scholarly journals Volumetric extrusive rates of silicic supereruptions from the Afro-Arabian large igneous province

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jennifer E. Thines ◽  
Ingrid A. Ukstins ◽  
Corey Wall ◽  
Mark Schmitz
Keyword(s):  
Environmental Change ◽  
Global Environmental Change ◽  
Volcanic Eruptions ◽  
Large Igneous Province ◽  
Silicic Volcanism ◽  
Global Environmental ◽  
Igneous Province ◽  
Geomagnetic Polarity

AbstractThe main phase of silicic volcanism from the Afro-Arabian large igneous province preserves some of the largest volcanic eruptions on Earth, with six units totaling >8,600 km3 dense rock equivalent (DRE). The large volumes of rapidly emplaced individual eruptions present a case study for examining the tempo of voluminous silicic magma generation and emplacement. Here were report high-precision 206Pb/238U zircon ages and show that the largest sequentially dated eruptions occurred within 48 ± 34 kyr (29.755 ± 0.023 Ma to 29.707 ± 0.025 Ma), yielding the highest known long-term volumetric extrusive rate of silicic volcanism on Earth. While these are the largest known sequential silicic supereruptions, they did not cause major global environmental change. We also provide a robust tie-point for calibration of the geomagnetic polarity timescale by integrating 40Ar/39Ar data with our 206Pb/238U ages to yield new constraints on the duration of the C11n.1r Subchron.

Magma flux of silicic supereruptions from the Afro-Arabian large igneous province

2021 ◽  
Author(s):  
Jennifer Thines ◽  
Ingrid Ukstins ◽  
Corey Wall ◽  
Mark Schmitz
Keyword(s):  
High Precision ◽  
Volcanic Eruptions ◽  
Large Igneous Province ◽  
Silicic Volcanism ◽  
Zircon Dating ◽  
Igneous Province ◽  
Magma Flux ◽  
Silicic Magmas ◽  
Geomagnetic Polarity

Abstract The Main Silicics phase of the Afro-Arabian large igneous province preserves some of the largest volcanic eruptions on Earth, with six units totaling >8,600 km3 dense rock equivalent (DRE). The large volumes of rapidly emplaced individual eruptions present a case study for examining the tempo of generation and emplacement of voluminous silicic magmas. We use high-precision 206Pb/238U zircon dating to differentiate individual eruption ages and show that the largest sequentially dated eruptions occurred within a timeframe of 48 ± 34 kyr (29.755 ± 0.023 Ma to 29.707 ± 0.025 Ma), yielding a maximum magma flux of 3.09 x 10-1 km3/yr for 4,339 km3 DRE and making this sequence the highest known flux of silicic volcanism on Earth. The Main Silicics phase of volcanism occurred within a timeframe of 130 ± 150 kyr (29.80 ± 0.80 Ma to 29.67 ± 0.13 Ma), yielding a maximum magma flux of 3.05 x 10-2 km3/yr. We also provide a robust tie-point for calibration of the geomagnetic polarity timescale by integrating recalculated 40Ar/39Ar data with our high-precision 206Pb/238U ages to yield new constraints on the duration of the C11n.1r Subchron.

scholarly journals Using herbaria to study global environmental change

2018 ◽  
Author(s):  
Patricia L M Lang ◽  
Franziska M Willems ◽  
J F Scheepens ◽  
Hernán A Burbano ◽  
Oliver Bossdorf
Keyword(s):  
Global Change ◽  
Environmental Change ◽  
Global Environmental Change ◽  
Herbarium Specimens ◽  
Long Term Effects ◽  
Temporal Dimension ◽  
Global Environmental ◽  
Evolutionary Changes ◽  
Global Change Research

During the last centuries, humans have transformed global ecosystems. With their temporal dimension, herbaria provide the otherwise scarce long-term data crucial to track ecological and evolutionary changes over these centuries of global change. The sheer size of herbaria, together with their increasing digitization and the possibility of sequencing DNA from the preserved plant material, makes them invaluable resources to understand ecological and evolutionary species responses to global environmental change. Following the chronology of global change, we highlight how herbaria can inform about long-term effects on plants of at least four of the main drivers of global change: pollution, habitat change, climate change, and invasive species. We summarize how herbarium specimens so far have been used in global change research, discuss future opportunities and challenges posed by the nature of these data, and advocate for an intensified use of these 'windows into the past' for global change research and beyond.

