The importance of overbank deposits and paleosol analyses for comprehensive volcanic hazard evaluation: The case of Holocene volcanism at Miravalles Volcano, Costa Rica

2021 ◽  
Author(s):  
Peter Crowley Ryan ◽  
Guillermo Alvarado ◽  
Molly McCanta ◽  
Malia Barca ◽  
Gabrielle Davis ◽  
...  
Keyword(s):  
Radiocarbon Dating ◽  
Phase 1 ◽  
Active Phase ◽  
Debris Avalanche ◽  
Hazard Evaluation ◽  
The Past ◽  
Andesitic Lava ◽  
Volcanic Debris ◽  
Floodplain Deposits ◽  
Holocene Activity

Abstract On the flanks of the dormant Miravalles volcano, systematic fieldwork and radiocarbon dating of buried humus-rich soils (paleosols) and wood fragments, augmented by mineralogical and geochemical analysis, reveal extensive and previously undocumented Holocene activity. Phase 1 consisted of 8.3 ka (~6300 BCE) volcanic debris avalanche and thick lapilli blast and fallout deposit that appear coeval. Hiatus 1 marks 2600 years of inactivity ensued followed by Phase 2 lapilli interbedded with ~5.5 ka lahars below a 5.3 ka basaltic lava flow (~3400 BCE). Hiatus 2 lasted 1800 years from 5.3 ka to 3.5 ka (3300-1500 BCE), after which a very active Phase 3 ensued (3.5 to 0.5 ka; 1600 BCE to 1500 CE) with > four lapilli eruptions, > 4 lahars, > 6 layers of ash and pumice, and small andesitic lava flows. The most recent evidence for eruption is an 880-year-old (0.9 ka; 1070 CE) lapilli overlain by gravels that may represent distal lahar sediments. Evidence indicates the occurrence of at least two, if not three, destructive lahars on the southwest flank of Miravalles in the past 500 years. The overbank sedimentary record indicates much more activity of Miravalles volcano over the past 3500 years (since 1500 BCE) than previously known, with a minimum of 24 events in that span. Overbank floodplain deposits are likely to contain the most compete record of recent activity in active and dormant volcanoes, and in the absence of dateable vegetation fragments, radiocarbon dating of paleosol A-horizons is very useful, with a precision of ~ 10%, i.e. 800 + 80 ybp.

SUITABILITY OF ACID-SOLUBLE AND ACID-INSOLUBLE LEATHER FRACTIONS IN RADIOCARBON DATING

Radiocarbon ◽  
2020 ◽  
pp. 1-8
Author(s):  
Alyssa M Tate ◽  
Brittany Hundman ◽  
Jonathan Heile
Keyword(s):  
Radiocarbon Dating ◽  
Insoluble Fraction ◽  
Economic Life ◽  
Chemical Pretreatment ◽  
Acid Base ◽  
The Past ◽  
Acid Soluble Collagen ◽  
Method Of Production ◽  
Insight Into

ABSTRACT Leather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.

scholarly journals Radiocarbon Dating of Calcined Bones: Where Does the Carbon Come from?

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 601-611 ◽  
Author(s):  
A Zazzo ◽  
J-F Saliège ◽  
A Person ◽  
H Boucher
Keyword(s):  
Radiocarbon Dating ◽  
Tooth Enamel ◽  
Skeletal Remains ◽  
Archaeological Sites ◽  
Carbonate Content ◽  
The Past ◽  
Mineral Fraction ◽  
Different Temperatures ◽  
C Value ◽  
Paleodietary Reconstruction

Over the past decade, radiocarbon dating of the carbonate contained in the mineral fraction of calcined bones has emerged as a viable alternative to dating skeletal remains in situations where collagen is no longer present. However, anomalously low δ13C values have been reported for calcined bones, suggesting that the mineral fraction of bone is altered. Therefore, exchange with other sources of carbon during heating cannot be excluded. Here, we report new results from analyses on cremated bones found in archaeological sites in Africa and the Near East, as well as the results of several experiments aiming at improving our understanding of the fate of mineral and organic carbon of bone during heating. Heating of modern bone was carried out at different temperatures, for different durations, and under natural and controlled conditions, and the evolution of several parameters (weight, color, %C, %N, δ13C value, carbonate content, crystallinity indexes measured by XRD and FTIR) was monitored. Results from archaeological sites confirm that calcined bones are unreliable for paleoenvironmental and paleodietary reconstruction using stable isotopes. Experimental results suggest that the carbon remaining in bone after cremation likely comes from the original inorganic pool, highly fractionated due to rapid recrystallization. Therefore, its reliability for 14C dating should be seen as close to that of tooth enamel, due to crystallographic properties of calcined bones.

