Chapter 7.4 Active volcanoes in Marie Byrd Land

AbstractTwo volcanoes in Marie Byrd Land, Mount Berlin and Mount Takahe, can be considered active, and a third, Mount Waesche, may be as well; although the chronology of activity is less well constrained. The records of explosive activity of these three volcanoes is well represented through deposits on the volcano flanks and tephra layers found in blue ice areas, as well as by the presence of cryptotephra layers found in West and East Antarctic ice cores. Records of effusive volcanism are found on the volcano flanks but some deposits may be obscured by pervasive glacerization of the edifices. Based on a compilation of tephra depths–ages in ice cores, the activity patterns of Mount Takahe and Mount Berlin are dramatically different. Mount Takahe has erupted infrequently over the past 100 kyr. Mount Berlin, by contrast, has erupted episodically during this time interval, with the number of eruptions being dramatically higher in the time interval between c. 32 and 18 ka. Integration of the Mount Berlin tephra record from ice cores and blue ice areas over a 500 kyr time span reveals a pattern of geochemical evolution related to small batches of partial melt being progressively removed from a single source underlying Mount Berlin.

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Chapter 6.1 Marine record of Antarctic volcanism from drill cores

Geological Society London Memoirs ◽

10.1144/m55-2018-49 ◽

2021 ◽

pp. M55-2018-49 ◽

Cited By ~ 3

Author(s):

Alessio Di Roberto ◽

Paola Del Carlo ◽

Massimo Pompilio

Keyword(s):

Marine Sediments ◽

Time Span ◽

Explosive Activity ◽

Eruptive Dynamics ◽

Volcanic Material ◽

Tephra Layers ◽

Antarctic Continent ◽

The Antarctic ◽

Different Sources ◽

Drill Cores

AbstractWe review here data and information on Antarctic volcanism resulting from recent tephrostratigraphic investigations on marine cores. Records include deep drill cores recovered during oceanographic expeditions: DSDP, ODP and IODP drill cores recovered during ice-based and land-based international cooperative drilling programmes DVDP 15, MSSTS-1, CIROS-1 and CIROS-2, DVDP 15, CRP-1, CRP-2/2A and CRP-3, ANDRILL-MIS and ANDRILL-SMS, and shallow gravity and piston cores recovered in the Antarctic and sub-Antarctic oceans. We report on the identification of visible volcaniclastic horizons and, in particular, of primary tephra within the marine sequences. Where available, the results of analyses carried out on these products are presented. The volcanic material identified differs in its nature, composition and emplacement mechanisms. It was derived from different sources on the Antarctic continent and was emplaced over a wide time span.Marine sediments contain a more complete record of the explosive activity from Antarctic volcanoes and are complementary to those obtained by land-based studies. This record provides important information for volcanological reconstructions including approximate intensities and magnitudes of eruptions, and their duration, age and recurrence, as well as their eruptive dynamics. In addition, characterized tephra layers represent an invaluable chronological tool essential in establishing correlations between different archives and in synchronizing climate records.

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Independent verification of age tie points and planktic reservoir ages deduced for two marine sediment records at the Chilean continental margin by 14C plateau tuning

10.5194/egusphere-egu2020-5683 ◽

2020 ◽

Author(s):

Kevin Küssner ◽

Michael Sarnthein ◽

Frank Lamy ◽

Elisabeth Michel ◽

Gesine Mollenhauer ◽

...

Keyword(s):

