Search

Shalaii Cave is a closed system cave that contains old and active speleothems. It is located on the northeast limb of the Ashdagh anticline in Sangaw district in northeastern Iraq. The study presents new data on cave monitoring and the geochemistry of stalagmite archives relevant for the palaeoclimate of Iraq. An extensive cave monitoring program was conducted from June 2014 to March 2015, which included analyses of cave air temperature, relative humidity, cave air, dripwater, and modern calcite precipitates on glass slides. Physical parameters were measured monthly and continuously using data loggers and meteorological data; rainwater and dripwater samples were acquired for stable isotope analyses and hydrochemistry analysis. Stable isotopes of oxygen and carbon and absolute dating of U/Th series dating was used to determine palaeoclimate conditions. The microclimate of Shalaii Cave during the studied period (June-2014 to March-2015), the average temperature at the entrance point and inside the monitored cave was 17.05 °C and 20.18 °C respectively. The relative humidity at the entrance point and inside the cave was 66.6% and 100% respectively. Eleven samples of dripwater and five samples of rainwater were acquired for isotope analyses and thirteen samples of dripwater for hydrochemical analysis. From the environmental isotopes analysis (2H and 18O), all water samples fall between the global meteoric water line (GMWL) and Sangaw meteoric water line (SMWL). The precipitation samples plot well above the GMWL. The mechanism of recharge is direct recharge. Two stalagmites (SHC-01 and SHC-02) were sampled from the cave. The first sample (SHC-01) is dated from 1012 ± 42 to 494 ± 29 yr B.P. and the second sample (SHC-02) dates between 8025 ± 38 to 6977 ± 219 yr B.P. Oxygen and carbon isotope results show that there are two climate conditions for palaeoclimate reconstruction in the Sangaw district. Conditions were generally wetter and colder during 8025 ± 38 to 6977 ± 219 yr B.P. than current conditions; from 1012 ± 42 to 494 ± 29 yr B.P., drier and warmer conditions prevail, more similar to today.

The archaeological site of Saruq al-Hadid, Dubai, United Arab Emirates, presents a long sequence of persistent temporary human occupation on the northern edge of the Rub’ al-Khali desert. The site is located in active dune fields, and evidence for human activity is stratified within a deep sequence of natural dune deposits that reflect complex taphonomic processes of deposition, erosion and reworking. This study presents the results of a program of radiocarbon (14C) and thermoluminescence dating on deposits from Saruq al-Hadid, allied with studies of material remains, which are amalgamated with the results of earlier absolute dating studies provide a robust chronology for the use of the site from the Bronze Age to the Islamic period. The results of the dating program allow the various expressions of human activity at the site—ranging from subsistence activities such as hunting and herding, to multi-community ritual activities and large scale metallurgical extraction—to be better situated chronologically, and thus in relation to current debates regarding the development of late prehistoric and early historic societies in southeastern Arabia.

Many alluvial valleys in the American Southwest are entrenched within continuous arroyos, and stratigraphic evidence indicates that these fluvial systems experienced repeated periods of entrenchment and aggradation during the mid- to late-Holocene. Previous research suggests arroyo dynamics were regionally quasi-synchronous, implying that they were driven by allogenic forcing due to hydroclimatic fluctuations. However, several of these interpretations rely on records with limited age control and include distal correlations across the American Southwest. While hydroclimatic variability must exert some role, autogenic mechanisms related to catchment-specific geomorphic thresholds are hypothesized to partially control the timing of arroyo dynamics. If driven by autogenic processes, episodes of arroyo cutting and filling may not be regionally contemporaneous. Recent improvements in dating methods permit more detailed reconstructions of the timing and evolution of arroyo dynamics, allowing for a more nuanced assessment of these competing hypotheses. Here we present a uniquely large and focused chronostratigraphic data set from two alluvial reaches of Kanab Creek, located in the Grand Staircase region of southern Utah. Episodes of prehistoric arroyo cutting and filling are reconstructed from 27 sites through recognition of soils and buttressed unconformities in the arroyo-wall stratigraphy, and age control derived from 54 optically stimulated luminescence (OSL) ages and 50 radiocarbon ages. Our chronostratigraphic data set indicates five periods of channel aggradation occurred since ca. 6.0 ka, with each interrupted by an episode of arroyo entrenchment. Repeated aggradation to a similar channel elevation suggests attainment of a threshold profile, and comparison of the pre-entrenchment longitudinal profile with the modern arroyo channel demonstrates that changes between end-member entrenched and aggraded states are expressed in channel concavity and slope. We propose that arroyo dynamics are partially driven by sediment supply and the rate of channel aggradation, and that these systems must approach complete re-filling before they become sensitive to incision. Entrenchment itself appears to be associated with rapid transitions from pronounced decadal-scale aridity to pluvial (wetter) periods. Not all such hydroclimatic fluctuations are associated with arroyo entrenchment, which highlights the importance of threshold controls on the behavior of these systems. The collective period of “dynamic instability” characterized by epicycles of arroyo entrenchment and aggradation did not initiate until the mid-Holocene, when a climatic shift toward warmer and drier conditions likely increased fine-grained sediment supply to the fluvial system.

Existing structural models of the Himalayan fold-thrust belt in Kumaun, northwest India, are based on a tectono-stratigraphy that assigns different stratigraphy to the Ramgarh, Berinag, Askot, and Munsiari thrusts and treats the thrusts as separate structures. We reassess the tectono-stratigraphy of Kumaun, based on new and existing U-Pb zircon ages and whole-rock Nd isotopic values, and present a new structural model and deformation history through kinematic analysis using a balanced cross section. This study reveals that the rocks that currently crop out as the Ramgarh, Berinag, Askot, and Munsiari thrust sheets were part of the same, once laterally continuous stratigraphic unit, consisting of Lesser Himalayan Paleoproterozoic granitoids (ca. 1850 Ma) and metasedimentary rocks. These Paleoproterozoic rocks were shortened and duplexed into the Ramgarh-Munsiari thrust sheet and other Paleoproterozoic thrust sheets during Himalayan orogenesis. Our structural model contains a hinterland-dipping duplex that accommodates ∼541–575 km or 79%–80% of minimum shortening between the Main Frontal thrust and South Tibetan Detachment system. By adding in minimum shortening from the Tethyan Himalaya, we estimate a total minimum shortening of ∼674–751 km in the Himalayan fold-thrust belt. The Ramgarh-Munsiari thrust sheet and the Lesser Himalayan duplex are breached by erosion, separating the Paleoproterozoic Lesser Himalayan rocks of the Ramgarh-Munsiari thrust into the isolated, synclinal Almora, Askot, and Chiplakot klippen, where folding of the Ramgarh-Munsiari thrust sheet by the Lesser Himalayan duplex controls preservation of these klippen. The Ramgarh-Munsiari thrust carries the Paleoproterozoic Lesser Himalayan rocks ∼120 km southward from the footwall of the Main Central thrust and exposed them in the hanging wall of the Main Boundary thrust. Our kinematic model demonstrates that propagation of the thrust belt occurred from north to south with minor out-of-sequence thrusting and is consistent with a critical taper model for growth of the Himalayan thrust belt, following emplacement of midcrustal Greater Himalayan rocks. Our revised stratigraphy-based balanced cross section contains ∼120–200 km greater shortening than previously estimated through the Greater, Lesser, and Subhimalayan rocks.