scholarly journals Using herbaria to study global environmental change

2018 ◽  
Author(s):  
Patricia L M Lang ◽  
Franziska M Willems ◽  
J F Scheepens ◽  
Hernán A Burbano ◽  
Oliver Bossdorf
Keyword(s):  
Global Change ◽  
Environmental Change ◽  
Global Environmental Change ◽  
Herbarium Specimens ◽  
Long Term Effects ◽  
Temporal Dimension ◽  
Global Environmental ◽  
Evolutionary Changes ◽  
Global Change Research

During the last centuries, humans have transformed global ecosystems. With their temporal dimension, herbaria provide the otherwise scarce long-term data crucial to track ecological and evolutionary changes over these centuries of global change. The sheer size of herbaria, together with their increasing digitization and the possibility of sequencing DNA from the preserved plant material, makes them invaluable resources to understand ecological and evolutionary species responses to global environmental change. Following the chronology of global change, we highlight how herbaria can inform about long-term effects on plants of at least four of the main drivers of global change: pollution, habitat change, climate change, and invasive species. We summarize how herbarium specimens so far have been used in global change research, discuss future opportunities and challenges posed by the nature of these data, and advocate for an intensified use of these 'windows into the past' for global change research and beyond.

Long-term biomonitoring of lichen and bryophyte biodiversity at Burnham Beeches SAC and global environmental change

2010 ◽  
Vol 8 (2) ◽  
pp. 193-208 ◽  
Author(s):  
O. William Purvis ◽  
I. Tittley ◽  
P. D. Jim Chimonides ◽  
Roger Bamber ◽  
Peta A. Hayes ◽  
...  
Keyword(s):  
Environmental Change ◽  
Global Environmental Change ◽  
Global Environmental

scholarly journals Annual dynamics of global land cover and its long-term changes from 1982 to 2015

2020 ◽  
Vol 12 (2) ◽  
pp. 1217-1243 ◽  
Author(s):  
Han Liu ◽  
Peng Gong ◽  
Jie Wang ◽  
Nicholas Clinton ◽  
Yuqi Bai ◽  
...  
Keyword(s):  
Land Cover ◽  
Environmental Change ◽  
Global Environmental Change ◽  
Google Earth ◽  
Spatiotemporal Pattern ◽  
Barren Land ◽  
Global Land Cover ◽  
Global Environmental ◽  
Global Land

Abstract. Land cover is the physical material at the surface of the Earth. As the cause and result of global environmental change, land cover change (LCC) influences the global energy balance and biogeochemical cycles. Continuous and dynamic monitoring of global LC is urgently needed. Effective monitoring and comprehensive analysis of LCC at the global scale are rare. With the latest version of GLASS (Global Land Surface Satellite) CDRs (climate data records) from 1982 to 2015, we built the first record of 34-year-long annual dynamics of global land cover (GLASS-GLC) at 5 km resolution using the Google Earth Engine (GEE) platform. Compared to earlier global land cover (LC) products, GLASS-GLC is characterized by high consistency, more detail, and longer temporal coverage. The average overall accuracy for the 34 years each with seven classes, including cropland, forest, grassland, shrubland, tundra, barren land, and snow/ice, is 82.81 % based on 2431 test sample units. We implemented a systematic uncertainty analysis and carried out a comprehensive spatiotemporal pattern analysis. Significant changes at various scales were found, including barren land loss and cropland gain in the tropics, forest gain in the Northern Hemisphere, and grassland loss in Asia. A global quantitative analysis of human factors showed that the average human impact level in areas with significant LCC was about 25.49 %. The anthropogenic influence has a strong correlation with the noticeable vegetation gain, especially for forest. Based on GLASS-GLC, we can conduct long-term LCC analysis, improve our understanding of global environmental change, and mitigate its negative impact. GLASS-GLC will be further applied in Earth system modeling to facilitate research on global carbon and water cycling, vegetation dynamics, and climate change. The GLASS-GLC data set presented in this article is available at https://doi.org/10.1594/PANGAEA.913496 (Liu et al., 2020).

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