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EN
We review published data to explain climatic and environmental changes as recorded in the deposits and landforms of the Quaternary of Poland. A wide range of research methods have been used to reconstruct the environmental conditions at many sites and selected studies summarized here include those of interglacial palaeolake deposits at Ossówka and periglacial structures at Wierzchuca Nagórna (both in the Podlasie Region), a loess profile at Wąchock and sandy deposits in Korzecko (both in the Holy Cross Mountains), carbonate cementation forms at Reńsko (Wielkopolska Region), and well-preserved glacial landforms in the Dobrzyń Lakeland, Suwałki Lakeland and the Carpathians including the Tatra Mountains. The terrestrial record described is far from complete but it demonstrates that climate change in the Quaternary glacial and interglacial periods occurred with high frequency, varying intensity and cyclicity. Climate instability during cold phases of the Pleistocene is more evident, as expressed by terminal moraines in the Polish Lowland and in the mountains. In warmer periods, climatic instability was expressed mainly through high-resolution records. The examples provided from both cold and warm Quaternary phases clearly show climate changes as common and natural phenomena.
EN
Cyclical climate change is characteristic of the Holocene, with successive warmings and coolings. A solar forcing mechanism has steered Holocene climate change, expressed by 9 cooling phases known as Bond events. There is reliable geological evidence that the temperatures of most warming phases in the Holocene were globally higher or similar to that of the current warming period, Arctic sea ice was less extensive and most mountain glaciers in the northern hemisphere either disappeared or were smaller. During the African Humid Period in the Early and Middle Holocene, much stronger summer monsoons made the Sahara green with growth of savanna vegetation, huge lakes and extensive peat bogs. The modern warming is part of a climatic cycle with a progressive warming after the Little Ice Age, the last cold episode of which occurred at the beginning of the 19th century. Successive climate projections of the Intergovernmen¬tal Panel on Climate Change are based on the assumption that the modern temperature rise is steered exclusively by the increasing content of human-induced CO2 in the atmosphere. If compared with the observational data, these projected temperatures have been highly overestimated.
EN
High-resolution biological proxies (pollen, macrofossils, Cladocera, Chironomidae, malacological analysis and diatoms), geochemical analyses, and AMS radiocarbon dating were employed to reconstruct the responses of the Smólsk palaeolake (Kuyavian Lakeland, central Poland) to rapid climatic and environmental changes during the Late Glacial-Early Holocene transition. The integration of palaeoecological and geochemical data enabled detailed insights into the dynamics of short-term shifts in terrestrial and aquatic ecosystems triggered by abrupt climate events. Precise age control and high-resolution sampling allowed the identification of temporal leads and lags between proxy responses to climatic shifts during this transitional period. Key findings include: (1) the coolest lake development phase, corresponding to the Late Glacial (9.050–5.400 m; 13,835–12,800 cal14C BP); (2) evidence of an open landscape and decreased water levels in the Late Glacial, resulting in intensified catchment erosion; (3) a change in sediment deposition at a depth of 5.35 m (~11,000 cal14C BP), marked by a transition from silt to calcareous gyttja and peat, indicating a lowering of groundwater levels and improved climatic conditions at the beginning of the Holocene; (4) a hiatus between the Late Glacial and Early Holocene recorded across all proxies; and (5) progressive eutrophication during the Holocene, characterized by reed belt development, reduced sedimentation, and the cessation of terrigenous sediment input. These findings highlight the lake system’s sensitivity to rapid climatic and environmental changes during this critical period.
EN
Palynological analysis of samples taken from the lignite, exposed in the Chłapowo Cliff on the southern Baltic coast, allowed the reconstruction of the vegetation and palaeoclimate that predominated during the accumulation of the peat, from which the lignite was formed. In addition to pollen grains and spores, particular attention was given to non-pollen palynomorphs, such as algal, fungal and invertebrate micro-remains (Cladocera) that enabled a more accurate reconstruction of the palaeoenvironment. The lignite belongs to the 2nd Lusatian seam, which is an important correlation level in Central Europe, dated to the latest Early Miocene to the early Middle Miocene. The textural and structural features of the lignite seam indicate that the depositional environment of the peat is loosely combined with the overbank zone of an anastomosing or meandering river system. The results of the palynological study show the presence of wetland vegetation, including shrub bogs (most similar in their composition to modern pocosins, growing between river channels) and riparian forests, growing on periodically flooded areas and mesophilous vegetation, occurring in the vicinity. The composition of the palynoflora, including the thermophilic taxa, such as Sapotaceae and Meliaceae, indicates that the climate was warm, close to subtropical, with a mean annual temperature range of 15.7–17.8 °C.