Luristan Iron Mask Swords have been recovered mostly from illegal diggings in the 1920s. The about 90 known objects are characterized by a disk-shaped pommel on the top of the handle with two mounted bearded heads on two sides. According to the similarity in form and radiocarbon (14C) measurements on two swords from museum collections, an overall short production period was assumed around 1000 BC (Moorey 1991; Rehder 1991). Here we present the results of metallurgical analysis and 14C measurements for three newly acquired Luristan swords, which were donated to the Royal Museums of Art & History, Brussels. Metallurgical analysis indicates an iron production via the bloomary furnace technique. Analyzed samples show large slag inclusions (Fayalite, Wüstite, glass) within a mostly ferritic and pearlitic iron. The carbon contents varied between 0.2 wt% to around 0.8 wt%). 14C measurements on thermally extracted carbon give 14C ages between 2800 BP–3360 BP (calibrated ∼1745 BC–900 BC). The reliability of the 14C measurements are discussed with respect to external (contamination during handling) and intrinsic contamination (e.g. fossil carbon sources during manufacture).

For a long time, the Eneolithic of the Don forest-steppe remained one of the least studied epochs in the archaeological scheme of the region. However, since the late 1960s, sites with materials of the Eneolithic have been actively explored on the territory of the Voronezh and Lipetsk Regions. By the 1980s, researchers had a concept for the development of copper-stone age cultures within the system of the Mariupol cultural-historical region of the Dnieper-Don-Ural interfluve, which is still relevant today. The criteria for distinguishing the Eneolithic era in the steppe and forest-steppe spaces of the East European steppe and forest-steppe were substantiated. The idea of their synchronization with complexes of the Tripolye A period was designated. The early Eneolithic in the Don forest-steppe was marked by the appearance of a population with specific ceramics of Nizhnedonskaya culture. Questions of the chronology of the early Eneolithic were solved exclusively by methods of analogies with the materials of neighboring territories and synchronization with the local Neolithic complexes. The paper deals with the problems of chronology, periodization and synchronization of materials from the early Aeneolithic of the territory of the Don forest-steppe. The focus is on the absolute dating of the Nizhnedonskaya culture of the Mariupol cultural-historical region and its synchronization with the early Tripolye Culture. According to all the data available to date, the regions early Eneolithic can be dated from 5300 to 4250 BC.

The final phase of Late Pleistocene of Zagros Mountains has been introduced as Upper Paleolithic cultural material of Baradostian/Zagros Aurignacian, but differences between UP lithic industry in central and Southern Zagros has led to definition of another techno-complex in Southern Zagros named Rostamian. Another Late Paleolithic industry is Zarzian Epipaleolithic which is defined based on few absolute dating and excavated sites in the region. The nature of relationships and the territories of Late Paleolithic hunter-gatherers in the region is obscure. In this article an intermediate region between central and Southern Zagros with Late Paleolithic evidence is introduced based on surface survey of Izeh and Pion Plains in Southwestern Iran. Pion Plain in northwest of Izeh was surveyed in 2008 aiming at identifying the whole range of extant sites. 19 sites were dated to Late Paleolithic based on their surface lithic assemblages, and divided to minor and major sites regarding their surface material density and cultural deposits. Regarding different viewpoints about the homogeneity or variation of hominin groups during earlier phases of UP in the region, the lithic industry of Izeh and Pion lacks some of the most important typological elements of both UP and EP. Such a difference could be explained either as a chronological marker of the sites as belonging to later phase of Baradostian and earlier phase of Zarzian industry. On the other hand, it could be taken as an evidence of variation among techno-complexes in Late Paleolithic of Zagros Mountains. Chipped stone assemblages from the outer slopes of these caves and rock shelters present an industry from late UP and early EP which makes the Paleolithic sites with obvious cultural deposits inside them a proper candidate for excavations targeted at identification of the transitional processes from UP to EP in Zagros Mountains.

Strata of the Lower Cretaceous McMurray Formation in the McMurray Sub-Basin (MSB) of Alberta and Saskatchewan, Canada, comprise marginal marine, tidal-fluvial, fluvial and interfluve deposits. In the Firebag Tributary located in the northeastern portion of the sub-basin, a thick coal seam (up to >20 m) forms a semi-continuous bed at the top of the lowermost McMurray Fm deposits (herein referred to as Lower McMurray). In coastal plain settings, peat-forming mires are highly sensitive archives of base-level. We investigate the stratigraphic significance of coals in the Firebag Tributary by analyzing coal petrography (4 cores), coal geochemistry (2 cores), and coal distribution in ~4500 wells. Additionally, we record the first absolute age for the McMurray Fm through the dating of an ash layer within the coal seam. The petrographic character and distribution of coals in the northeastern part of the MSB suggest a complex history of base-level rise at the end of Lower McMurray deposition. Wetting-upward character coal seams record initial transgression of the Boreal Sea during a 4th order sea level rise (Milankovitch-scale) within lowstand to early transgressive systems tract conditions. Sea-level rise during Lower McMurray times was estimated based on temperate climate peat formation rates, as well as peat-to-coal compaction factors, and probably occurred on a scale of 0.5–3 mm a−1. Seam-internal wetting-upward cycles suggest that base-level rise was punctuated. Locally, compound and drying-upward character coals represent zones of high accommodation, wherein peat accumulation in mires was influenced by phases of syn-depositional subsidence and karst collapse. The thickest coals in the study area form an arc on a coastal plain as the Boreal Sea inundated east- to southeastward into the Firebag Tributary. Within the arc of thick coals, a north-south decrease in coal thickness is interpreted to reflect the general southward inundation of the Boreal Sea across the MSB. Exceptionally thick coals (>10 m) likely formed where basement processes (e.g., karsting in Devonian carbonates) provided preferential groundwater pathways. Chemical abrasion thermal ionization mass spectrometry dating of 5 sharply faceted zircons recovered from an ash bed within the coal provides the first absolute age (121.39 ± 0.2 Ma – Aptian) to the southward transgression of the Boreal Sea. We hypothesize that initial inundation of the MSB was related to tectonic activity in the Canadian Cordillera and the onset of magmatic flow in the western Coast Plutonic Complex.

Giordano Bruno is a lunar farside Copernican-age crater. The relatively few superposed impact craters on its floor and ejecta blanket and extensive bright rays indicate its youth. High-resolution Lunar Reconnaissance Orbiter Camera images reveal that the frequency and the characteristics of the cumulative size-frequency distributions of the small-diameter impact craters and their morphology vary across the clastic ejecta and impact melt covered surfaces. Crater frequencies (N(10) defined as ≥10 m km−2) vary by a factor of 10 s–100 s (N(10) 2–700) across the ejecta blanket, and between the ejecta and the melt deposits. Numerous craters on the ejecta blanket are degraded and buried by debris and impact melt, indicating that these partially buried craters formed during the deposition of the ejecta and prior to or during the emplacement of the impact melt. From geologic relations and crater statistics we conclude that a significant fraction of the craters observed on the ejecta blanket and the melt were formed during the cratering process itself and represent "self-secondaries." Further, we conclude that these craters do not represent an extra-lunar primary impact production population. Self-secondary craters are formed by material launched into near-vertical trajectories and having velocities such that their flight time is sufficiently long that the bulk of the clastic ejecta and impact melt are deposited before that material impacts the surface. The presence of a significant number of self-secondary craters on the ejecta makes the determination of relative and absolute age dates problematic. Crater counts would indicate an inappropriately old age. Using data for craters on the melt surfaces and for small-diameter bright ejecta craters, an absolute model age of 1 Ma is estimated. This age is considerably younger than that estimated by other studies and probably represents a maximum age.

