ams radiocarbon dating
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2022 ◽  
Vol 07 (01) ◽  
pp. 116-124
Author(s):  
N. Kanthilatha

Chronological framework can be used to identify the distribution of occupation patterns. This study was based on fourteen radiocarbon samples from the eight excavation pits at Ban Non Wat and Nong Hua Raet archaeological sites. The chronology of the cultural layers was developed using AMS radiocarbon dating to supplement existing data, specifically to examine the dating of the end of the Iron Age occupation. The objective of this study was to continue testing the premise that the end of the Iron Age on the Mun river floodplain in Northeast Thailand that is better defined as either a singular more or less contemporaneous de-population event characterized by widespread abandonment of settlements or a gradual transition from dispersing a rural settlement to more concentrated urban style of settlement. The results support the existing chronological framework of the study area and suggest that the end of the Iron Age in the Mun River valley is better defined as a gradual transition from dispersed rural settlements to a more concentrated urban style settlement. Occupation commenced at the center of the mound of Ban Non Wat during the Neolithic period, and gradually spread radially to the margin by the Iron Age. Occupation at the neighboring site of Nong Hua Raet commenced during the Iron Age period, parallel to that at Ban Non Wat.


2021 ◽  
Author(s):  
Pakpadee Yukongdi ◽  

Recently in 2021the 11th office of the Fine Arts Department, Songkhla has reported their annual excavations in Trang Province that archaeologists have found some set of rice while excavation in process namely,1) Khao Kurum Archaeological Site, Huai Yod District and 2) Napala Archaeological Site, Muang District. The artifacts which were found associated with the rice grains on the habitation layer consisted of potsherds, animal bones, grindstone, beads, etc. The grains of rice are short and brown in colour which is examined as carbonized since the beginning at its first left. The primary examination by archaeologists has classified the rice of Napala Archaeological Site as short grain of probably Orysa sativa (Indica or Aus) rice. AMS Radiocarbon dating by Beta Analytic Testing Laboratory shows the AMS standard results and calibration dating of charred material measured radiocarbon age:1440±30BP. Because of their geographical location, both sites are incredibly located on one side of the hill slope, where they were suitable for habitat and plantation, especially tiny paddy fields and farms with sufficient water supply either small stream or well. The found rice, which now still grows uphill, probably called ‘Khao rai’ needs less water or no marsh. Comparative study of ethnographic “Atong” 1 of 12 sub-tribes of the “Garos” Tibeto-Burman in Meghalaya, India which originated slash-and-burnt socio-groups, have shown an interest in growing rice activity. According to their ritual ceremony for planting of paddy, other grain, and seeds takes place. There are many ritualistic offerings of rice such as (1) flattened rice by asking for permission to cultivate the land from the first harvested paddy in May. (2) After the harvesting in September or October, the 1st ceremony of the agricultural year is a thanksgiving ceremony to mark the end of a period of toil in the fields and harvesting of bumper crops, which is probably the most important festival of the Garos locally called “Maidan syla” meant to celebrate the after-harvested festival or burnt rice festival. Their 2nd ceremony is to revive the monsoon clouds. People throw cooked rice on the floor to symbolize hailstones. Noticing the rice, were probably the assemblage of “Khao San Dam” in many activities of these ceremonies, that is the archaeological evidence found in Khao Kurum and Napala Archaeological Sites. In the Southern part of Thailand, once the crops have already cultivated, people celebrate to welcome their outcrops most probably at the end of September to October and mark their end of plantation before the monsoon come. People prepare 4 main rice desserts put together with other necessity stuffs in the “hmrub” special large containers and donate to the ancestors through Buddhist ceremony. Though archaeological evidence shows that southern peninsular was where the migrants from the west especially India origins, who shared same habitat of hillslope, might brought their different traditions through both land trans-peninsular and sea routes then settled down inner western or eastern coast since prehistoric times. The beliefs in animism might belong to some other western migrants and with having “hmrub” is one of their unique cultural characteristic material and tradition remain. Once they settled down then converged to Buddhism, the ritual ceremony may be changed due to religion, but tradition remains the same today, that is, Bun Duean Sib on the 10th of the lunar month or September-October.


2021 ◽  
Author(s):  
Kelsie Long ◽  
Nicola Stern ◽  
Ian S. Williams ◽  
Rachel Wood ◽  
Katarina Sporcic ◽  
...  

Fish otoliths from the Willandra Lakes Region World Heritage Area (south-western New South Wales, Australia) have been analysed for oxygen isotopes and trace elements using in situ techniques, and dated by radiocarbon. The study focused on the lunettes of Lake Mungo, an overflow lake that only filled during flooding events and emptied by evaporation, and Lake Mulurulu, which was part of the running Willandra Creek system. Samples were collected from two different contexts: from hearths directly associated with human activity, and isolated surface finds. AMS radiocarbon dating constrains the human activity documented by five different hearths to a time span of less than 240 years around 19,350 cal. BP. These hearths were constructed in aeolian sediments with alternating clay and sand layers, indicative of fluctuating lake levels and occasional drying out. The geochemistry of the otoliths confirms this scenario, with shifts in Sr/Ca and Ba/Ca marking the entry of the fish into Lake Mungo several years before their death, and a subsequent increase in the δ18O by ∼4‰ indicating increasing evaporation of the lake. During sustained lake-full conditions there are considerably fewer traces of human presence. It seems that the evaporating Lake Mungo attracted people to harvest fish that might have become sluggish through oxygen starvation in an increasingly saline water body (easy prey hypothesis). In contrast, surface finds have a much wider range in radiocarbon age as a result of reworking, and do not necessarily indicate evaporative conditions, as shown by comparison with otoliths from upstream Lake Mulurulu.