EN
On the basis of palynologic and palynofacies data from the Biały Kamień Formation in the Intra-Sudetic Basin (ISB), the composition of parent plant communities and the depositional environment during sedimentation of this unit were reconstructed. The results were then compared with earlier published palynological data from the stratigraphically older and younger lithostratigraphical units, the Wałbrzych and Žacléř formations, allowing a general interpretation of floristic and environmental changes throughout the Serpukhovian to Moscovian interval. The floras in the Serpukhovian resemble the composition in the Moscovian. In both, their main feature is low lycopsid abundance, indicating relatively dry palaeoclimatic conditions. In contrast, the Bashkirian records a gradual increase in lycopsids and sphenopsids, peaking in the late Bashkirian during the maximum humid phase. This was followed in the Moscovian by a marked decline in lycopsids and a shift toward fern dominance, reflecting a transition to a drier climate associated with the First Dry Interval, proposed by Phillips and Peppers (1984). At the same time, the miospore record shows no evidence of abrupt floristic changes, contradicting the concept of a “floristic leap” at the Namurian A/B boundary.
EN
The year of publication and bibliographic reference of Pecten nodosiformis have been quoted incorrectly. It is concluded herein that the name was originally published in Pusch’s Geognostische Beschreibung von Polen, and that the correct year is 1836. This highly distinctive pectinid species, with the left valve ornamented with nodules, and presently assigned to the genus Gigantopecten Rovereto, 1899, is a reliable guide to the Lower Badenian (upper Langhian, Middle Miocene) of Poland and Ukraine. Its occurrence in this area, restricted to carbonate deposits dated to the Orbulina suturalis planktonic foraminifera zone and the upper NN5 calcareous nannoplankton zone, help to refine the knowledge of palaeoclimatic changes during the Middle Miocene in individual Paratethyan basins. The comparison of many Polish, Ukrainian and Slovak specimens allows the demonstration of changes in the shape of the shell and its ornamentation during ontogeny. This was the reason for assigning herein numerous species as junior synonyms of Gigantopecten nodosiformis. Moreover, this paper presents a review of studies on the Middle Miocene sedimentary succession and its fossil content in Skotniki Quarry, the type locality of Gigantopecten nodosiformis, one of the most important geological exposures in the Holy Cross Mountains, studied already in the early 19th century by Pusch.
EN
The Anthracosia Shales are lacustrine deposits within the volcano-sedimentary Pennsylvanian– Lower Permian succession of the Intra-Sudetic Basin. Core from the Rybnica Leśna PIG 1 borehole, which penetrated the Lower Anthracosia Shales, was analysed to explore the influence of climate on the evolution of the palaeolake, as distinct from tectonic and volcanic forcing. This reconstruction was made using mineralogical and geochemical proxies (elemental and mineralogical composition, TOC values, presence of framboidal pyrite and siderite). Based on the results, three chemically different intervals previously introduced by Wójcik-Tabol et al. (2021) are described. They represent the following stages of lake evolution: transgression (interval I), open lake (interval IIA and IIB), and termination (interval IIC and III). The initial stage of the lake (interval I) was probably related to a rise in humidity in the Late Pennsylvanian, linked to a southern Gondwana interglacial episode. Interval IIA represents the deepest facies of the Anthracosia Basin, where lake-floor anoxia prevailed. This stage was followed by a gradual lake-level fall recorded in interval IIB, with documented seasonality in humid and warm conditions. Interval IIC represents a stepwise lake regression attributed to aridification, as indicated by proxies showing a decrease in chemical weathering. Turbiditic sandy laminae in interval III reflect the terminal stage of lake infill.