The Ordovician-Cambrian aquifer system in the northern Baltic Artesian Basin contains glacial palaeogroundwater that originates from the Scandinavian Ice Sheet that covered the study area in the Pleistocene. Previously, no absolute dating of this palaeogroundwater has been attempted. In this multi-tracer study, we use 3H, 14C, 4He and stable isotopes of water to constrain the age distribution of groundwater. We apply the geochemical modelling approach developed by van der Kemp et al. (2000) and Blaser et al. (2010) to calculate the theoretical composition of recharge waters in three hypothetical conditions: modern, glacial and interstadial for 14C model age calculations. In the second phase of the geochemical modelling, the calculated recharge water compositions are used to calculate the 14C model ages using a series of inverse models developed with NETPATH. The calculated 14C model ages show that the groundwater in the aquifer system originates from three different climatic periods: (1) the post-glacial period; (2) the Late Glacial Maximum (LGM) and (3) the pre-LGM period. A larger pre-LGM component seems to be present in the southern and north-eastern parts of the aquifer system where the radiogenic 4He concentrations are higher (from ∼3.0·10−5 to 5.5·10−4 cc·g−1) and the stable isotopic composition of water is heavier (δ18O from −13.5‰ to −17.3‰). Glacial palaeogroundwater from the north-western part of the aquifer system is younger and has 14C model ages that coincide with the end of the LGM period. It is also characterized by lower radiogenic 4He concentrations (∼2.0·10−5 cc·g−1) and lighter stable isotopic composition (δ18O from −17.7 to −22.4‰). Relations between radiogenic 4He and 14C model ages and between radiogenic 4He and Cl− concentration show that groundwater in the aquifer system does not have a single well-defined age. Rather, the groundwater age distribution has been influenced by mixing between waters originating from end-members with strongly differing ages. Overall the results suggest, that in the shallower northern part of the aquifer system, significant changes in groundwater composition can be brought about by glacial meltwater intrusion during a single glaciation. However, multiple cycles of glacial advance and retreat are needed to transport glacial meltwater to the deeper parts of the aquifer system.

The Luonan Basin is a key region of early human settlement in Central China with more than 300 discovered Paleolithic sites. Artifact layer 1 of the Liuwan site was dated to approximately 0.6 million years (Ma) based on correlation with the well-dated loess–paleosol sequence of the central Chinese Loess Plateau. This study reassessed the age of the Liuwan artifact layer via an absolute dating method, namely, 26Al/10Be burial dating. We determined the burial age of artifact layer 1, which was most likely at least 0.60 ± 0.12 Ma (1ơ), using three simple burial ages. The new burial age confirmed the previous estimated age and provided a considerably accurate age range. Therefore, we suggest the use of the 26Al/10Be burial dating method in thin loess-covered Paleolithic sites around the Qinling Mountain Range is helpful to understand the early human behavior.

International audience; Absolute dating is needed to check and calibrate the relative Martian chronology presently available from meteoritic crater counting. For such purpose, a new analytical system (KArMars) has been developed to experiment the feasibility of in-situ K-Ar for future landing planetary missions. It consists in a laser ablation-based system built to vaporize a reproducible volume of rock. Potassium content is measured by laser-induced breakdown spectroscopy (LIBS) and argon by Quadrupole Mass Spectrometry (QMS). Instrument calibration, and checking of the reliability of the measurements for Martian analyses, requires terrestrial analogues. For such purpose, total chemistry, electron microprobe analyses, flame absorption spectrometry and mass spectrometry have been performed in order to qualify the stoichiometry, the mineralogy, the K concentration and the Ar isotopic composition from a collection of old terrestrial rocks. These new analyses coupled with published data allowed us to select mineral phases (e.g. feldspars, phlogopite, muscovite, amphibole) showing a large range of K content (0.3–8.5 wt%). All these mineral phases display a K-Ar age older than 300 Ma. Hence, the content of radiogenic Ar atoms per gram is within the range of Martian samples (on the order of 1 Ga for 0.4 wt% of K). We have shown that the ablated mass can be precisely estimated by measurement of Ar extracted from a similar mineral of known amount of radiogenic Ar content per gram. Then, it has been possible to derive a well-defined relationship between the ablation time and the sample mass extracted from UV-laser ablations for different minerals. Using an isochron approach from multiple ablations of several samples analyzed as unknowns, we have shown that KArMars can be successfully used for dating samples with different compositions, and with ages varying by an order of magnitude from 0.3 to 3 Ga. In-situ K-Ar ages obtained here for plagioclase and amphibole crystals display uncertainties as low as about 10%, and with accuracy, i.e. difference with the reference age, of only 10%. Such results further support in-situ K-Ar dating based on QMS and LIBS instruments as a reliable approach to be implemented onboard Martian rovers. In case a return mission is made possible, KArMars can also be a valuable tool to select the most relevant samples for return and ensure onsite which samples are representative of most of the surface at a given landing site.

In absence of organic remains suitable for radiocarbon dating, archaeomagnetic dating can contribute significantly to the better understanding and rescue of our past and cultural heritage. Nowadays, in the archaeological research is fundamental to obtain as much information as possible, including precise dates of the archaeological sites; indeed, the rapid expansion of urban areas implies the destruction of archaeological structures, causing the loss of knowledge about our past. In this effort, we report an archaeomagnetic and rock-magnetic study on burnt archaeological samples from two kilns discovered at the monastery of San Pelayo del Cerrato (Cevico Navero, Palencia, Spain). This was a rescue excavation where arose the possibility of studying archaeomagnetically two ovens for the manufacture of tiles and bells before their destruction due to the restoration works of the monastery. Given their suitable conditions and the lack of independent absolute dating, the aim of the study is to archaeomagnetically date their last use. The main magnetic carrier is pseudo-single domain (PSD) Ti-poor titanomagnetite, indicating that the magnetic signal is stable. The comparison of mean full-vector values (mean direction and absolute archaeointensity determinations) with the SCHA.DIF.14k model determined their last use between 1301–1391 CE (bells´ kiln) and 1295–1404 CE (tiles´ kiln) at 95% confidence level, respectively. These dates agree well with the archaeological evidence indicating that the last use of both kilns occurred almost simultaneously or closely confined in time (14th century AD). The dating resolution obtained is comparable to the radiocarbon with the benefit that archaeomagnetism dates the last use (abandonment) of the structures and no material associated to it which might be slightly younger.

Prehistoric population decline is often associated with social collapse, migration and environmental change. Many scholars have assumed that the abandonment of the fortified tell sites of the Great Hungarian Plain c. 1500–1450 BC led to significant regional depopulation. The authors investigate the veracity of this assumption by dating graves from Bekes 103—a recently excavated Bronze Age cemetery in eastern Hungary. Using decorative motifs and radiocarbon dates to measure changing ceramic styles over more than 1300 years, they consider the implications for non-tell sites known only through surface survey. The results suggest that, even though people abandoned tell sites, regional populations were maintained.

Gordion has long served as an archaeological type site for Iron Age central Anatolia and provided pioneering radiocarbon (14C) determinations as reported in the first issue ofRadiocarbon(1959). Absolute dating of key events at Gordion continue to reshape our understanding of regional development and interaction in the Iron Age, with a major conflagration in the late 9th BCE century at this site the most recent focus of attention (DeVries et al. 2003). Here we present the latest series of14C determinations for Gordion from Late Bronze Age and Early Iron Age contexts. Fifteen absolute dates provide a critical new framework for establishing the timing and tempo of cultural transformation from the collapse of the Hittite Empire through to the subsequent formation of the Phrygian polity that dominated central Anatolia from the 9th to the 7th c. BCE. This chronometric revision transforms our perspective on the LBA/EIA transition at this site: from disengagement from Hittite hegemony in the 12th c. BCE, to the precocious emergence of the Phrygian capital in the early 9th c. BCE.