Continental Margin ◽

Marine Sediment ◽

Sediment Cores ◽

Ice Cores ◽

Time Interval ◽

Stratigraphic Correlation ◽

Short Term ◽

Planktic Foraminifera ◽

Last Glacial ◽

Tephra Layers

On the basis of 14C plateau tuning we established a robust centennial-scale age control for last glacial-to-deglacial sediment sections in two marine sediment cores MD07-3088 and PS97-137 from the upper Chilean continental margin to facilitate a precise stratigraphic correlation between short-term changes in South Pacific oceanography and global paleoclimate signals recorded in ice cores from Antarctica and elsewhere (K&#252;ssner et al., in prep.). Age tie points and reservoir ages were derived from tuning a suite of planktic 14C plateaus to a suite of pertinent atmospheric 14C plateaus defined at Lake Suigetsu (Sarnthein et al., 2015). Off central Chile four tephra layers in Core MD07-3088 provide independent proof both for the age assignment and for short-term changes in planktic reservoir age we deduced by means of 14C plateau tuning. Reservoir ages derived from 14C plateau tuning at 11&#8211;16.5 cal. ka closely match, one-by-one, four reservoir ages that have been deduced from the difference between the 14C ages of planktic foraminifera associated with the tephra layers in marine sediments and the atmospheric 14C ages of plants associated with paired tephras analyzed nearby on land (Siani et al. 2013). &#8211; In Core PS97-137, near to the southern tip of Chile, sediments of the Last Glacial Maximum show a section with distinct lamination of 5-7 layers / cm depth, associated with atmospheric 14C Plateau 6a by plateau tuning. A rough count of the layers in the 160 cm long sediment section of the planktic 14C Plateau 6a gives a number that comes extremely close to the ~900 year-long time span of the atmospheric 14C Plateau 6a, thus provides independent proof for both the accuracy of the time interval assigned to correlated atmospheric &#8216;Plateau 6a&#8217; and the approach of plateau tuning in general.&#160;K&#252;ssner et al., Paleoceanography, in prep.,Sarnthein et al., Radiocarbon, 2015, 57 (1), 129&#8211;151.Siani et al., 2013, Nature comm., 4, 2758.

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Enhanced Carbonate Counter Pump efficiency during interglacials of the past 800 000 years in the Indian sector of the Southern Ocean and its impact on the carbon cycle

10.5194/egusphere-egu21-8610 ◽

2021 ◽

Author(s):

Margaux Brandon ◽

Stéphanie Duchamp-Alphonse ◽

Elisabeth Michel ◽

Amaëlle Landais ◽

Gulay Isguder ◽

...

Keyword(s):

Southern Ocean ◽

Planktonic Foraminifera ◽

Ice Cores ◽

Time Interval ◽

Pump Efficiency ◽

Biological Pump ◽

Carbonate Production ◽

The Past ◽

The Impact ◽

Indian Sector

The Southern Ocean (SO) is a key region for ocean-atmosphere CO2 exchanges, as it witnesses significant changes in physical and biological pump dynamics. While numerous studies have highlighted the central role of reinvigorated SO upwelling behind rapid increases in atmospheric CO2 during glacial terminations, a very few studies have yet focused on the impact of the Biological Carbon Pump and more specifically of the Carbonate Counter Pump (CCP) that, contrary to the Soft Tissue Pump, participates to increase the concentration of dissolved CO2 in oceanic surface waters and thus, in the atmosphere.Amongst the last 9 interglacials, Marine Isotope Stage (MIS) 11 (~ 400 ka) is the longest interglacial of the past 800,000 years, characterised by a ~30 ka-long plateau with atmospheric CO2 hovering around 280 ppm. Reconstructions of past global biosphere productivity based on &#916;17O of O2 measurements on air bubbles trapped in ice cores, show that MIS 11 registers the strongest global biosphere productivity (~ 20% higher) compared to the other 8 interglacials (Brandon et al., 2020; Yang et al., EGU21) Meanwhile, marine sedimentary records suggest strong carbonate production and export. Studying the detailed variations of the CCP during this specific period can therefore be useful to better understand its relationship with biospheric productivity changes and to better constraint its impacts on atmospheric CO2.As calcifying organisms, coccolithophores and planktonic foraminifera represent the major producers of CaCO3 in pelagic environments and are therefore useful tools to reconstruct past variations in the CCP strength. Here, we calibrate CaXRF and CaCO3 signals from marine core MD04-2718 located in the Indian sector of the SO (48&#176;53 S; 65&#176;57 E) in terms of coccolith and planktonic carbonate production and export signals over the last 800 ka, with a focus on the interval MIS 12 to MIS 10. We compare our results with published micropaleontological and geochemical records from the subantarctic zone (SAZ) in order to reconstruct past changes in CCP efficiency and circulation at the SO scale and understand their relationships with atmospheric CO2 patterns.We show an increase in CCP efficiency during interglacial periods, with an exceptional high carbonate export production during MIS 11. We demonstrate that enhanced CCP efficiency at the beginning of MIS 11 is likely the consequence of both higher SST conditions and nutrient contents in the upper water column of the SAZ, that increase coccolithophore and planktonic foraminifera productions, thanks to the southward migration of SO fronts and the reinvigoration of southern upwelling. While the sharp increase in atmospheric CO2 during Termination V seems correlated with the reinvigoration of the SO upwelling, enhanced CCP at the beginning of MIS 11 might have greatly reduced the efficiency of the biological pump, impacting the CO2 flux from the ocean to the atmosphere. The strong global biological productivity registered during this interval might have permitted to sustain the 30 ka-long plateau of atmospheric CO2 that characterize this time interval.