EN
For modern fluvial systems, stage height, velocity, and cross-section help estimate a river’s discharge. However, understanding the amount and fluctuations of past discharges remains a challenge. The dimen-sions of the meander loops/oxbow lakes are directly proportional to the river’s discharge and the sedi-ment load type. Central West Bengal, India, has a complex network of numerous oxbow lakes as a rem-nant of the river Hooghly, a major distributary of the River Ganga. The present work revisits Schumm’s classic work to estimate river discharges from the meander loops and explores a potential proxy for es-timating past discharges. Thus, it is extended to reconstruct past climate using grain size data, facies analysis, and the dimension of the meander loops coupled with the luminescence chronology of oxbow lakes. The study reveals that the region received good rainfall during reported periods of intense mon-soon, and the increased discharge at different time intervals has given rise to numerous oxbow lakes. The discharge values have shown considerable fluctuations, rising to 15 to 20 times the current value and very few anomalously high, even up to 250 to 300 times, left unrecorded from other archives. The study shows the preservation of systematic growth of discharges and the meander loops with climate re-vealing events with anomalously high (and so highly disastrous) discharges at the scale of tens of thou-sands of years, usually missed from other archives. Results from Ichhamati and Hooghly River meander loops in West Bengal, India, indicate a manifold increase of discharges from the current during 1–1.5 ka (known as the Medieval Warm Period); around 2.2 ka and around 3.9 ka with low or gaps of enhanced monsoon, e.g., Little Ice Age and during 2.5–3.5 ka. This is an effort to show the potential of past mean-der loops to be explored well for comprehensive records.
EN
One hundred and nine taxa of carpological remains, 3 taxa of leaves, and 103 taxa of sporomorphs are identified from the late Oligocene to Early Miocene deposits at the Tetta Clay Pit, eastern Germany. Palynological analysis was performed for the first time for this site. Among the carpological remains, 82 taxa are documented for the first time for this site, including two new fossil-genera (Paranothotsuga Kowalski gen. nov., Pterosinojackia Kowalski gen. nov.), and one new fossil-species (Sparganium tuberculatum Kowalski sp. nov.). New combinations are also introduced (Paranothotsuga jechorekiae (Czaja) Kowalski n. comb., Magnolia germanica (Mai) Kowalski n. comb., and Morella stoppii (Kirchheimer) Kowalski n. comb.). Discovered microremains of Pesavis tagluensis fungus extend the age range of the sedimentary sequence from the previously suggested Middle Miocene to at least the latest Oligocene. Two biostratigraphic units, the Rott-Thierbach and Wiesa-Eichelskopf floristic complexes are recognized for the first time in Tetta. Beech forests are indicated as the most common vegetation type. All of these fossil assemblages evidence a warm temperate climate, but a shift toward a warmer subtropical climate is inferred in the uppermost part of the studied profile.
EN
The N–E Tunisian coast (Bizerte region) shows several Quaternary sedimentary archives of middle to late Pleistocene age. Sedimentological analyses carried out (grain size, morphoscopy, exoscopy, petrography, mineralogy, and fossil content) on 12 sections reveal a succession that begins with infratidal deposits attributed to the last Interglacial period, followed by intertidal, continental (palaeosol) and/or aeolian deposits (aeolianites). The arrangement of these deposits, their lithological characteristics and their faunal contents are the basis for a palaeoenvironment reconstruction and estimation of palaeoclimatic conditions. A warmer climate and a high sea level characterize the beginning of this interval, followed by a sea level fall accompanied by an alternation of humid and arid climate. This alternation is reflected by intercalations of the palaeosol levels between the aeolian deposits.
EN
Non-perennial to ephemeral fluvial systems dominated by seasonal discharge fluctuations and episodic rapid flood-flow events are typical of arid to semi-arid climatic conditions. Dryland fluvial systems have been described from many ancient and modern, predominantly tectonically-controlled sedimentary basins across the globe. This study provides detailed sedimentological analysis and palaeoenvironmental interpretation of the lowermost part of the early Permian (?Asselian) Krajanów Formation exposed within the continental, fault-bounded Intra-Sudetic Basin (ISB), located on the NE periphery of Bohemian Massif. High-resolution sedimentological logging and facies analysis indicate that the early Permian fluvial system in this area was dominated by ephemeral fluvial processes influenced strongly by a semi-arid to arid climate. Rapid (?catastrophic) flood events led to episodic sedimentation of vertically and laterally amalgamated fluvial channel infills, with abundant upper flow regime structures as well as poorly channelized, laterally extensive sheet-like bodies of sandstone. The overbank deposits are poorly preserved due to frequent lateral shifting of the channels. Soft-sediment deformation structures formed due to events of river bank collapse as well as debris flow facies point to high-energy, waning flows. It is concluded that deposition occurred on broad, terminal-type alluvial fans, probably in their proximal- to medial segments within a distributive fluvial system of the Permian Intra-Sudetic Basin. Petrographic composition and measured palaeocurrent directions show that the sediment was sourced from the neighbouring massifs – the Sowie Mts. Massif to the east, the Bardo Structure and a hypothetical Southern Massif to the south/south-east.