Northwest Africa (NWA) 6704/6693 are medium- to coarse-grained achondrites with unique petrologic and geochemical traits that are distinct from the currently established meteorite groups. Here, we report on the extinct 26Al-26Mg and 53Mn-53Cr systems to establish fine-scale chronology of its formation and Cr and Ti isotopic anomalies to constrain the composition of the source reservoir of NWA 6704/6693. Excesses in the neutron-rich 54Cr and 50Ti isotopes, due to nucleosynthetic anomalies, separate NWA 6704/6693 from the vast majority of established achondrites and instead resemble the excesses seen among the carbonaceous chondrites; specifically, the CR-type chondrites. The excesses in these isotopes indicate a common feeding zone during accretion in the protoplanetary disk between the source of NWA 6704/6693 and that of the carbonaceous chondrites. The 26Al-26Mg data for pyroxene and plagioclase from NWA 6704 yield a (26Al/27Al)0 = (3.15 ± 0.38)×10−7 (MSWD = 0.49) and an initial δ26Mg∗ = −0.004 ± 0.005 at the time of isotopic closure. This initial (26Al/27Al)0 translates to an absolute age of 4563.14 ± 0.38 Ma, relative to the D’Orbigny angrite. However, given the potential heterogeneity of 26Al, the D’Orbigny angrite might not be a good age anchor for the purpose of calculating 26Al-26Mg ages. The 26Al-26Mg age relative to another carbonaceous achondrite, NWA 2976, is 4562.66 ± 0.60 Ma. The 53Mn-53Cr systematics of NWA 6704/6693 indicate a (53Mn/55Mn)0 of (2.59 ± 0.34) × 10−6 (MSWD = 1.2) with an evolved initial e53Cr of +0.14 ± 0.03. The (53Mn/55Mn)0 yields an 53Mn-53Cr age of 4562.17 ± 0.76 Ma relative to the D’Orbigny angrite. Concordant ages determined using the short-lived 26Al-26Mg and 53Mn-53Cr systems and extant 207Pb-206Pb system (4562.60 ± 0.30 Ma for NWA 6704/6693; Amelin et al., 2019) indicate rapid cooling and nearly contemporaneous closing of multiple isotope systems. The ancient crystallization ages and positive 54Cr and 50Ti anomalies of NWA 6704/6693 indicate widespread melting and differentiation processes occurring in both non-carbonaceous (NC) and carbonaceous chondrite (CC) regions of the protoplanetary disk. Additionally, we report the Cr and Ti isotopic composition for a petrologic range of CR-type materials (CR2, CR6, and achondrites). The additional Cr and Ti isotopic data for these CR-type materials indicates a range in isotopic composition not previously observed based on CR2 chondrites alone.

Impact cratering on the Moon and the associated size-frequency distribution of impact craters has been used to determine the ages of the lunar and planetary surfaces across the Solar System1,2. Radiometric age-dating of lunar samples plays a critical role in this endeavour3. However, due to paucity of pristine samples and challenges associated with interpreting the isotopic data, the lunar crater-chronology function remains poorly constrained above 3.9 billion years (Gyr), and with only a handful of craters with ages < 1 Gyr4. Additionally, much of the timescale for the earliest lunar cratering history hinges on the formation age of the Serenitatis basin – a topic of vigorous debate5–9. Here we report on U-Pb isotopic data and nanoscale observation of phosphate minerals within shocked lunar norites from the Apollo 17 Station 8 boulder that record a discordant array between an older event at ~4.2 Gyr, and a younger disturbance at ~0.5 Gyr. Based on available lunar cratering records and new impact modelling, we propose that the Station 8 boulder was likely ejected when the Dawes crater, located on the southeastern rim of the Serenitatis basin, formed ~0.5 Gyr ago10. Formation of the Dawes crater excavated the highly-shocked noritic basement, which had also recorded a ~4.2 Gyr impact event – an age we ascribe to the formation of the Serenitatis basin. Implications of ancient (pre-Nectarian), ~4.2 Gyr age of the Serenitatis basin are far-reaching, challenging the paradigm of the Late Heavy Bombardment and setting important constraints on the older segment of the crater size-frequency function.

International audience; Casas Grandes is a prehistoric culture area located between Chihuahua, northern Mexico, and New Mexico, southwest of United States of America. It had an intense occupation with large buildings during the ceramic period, from 0 to 1450 CE, developing very particular painted potteries. In this study, magnetic properties and archaeointensity experiments were investigated on two special ceramic types called Mimbres and polychrome Ramos. They come from four archaeological sites from Casas Grandes region in northern Chihuahua: Paquimé, Villa Ahumada, Galeana, and Samalayuca. Archaeological timing and typology assign Mimbres and Ramos to an age period between 900 and 1450 CE, but no absolute ages are available. Magnetic properties show that Mimbres and Ramos have different magnetomineralogical properties, suggesting that pottery making materials were different. Mean archaeointensity results were obtained from nine different pottery sherds, five from Mimbres and four from Ramos polychrome, for a total of 35 specimens. Intensity value range from 49 to 59 µT for Mimbres type and from 41 to 49 µT for Ramos type. Archaeomagnetic dating was performed using the SHAWQ2k global model and the Maghoub regional paleosecular variation curve. Archaeomagnetic dating give an absolute age range of 960–1100 CE for Mimbres type, and of 1300–1600 CE for Ramos samples, confirming that both ceramic types were manufactured at different times. These results highlight the potential of archaeomagnetism to precise the chronological framework of Casas Grandes culture.

The dating of ink in questioned documents remains a significant challenge in forensic investigations in Vietnam and other countries. Many forensic examination methods have been usually applied to ensure the highest accuracy of the assessment results while maintaining high environment awareness. In this study, paper characteristics were physically tested to confirm source similarity, and the relative ink dating was established by high-performance thin-layer chromatography (HPTLC). Absolute ink dating by solvent and dye identification was performed by Raman spectrometry—a green technique, using a time-dependent degradation model for crystal violet and the comparison between 2-phenoxyethanol peak intensities. We found that the relative dating of the questioned document was 14 ± 3 months lesser than that of the reference samples, i.e., the absolute age of the questioned samples was estimated to be 24 ± 3 months. The combination of the conventional HPTLC method with the dynamic crystal violet degradation Raman model provides promising results for relative and absolute ink dating of ballpoint pens, which can be applied for documents written 1–15 years prior to the time of examination. The combination of the abovementioned methods demonstrated an acceptable error margin, affording highly practical applications in modern forensic science.

summary Pollen analysis and 14C dating of 5.5m of organic-rich soil and fluviatile deposits from Newall Creek (altitude 140 m) indicate that temperate rainforest (0-11 K yr B.P.) was preceded by grassland-herbland (11 to 21 K yr B.P.), and then by open grassy Eucalyptus woodland. Comparison with a lake-swamp site at Tullabardine Dam showed that the main vegetation changes were comparable making allowance for some spatial variations in the taxa represented and the lower quantity of pollen in the fluviatile deposits. The inferred sequence of climatic change was from a cool moist interstadial through a cold last glacial maximum to a warm moist Holocene environment, a sequence also indicated at Tullabardine.

