Holocene

Kozanoglou, Caterina; Triantaphyllou, Maria V; Geraga, Maria; Rousakis, Grigoris; Papatheodorou, George; Arabas, Agnieszka; Dimiza, Margarita D; Gogou, Alexandra

2023 Holocene

doi: 10.1177/09596836231185831

High-resolution data for planktonic foraminifera and their groups of ecological interest, including Herbivores and Carnivores, combined with benthic foraminifera and a great variety of biogeochemical indices from the SE Aegean sediment core ST5, contribute to a detailed study concerning major and minor climatic episodes during Holocene. The ST5 sediment record, retrieved from the Tilos-Symi marine basin, evidences the impact of the nearby land, the local climate, and the Rhodes Gyre imprint on the eastern Mediterranean water circulation. Pronounced environmental changes are detected during a preconditioning period of ~400 years before the onset of sapropel S1 deposition and during the deposition phases S1a (10.0–8.4 ka BP) and S1b (8.0–6.1 ka BP). Major freshwater influx episodes (10.5 ka BP, 9.2–8.9 ka BP, 7.4 ka BP, 4.5–4.3 ka BP, and few additional during the Late-Holocene) are revealed, prominent oxygen deficiency time intervals (including a distinct brief anoxic period) as well as several drier, cooler and warmer climatic events. Herbivore planktonic foraminifera alternate their dominance with the Carnivores at the preconditioning period before the S1 onset and at the Late-Holocene (2.0–1.5 ka BP) when conditions of good seawater circulation, oxygenation, and productivity alternate with stratified low oxygenation waters and high freshwater influx from the land.

Wu, Xiner; Lemay-Tougas, Mathieu; de Vernal, Anne; Garneau, Michelle; Fréchette, Bianca; Audet, Tiffany; Hillaire-Marcel, Claude

2023 Holocene

doi: 10.1177/09596836231185827

The micropaleontological and palynological content, and geochemical and isotopic composition of a marine sediment core collected off Pointe-des-Monts in eastern Québec, Canada, reveal regional palaeoclimatic and paleoceanographic conditions in the Lower St. Lawrence Estuary over the last ~8200 years. The pollen and spore content allows comparison with the terrestrial palynostratigraphy, whereas dinoflagellate cysts and benthic foraminifera are used to reconstruct sea-surface conditions and bottom water properties, respectively. The dinocyst-based reconstructions indicate shifts between estuarine and oceanic conditions with important changes in sea-surface temperature, salinity, and primary productivity. Both the dinocyst assemblages and the quantitative sea-surface estimates highlight a distinct transition at ca. 4200 cal years BP. It is notably marked by a change towards higher salinity, which suggests reduced freshwater discharge, hence lower precipitation in the watershed, during the Late-Holocene. The isotopic composition (δ18O and δ13C) and assemblages of the benthic foraminifera indicate centennial to millennial frequency variability of bottom water properties, over a general trend towards decreasing temperatures and increasing ventilation from the beginning of the Middle Holocene until the last century. Since then, reverse trends with abrupt warming and decreasing dissolved oxygen content in bottom water have been observed.

Martínez, Rubén Pardo; Cobo, José Antonio Olmedo; Zotano, José Gómez; Sánchez, Francisca Alba

2023 Holocene

doi: 10.1177/09596836231185835

The mountains of the southern Iberian Peninsula are important biodiversity hotspots. They are also home to several relict species that are threatened with extinction in the face of global change. One of the best examples is the Serranía de Ronda, a system of mountainous reliefs located at the western end of the Baetic Cordillera. Its tree cover includes, among other unusual taxa, endemic formations such as the Spanish fir (Abies pinsapo) and Portuguese oak (Quercus faginea) forests. However, despite the ecological exceptionality of this mountainous area, little is known about its paleobiogeography. To remedy this, in this research we take a multidisciplinary approach based on the application of several different paleoecological disciplines, of which pedoanthracology is the main methodological tool. Six new soil surveys were performed, which were added to the existing pedoanthracological network, making a total of 43 soil sampling sites. The taxonomic analysis revealed several taxa, such as Abies, Fraxinus, Pinus and Pinus sylvestris-type, which are currently absent in several of the sampled sites. After contextualizing the 36 new radiocarbon dates obtained, the results confirm the antiquity of certain paleoendemic forests in the Serranía de Ronda, and the important role played by certain mountain enclaves as refuges for conifers such as A. pinsapo and Pinus sylvestris-type during the Pleistocene-Holocene transition. The dissemination of the results of this research will enable them to be implemented in the different strategies of adaptive management of the most threatened forests of the Serranía de Ronda.