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Smart Estimation Ver-H.1.0

10.31227/osf.io/2tyqk ◽

2018 ◽

Author(s):

Sigit Haryadi

Keyword(s):

Sample Size ◽

Confidence Level ◽

Time Span ◽

Regression Equation ◽

Weight Factor ◽

The Past ◽

Level Of Confidence ◽

The Future ◽

Future Value ◽

The Difference

We cannot be sure exactly what will happen, we can only estimate by using a particular method, where each method must have the formula to create a regression equation and a formula to calculate the confidence level of the estimated value. This paper conveys a method of estimating the future values, in which the formula for creating a regression equation is based on the assumption that the future value will depend on the difference of the past values divided by a weight factor which corresponding to the time span to the present, and the formula for calculating the level of confidence is to use "the Haryadi Index". The advantage of this method is to remain accurate regardless of the sample size and may ignore the past value that is considered irrelevant.

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Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere

Science Advances ◽

10.1126/sciadv.abc1379 ◽

2021 ◽

Vol 7 (22) ◽

pp. eabc1379

Author(s):

Pengfei Liu ◽

Jed O. Kaplan ◽

Loretta J. Mickley ◽

Yang Li ◽

Nathan J. Chellman ◽

...

Keyword(s):

Southern Hemisphere ◽

Radiative Forcing ◽

Ice Core ◽

Ice Cores ◽

Terrestrial Ecosystems ◽

Rapid Expansion ◽

Past Century ◽

Fire Emissions ◽

The Past ◽

Fire Activity

Fire plays a pivotal role in shaping terrestrial ecosystems and the chemical composition of the atmosphere and thus influences Earth’s climate. The trend and magnitude of fire activity over the past few centuries are controversial, which hinders understanding of preindustrial to present-day aerosol radiative forcing. Here, we present evidence from records of 14 Antarctic ice cores and 1 central Andean ice core, suggesting that historical fire activity in the Southern Hemisphere (SH) exceeded present-day levels. To understand this observation, we use a global fire model to show that overall SH fire emissions could have declined by 30% over the 20th century, possibly because of the rapid expansion of land use for agriculture and animal production in middle to high latitudes. Radiative forcing calculations suggest that the decreasing trend in SH fire emissions over the past century largely compensates for the cooling effect of increasing aerosols from fossil fuel and biofuel sources.

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Significant increase in quantity and quality of knee arthroplasty related research in KSSTA over the past 15 years

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-021-06555-2 ◽

2021 ◽

Author(s):

Stephanie Kirschbaum ◽

Thilo Kakzhad ◽

Fabian Granrath ◽

Andrzej Jasina ◽

Jakub Oronowicz ◽

...

Keyword(s):

