Volcanic soils: their nature and significance for archaeology

James, P; Chester, David K.; Duncan, A. M.

doi:10.1144/gsl.sp.2000.171.01.23

Cited by 10 publications

(5 citation statements)

References 87 publications

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“…The generally poorly developed paleosols on top of the phreatomagmatic deposits suggest a maximum timespan of 200-500 years between the eruptive phases and subsequent covering by lava flows, taking into account the rapidity of paleosol formation in a tropical climate (James et al 2000). We infer that the three phreatomagmatic phases of Mt Goma succeeded one another within the same eruptive episode or a few hundred years at maximum, considering they are separated from each other by sharp contrasts in consolidation and facies type, but without evidence of paleosol development.…”

Section: Chronology Of Lake Level Fluctuations and Phreatomagmatic Er...mentioning

confidence: 99%

Holocene phreatomagmatic eruptions alongside the densely populated northern shoreline of Lake Kivu, East African Rift: timing and hazard implications

et al. 2016

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The Virunga Volcanic Province (VVP) represents the most active zone of volcanism in the western branch of the East African Rift System. While the VVP's two historically active volcanoes, Nyamulagira and Nyiragongo, have built scoria cones and lava flows in the adjacent lava fields, several small phreatomagmatic eruptive centers lie along Lake Kivu's northern shoreline, highlighting the potential for explosive magma-water interaction. Their presence in the densely urbanized Sake-Goma-Gisenyi area necessitates an assessment of their eruptive mechanisms and chronology. Some of these eruptive centers possess multiple vents, and depositional contacts suggest distinct eruptive phases within a single structure.Depositional facies range from polymict tuff breccia to tuff and loose lapilli, often impacted by blocks and volcanic bombs. Along with the presence of dilute pyroclastic density current (PDC) deposits, indicators of magma-water interaction include the presence of fine palagonitized ash, ash aggregates, cross-bedding and ballistic impact sags. We estimate that at least 15 phreatomagmatic eruptions occurred in the Holocene, during which Lake Kivu rose to its current water level. Radiocarbon dates of five paleosols in the top of volcanic tuff deposits range between ~2,500 and ~150 cal. yr BP, and suggest centennial-to millenial-scale recurrence of phreatomagmatic activity. A vast part of the currently urbanized zone on the northern shoreline of Lake Kivu was most likely impacted by products from phreatomagmatic activity, including PDC events, during the Late Holocene, highlighting the need to consider explosive magma-water interaction as a potential scenario in future risk assessments.

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Section: Chronology Of Lake Level Fluctuations and Phreatomagmatic Er...mentioning

confidence: 99%

Holocene phreatomagmatic eruptions alongside the densely populated northern shoreline of Lake Kivu, East African Rift: timing and hazard implications

et al. 2016

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“…Some coagulated lavas, as for example, some basalts, have a very low permeability that prevents minerals to be in contact with weathering agents as water, but ash has a high permeability, thus many options for contact between unstable ash minerals and agents, and weathering of ash is very fast. Minerals in volcanic ashes disintegrate quite rapidly, dissolve, or weather into clay minerals (James et al 2000;Yokota and Iwamatsu 2000). Weathering of volcanic deposits may be 30 times faster than weathering of granite or shale under the same conditions (Dosseto et al 2012).…”

Section: Volcanic Groundmassesmentioning

confidence: 99%

Weathering, Erosion, and Susceptibility to Weathering

Hack

2019

Soft Rock Mechanics and Engineering

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Soft grounds are often the result of weathering. Weathering is the chemical and physical change in time of ground under influence of atmosphere, hydrosphere, cryosphere, biosphere, and nuclear radiation (temperature, rain, circulating groundwater, vegetation, etc.). Erosion is the removal of material on or below the Earth surface due to flowing (ground-) water, ice, and wind. Quantities of weathered material do not need to be large to change the geotechnical properties of a groundmass, for example, weathering of discontinuity walls that reduce the shear strength. Weathering is the reason for many constructions and other engineering applications in which ground is used, to become a disaster. The processes involved in weathering are described briefly as well as the role of erosion in weathering and weathering depth. The dependence of weathering on lithology, implications for engineering applications, the methodology for describing and classification of weathering, and options for determining the susceptibility to weathering for forecasting future weathering are introduced. Hard layer or crust forming as result of weathering and tests for determining the state of weathering and susceptibility to weathering conclude the chapter.

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“…On a geologic timescale, soil formation occurred about 10,000 years ago, which coincides with the end of the last glacial period (Arnalds et al 1995). The basaltic tephra, which is the term for material of any size ejected by volcanoes, is one of the parent materials of soil types in Iceland (James, Chester and Duncan 2000;Arnalds 2008). The land-cover of Iceland is very dynamic.…”

Section: Introductionmentioning

confidence: 99%

Remote sensing analysis to map inter-regional spatio-temporal variations of the vegetation in Iceland during 2001–2018

Ólafsson

Rousta

2022

AGS

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Changes in the vegetation of the Arctic and sub-Arctic regions have been used as indicators of the impact and seriousness of climate change. In this study, 342 MODIS NDVI images were used to monitor and assess the variability and long-term changes in the vegetation in Iceland in the period 2001–2018. An insignificant trend in the changes of the vegetation coverage (R = 0.16, p-value = 0.05) was obtained, however, it also resulted that the area with the low values of the NDVI (< 0.6) is decreasing, whereas the area with higher values of the NDVI (> 0.6, mostly forests) is increasing. The NDVI index during the study period rose for the area of about 3260 km2, while it declined for 1635 km2. The results of this study can be used for organizing the strategies preventing climate change and global warming.

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Volcanic soils: their nature and significance for archaeology

Cited by 10 publications

References 87 publications

Holocene phreatomagmatic eruptions alongside the densely populated northern shoreline of Lake Kivu, East African Rift: timing and hazard implications

Holocene phreatomagmatic eruptions alongside the densely populated northern shoreline of Lake Kivu, East African Rift: timing and hazard implications

Weathering, Erosion, and Susceptibility to Weathering

Remote sensing analysis to map inter-regional spatio-temporal variations of the vegetation in Iceland during 2001–2018

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