de Vareilles, Anne; Woodbridge, Jessie; Pelling, Ruth; Fyfe, Ralph; Smith, David; Campbell, Gill; Smith, Wendy; Carruthers, Wendy; Adams, Stacey; le Hégarat, Karine; Allot, Lucy

2023 Holocene

doi: 10.1177/09596836231185836

The onset of prehistoric farming brought unprecedented changes to landscapes and their biodiversity. Past biodiversity patterns are broadly understood for different parts of Europe, and demonstrate trajectories that have been linked to prehistoric and historic demographic transitions, and associated land-use practices. To our knowledge, this paper is the first attempt to directly link evidence of agricultural practice from the archaeological record to biodiversity patterns. Records of fossil pollen are used to estimate plant and landscape diversity patterns, and novel approaches are employed to analyse 1194 harmonised archaeobotanical samples (plant macrofossil remains) spanning the prehistoric and Roman periods, from southern England. We demonstrate changes in the use of crops and gathered edible plants and non-linear trends in cultivation practices. Whilst, overall, cereal production is characterised by ever larger and extensive regimes, different trajectories are evident for most of early prehistory, the Middle Iron Age and the Late Roman period. Comparisons with the Shannon diversity of fossil pollen records from the same region suggest a positive relationship between developing agricultural regimes and landscape scale biodiversity during the prehistoric period. The Roman period represents a tipping point in the relationship between expanding agriculture and pollen diversity, with declining pollen diversity evident in the records from the region.

Gjerde, Marthe; Hoel, Oddmund Løkensgard; Nesje, Atle

2023 Holocene

doi: 10.1177/09596836231185830

This study presents a cross-disciplinary revision of the Little Ice Age (LIA) advance of Nigardsbreen glacier, an outlet from Jostedalsbreen ice cap in western Norway. The associated glacier foreland is characterised by a well-preserved moraine series succeeding the 1748 CE LIA culmination, and a robust age control of individual moraines exists from abundant historical written and pictorial information as well as extensive lichenometric studies. The retreat dynamics of Nigardsbreen ever since the LIA maximum extent was attained is considered well-known. The timing of initiation of the LIA advance and dynamics of the glacier growth prior to reaching its maximum extent, however, is less understood as any moraines predating 1748 CE have been subsequently overridden. Potential archives available for exploring the glacier advance are therefore mostly confined to historical data such as for example, tax records, paintings, and church books, which has resulted in a present-day consensus of the LIA onset of Nigardsbreen c. 1710 CE. However, we show that a lack of adequate critical analysis on the accuracy of published historical data has allowed erroneous ages of glacier terminus positions to manifest in literature, resulting in for example, overestimated glacial advance rates. Here, we combine a novel data set of local tax load directly reflecting glacial impact on farming productivity with a cross-disciplinary assessment of published historical data, including rejection of several data points of former glacier extents. As a result, we present a revised glacier length curve for the LIA advance of Nigardsbreen towards its maximum extent.

Yang, Xun; Becker, Fabian; Nykamp, Moritz; Ludwig, Bernhard; Doğan, Mehmet; Schütt, Brigitta