SUMMARY The results of investigating a series of 11 pollen and stratigraphic profiles in peats along a 350 m stream section are described. Each profile has a small pollen catchment overlapping little with its neighbour's and the diagrams therefore show fine spatial resolution of the vegetational history. Fine temporal resolution is provided by 1 cm, or for certain sections 1 mm, interval samples. There is evidence that during the Mesolithic distinct patches of the local forest vegetation, of the order of tens rather than hundreds of metres in diameter, were managed by burning and the regular lopping of branches, for periods of up to a few hundred years each. Peat inception is thought to have occurred as early as the 9th millenium BP in some parts of the stream and up to 3000 yr later in others. Lopping and burning was the immediate cause at most sites within the channel of the gill, although fine–scale topographic and geological variation affected the timing. The developing peat was bordered by an alder carr in the lower and middle reaches of the stream. Radiocarbon dating of the mid–Flandrian Ulmus decline shows it to be asynchronous. It was caused by a combination of factors including disease and the affect the mesolithic management practices had had on the soil earlier in the Flandrian.

SUMMARY Recent investigations at Camp Fauld in Buchan, Scotland have yielded two peat deposits of pre-Late Devensian age. Percentage pollen diagrams are presented. One peat is radiocarbon-dated to 34–39 ka DP, which prompts correlation with the Hengelo-Denekamp sequence of NW continental Europe, but the pollen evidence, revealing the presence of a birch-pine woodland, suggests an earlier stage. The second peat deposit records an open shrub-tundra in which Bruckenthalia spiculifolia is present. The peat yielded a radiocarbon date of 40–51 ka BP, but is suspected of having been contaminated by younger carbon. That suspicion and the presence of Bruckenthalia suggest that a correlation, based on the radiocarbon date, with the Glinde interstadial, identified in NW Germany, would be incorrect. Correlation with other Scottish pre-Late Devensian sites has proved to be difficult.

Two radioisotopic dating methods are applied to Quaternary fluviolacustrine detritus deposits in the commune of Morsott in northeastern Algeria. The studied profile shows an open and contaminated environment. In the case of the shells of molluscs, the choice of identical samples for both the dating methods is wise. Obtained results are different; thus, positioning the chronology of the Quaternary sequence is difficult. The uranium–thorium (U–Th) series technique gives a younger age than that provided by radiocarbon (14C) in Holocene. For carbonates at the base of the study sequence, the age difference is 278,154 ka BP. In the lowermost level of limestone crusts in the last Pleistocene, 14C gives a younger age than that provided by the U–Th series technique, rendering the chronological order of the levels inconsistent. Despite the corrections of the U–Th series technique and the age calibrations of 14C, this method is recommended for open systems (environments). Contamination related to either post depositional parameters or sample preparation techniques is certain in this type of open environments. In open environment applications, the reliability of the U–Th series or 14C technique changes from the upper to the bottom of the studied series as the function of various external parameters. For this reason, including other techniques is necessary to confirm and understand the chronology of Quaternary.

Radiocarbon dating by AMS (Accelerator Mass Spectrometry) is a well-established absolute dating technique widely used in different areas of research for the analysis of a wide range of organic materials. Precision levels of the order of 0.2–0.3% in the measured age are nowadays achieved while several international intercomparison exercises have shown the high degree of reproducibility of the results. This paper discusses the applications of 14C dating related to the analysis of samples up-taking carbon from marine carbon pools such as the sea and the oceans. For this kind of samples relevant methodological issues have to be properly addressed in order to correctly interpret 14C data and then obtain reliable chronological frameworks. These issues are mainly related to the so-called “marine reservoirs effects” which make radiocarbon ages obtained on marine organisms apparently older than coeval organisms fixing carbon directly from the atmosphere. We present the strategies used to correct for these effects also referring to the last internationally accepted and recently released calibration curve. Applications will be also reviewed discussing case studies such as the analysis of marine biogenic speleothems and for applications in sea level studies.

Archaeological science, also known as Archaeometry, is related to the application of scientific techniques, physical and chemical, for the analysis of archaeological materials, with the main goal of dating them. Dating methods used not only for archeology, are two, relative and absolute dating. Relative dating is the science of determining the relative order of past events. Before the discovery of radiometric dating in the early 20th century has been used in geology, to correlate rock or superficial deposits, fossils and lithologies and determine the sequential order in which a series of events occurred. Absolute dating, on the other hand, is usually based on the physical, chemical, and life properties of the materials of artifacts, buildings, or other items that have been modified by humans and by historical associations with materials with known dates i.e. coins and written history. Techniques include tree rings in timbers, radiocarbon dating of wood or bones, and trapped-charge dating methods such as thermoluminescence dating of glazed ceramics., Dating Methods in Archaeology: Absolute and Relative dating, {"references":["Καλογερόπουλος, Κ. 2021. \"Μέθοδοι χρονολόγησης στην Αρχαιολογία\". Archive 17(1) (6 Μαρ): 39-50 DOI: 10.5281/zenodo.4587318"]}

In the search for very old ice, finding the age of the ice is a key parameter necessary for its interpretation. Most ice core dating method are based on chronological markers that require the ice to be in stratigraphic order. However, the oldest ice is likely to be found at the bottom of ice sheets, where the stratigraphy is disturbed, or in ablation areas, where the classical methods cannot be used. Absolute dating techniques have recently been developed to provide new constraints on the age of old ice, but their development in the context of ice cores is limited by the large sample size required. Here, we discuss the analytical performances of a new technique for 40Ar dating, which allows us to provide a reliable age with 80g of ice rather than 800g, as previously published. We present an application to the dating of the bottom of the TALDICE and Dome C ice cores. This method represents a significant advance for its application to the very precious ice at the bottom of ice cores.

During its late-stage evolution, the European Alpine orogen witnessed a northwest-directed propagation of its deformation front along an evaporitic basal decollement into the foreland. This ...

The dating of past landslide events is one of the most crucial aspects of landslide research, leading to a better understanding of past landslide activity. Landslides can be extremely dangerous natural hazards, and thus, solving the relationships between their activity and climate variations is of high importance. For these purposes, data about past landslide activity are fundamental for such analyses. Various methods of landslide absolute dating exist, but the most precise approach that dates back several centuries is based on tree-ring analysis (dendrogeomorphology). Landslide movements can affect the growth of trees in response to specific growth disturbances. Although dendrogeomorphic methods are successfully used for dating other geomorphic processes, their use in landslide research is actually the most frequent. Dendrogeomorphic research on landslides is strongly influenced by general approaches of landslide signal extraction from tree-ring series of disturbed trees and by the type of landslide (varying by morphology, material and mechanism of movement). This study provides an overview of basic aspects of dendrogeomorphic research on landslides, and more specifically, it reviews basic tree-ring-based approaches of landslide dating. Presented review focuses on various landslide types and their effect on dendrogeomorphic dating. This review is built from the extensive database of all accessible dendrogeomorphic studies of landslides from 1893 to 2020. Moreover, recommendations for specific sampling and approach choice in individual landslide types are presented. Finally, limits of tree-ring-based approaches are presented, including provided proposals for further research.

