Quaternary International最新文献

This study presents a multidisciplinary approach between palaeoecology and the analysis of historical archives to reconstruct forest history subjected to long-term human activities. We focus on a case study from the southern French Alps (the Bléone Valley), for which a rich historical corpus but little palaeoenvironmental data are available. We compared and contrasted (i) pedoanthracological data obtained along an altitudinal transect (ca 400 m), (ii) dendrochronological data from historical buildings and old living trees, and (iii) historical data from written sources on forest management and land-use change. The aim of this paper is to demonstrate that the comparison between different proxy data to understand the history of mountain forest ecosystems and human-forest interactions is very challenging. We show that the spatial distribution of forest and treeline position have been impacted by human activities, mainly due to agro-sylvo-pastoral practices through the use of fire and forest cutting to maintain open pasture lands and local building purposes. Despite centuries of local agro-sylvo-pastoral activities, the forest composition has remained relatively unchanged since the Middle Ages. Our comparison of historical documents with dendrochronological data on local buildings and soil charcoal data shows that the local demands of wood cannot explain the observed large-scale changes in forest spatial continuity. Curiously, the highest demand for wood by local residents did not occur in pace with modern demographic boom (17th century), as would be expected. Thus, we suggest that supra-regional external regulations and State's control played a more important role in forest management. Royal shipbuilding industry, more lucrative economic stakes, and expanded demand for timber for construction of buildings in urban areas of the lower valleys and plains are among the external factors which impacted forest exploitation during periods when logging was prohibited.

The drainage basins of Peninsular India are characterized by silicate-dominated lithologies, and influenced by Indian Summer Monsoon (ISM) precipitation. The Godavari River Basin (GRB), the largest river basin in Peninsular India situated within the ISM region, represents an ideal case for assessing weathering and climate interaction at different timescales. In this contribution, major and trace elemental geochemistry of a radiocarbon-dated sediment core (CY; 54.2 m long) from the Godavari delta region was investigated to reconstruct erosional changes in the Godavari basin in response to ISM variations during the Late Holocene. Comparison of geochemical data for the CY sediments and their possible sources confirm dominant sediment supply from the Deccan basalts and Archean Gneisses to the site. A distinct increase in Ti/Al, Ca/Al, and Cr/Al, along with a decrease in CIA* and LREE/HREE at 3.2 ka BP, point to relative increase in sediment supply from the Deccan Traps. Inverse model calculations of Al-normalized ratios of selected elements (Ti, Fe, V, Cr, Cu, Co) estimate that the core site on average receives ∼41 % sediments from the Deccan regions, which increased by ∼20% since last 3.2 ka BP. This accelerated erosion is attributed to the coupled effect of aridity-induced Deccan upland erosion with a relative decrease from the Archean rock source. This period of accelerated erosion coincides with the abandonment of Chalcolithic settlements.

In this study, we aim to reconstruct southern India's intrinsic environmental changes over the past 1500 years from 3330 to 1830 cal BP by investigating the sedimentation and weathering dynamics in Lake Shantisagara, one of Karnataka's largest lakes. Four distinct climatic phases were delineated based on sedimentological, geochemical, and End Member Modelling Analysis (EMMA) results. Phase 1 (3330-3100 cal BP) is a short-term low rainfall zone characterized by a calm hydrodynamic environment and weak chemical weathering. Phase 2 (3100-2800 cal BP) is a climatically unstable phase, fluctuating between low and high rainfall conditions. Phase 3 (2800-2200 cal BP) is characterized by a stable, low rainfall climate with weak fluvial activity and chemical weathering. It is followed by a highly unstable phase marked by frequent extreme climatic events (Phase 4; 2200-1830 cal BP). Our study reveals a highly unstable hydrodynamic condition that culminated in potentially catastrophic high rainfall events that triggered intense and frequent floods in southern India around ∼2208, 2054, 1958, and 1891 cal BP. Comparative studies of regional records show that the regional climate pattern is similar. There is a strong effect of Total Solar Irradiance (TSI), Sea Surface Temperature (SST) off the Malabar coast, location of the Intertropical Convergence Zone (ITCZ), and the El Niño Southern Oscillation (ENSO) on the monsoon system in southern India. This suggests that there is a global teleconnection.

In Central America and the Caribbean, periods of increased aridity that correspond to the Terminal Classic Drought (TCD; 1200–850 cal yr BP) and the Little Ice Age (LIA; 500–100 cal yr BP) have been documented in many paleoclimate records. Compound-specific hydrogen (δD_alkane) and carbon (δ¹³C_alkane) isotopic compositions of n-alkanes in lake sediment can be used to interpret changes in paleoprecipitation and terrestrial paleovegetation, respectively. To assess the climate forcing mechanisms that drove the TCD and LIA, we established a multidecadal to centennial-scale late-Holocene reconstruction of precipitation variability and vegetation change at mid-elevation on the Caribbean slope of Costa Rica, developed from new δD_alkane, δ¹³C_alkane, and geochemical analyses and previous pollen and microscopic charcoal analyses from a sediment core from Laguna María Aguilar. Laguna María Aguilar is a freshwater lake located at 770 m elevation on the Caribbean slope of the Cordillera Central. During the TCD, δD_alkane data for María Aguilar indicate relatively wet conditions compared to the mean δD_alkane value for the entire record. Other proxy records for the TCD indicate that the Pacific slope of Costa Rica and sites above 3400 m near the continental divide experienced generally drier conditions than mid- and low-elevations on the Caribbean slope. We conclude that the TCD may have been driven by both Pacific and Atlantic climate-forcing mechanisms. During the LIA, the Laguna María Aguilar δD_alkane record indicates an increase in hydroclimate variability, with some of the highest recorded δD_alkane values (driest conditions) during the earliest portions of the LIA, but conditions were not persistently dry for the entirety of the LIA. Based on regional paleoclimate records overall, the LIA drought appears to be more clearly expressed on the Caribbean slope than on the Pacific slope of Costa Rica, indicating that the LIA was perhaps driven primarily by Atlantic Ocean conditions and climate dynamics.