2023 Holocene

doi: 10.1177/09596836231185837

The Pergamon micro-region (western Türkiye) has experienced several phases of increased geomorphodynamics during the Holocene. However, the role of local–regional human activities during a transformation between Hellenism and the Roman Imperial period and supra-regional climate fluctuations is still under discussion. Five sediment profiles from the alluvial fan of the rural Deliktaş catchment are analyzed and radiocarbon-dated to provide a sedimentological record covering the Holocene. Our results indicate seven phases of changing sediment dynamics. Five Holocene cycles of coarse- and fine-textured fan sediment deposition covered the paleochannel deposits of the Çaylak creek, and the floodplain sediments of the receiving Geyikli river which aggraded toward the piedmont during the Mid-Holocene. The landscape became stable on the Deliktaş fan and Geyikli floodplain at least ca. 4–3.4 cal ka BP as indicated by paleosols. These paleosols were again buried by fan sediments marking the first phase of accelerated geomorphodynamics during the Late Holocene. Both the local onset of human activities and the regional Mid-Holocene aridization with rapid climate changes play a role. The increased number of archeological sites and high human pressure on the environment during the Hellenistic–Roman transformation in the Deliktaş area and Pergamon micro-region were hypothesized to contribute to a phase of increased geomorphodynamic activity during the last 2.5 ka. This, however, is less apparent in our record. Our study emphasizes the importance of both, the climatic system and rural-urban cultural history, on landscape development, suggesting potential responses of locally diverse geomorphodynamics on regional-scale transformation in the eastern Mediterranean.

Ninard, Krzysztof; Stolarczyk, Mateusz; Łapcik, Piotr; Uchman, Alfred

2023 Holocene

doi: 10.1177/09596836231185838

The paleopedological record documented in aeolian dunes of the eastern European Sand Belt comprises predominantly Arenosols and only occasionally well-developed Podzols. There are several Late Pleistocene pedostratigraphic marker horizons of varied soil types designated in the European dune and loess deposits, but none falls within the range of the Holocene. Buried Podzol occurrences found recently in 10 inland dune sites dispersed throughout Central and Eastern Poland share similar pedological properties, geomorphological setting, and age in the 5th–15th century AD range of the historical Middle Ages. Therefore, they meet the criteria for distinction as a pedostratigraphic marker under the name Grębociny soil, after a locality with the most advanced podzolization of the paleosol dated to the High Middle Ages (1000–1300 AD). Preservation of the soils was enabled by burial during anthropogenically induced dune remobilization. At least some of the investigated dunes were used as pasture during soil development, as evidenced by tetrapod hoofprints recorded in and above the buried Podzols. Prevalent podzolization during the Middle Ages, in contrast to preceding and later times, could be facilitated by not only an impact of agriculture and forestry, but also relative warmth and humidity of the Medieval Climatic Optimum (ca. 900–1400 AD).

Nikolaeva, Svetlana; Tolstobrov, Dmitry; Ryazantsev, Pavel

2023 Holocene

doi: 10.1177/09596836231197738

In this article we describe and interpret disturbances in the sedimentary records of four lakes on the western flank of Lake Imandra (NE Fennoscandia, Kola Peninsula). The research framework comprises sedimentological and textural criteria for a visual description of sedimentary structures sediment core data, chronological (radiocarbon dating) data, and ground-penetrating radar (GPR) data. Disturbances preserved in lake sequences contain a mixture of chaotic fragments of sand, silt, polychromatic gyttja, peat, and wood fragments embedded in the organogenic matrix. The synchronicity of disturbances, fast sediment accumulation in lakes, relationship with Quaternary faults, the observed mass movements in lake sediments are interpreted as potential consequences of the earthquake shaking. A seismic event with a magnitude Mw no less than 4.5–5 and intensity of shaking I0 = IV–VI took place in the Middle Holocene, 6400–6100 cal. yr BP. Our studies show that although this area is not seismically active today, some of the main fault zones experienced short periods of reactivation also in the postglacial time, when glacioisostatic rebound after the ice retreat was already very low.

Abegunrin, Ayobami; Hepp, Daniel A; Gugliotta, Marcello; Mörz, Tobias

2023 Holocene

doi: 10.1177/09596836231197732

During the Late Pleistocene, the Palaeo-Ems system (PES) was one of the major tributary channels feeding the Elbe Palaeovalley (EPV) and formed an important part of the drainage system of the continental northwestern Europe unglaciated hinterland. In this study, a detailed interpretation of high-resolution 2D sub-bottom profiler and Boomer grids were used to map the overall course of the submerged PES channel, as well as its spatial and stratigraphic relationships with other Quaternary geological units in the German North Sea. Mapping of buried tunnel valleys, a lacustrine-fill unit, straight channel structures was also carried out. The sedimentary record of the PES is represented by a low gradient and meandering channel which branched into two major pathways as it approached the EPV western flank. Its upstream to downstream trends, coupled with seaward decreasing gradient and sinuosity, are similar to those visible in present-day river deltas. Both the PES and EPV subsequently formed a combined depositional system, which was successively drowned due to the fast-rising relative sea level that overwhelmed the adaptation capabilities of the joint drainage system. For the first time, this study sheds light onto the PES/EPV morpho-stratigraphic relationships which played a key role in the coastal landscape architecture of the German North Sea since the Late Pleistocene.