The nature and timing of the shift from the Late Middle Paleolithic (LMP) to the Early Upper Paleolithic (EUP) varied geographically, temporally, and substantively across the Near East and Eurasia; however, the result of this process was the archaeological disappearance of Middle Paleolithic technologies across the length and breadth of their geographic distribution. Ortvale Klde rockshelter (Republic of Georgia) contains the most detailed LMP-EUP archaeological sequence in the Caucasus, an environmentally and topographically diverse region situated between southwest Asia and Europe. Tephrochronological investigations at the site reveal volcanic ash (tephra) from various volcanic sources and provide a tephrostratigraphy for the site that will facilitate future correlations in the region. We correlate one of the cryptotephra layers to the large, caldera-forming Nemrut Formation eruption (30,000 years ago) from Nemrut volcano in Turkey. We integrate this tephrochronological constraint with new radiocarbon dates and published ages in an OxCal Bayesian age model to produce a revised chronology for the site. This model increases the ages for the end of the LMP (∼47.5–44.2 ka cal BP) and appearance of the EUP (∼46.7–43.6 ka cal BP) at Ortvale Klde, which are earlier than those currently reported for other sites in the Caucasus but similar to estimates for specific sites in southwest Asia and eastern Europe. These data, coupled with archaeological, stratigraphic, and taphonomic observations, suggest that at Ortvale Klde, (1) the appearance of EUP technologies of bone and stone has no technological roots in the preceding LMP, (2) a LMP population vacuum likely preceded the appearance of these EUP technologies, and (3) the systematic combination of tephra correlations and absolute dating chronologies promises to substantially improve our inter-regional understanding of this critical time interval of human evolution and the potential interconnectedness of hominins at different sites.

The base of the Priabonian Stage is one of two stage boundaries in the Paleogene that remains to be formalized. The Alano section (NE Italy) was elected by consensus as a suitable candidate for the base of the Priabonian during the Priabonian Working Group meeting held in Alano di Piave in June 2012. Further detailed research on the section is now followed by a formal proposal, which identifies the base of a prominent crystal tuff layer, the Tiziano bed, at meter 63.57 of the Alano section, as a suitable candidate for the Priabonian Stage. The choice of the Tiziano bed is appropriate from the historical point of view and several bio-magnetostratigraphic events are available to approximate this chronostratigraphic boundary and guarantee a high degree of correlatability over wide geographic areas. Events which approximate the base of the Priabonian Stage in the Alano section are the successive extinction of large acarininids and Morozovelloides (planktonic foraminifera), the Base of common and continuous Cribrocentrum erbae and the Top of Chiasmolithus grandis (nannofossils), as well as the Base of Subchron C17n.2n and the Base of Chron C17n (magnetostratigraphy). Cyclostratigraphic analysis of the Bartonian-Priabonian transition of the Alano section as well as radioisotopic data of the Tiziano tuff layer provide an absolute age (37.710 – 37.762 Ma, respectively) of this bed and, consequently, of the base of the Priabonian Stage.

The research of Neolithic pile-dwellings and wetland sites in the Northwestern pre-alpine forelands reveals a settlement pattern that is characterized by high internal dynamics. Absolute dating facilitated by dendrochronology allows for the reconstruction of mean house ages of a few years only, and the settlement duration is not much longer in many cases. Based on the good archaeobiological database and exact dating due to dendrochronology, various hypotheses on land-use strategies have been put forth that partly try to explain this phenomenon. In this article, I present an agent-based simulation model (ABM) named WELASSIMO (Wetland Settlement Simulator). Its aims are to test whether any of the existing hypotheses would justify a settlement relocation for systemic reasons. Furthermore, a new model integrating elements of the existing ones is presented, which arguably provides better explanations for the observed patterns. It is shown that for relatively small communities, the non-finite resources related to their land-use most likely have not been limiting and thus did not determine the observed settlement pattern. Instead, it is argued that the continuous duration of moderate land-use did increase the economic value of the evolving landscape. Thus it is proposed, that relocations happened mostly inside of the relevant landscapes as a combined consequence of the poor durability of wooden houses in waterlogged environs and the spatiotemporal variability of suitable timber. This does not exclude the possibility, that also cultural/social reasons may have been involved.

Geochronology is the study of time as it relates to the geological events of Earth history. Relative age dating places geological materials such as fossils and rock strata or geological events such as magmatism, erosion/sedimentation, and faulting in sequential order. Absolute age dating determines the amount of time that has passed since a given geological event, and the quantitative measurement of absolute ages over the past century has been essential to our present understanding of planetary evolution and the geologic processes that formed the Earth. This article provides an introduction to, and overview of, the modern field of geochronology that uses measured time both as a fundamental tool and as a framework for understanding the workings of our planet and the solar system. The dating methods introduced here are discussed in detail in the separate articles of the geochronology section of this volume.

Specialized and systematic underwater fieldwork at the prehistoric site of Ploča Mičov Grad at Gradište (North Macedonia) on the eastern shore of Lake Ohrid was undertaken in 2018 and 2019. It has substantiated the archeological site's outstanding preservation condition, and furthermore proven the numerous construction timbers’ suitability for dendrochronological analysis. Dendrochronological analysis on archaeological timbers was applied, combined with radiocarbon dating. Bayesian radiocarbon modeling allowed to ‘wiggle match’ the dendrochronological mean curves, i.e. allowed the precise chronological anchoring of ‘floating’ tree-ring sequences. Furthermore, radiocarbon dates of plant remains from the site's main archaeological layer are statistically evaluated. Based on the new findings, the strikingly high density of wooden piles at the site can be attributed to several construction phases of Neolithic (middle of 5th millennium BC) and Bronze Age (2nd millennium BC: 1800, 1400 and 1300 BCE) settlements. Intense settlement activity is furthermore evidenced by a cultural layer of mainly organic material under the lakebed up to 1.7 m in thickness, which accumulated during the Neolithic occupation of the bay in the middle of the 5th millennium BC. The presented research enables precise absolute dating of a series of settlement phases at Ploča Mičov Grad from the Neolithic and the Bronze Age, and hence provides important reference points for an absolute chronological framework for the prehistory of the southwestern Balkans. The investigations underline the potential of future research on waterlogged prehistoric settlements in the region., Journal of Archaeological Science: Reports, 38

Loess deposits intercalated by paleosols are detailed terrestrial archives of Quaternary climate variability providing information on the global dust cycle and landscape dynamics. Their paleoclimatic significance is often explored by quantifying their mineral magnetic properties due to their sensitivity to local/regional hydroclimate variability. Detailed chronological assessment of such regional proxy records around the climatic transitions allow a better understanding of how regional records react to major global climatic transitions such as the Pleistocene-Holocene climatic transition. Logs of high-resolution magnetic susceptibility and its frequency dependence were used as paleoclimatic proxies to define the environmental transition from the last glacial loess to the current interglacial soil as reflected in nine loess-paleosol sequences across the northern hemisphere, from the Chinese Loess Plateau, the southeastern European loess belt and the central Great Plains, USA. The onset of increase in magnetic susceptibility above typical loess values was used to assess the onset of, and developments during, the Pleistocene-Holocene climatic transition. High-resolution luminescence dating was applied on multiple grain-sizes (4–11 μm, 63–90 μm, 90–125 μm) of quartz extracts from the same sample in order to investigate the timing of Pleistocene-Holocene climatic transition in the investigated sites. The magnetic susceptibility signal shows a smooth and gradual increase for the majority of the sites from the typical low loess values to the interglacial ones. The initiation of this increase, interpreted as recording the initiation of the Pleistocene-Holocene climatic transition at each site, was dated to 14–17.5 ka or even earlier. Our chronological results highlight the need of combining paleoclimatic proxies (magnetic susceptibility) with absolute dating when investigating the Pleistocene-Holocene climatic transition as reflected by the evolution of this proxy in order to avoid chronostratigraphic misinterpretations in loess-paleosol records caused by simple pattern correlation. The detailed luminescence chronologies evidence the continuity of eolian mineral dust accumulation regardless of glacial or interglacial global climatic regimes. Coupled with magnetic susceptibility records this indicates that dust sedimentation and pedogenesis act simultaneously and result in a non-negligible accretional component in the formation of Holocene soils in loess regions across the Northern Hemisphere. The luminescence ages allowed the modeling of accumulation rates for the Holocene soil which are similar for European, Chinese and U.S.A. loess sites investigated and vary from 2 cm ka−1 to 9 cm ka−1. While accretional pedogenesis has often been implicitly or explicitly assumed in paleoclimatic interpretation of loess-paleosol sequences, especially in the Chinese Loess Plateau, our luminescence data add direct evidence for ongoing sedimentation as interglacial soils formed.