2021 ◽  
Vol 66 (3) ◽  
pp. 255-263
Author(s):  
Adrian Patrut ◽  
◽  
Laszlo Rakosy ◽  
Roxana T. Patrut ◽  
Victor Bocos-Bintintan ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Kehlmaier ◽  
Luis F. López-Jurado ◽  
Nayra Hernández-Acosta ◽  
Antonio Mateo-Miras ◽  
Uwe Fritz

AbstractWe examined the type material of the extinct tortoise species Geochelone atlantica López-Jurado, Mateo and García-Márquez, 1998 from Sal Island, Cape Verde, using aDNA approaches and AMS radiocarbon dating. High-quality mitochondrial genomes obtained from the three type specimens support that all type material belongs to the same individual. In phylogenetic analyses using mitochondrial genomes of all species groups and genera of extant and some recently extinct tortoises, the type material clusters within the extant South American red-footed tortoise Chelonoidis carbonarius (Spix, 1824). Our radiocarbon date indicates that the tortoise from which the type series of G. atlantica originates was still alive during 1962 and 1974. These results provide firm evidence that the type material of G. atlantica does not belong to the Quaternary tortoise bones excavated on Sal Island in the 1930s, as originally thought. Thus, the extinct tortoise species remains unstudied and lacks a scientific name, and the name G. atlantica has to be relegated into the synonymy of C. carbonarius. The circumstances that led to this confusion currently cannot be disentangled.


2021 ◽  
pp. 92-100
Author(s):  
Katarina Botić

In this chapter the results of AMS radiocarbon dating of 26 charcoal samples from four sites are discussed. The primary aim was to explore the scope of (dis)continuity of temporally and functionally interconnected types of sites (settlement and iron production workshop). A Bayesian model was created based on the acquired data from excavated sites with three sequences in the model determined. The results show great accordance with the archaeologically based data, with some exceptions that are most probably a result of modelling strategy used. Contemporaneity of all four sites is mostly attested with a possible and very short temporal hiatus around AD 600. Occupation of workshop and residential areas at that time or slightly after may have been linked to the globally attested environmental change during the Bond 1 event when dry and cool conditions prevailed and which could have had an impact on bog iron formation processes.


2020 ◽  
Vol 46 ◽  
pp. 102-107
Author(s):  
Gianluca Quarta ◽  
Marisa D’Elia ◽  
Stefania Paparella ◽  
Antonio Serra ◽  
Lucio Calcagnile

Author(s):  
Zhiyi Tang ◽  
Chao Cao ◽  
Kunxian Tang ◽  
Hongshuai Qi ◽  
Yuanmin Sun ◽  
...  

Carbon and nitrogen contents and their isotopic components and AMS radiocarbon dating ages were measured for 57 coastal sediments from Weizhou Island to analyze the distribution of total inorganic carbon (TIC) and its carbon and oxygen isotopic components (δ13Ccarb and δ18Ocarb), total organic carbon (TOC) and total nitrogen (TN) contents and their stable isotopic components (δ13CTOC and δ15NTN) and environmental significance. The results showed that the oldest age of coastal sediments on Weizhou Island was 2750 cal. a BP, and the average TIC contents of A1, A2, B1, C1, and D1 in the intertidal zone were all greater than 5%, where δ13Ccarb and δ18Ocarb were enriched, while the TIC contents in A3, C2, and D2 of the supra-tidal zone were low, where δ13Ccarb and δ18Ocarb were depleted. Moreover, TIC decreased sharply from the estuary to upstream region in the C1-C2 section. The average C/N ratio was 7.02, and δ13CTOC and δ15NTN were between -14.96‰~-27.26‰ and -14.38‰~4.12‰, respectively. These measurements indicated that the TIC in coastal sediments mainly came from seawater. A1, A2, and B1 in the northern intertidal zone exhibited organic terrestrial signals because of C3 and C4 plant inputs, which proved that the important source of the northern coast of Weizhou Island came from the island. The lacustrine facies deposits were mainly distributed in the upper reaches of the river, the northern coastline was rapidly advancing toward the sea, and part of the southwestern coastal sediments rapidly accumulated to the shore under the influence of a storm surge. The relative sea level of the Weizhou Island area has continuously declined at a rate of approximately 2.07 mm/a, using beach rock as a marker, since the Holocene.


2020 ◽  
Vol 95 ◽  
pp. 142-153
Author(s):  
Eric C. Carson ◽  
John W. Attig ◽  
J. Elmo Rawling ◽  
Paul R. Hanson ◽  
Stefanie E. Dodge

AbstractWe used a combination of accelerator mass spectrometry (AMS) radiocarbon dating, optically stimulated luminescence (OSL) age estimates, and stratigraphic data from cores collected along the southern margin of the Green Bay Lobe (GBL) of the Laurentide Ice Sheet to provide new information on the timing and dynamics of the end of advance of the GBL and the dynamics of the ice sheet while very near its maximum position. Coring at multiple sites along the margin of the GBL indicate that ice had reached a stable position near its maximum extent by 24.7 ka; that ice advanced several kilometers to the Marine Isotope Stage 2 maximum position sometime shortly after 21.2 ka; and that ice remained at or beyond that position through the time interval represented by an OSL age estimate of 19.2 ± 3.2 ka. The timeline developed from these chronological data is internally consistent with, and further refines, AMS radiocarbon ages and OSL age estimates previously published for the southern margin of the GBL. It also provides new chronological control on the expansion of the GBL from its late Marine Isotope Stage (MIS) 3 extent to its MIS 2 maximum.


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