary and regionally concentrated in the eastern Indian Ocean. Three older deposits (Middle, and Old Toba Tuff as well as Haranggaol Dacite Tuff) are also attributed to Toba caldera, with their eruption products distributed over the Indian Ocean. We present the Quaternary marine tephra record from an array of 14 sites and 28 holes from deep ocean drilling programs, complementing earlier work on distal to ultra-distal Indian Ocean sediment cores and terrestrial distribution data of Toba deposits. A unique set of major and trace element glass-shard compositions on 115 primary ash layers together with glass shard morphologies, core pictures and statistical analysis support geochemical fingerprinting between marine tephra layers and known deposits from Toba and five so far unidentified medium to large eruptions assigned to northern Sumatra. Additionally, zircon crystallization ages have been determined for the Haranggaol Dacite Tuff resulting in a new maximum eruption age of 1.42 ± 0.034 Ma. Tephra volumes and magma masses for the (co-ignimbrite) fallout are estimated based on the compiled marine tephra distribution that are complemented by published proximal ignimbrite volumes. For YTT the resulting tephra and DRE volumes of 5600 km3 and 3600 km3, respectively, are in between the previous estimates. For MTT (253 km3 DRE), ODT (1550 km3 DRE), HDT (129 km3 DRE), and the five additionally identified eruptions from Northern-Sumatran volcanoes, new magma volumes have been determined. Overall, the Indian Ocean tephra record reveals in one large eruption every 200 kyr in the Quaternary that is derived from northern Sumatra.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
    facet.materialart.
    Unknown
    Volcaniclastic deposits and sedimentation processes around volcanic ocean islands: the central Azores (2023)
    GSL (Geological Society London)
    Details
    Publication Date: 2023-01-19
    Description: Geological histories of volcanic ocean islands can be revealed by the sediments shed by them. Hence there is an interest in studying cores of volcaniclastic sediments that are particularly preserved in the many flat-floored basins lying close to the Azores islands. We analyse four gravity cores collected around the central group of the islands. Three sedimentary facies (F1-F2a, F2b) are recognized based on visual core logging, particle morphometric and geochemical analyses. F1 is clay-rich hemipelagite comprising homogeneous mud with mottled structures from bioturbation. F2a and F2b are both clay-poor volcaniclastic deposits, which are carbonate-rich and carbonate-poor, respectively. More biogenic carbonate in F2a reflects the incorporation of unconsolidated calcareous material from island shelves or bioturbation. Within F2a and F2b we identify deposits emplaced by pyroclastic fallout, primary or secondary turbidity currents by combining multiple information from lithological composition, sedimentary structures, chemical composition of volcanic glass shards and morphometric characteristics of volcanic particles. Primary volcaniclastic sediments were found in all four cores, echoing activity known to have occurred up to historical times on the adjacent islands. These preliminary results suggest that greater details of geological events could be inferred for other volcanic islands by adopting a similar approach to core analysis.
    Type: Book chapter , NonPeerReviewed , info:eu-repo/semantics/bookPart
    Format: text
    Format: text
    Format: text
    Format: text
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Book chapter
  • 6
    facet.materialart.
    Unknown
    Tephra layers in the marine environment: a review of properties and emplacement processes (2023)
    GSL (Geological Society London)
    Details
    Publication Date: 2023-01-19
    Description: This review focuses on the recognition of volcanic ash occurrences in marine sediment cores and on using their appearance and properties to deduce their origin. Widespread marine tephra layers are important marker horizons for both volcanological as well as general geological investigations. We describe ash detection by visual inspection and logging of sediment cores. Ash layer structure and texture, particle morphologies and lithological compositions of primary volcanic deposits are summarized and processes modifying them are discussed, both natural processes acting on and in the seafloor, i.e. erosion and bioturbation, and anthropogenic modifications during drilling/coring and core preparation. We discuss primary emplacement processes of marine fall and flow tephra deposits derived from either subaerial or submarine sources in order to identify distinguishing properties. We also elaborate on processes generating secondary, resedimented volcaniclastic layers such as submarine landslides and shelf erosion as well as fluvial input and ice-rafting, and how they can be distinguished from primary volcaniclastic deposits, which is essential in tephrostratigraphy. Finally, methods of tephra correlation between cores and on-land deposits/volcanoes are illustrated because they allow us to extend the 1D information from single cores to 3D distribution and facies changes of tephras and to bridge the land–sea gap.
    Type: Book chapter , NonPeerReviewed , info:eu-repo/semantics/bookPart
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Book chapter
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...