de Graauw, Kristen; Rochner, Maegen; van de Gevel, Saskia; Stachowiak, Lauren; Collins-Key, Savannah; Henderson, Joseph; Merrill, Zachary; Hessl, Amy

2023 Holocene

doi: 10.1177/09596836231200437

Dendroarchaeological data from historic structures and artefacts have the potential to extend tree-ring chronologies spatially and temporally, especially where old-growth forests have been extensively modified or harvested. While these data may contribute to an improved understanding of past climate and ecology, critical differences in the properties of live-tree and historic-timber data might affect results and interpretations of large-scale studies, such as those relying on large datasets from public databases like the International Tree-Ring Data Bank (ITRDB). The objective of this work was to compare summary measures of live-tree versus historic-timber datasets likely to affect outcomes and inferences of typical paleoenvironmental applications. We used 99 live-tree (LT) and 41 historic-timber (HT) datasets collected in the Appalachian region of the eastern United States and compared common analytical measures for understanding past climate and ecology, including temporal coverage, species composition, recruitment patterns, segment length, series coherence/mean interseries correlation (as Rbar), expressed population signal (EPS), subsample signal strength (SSS) and response to drought and extreme climate events. We found that tree-ring data from historic timbers record some ecological events similarly to live trees and are sensitive to some climate conditions, with important caveats related to the influence of site and tree selection on analytical measures. In some cases, these caveats can be overcome through improved collection of metadata and additional analyses. In all cases, potential differences in LT and HT data should be considered by those who perform large-scale analyses using public tree ring databases, especially as more scientists contribute historic-timber datasets.

Zhuang, Yijie; Wei, Xingtao; Zhuang, Lina; Zhang, Xiaohu; Xu, Junjie

2023 Holocene

doi: 10.1177/09596836231197736

The history of water management is closely intertwined with evolution of social structures. In particular, the emergence of rice farming and transition to sedentary life contributed significantly to the development of water management practices, with increasing labour and economic investments to build and operate water-management infrastructures. Here we present archaeological, archaeobotanical and geoarchaeological evidence of early water management obtained from the excavations of three early-to-middle Holocene sites in the upper and middle Huai River region (UMHR), including Hanjing from Sihong County of Jiangsu Province and Xielaozhuang and Zhangwangzhuang from Luohe City and Zhumadian City of Henan Province. Our 14C dates suggest multiple episodes of regional inhabitation in the UMHR region. Our results also reveal that the wells at Xielaozhuang represent some of the earliest attempts to ensure water consumption in the village, and importantly, the rice-field-like structures at Hanjing and Zhangwangzhuang are evidence of a more systematic effort to modify and transform local landscapes for rice cultivation and related economic activities. In line with the results from published phytolith studies, we found that the early experiment of rice cultivation altered local soil and hydrological conditions at these sites. These early forms of rice fields share some similarities in micro-and-macro- morphologies and represent successful adaptations to the low-lying plains that continued to have fluctuating hydrological regimes. The construction and operation of these wells, moats and rice-field-like structures stimulated collaboration beyond individual households and groups in these early-to-middle Holocene villages in the UMHR region and thus would have had profound social and economic ramifications.

Wogau, Kurt H.; Keenan, Benjamin; Arz, Helge W.; Böhnel, Harald N.