Knee Arthroplasty ◽

Special Topic ◽

Computer Assisted ◽

Time Interval ◽

Search Term ◽

Level Of Evidence ◽

The Past ◽

Patient Reported ◽

Over Time ◽

Number Of Authors

Abstract Purpose This study aimed to evaluate both publication and authorship characteristics in Knee Surgery, Sports Traumatology, Arthroscopy journal (KSSTA) regarding knee arthroplasty over the past 15 years. Methods PubMed was searched for articles published in KSSTA between January 1, 2006, and December 31st, 2020, utilising the search term ‘knee arthroplasty’. 1288 articles met the inclusion criteria. The articles were evaluated using the following criteria: type of article, type of study, main topic and special topic, use of patient-reported outcome scores, number of references and citations, level of evidence (LOE), number of authors, gender of the first author and continent of origin. Three time intervals were compared: 2006–2010, 2011–2015 and 2016–2020. Results Between 2016 and 2020, publications peaked at 670 articles (52%) compared with 465 (36%) published between 2011 and 2016 and 153 articles (12%) between 2006 and 2010. While percentage of reviews (2006–2010: 0% vs. 2011–2015: 5% vs. 2016–2020: 5%) and meta-analyses (1% vs. 6% vs. 5%) increased, fewer case reports were published (13% vs. 3% vs. 1%) (p < 0.001). Interest in navigation and computer-assisted surgery decreased, whereas interest in perioperative management, robotic and individualized surgery increased over time (p < 0.001). There was an increasing number of references [26 (2–73) vs. 30 (2–158) vs. 31 (1–143), p < 0.001] while number of citations decreased [30 (0–188) vs. 22 (0–264) vs. 6 (0–106), p < 0.001]. LOE showed no significant changes (p = 0.439). The number of authors increased between each time interval (p < 0.001), while the percentage of female authors was comparable between first and last interval (p = 0.252). Europe published significantly fewer articles over time (56% vs. 47% vs. 52%), whereas the number of articles from Asia increased (35% vs. 45% vs. 37%, p = 0.005). Conclusion Increasing interest in the field of knee arthroplasty-related surgery arose within the last 15 years in KSSTA. The investigated topics showed a significant trend towards the latest techniques at each time interval. With rising number of authors, the part of female first authors also increased—but not significantly. Furthermore, publishing characteristics showed an increasing number of publications from Asia and a slightly decreasing number in Europe. Level of evidence IV.

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Dating Late Pleistocene Pluvial Events and Tephras by Correlating Paleomagnetic Secular Variation Records from the Western Great Basin

Quaternary Research ◽

10.1016/0033-5894(92)90029-i ◽

1992 ◽

Vol 38 (1) ◽

pp. 46-59 ◽

Cited By ~ 17

Author(s):

Robert M. Negrini ◽

Jonathan O. Davis

Keyword(s):

Great Basin ◽

Secular Variation ◽

Hot Springs ◽

Time Interval ◽

Lake Basin ◽

Lake Surface ◽

Surface Level ◽

Sedimentary Sequences ◽

Tephra Layers ◽

Geologic Record

AbstractPaleomagnetic records are used to correlate sedimentary sequences from pluvial Lakes Chewaucan and Russell in the western Great Basin. This correlation is the basis for age control in the relatively poorly dated sequence from Lake Chewaucan. The resulting chronology supports a lack of sedimentation in Lake Chewaucan during the interval 27,400 to 23,200 yr B.P., an assertion supported by the presence of a lag deposit at the corresponding stratigraphic horizon. Because the Lake Chewaucan outcrop (near Summer Lake, Oregon) is near the bottom of the lake basin, we conclude that Lake Chewaucan was at a lowstand during this time interval. The Chewaucan lowstand is coeval with the lowstand accompanying the Wizard's Beach Recession (isotope stage 3) previously seen in the geologic record from nearby pluvial Lake Lahontan. The ages of six tephra layers, including the Trego Hot Springs tephra, were also estimated using the paleomagnetic correlation. Together, the new age of the Trego Hot Springs tephra (21,800 yr B.P.) and the lake surface level prehistory of Lake Chewaucan imply a revised model for the lake surface level prehistory of Lake Lahontan. The revised model includes a longer duration for the Wizard's Beach Recession and the occurrence of a younger lowstand of short duration soon after the lowstand corresponding to the Wizard's Beach Recession.

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Were they really laughed at? That much? Gelotophobes and their history of perceived derisibility

Humor - International Journal of Humor Research ◽

10.1515/humr.2009.010 ◽

2009 ◽

Vol 22 (1-2) ◽

Cited By ~ 10

Author(s):

René T. Proyer ◽

Christian F. Hempelmann ◽

Willibald Ruch

Keyword(s):