scholarly journals The Integration of Radiocarbon Dating in Archaeology

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 639-644 ◽  
Author(s):  
H T Waterbolk
Keyword(s):  
Radiocarbon Dating ◽  
The Other ◽  
New Method ◽  
Time Range ◽  
Traditional Methods ◽  
Radiocarbon Dates ◽  
Fully Integrated ◽  
Expected Time ◽  
The Past

In the past 30 years many hundreds of archaeologic samples have been dated by radiocarbon laboratories. Yet, one cannot say that 14C dating is fully integrated into archaeology. For many archaeologists, a 14C date is an outside expertise, for which they are grateful, when it provides the answer to an otherwise insoluble chronologic problem and when it falls within the expected time range. But if a 14C date contradicts other chronologic evidence, they often find the ‘solution’ inexplicable. Some archaeologists are so impressed by the new method, that they neglect the other evidence; others simply reject problematic 14C dates as archaeologically unacceptable. Frequently, excavation reports are provided with an appendix listing the relevant 14C dates with little or no discussion of their implication. It is rare, indeed, to see in archaeologic reports a careful weighing of the various types of chronologic evidence. Yet, this is precisely what the archaeologist is accustomed to do with the evidence from his traditional methods for building up a chronology: typology and stratigraphy. Why should he not be able to include radiocarbon dates in the same way in his considerations?

scholarly journals Seismic hazard evaluation

2000 ◽  
Vol 33 (3) ◽  
pp. 371-386 ◽  
Author(s):  
Paul Somerville
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Earthquake Source ◽  
Hazard Evaluation ◽  
Data Set ◽  
Motion Models ◽  
The Past ◽  
Ground Motion Models

This paper reviews concepts and trends in seismic hazard characterization that have emerged in the past decade, and identifies trends and concepts that are anticipated during the coming decade. New methods have been developed for characterizing potential earthquake sources that use geological and geodetic data in conjunction with historical seismicity data. Scaling relationships among earthquake source parameters have been developed to provide a more detailed representation of the earthquake source for ground motion prediction. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude - distance - soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near- fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes. The probabilistic approach to characterizing the ground motion that a given site will experience in the future is very compatible with current trends in earthquake engineering and the development of building codes. Performance based design requires a more comprehensive representation of ground motions than has conventionally been used. Ground motions estimates are needed at multiple annual probability levels, and may need to be specified not only by response spectra but also by suites of strong motion time histories for input into time-domain non-linear analyses of structures.

scholarly journals PERBEDAAN TEKNIK KOMPRES AIR HANGAT DAN TEKNIK MASSAGE UNTUK MENGURANGI NYERI PERSALINAN KALA I FASE AKTIF DI RSUD KOTA MAKASSAR PERIODE APRIL – MEI 2018

2019 ◽  
Author(s):  
nurul ikawati
Keyword(s):  
Phase 1 ◽  
Research Result ◽  
Sampling Technique ◽  
Active Phase ◽  
Labor Pain ◽  
Warm Water ◽  
Primary Data ◽  
Primary Data Source ◽  
Data Source ◽  
The Difference