EN
The Warta River valley was greatly influenced by the ice sheet of the Last Glacial Maximum (LGM). A small peatland located in the Warta drainage system is here used as a palaeoarchive of climatic and habitat changes during the Late Glacial (Weichselian). The Ługi sediment profile was investigated using multi-proxy (pollen, Chironomidae, Cladocera and geochemistry) analyses that recorded changes in a fluviogenic sedimentary depression. After the Poznań Phase (LGM), Ługi functioned as an oxbow lake that was cut off from the active river channel as a result of fluvial erosion. Since that time, the Warta River has flowed only along the section now occupied by the Jeziorsko Reservoir. Sedimentation of lacustrine deposits started at the beginning of the Late Glacial. Summer temperature reconstructions indicate cool Oldest and Younger Dryas, but no clear cooling in the Older Dryas. During the Younger Dryas the palaeolake was completely occupied by a peatland (fen), which periodically dried out during the Holocene. Investigation of this site has tracked the reaction of the habitat to climatic, hydrological and geomorphological changes throughout the Late Weichselian.
EN
The Bełchatów lignite deposits are a rich archive allowing palaeoenvironmental, palaeoecological and palaeoclimatic reconstructions from the Neogene and Quaternary periods. We describe the results of palynological studies (including non-pollen palynomorphs) of eight samples from the lower Miocene KRAM-P 211/214 collection of plant macroremains. The results of this palynological analysis are consistent with the results of previous studies of plant macroremains and significantly enrich our knowledge of vegetation and palaeoenvironment. Both studies indicate the presence of a freshwater body (a moderately large and deep lake) surrounded by wetland vegetation (including swamp forests with Glyptostrobus, Taxodium, Nyssa and Osmunda) and upland mesophytic forests. Evergreen or at least semi-evergreen forest communities grew along the ancient shores of the lake and on the slopes of the Mesozoic calcareus rocks surrounding the lake. In the lake, green algae (Pediastrum, Tetraedron and some Botryococcus) and freshwater peridinoid dinoflagellates were major components of the algal community. The same lake was the source of previously identified animal remains: freshwater fishes, molluscs, and mammals, including Megachiroptera bats. Our analysis shows that the climate was subtropical and humid, with an estimated mean annual temperature of 16.8–17.8°C.
EN
The Başkale Basin is located in the easternmost part of Türkiye, within a tectonically active area, and located at the intersection of Europe, Asia and the Middle East. In this study, the Dereiçi travertines, one of the most important products of neotectonism in the basin, were investigated sedimentologically, mineralogically and geochemically. To understand the neotectonic evolution of the travertine succession, the sequence was studied from bottom to top as regards morphology, lithofacies and U/Th dates. Crystalline crust, coated gas bubbles, shrub, paper-thin raft and palaeosol lithofacies have been detected in the Dereiçi travertines, which are morphologically of layer type, two ridge types and terrace type. The Dereiçi travertines commenced to precipitate at the intersection of the Işıklı and Ilıcak faults at 255.56 ±9.01 ka, and their deposition continues today. Travertine deposition paused twice between 198.31 ±18–143.07 ±1.5 ka and 96.73 ±8.34–61.59 ±5.4 ka, when palaeosol development took place. According to field and laboratory studies, the Dereiçi travertines developed under climate and tectonic control. The Işıklı and Ilıcak faults played active roles in the development of the travertines. As the travertine ages are linked to movement on both faults, the age of the Işıklı Fault should be 255.56 ±9.01 ka or earlier, and that of the Ilıcak Fault should be 143.07 ±1.5 ka or earlier.