Empirical Study ◽

Large Degree ◽

Time Span ◽

Corpus Study ◽

The Past ◽

History Of ◽

University Of Zurich

AbstractThe List of Derisible Situations (LDS; Proyer, Hempelmann and Ruch, List of Derisible Situations (LDS), University of Zurich, 2008) consists of 102 different occasions for being laughed at. They were retrieved in a corpus study and compiled into the LDS. Based on this list, information on the frequency and the intensity with which people recall being laughed at during a given time-span (12 months in this study) can be collected. An empirical study (N = 114) examined the relations between the LDS and the fear of being laughed at (gelotophobia), the joy of being laughed at (gelotophilia), and the joy of laughing at others (katagelasticism; Ruch and Proyer this issue). More than 92% of the participants recalled having been laughed at at least once over the past 12 months. Highest scores were found for experiencing an embarrassing situation, chauvinism of others or being laughed at for doing something awkward or clumsy. Gelotophobia, gelotophilia, and katagelasticism were related about equally to the recalled frequency of events of being laughed at (with the lowest relation to katagelasticism). Gelotophobia, gelotophilia, and katagelasticism yielded a distinct and plausible pattern of correlations to the frequency of events of being laughed at. Gelotophobes recalled the situations of being laughed at with a higher intensity than others. Thus, the fear of being laughed at exists to a large degree independently from actual experiences of being laughed at, but is related to a higher intensity with which these events are experienced.

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Longitudinal study of fingerprint recognition

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1410272112 ◽

2015 ◽

Vol 112 (28) ◽

pp. 8555-8560 ◽

Cited By ~ 56

Author(s):

Soweon Yoon ◽

Anil K. Jain

Keyword(s):

Statistical Models ◽

Recognition Accuracy ◽

Temporal Stability ◽

Poor Quality ◽

Time Span ◽

Fingerprint Recognition ◽

Time Interval ◽

General Belief ◽

Probability Of Error ◽

Fingerprint Database

Human identification by fingerprints is based on the fundamental premise that ridge patterns from distinct fingers are different (uniqueness) and a fingerprint pattern does not change over time (persistence). Although the uniqueness of fingerprints has been investigated by developing statistical models to estimate the probability of error in comparing two random samples of fingerprints, the persistence of fingerprints has remained a general belief based on only a few case studies. In this study, fingerprint match (similarity) scores are analyzed by multilevel statistical models with covariates such as time interval between two fingerprints in comparison, subject’s age, and fingerprint image quality. Longitudinal fingerprint records of 15,597 subjects are sampled from an operational fingerprint database such that each individual has at least five 10-print records over a minimum time span of 5 y. In regard to the persistence of fingerprints, the longitudinal analysis on a single (right index) finger demonstrates that (i) genuine match scores tend to significantly decrease when time interval between two fingerprints in comparison increases, whereas the change in impostor match scores is negligible; and (ii) fingerprint recognition accuracy at operational settings, nevertheless, tends to be stable as the time interval increases up to 12 y, the maximum time span in the dataset. However, the uncertainty of temporal stability of fingerprint recognition accuracy becomes substantially large if either of the two fingerprints being compared is of poor quality. The conclusions drawn from 10-finger fusion analysis coincide with the conclusions from single-finger analysis.

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Data-driven modeling decadal-to-centennial ENSO variability and its response to external forcing

10.5194/egusphere-egu21-8370 ◽

2021 ◽

Author(s):

Aleksei Seleznev ◽

Dmitry Mukhin ◽

Andrey Gavrilov ◽

Alexander Feigin

Keyword(s):

Co2 Concentration ◽

Data Driven ◽

Time Interval ◽

Solar Forcing ◽

Russian Science ◽

Dynamical Mechanism ◽

Enso Variability ◽

The Past ◽

Sst Variability ◽

Data Driven Modeling

We investigate the decadal-to-centennial ENSO variability based on nonlinear data-driven stochastic modeling. We construct data-driven model of yearly Ni&#241;o-3.4 indices reconstructed from paleoclimate proxies based on three different sea-surface temperature (SST) databases at the time interval from 1150 to 1995 [1]. The data-driven model is forced by the solar activity and CO2 concentration signals. We find the persistent antiphasing relationship between the solar forcing and Ni&#241;o-3.4 SST on the bicentennial time scale. The dynamical mechanism of such a response is discussed.The work was supported by the Russian Science Foundation (Grant No. 20-62-46056)1. Emile-Geay, J., Cobb, K. M., Mann, M. E., & Wittenberg, A. T. (2013). Estimating Central Equatorial Pacific SST Variability over the Past Millennium. Part II: Reconstructions and Implications, Journal of Climate, 26(7), 2329-2352.

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