The grave mound 8 the in city of Cimişlia, Republic Moldova is located on the first terrace of the Cogâlnic River. Burials from the Eneolithic to the Sarmatian period, a ditch and cult structure have been discovered in it. The relative and absolute dating of the burial series of the Eneolithic — Early Bronze Age is being clarified. В кургані 8 в місті Чимішлія, Республіка Модова, досліджені десять поховань від енеоліту до сарматського періоду, рів та культова споруда. Курган розташований на першій терасі маленької р. Когильник. Висота кургану дорівнює 0,8 м, діаметр 36 м, він інтенсивно розорювався, входив до групи з шести курганів. На підставі аналізу стратиграфії та серії радіовуглецевих дат встановлюється відносна та абсолютна хронологія поховань доби енеоліту — раннього бронзового віку. Перша група поховань — пізньоенеолітичного часу. Найдавніше поховання 3 датується між 3800 та 3647 рр. до н. е. На основі радіовуглецевих даних не можна виявити часової різниці між цим похованням та культовою спорудою. Цей факт у поєднанні з безпосередньою просторовою близькістю двох комплексів свідчить про те, що вони існували одночасно. Подібні споруди відомі в регіоні на північний захід від Чорного моря, в басейні Дніпра та річці Молочній. Друга група поховань — животилівської культури. Їх калібровані дати майже однакові — 3356 і 3104 cal. BC — і добре вписуються в хронологічну рамку трипільської фази С2 та фінального енеоліту в степовій зоні на північ від Чорного моря. Третя група поховань — ямної культури. Діапазон дат для поховання 1 значно давніший, ніж поховання 6. Це вказує на те, що перше є одним із дуже ранніх поховань ямної культури. Воно, очевидно, було впущене в існуючий курган. За допомогою Байєсівського моделювання діапазон дат був значно скорочений до 3086—2917 cal. BC. Можливо, лише через одне—два покоління, між 2895 та 2671 рр. до н. е., поховання 6 ямної культури було здійснено. Порівняно широкі калібровані діапазони дат, отримані для багатьох могил Чимішлії, зумовлені численними хитаннями на калібрувальній кривій. Абсолютні дати для поховання 6 добре поєднуються з багатьма іншими датами, отриманими для поховань ямної культури в регіоні на північний захід від Чорного моря.

�� �������������������� �������������� ���������� �� �������������� �������������� ��. �������� ����������������������, ������ �� ��������������������-�������������������� ������������������������ �� ������������������������ �������������� �������������������������������� �� ���������������������������������� �������������������� ���������������� ������������������������ ������������������ �������������� ������������������������ �� ���������������� �������������������������������� ���������������������� �� ������������ �������������������� ��������������������. ������-������������������ ���������������������� �������������������� �������������������������� ������������������������ ���������� �������������������������������� ���������������������������������� ������������, �������������� ���������������������������� �� ���������������������������� ���������������� �� �������������� ���������� 50 �� ������. ������������. ���������� ���������� ����������������, ���������������� ������������ ������������ �� ���������������� ������������ ���������������������������� ������������������������ �������������������������� ���������� ��������������������������. ���������������������� �������������������� ���������� ���������������� ������������������������������ ������������������, ������ �������������� �������������� �������� ������������������ �������� 16 �� ������. ������������. ������ �������������� ���������������������� �� ���������������� ���� ���������������������� ������������ �� ��������������������������. �������������������� ������������������ �������������� ���������� ���������������������� ���� ������������ 14���� ������-����������������������., As a result of field work at Neva River region, it was found that the structural and textural features and material composition of the Middle and Late Valdai deposits, regular changes in the sedimentation conditions were expressed in the conditions of progressive cooling at the beginning of the last glaciation. In the Late Glacial period a fluvioglacial delta was located at the southeastern side of the Koltushskaya upland. This delta was formed in a proglacial basin with a level of about 50 m abs. height. The fall of the water level, the decrease in the basis of erosion and deep erosion were accompanied by the formation of a specific section of catastrophites. The Baltic glacial lake experienced a short-term regression in which the water level dropped below 16 m abs. height. This event is recorded in sections on buried soils and cryoturbations. The chronology of these events will be established on the basis of 14Cand OSL-dating.

Accepted manuscript version, licensed CC BY-NC-ND 4.0. Several attempts at reconstructing geological settings and palaeoclimatic changes of the siliciclastic deposits of the Dahomey Basin, SW Nigeria, using relative age dating and correlation methods, have resulted in serious discrepancies on the ages. Therefore, a chronology framework established by an absolute age dating method is requisite to constrain the geological interpretation. This research focuses on quartz optically stimulated luminescence (OSL) dating of the upper siliciclastic sediments to help bridge the lacuna that arose from previous relative geologic dating. Ten sub-surface sediment samples were collected from the eastern part of the basin, and quartz OSL dating using single-aliquot regenerative-dose protocol was conducted for all the samples. The OSL signals appear well bleached prior to deposition and the OSL ages are reliable and robust. Through the application of OSL, the age framework of the uppermost part of sediments in the study area was established. The OSL dating results revealed that these depositional periods fall within the Holocene and are concentrated during two groups: 3.52 ka–1.55 ka, and 0.64 ka–0.05 ka. The samples with ages of 3.52 ka–1.55 ka distribute in the belt-like inland zone approximately parallel to the coastline. This deposition episode appears to be caused by the decrease in relative sea level during late Holocene. Thus, this study sheds light on the understanding past coast dynamics in the region

The path to mammalness is well documented in the fossil record of Therapsida. Cynodontia is a group that includes living mammals and a series of stem fossil taxa that are individualized under the paraphyletic name of non-mammalian cynodonts. In this chapter I summarize the cynodont record of the late Permian, the post end-Permian extinction record and the remainder of the Triassic; and also examine two groups with strong morphological changes toward mammalness: Mammaliamorpha and Mammaliaformes (with the review of the last group restricted to the very basal forms documented in the Late Triassic-Early Jurassic). The final section of this contribution summarizes the advances in different areas of knowledge of cynodonts in the first 19 years of the 21st century. Among other topics considered are a tally of new species proposed, the discovery of new fossil sites with records of cynodonts, the phylogenetic hypotheses presented for different groups, and the tempo of cynodont evolution in light of recent changes in the geological temporal scale and the results of absolute dating.

The limestone research within the Limboto Basin of Gorontalo Province becomes a new challenge, particularly for the study of planktonic foraminiferal biostratigraphy. This study uses the data obtained from the measured section in the north-western part of Limboto Lake. The purpose of this study is to determine the planktonic foraminiferal biozonation and the relative age of Limboto limestones. The analyzed planktonic foraminiferal fossils can be classified as well to moderately preserved of various species, in the context of abundance, categorized as frequent to abundant. There are three recognized planktonic foraminiferal biozones, i.e., two biozones for Miocene age (M13b and M14) and one biozone for Pliocene age (PL1). The Miocene biozones are named as Globorotalia plesiotumida partial range zone (M13b) and Pulleniatina primalis-Globoquadrina dehiscens concurrent range zone (M14), while the name of Pliocene biozone is Globorotalia acostaensis partial range zone (PL1). The results of this study can be a reference to propose an age of Limboto Limestone Formation. Identification and demarcation of the Limboto Limestone Formation are based on the time interval and relative age of the formation based on planktonic foraminifera.