EN
Fossil charcoal is the primary source of evidence for palaeo-wildfires and has gained increasing interest as a proxy in the reconstruction of past climates and environments. Today, increasing temperatures and decreasing precipitation/humidity appear to correlate with increases in the frequency and intensity of wildfires in many regions worldwide. Apart from appropriate climatic conditions, sufficient atmospheric oxygen (>15%) is a necessary precondition to sustain combustion in wildfires. The Triassic has long been regarded as a period without evidence of wildfires; however, recent studies on macro-charcoal have provided data indicating their occurrence throughout almost the entire Triassic. Still, the macro-palaeobotanical record is scarce and the study of micro-charcoal from palynological residue is seen as very promising to fill the gap in our current knowledge on Triassic wildfires. Here, the authors present the first, verified records of micro-charcoal from the Triassic of the Germanic Basin, complementing the scarce macro-charcoal evidence of wildfires during Buntsandstein, Muschelkalk and Keuper (Anisian-Rhaetian). The particles analysed by means of scanning electron microscopy (SEM) show anatomical features typical of gymnosperms, a major element of the early Mesozoic vegetation following the initial recovery phase after the PT-boundary event. From the continuously increasing dataset of Triassic charcoal, it becomes apparent that the identification of wildfires has a huge potential to play a crucial role in future studies, deciphering Triassic climate dynamics. The first SEM study of micro-charcoal from palynological residue spanning the entire Triassic period, presented here, is a key technique to further unravel the charcoal record as a puzzle piece in palaeoclimate reconstruction.
EN
Palynological analysis of the 1st mid-Polish lignite seam (MPLS-1) of the Drzewce deposit (Konin region, central Poland) was used as the data source for palaeoenvironmental and palaeoclimatic interpretations. Lignites of the 1st group developed in the middle Miocene, during and shortly after the last peak of the Mid-Miocene Climatic Optimum, over a large area of Poland, and they are the youngest of the main Neogene lignite seams in Poland. In the Konin region, these lignites have a relatively significant thickness (up to 20 m) and therefore they are (or were in the past) exploited in several open-pit mines. A total of 36 palynological samples from the 6.3-m-thick seam of the Drzewce opencast mine was studied in detail. Palynological analysis of the lignite seam indicates that the area was overgrown by palustrine wetland communities, similar in composition to modern pocosins. The most characteristic elements of them were shrubs in the Ericaceae family. The climate at that time was warm temperate and humid. The estimated mean annual temperature (MAT) for the lignite seam at Drzewce is 15.7–17.8 °C. Comparison with other palynofloras from the MPLS-1 shows that the climate during the formation of the group of seams was more or less homogenous across the entire Polish Lowlands. Sedimentological data and results of palynological studies (including NPPs) at Drzewce indicate that the palaeomires were relatively distant from the channels of the river system in the Konin Basin. The fossil fungal assemblage indicates dense vegetation on damp, swampy soils and the presence of small, shallow-water bodies, with a variable water level or even periodic reservoirs, existing only during the wet season or after floods. In small, flooded depressions, such as the pools in bogs, filamentous green algae occurred. The presence of zygospores of the desmids Desmidiaceaesporites cosmarioformis most probably indicates relatively nutrient-poor (ombrotrophic) conditions. Fluctuations in the frequency of individual plant taxa (including Sequoia and Sciadopitys) are likely to reflect changes in water level and trophic conditions.
EN
This paper presents the Late Glacial stage of the development of the Białe Ługi peatland in the southern Holy Cross Mountains, based on a comprehensive palaeoenvironmental data. A complex analysis of palynology, Cladocera, sedimentology, geochemistry and 14C dating were used. Organic deposition was initiated during the Oldest Dryas. The sedimentary record of the aquatic and terrestrial ecosystems reflects considerable difference between cooler (Oldest, Older and Younger Dryas) and warmer phases (Bølling and Allerød). Periods of intensified interaction between Aeolian processes and peatland are related to stages of disappearing vegetation and changes in aquatic invertebrate communities. We therefore suggest that peatlands were created as a result of local lithological-structural, tectonic, hydrogeological and morphological conditions, and the peatland development rate was largely influenced by changing climatic conditions, which determined local vegetation development, intensity of denudation processes and water level changes. The results validate significance of selection and use of several methods, as well as value of biogenic deposits from the Białe Ługi peatland as archives of past climate change in the Małopolska Upland. Relatively stable water conditions and uninterrupted biogenic sedimentation in the Late Glacial that were provided by the geological structure and relief suggest the studied peatland is a leading one in the region.