PERBEDAAN TEKNIK KOMPRES AIR HANGAT DAN TEKNIK MASSAGE UNTUK MENGURANGI NYERI PERSALINAN KALA I FASE AKTIF DI RSUD KOTA MAKASSAR PERIODE APRIL – MEI 2018(The Difference between Warm Water Compress Technique and Massage Technique to Reduce Labor Pain During Active Phase 1 in RSUD Makassar Cityof April – May 2018 PeriodNurul IkawatiProdi D4 Bidan PendidikUniversitas Mega Rezky MakassarABSTRAKPenelitian ini menggunakan desain true eksperimen dengan rancanagan Pretest dan Posttest, dengan jumlah responden sebanyak 44 responden dengan 22 responden sebagai kelompok teknik kompres air hangat dan 22 responden sebagai kelompok teknik massage, teknik pengambilan sampel adalah purposive sampling, instrumen penelitian menggunakan lembar observasi yang dijadikan sumber data primer, analisis data menggunakan uji T Paired sampel t-testHasil penelitian ini menunjukan bahwa kelompok teknik kompres air hangat mengalami pengurangan nyeri sebanyak 5,05 dan kelompok teknik massage mengalami pengurangan nyeri sebanyak 4,50. Kesimpulan dari hasil penelitian menunjukan bahwa ada perbedaan antara teknik kompres air hangat dan teknik massage untuk mengurangi nyeri persalinan kala I fase aktif. Dengan demikian disarankan kepada bidan atau perawat agar dapat membantu memenuhi kebutuhan ibu dalam memberikan rasa nyaman untuk mengurangi rasa nyeri dengan memberikan teknik massage. Kata Kunci : teknik Kompres Air hangat, Teknik Massage, Nyeri Persalinan Daftar Pustaka : 10 buku + 5 jurnal (2013 - 2018)ABSTRACTThis research used experimental research with pretest and posttest design with 44 respondents, 22 respondents were treated by warm water compress technique and 22 others are treated by massage technique. The samples were taken by using purpossive sampling technique, the research instrument used were observation sheet as primary data source and the data analysis used paired sample t-test. The resyult of this research showed that the warm water compress technique group reduce the labor pain as much as 5,05 and massage technique group reduce the labor pain as much as 4,50. The conclusion of research result showed that there is difference between warm water compress technique and massage technique to reduce labor pain during active phase 1. It is suggested to midwiferies and nurses to fulfil mothers’ need to feel comfortable and reduce labor pain by applying massage technique. Keywords: Warm Water Compress Technique, Massage Technique, Labor Pain References: 10 books + 5 Journals (2013 – 2018)

scholarly journals Freshwater Reservoir Effect Variability in Northern Germany

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1085-1101 ◽  
Author(s):  
Bente Philippsen ◽  
Jan Heinemeier
Keyword(s):  
Radiocarbon Dating ◽  
Potential Problem ◽  
Northern Germany ◽  
Reservoir Effect ◽  
The Past ◽  
Human Bones ◽  
Age Correction ◽  
Order Of Magnitude ◽  
Freshwater Reservoir ◽  
Reservoir Age

The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of freshwater-based samples requires knowing the order of magnitude of the reservoir effect and its degree of variability. Measurements on modern riverine materials may not give a single reservoir age correction that can be applied to archaeological samples, but they show the order of magnitude and variability that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany.

scholarly journals Age, Growth and Death of a National Icon: The Historic Chapman Baobab of Botswana

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 983 ◽  
Author(s):  
Adrian Patrut ◽  
Stephan Woodborne ◽  
Roxana T. Patrut ◽  
Grant Hall ◽  
Laszlo Rakosy ◽  
...  
Keyword(s):  
Growth Rate ◽  
Radiocarbon Dating ◽  
Radiocarbon Date ◽  
Rate Variation ◽  
The Past ◽  
Open Ring ◽  
Climate Evolution ◽  
National Icon ◽  
Ring Shaped Structure ◽  
Past 1000 Years

The year 2016 witnessed the fall of a symbol of the botanical world: the historic Chapman baobab of Botswana. This article presents the results of our investigation of the standing and fallen tree. The Chapman baobab had an open ring-shaped structure composed of six partially fused stems. Several wood samples collected from the stems prior and after their collapse were analysed by using radiocarbon dating. The radiocarbon date of the oldest sample was 1381 ± 22 BP, which corresponds to a calibrated age of 1345 (+10, −15) calendar years. The dating results show that the six stems of the Chapman baobab belonged to three different generations, which were 1350–1400, 800–1000 and 500–600 years old. The growth rate variation of the largest and oldest stem is presented and correlated with the climate evolution in the area over the past 1000 years. The factors that determined the sudden fall and death of the Chapman baobab are also presented and discussed.

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