Zircon U–Pb geochronology is a staple of crustal evolution studies and sedimentary provenance analysis. Constructing (detrital) U–Pb age spectra is straightforward for concordant 206Pb/238U and 207Pb/206Pb compositions. But unfortunately, many U–Pb datasets contain a significant proportion of discordant analyses. This paper investigates two decisions that must be made when analysing such discordant U–Pb data. First, the analyst must choose whether to use the 206Pb/238U or the 207Pb/206Pb date. The 206Pb/238U method is more precise for young samples, whereas the 207Pb/206Pb method is better suited for old samples. However there is no agreement which “cutoff” should be used to switch between the two. This subjective decision can be avoided by using single-grain concordia ages. These represent a kind of weighted mean between the 206Pb/238U and 207Pb/206Pb methods, which offers better precision than either of the latter two methods. A second subjective decision is how to define the discordance cutoff between “good” and “bad” data. Discordance is usually defined as (1) the relative age difference between the 206Pb/238U and 207Pb/206Pb dates. However, this paper shows that several other definitions are possible as well, including (2) the absolute age difference; (3) the common-Pb fraction according to the Stacey–Kramers mantle evolution model; (4) the p value of concordance; (5) the perpendicular log ratio (or “Aitchison”) distance to the concordia line; and (6) the log ratio distance to the maximum likelihood composition on the concordia line. Applying these six discordance filters to a 70 869-grain dataset of zircon U–Pb compositions reveals that (i) the relative age discordance filter tends to suppress the young age components in U–Pb age spectra, whilst inflating the older age components; (ii) the Stacey–Kramers discordance filter is more likely to reject old grains and less likely to reject young ones; (iii) the p-value-based discordance filter has the undesirable effect of biasing the results towards the least precise measurements; (iv) the log-ratio-based discordance filters are strictest for Proterozoic grains and more lenient for Phanerozoic and Archaean age components; (v) of all the methods, the log ratio distance to the concordia composition produces the best results, in the sense that it produces age spectra that most closely match those of the unfiltered data: it sharpens age spectra but does not change their shape. The popular relative age definition fares the worst according to this criterion. All the methods presented in this paper have been implemented in the IsoplotR toolbox for geochronology.

The archaeological inquiries in Trans-Salt Range Zone of northern Punjab, Pakistan have unveiled the multifaceted data for the cultural development of the Early Harappan-Kot Diji phase of Indus Civilization during third millennium BC. Up until now, the urbanism of Indus Civilization is missing in the area while absolute dating at Sarai Khola, Jhang-Bahater & Hathial, has shown that Kot Diji phase has evolved in the Trans-Salt Range Zone parallel to Harappan phase of Indus Plains. The latterly found Kot Diji phase Mohra site in the area further strengthens this cultural phenomenon. This article will propose the data for the late development of Kot Diji phase at Mohra and its connection to other adjacent sites in a more wide spread context.

Made available in DSpace on 2020-12-12T01:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The Neogene Içá Formation is a major sedimentary deposit in central Amazonia (Brazil) that is critical to the understanding and modeling of the evolution of the Amazon Basin. However, its chronostratigraphy is poorly defined, mostly because it is not fossiliferous and it does not contain volcanic ash levels. This study is the first attempt at the absolute dating of the sediments and overlying soils of the Içá Formation by electron paramagnetic resonance (EPR) of radiation-induced defects in kaolinite (RIDs). Four profiles of unconsolidated sediments overlaid by lateritic soils from the Barcelos region (Amazonia, Brazil) were studied. The concentration of RIDs was assessed from EPR spectra through a simplified procedure on a selected set of samples, excluding those showing too strong of interference from the signal of trace vanadyl complexes. It is shown that in such sedimentary material, both the microscopic distribution of thorium (together with uranium) and the origin of kaolinite, either detrital or authigenic, are critical for kaolinite dating. Considering an argued authigenic origin and two scenarios of Th distribution, it appears that most of the present chronologic data support the stratigraphic correlation with the Madre de Dios sedimentary Formation in Peru previously proposed in the literature for the Içá Formation (9.5–2.5 Ma). This study also shows a rejuvenation process of kaolinite both in the uppermost soil and at depth of the profiles. This rejuvenation occurred during paleoclimatic periods already revealed in other weathering covers from the Amazon Basin and possibly resulted from downward weathering in the topsoil and water table or lateral weathering at depth. IMPMC UMR CNRS 7590 Sorbonne Université CPRM Serviço Geológico do Brasil UFG Universidade Federal de Goiás IPH UMR7194, 1 rue René Panhard UNESP Universidade Estadual Paulista UNESP Universidade Estadual Paulista

The paper presents the results of interdisciplinary research carried out at the Kobuleti Early Holocene site. Typological and use-wear analyses of stone artifacts helped to define the main branch of the economy of humans at the site. Palynological studies were conducted to reconstruct the paleoenvironment. The investigated plant spores proved that the climate in the Early Holocene was warm. Definition of an absolute date by means of the radiocarbon method (14C) represents an innovation conducted in the study of the Stone Age in Ajara.

The article discusses the results of the latest interdisciplinary research of Czermno stronghold and its immediate surroundings. The site is mentioned in chroniclers’ entries referring to the stronghold Cherven’ (Tale of Bygone Years, first mention under the year 981) and the so-called Cherven’ Towns. Given the scarcity of written records regarding the history of today’s Eastern Poland, Ukraine, and Belarus in the 10th and 11th centuries, recent archaeological research, supported by geoenvironmental analyses and absolute dating, brought a significant qualitative change. In 2014 and 2015, the remains of the oldest rampart of the stronghold were uncovered for the first time. A series of radiocarbon datings allows us to refer the erection of the stronghold to the second half/late 10th century. The results of several years’ interdisciplinary research (2012-2020) introduce qualitatively new data to the issue of the Cherven’ Towns, which both change current considerations and confirm the extraordinary research potential in the archeology of the discussed region.

International audience; The establishment of the Late Triassic time scale has given rise to considerable controversy, particularly regarding the Rhaetian duration and the inferred absolute age models. In this respect the astronomical polarity time scale (APTS) established from the continental successions of the Newark Basin (eastern North America) is considered as a reference record, although its completeness is questioned. Numerous magnetostratigraphic correlation schemes have been proposed between the APTS and biostratigraphically well-constrained Tethyan marine sections. This has led to two main contrasting options: a "short" Rhaetian duration (about 4-5 myr), and a "long" one (about 8-9 myr). Astronomical calibration of the Tethyan Rhaetian and estimate of its duration is necessary to help advance this debate. We have undertaken a cyclostratigraphic analysis of a Rhaetian composite record built from four overlapping Austrian reference sections. Magnetic susceptibility variations of the 131.5 m thick record are astronomically paced by the precession and 405-kyr orbital eccentricity cycles. 405-kyr orbital tuning allows to establish a floating time scale, and thus to suggest a minimum duration of 6.69 myr of the Rhaetian stage. Given the well-established radioisotopic age of the Rhaetian-Hettangian boundary of 201.36 Ma, an age no younger than 208.05 Ma for the Norian-Rhaetian boundary can be proposed. This result will contribute to the refinement of the Late Triassic time scale, but it does not solve the long-standing debate on bio-magnetostratigraphic correlations between the continental Newark APTS and the Tethyan marine sections, nor the question of the completeness of the Rhaetian Newark Basin.