EN
Deposits formed between the Neogene/Pleistocene transition and into the Early Pleistocene have been studied, mainly on the basis of drillings and at rare, small outcrops in the lowland part of Polish territory. At the Bełchatów lignite mine (Kleszczów Graben, central Poland), one of the largest opencast pits in Europe, strata of this age have long been exposed in extensive outcrops. The present paper is based on our field studies and laboratory analyses, as well as on research data presented by other authors. For that reason, it can be seen as an overview of current knowledge of lowermost Pleistocene deposits at Bełchatów, where exploitation of the Quaternary overburden has just been completed. The results of cartographic work, sedimentological, mineralogical and palynological analyses as well as assessment of sand grain morphology have been considered. All of these studies have allowed the distinction of three Lower Pleistocene series, i.e., the Łękińsko, Faustynów and Krzaki series. These were laid down in fluvial environments between the end of the Pliocene up to the advance of the first Scandinavian ice sheet on central Poland. The following environmental features have been interpreted: phases of river incision and aggradation, changes of river channel patterns, source sediments for alluvia, rates of aeolian supply to rivers and roles of fluvial systems in morphological and geological development of the area. The two older series studied, i.e., Łękińsko and Faustynów, share common characteristics. They were formed by sinuous rivers in boreal forest and open forest environments. The Neogene substratum was the source of the alluvium. The younger series (Krzaki) formed mainly in a braided river setting, under conditions of progressive climatic cooling. Over time, a gradual increase of aeolian supply to the fluvial system can be noted; initially, silt and sand were laid down, followed by sand only during cold desert conditions. These fluvio-periglacial conditions are identified in the foreground of the advance of the oldest ice sheet into this part of central Poland. The series studied have been compared with other fluvial successions which accumulated in the Kleszczów Graben during subsequent glaciations so as to document general changes in fluvial systems as reactions to climatic evolution. Thus, a palaeoenvironmental scenario has emerged which could be considered to be characteristic of central Poland during the Early Pleistocene.
EN
The Udryń PIG 1 research borehole drilled in northeastern Poland (54°14’49”N, 23°03’29”E, 223 m a.s.l.) revealed a permafrost layer, at least 93 m thick, within the sedimentary succession below a depth of 357 m. The base of the permafrost has not been reached at 450 m depth, where the drilling stopped, so its total present thickness remains unknown. The relict permafrost, unexpected in this part of Central Europe, is in the ice-water transition phase at a temperature slightly below the 0°C. Analysis of geophysical and hydrogeological data indicates the possibility of preserving the permafrost in the central part of sedimentary cover of the Suwałki Anorthosite Massif over an area of probably 50 km2. Preliminary results of geothermal modelling indicate maximum palaeothickness of permafrost at the end of the Last Glacial Maximum of probably ~600 m. The development of such a thick permafrost results both from a very low average annual temperature in the Weichselian Glaciation and a very low terrestrial heat flow density. It is very probable that similar zones of deep relict permafrost occurrences, undetected so far, may exist in other areas of the Precambrian Platform not only in Poland, but also in the neighbouring countries.
EN
A number of recent studies dealing with palaeoclimate and environmental reconstruction include the measurement of oxygen isotope composition of mammalian teeth. Some of them analyse a temporal sequence of the changes recorded in bioapatite from enamel layers representing the whole period of tooth development. Enamel samples display large intra-tooth δ18O variations that may reflect a seasonal fluctuation in the δ18O of local palaeoclimate parameters. The present paper provides an effective analytical protocol for sequential δ18O analysis of human teeth using SHRIMP IIe/MC ion microprobe. It is possible to follow the inner enamel layer along enamel-dentine junction on a high spatial scale in a range about 0.02 mm of spot diameter and 0.12–0.14 mm of the distance between spots. Using the methodology described herein, we can achieve an external precision for δ18O analysis <0.2‰ (1σ). The number of 60 to 90 single analyses covering the enamel layer between the incisal and apical ends is enough to obtain temporal resolution of less than one month and to document precisely seasonal fluctuation caused by local environmental and climate factors. The methodology of δ18O in situ measurements has been tested on human teeth from Tell Majnuna, a 4th millennium BCE cemetery in Northern Mesopotamia, which is a relatively arid area with high seasonal differences in precipitation and temperature. Observed pattern of δ18O variations is consistent with expected seasonal fluctuations, although the overall effect is blurred by some inertia in the enamel maturation.
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