2023 Holocene

doi: 10.1177/09596836231185828

The Northern Mesoamerican Frontier was a complex multicultural region characterized by frequent human settlement changes and shifts in agricultural conditions during the Late Preclassic period (~400 BCE-150 CE). Here, we report a high-resolution paleoenvironmental record from the varved sedimentary sequence of the crater maar La Alberca which spans the Late Preclassic (~400 BCE-150 CE) to part of the Early Classic period (~150 CE-250 CE) corresponding to Late Chupicuaro phase (400 BCE-100 CE) and Mixtlan phase (0–250 CE). Our work aims to study the paleoenvironmental conditions during the rise of agriculture in the Northern Mesoamerican Frontier and provide insights related to landscape alteration by human activity. To reach these aims, a multiproxy investigation was conducted by means of varve counting, high-resolution XRF scans, magnetic susceptibility, pollen data and fecal stanol biomarkers as a proxy for human population change. Our results reveal two varve type. Type 1 is characterized by the alternation of detrital-organic layers and aragonite layers, type 2 by alternating detrital-organic layers with an organic layer formed by diatom frustules and aragonite layers. This study suggest that the increase of erosion by human activity during the Late Chupicuaro phase (400 BCE-100 CE) and the start of the Mixtlan phase (0–250 CE) coincide with a high percentage of Amaranthaceae pollen, a rise of sedimentation rates, increase in nutrient content and the increase of human waste flux interpreted with the (Coprostanol + epi) :((Coprostanol + epi)+cholestanol biomarker. Moreover, a wetter period (~137 BCE-37 CE) interpreted during the Late Chupiacuaro phase and the start of the Mixtlan phase could suggest favorable environmental conditions for the establishment of agriculture.

Lundström, Victor

2023 Holocene

doi: 10.1177/09596836231185839

The use of archaeological proxy records representative of population dynamics is paramount for a richer understanding of prehistoric cultural change, but its use require a dialectic assessment between proximate climatic drivers and ultimate cultural responses. Focusing on the Stone Age archaeological record of Western Norway (11,500–4300 cal. BP), this paper presents an exhaustive empirical curation and statistical testing between changing climates and demographic responses among coastal hunter-fisher-gatherers. The results connect long-term demographic fluctuations with changes in annual mean temperatures and seasonality and the results are discussed in relation changes in technology, subsistence and mobility. The paper also highlights the process of population decline and cultural loss towards the end of the Late Mesolithic (ca. 7000–6000 cal. BP) and emerging cultural novelties and population re-growth during the Early and Middle Neolithic (ca. 6000–4300 cal. BP). However, despite its strong correlation, the archaeological record of Western Norway lacks sufficient detail to ascribe an exclusive explanatory role to climate change, especially in episodes of significant population decline. This helps to emphasise that changing climates, while evidently central, form but a part of a larger system of interactions leading to demographic fluctuations and cultural change, the substantiation of which requires significant empirical improvements to the archaeological record.

Topness, Rebecca G; Vachula, Richard S; Balascio, Nicholas L; D’Andrea, William J; Pugsley, Genevieve; Dia, Moussa; Tingley, Martina; Curtin, Lorelei; Wickler, Stephen; Anderson, R Scott

2023 Holocene

doi: 10.1177/09596836231185826

Paleofire records document fire’s response to climate, ecosystem changes, and human-activity, offering insights into climate-fire-human relationships and the potential response of fire to anthropogenic climate change. We present three new lake sediment PAH records and a charcoal record from the Lofoten Islands, Norway to evaluate the Holocene fire history of northern Norway and examine human impacts on fire in this region. All three datasets show an increase in PAH accumulation rate over the past c. 7500 cal years BP, with an increase c. 5000 cal years BP that signals initial human impacts on fire activity. More significant increases c. 3500 cal years BP reach a maximum c. 2000 cal years BP that correlates with the establishment and expansion of agricultural settlements in Lofoten during the Late Bronze Age and Pre-Roman Iron Age. Decreased PAH accumulation rates c. 1500–900 cal years BP reflect less burning during the Late Iron Age and early medieval period. A shift toward higher molecular weight PAHs and increasing PAHs overall from c. 1000 cal years BP to present, reflects intensified human activity. Sedimentary charcoal (>125 and 63–125 µm) in the Lauvdalsvatnet record does not vary until an increase in the last 900 years, showing a proxy insensitivity to human-caused fire. The Late-Holocene increase in fire activity in Lofoten follows trends in regional charcoal records, but exhibits two distinct phases of increased fire that reflect the intensity of burning due to human landscape changes that overwhelm the signal of natural variations in regional fire activity.