The mountainous region of central Shandong Province in eastern China is renowned for its high frequency of rainstorms, which often result in devastating flood disasters and have profoundly affected the evolution of local ancient civilizations. To identify ancient flood disaster events, recognizing sediment signatures via multiple indices is important. Here, we investigated the 2018 flood deposits in the Danhe River Basin and sampled short core DH2, on which the grain size, total organic matter (TOM) content, carbonate content, magnetic susceptibility (MS) and pollen were measured. The fine grain size of the flood sedimentary layer reveals that the flood energy in the alluvial plain area is usually weak. The pollen species and concentration and the tree pollen content in the flood layer are significantly greater than those in the soil layer, suggesting that the flood sediment mainly originates from the mountainous areas in the upper reaches of the river, which provides more forest vegetation information. The MS of flood deposits is lower than that of the soil layer, which is mainly related to the intensity of pedogenesis. The research results indicate that the flood sediments in the downstream floodplain areas of small watersheds are predominantly composed of fine-grained components, with characteristics of high loss on ignition, low magnetic susceptibility, high pollen abundance and diverse species. These findings establish a multi-index identification system for paleoflood sedimentation, which has important reference significance for the study of paleoflood sedimentology and hydrology.

This review paper delves into the geological history of Mallorca, focusing on the Middle to Late Pleistocene period and its impact on the landscape and climate of the island. The Quaternary, particularly, the Last Interglacial, represents a relatively short timeframe on the global chronological scale, yet it is notable for its climatic instability and complex alternation of glacial and interglacial phases, leading to fluctuations in sea levels. During the last interglacial, millennial-scale fluctuations, known as Dansgaard–Oeschger and Heinrich events, occurred. Aeolianites are thought to have formed during periods of sparse vegetation cover and abundant sediment availability from the sea bed or platform (Heinrich events), while colluvial deposits and paleosols are believed to represent periods of reduced sediment supply and enhanced pedogenesis (Dansgaard–Oeschger events). These different deposits reflect climatic shifts and sea-level changes, offering insights into the environmental history of the island. Fossil evidence, including Strombus bubonius (currently known as Thetystrombus lauts) or “Senegalese hosts,” reveals past warm climatic fluctuations, particularly during the Last Interglacial. Myotragus balearicus exemplifies evolutionary adaptation and isolation on the island, offering a unique perspective on its paleontological legacy. The integration of stratigraphic characteristics and literature research on Optically Stimulated Luminescence (OSL) dating techniques provides a comprehensive temporal framework, spanning from Marine Isotope Stage 6 (MIS 6) to Marine Isotope Stage 2 (MIS 2), enabling the precise dating of geological events and a stratigraphic correlation.

Laoya Cave is a significant prehistoric human site in Guizhou Province, Southwest China, and optically stimulated luminescence (OSL) and a Bayesian depositional model were used to update the chronology of the cave. Six OSL samples were dated to 16.7 ± 1.2, 18.0 ± 1.1, 28.8 ± 2.3, 32.1 ± 2.8, 57.7 ± 6.5, and 74.0 ± 5.9 ka, respectively, and the Bayesian deposition model has provided a coherent chronological framework, revealing boundaries with median ages of 18.5, 25.0, 27.5, 28.6, 29.9, and 74.4 ka for Boundaries 1/2, 2/3, 3/4, 4/5, 5/6, and 6/9, respectively. By comparing the new chronological framework with the related records of paleoclimate and human activities, we gain insight into the relationship between the environment and Paleolithic hominins at different times. During relatively warmer periods, humans tend to spread, while in relative colder climates, they tend to rely more heavily on caves and employ hunting strategies with an equal age distribution. These survival strategies help humans prevent the threats of cold weather. Additionally, the analysis of OSL dating results uncovers a discrepancy between OSL and accelerator mass spectrometry radiocarbon (AMS ¹⁴C) dating methods, with AMS ¹⁴C dates generally appearing older at later ages (<∼30 ka). This phenomenon may be due to disturbances caused by human activity, and OSL dating may recognize this to some extent.

This study uses increased specialisation in husbandry practice and the development of larger livestock as a proxy for spatial and temporal variation in Roman influence in southeast Europe. Data are presented from three regions subject to varying levels of Roman control: (a) the Balkan provinces, under long-term occupation; (b) Dacia, a province from 106 to 271/275 CE; and (c) regions beyond the Empire to the northwest and northeast. While little change in husbandry practice occurs during the early Roman occupation in the first centuries BCE and CE, clear changes are evident across occupied regions in the second and third centuries CE. A cattle-focused economic system develops, likely influenced by an increased focus on arable production, and a significant increase in cattle and sheep/goat size is observed. In the Balkan provinces, while larger livestock persist into the early Byzantine period, there is a decline in specialised cattle exploitation at rural sites in the late Roman period, and at urban sites in the early Byzantine period, concurrent with a decrease in Roman political control. In Dacia, in contrast, average livestock size decreases after the Roman withdrawal, while specialised cattle husbandry persists for several centuries. Beyond the Empire, specialised cattle husbandry is evident from the late Iron Age, but increases in the second and third centuries, perhaps indicating the spread of Roman influence beyond occupied regions.