Long-term records of wildfires and their controlling factors are important sources of information for informing land management practices. Here, dendrochronology and lake sediment analyses are used to develop a 3500-yr fire and vegetation history for a montane forest in Jasper National Park, Alberta, Canada. The tree-ring record (AD 1771-2012) indicates that this region historically experienced a mixed-severity fire regime, and that effective fire suppression excluded widespread fire events from the study area during the 20th century. A sediment core collected from Little Trefoil Lake, located near the Jasper townsite, is analyzed for subfossil pollen and macroscopic charcoal (>150 μm). When comparing the tree-ring record to the 3500-yr record of sediment-derived fire events, only high-severity fires are represented in the charcoal record. Comparisons between the charcoal record and historical climate and pollen data indicate that climate and vegetation composition have been important controls on the fire regime for most of the last 3500 yr. Although fire frequency is presently within the historical range of variability, the fire return interval of the last 150 yr is longer than expected given modern climate and vegetation conditions, indicating that humans have become the main control on fire activity around Little Trefoil Lake.

We reconstructed the late Holocene vegetation of the Nain region (northern Labrador, northeastern Canada) in order to assess the influence of climate and historic land use on past shifts in forest composition. Chronostratigraphy was used in combination with macrofossil and pollen data from monoliths sampled from four peatlands. Paleoecological reconstructions produced a vegetation history spanning 4900 years for the Nain region that is largely concordant with other studies in Labrador. An initial open forest tundra phase was followed by an increase in tree cover at around 2800 cal yr BP. Paludification began ∼200 cal yr BP. A decline in Picea and its subsequent disappearance from most of the sites occurred ∼170 cal yr BP (AD 1780) in a period of relatively mild conditions during the Little Ice Age. This event was followed by the establishment of Larix laricina in the region. Local anthropogenic factors are likely responsible for these later developments, as they were not observed in other regional studies. The period around AD 1780 corresponds to the establishment of the Moravian missionaries on the Labrador coast, which increased the need for fuel and lumber. We conclude that changes in land use are reflected in the patterns of vegetation and hydrological change at the study sites.

The Carolina Sandhills is a physiographic region of the Atlantic Coastal Plain province in the southeastern United States. In Chesterfield County (South Carolina), the surficial sand of this region is the Pinehurst Formation, which is interpreted as eolian sand derived from the underlying Cretaceous Middendorf Formation. This sand has yielded three clusters of optically stimulated luminescence ages: (1) 75 to 37 thousand years ago (ka), coincident with growth of the Laurentide Ice Sheet; (2) 28 to 18 ka, coincident with the last glacial maximum (LGM); and (3) 12 to 6 ka, mostly coincident with the Younger Dryas through final collapse of the Laurentide Ice Sheet. Relict dune morphologies are consistent with winds from the west or northwest, coincident with modern and inferred LGM January wind directions. Sand sheets are more common than dunes because of effects of coarse grain size (mean range: 0.35-0.59 mm) and vegetation. The coarse grain size would have required LGM wind velocities of at least 4-6 m/sec, accounting for effects of colder air temperatures on eolian sand transport. The eolian interpretation of the Carolina Sandhills is consistent with other evidence for eolian activity in the southeastern United States during the last glaciation.

Precipitation in Japan is strongly affected by the East Asian monsoon system, resulting in wet summer conditions and relatively dry winter conditions. Few paleo-monsoon records exist from northeastern Asia, especially records showing decadal- to centennial-scale variability. Here we present a molecular hydrogen isotope (δD) record from Lake Kaiike, a small coastal lake in southwest Japan, to provide insight into monsoonal precipitation over the past two millennia. The δD record of friedelin, a terrestrial higher plant lipid, reveals three major shifts in precipitation: a decline from >-185‰ to <-190‰ at 1700 cal yr BP suggests a change to wetter conditions; values between -187.5‰ and -180‰ from 1480 to 800 cal yr BP indicate reduced precipitation; and a decline to below -195‰ after 800 cal yr BP reflects moist conditions during the Little Ice Age. These results highlight variability in the intensity of the East Asian Summer Monsoon occurring on decadal to centennial time scales. El Niño-like conditions are likely responsible for periods of high monsoon intensity, but comparison with other records in the region (northeast China and Japan) shows that contradicting patterns also exist, and so explaining these rainfall patterns is not straightforward.

Archaeologists commonly use the onset of the construction of large burial monuments as a material indicator of a fundamental shift in authority in prehistoric human societies during the Holocene. High-quality direct evidence of this transition is rare. We report new interdisciplinary research at the archaeological site of Nan Madol that allows us to specify where and when people began to construct monumental architecture in the remote islands of the Pacific. Nan Madol is an ancient administrative and mortuary center and the former capital of the island of Pohnpei. It was constructed over 83 ha of lagoon with artificial islets and other architecture built using columnar basalt and coral. We employed geochemical sourcing of basalt used as architectural stone and high-precision uranium-thorium series dates (230Th/U) on coral from the tomb of the first chief of the entire island to identify the beginning of monument building at Nan Madol in AD 1180-1200. Over the next several centuries (AD 1300-1600) monument building began on other islands across Oceania. Future research should be aimed at resolving the causes of these social transformations through higher quality data on monument building.

Using phytolith analysis from a well-dated and high-resolution sediment sequence in the apex of northern Yangtze Delta, we investigate environmental changes, the rise and decline of rice exploitation and possible impacts of environment on rice exploitation during the early mid-Holocene. The phytolith sequence documents a relatively warm and dry interval during ca.9000 to 8200 cal yr BP, followed by climatic amelioration before 7200 cal yr BP. Phytolith evidence indicates that rice exploitation at the apex of northern Yangtze Delta began at 8200 cal yr BP, flourished by 7700 cal yr BP and ceased after 7400 cal yr BP. The first emergence of marine diatom species approximately 7300 cal yr BP likely indicates an accelerated sea-level rise. The apparent correlation of the initiation of rice exploitation with climatic amelioration during the early mid-Holocene suggests that climatic changes may have played an important role in facilitating rice exploitation. Both the ideal climatic conditions and stable sea level enabled flourishing rice exploitation during 8200 to 7400 cal yr BP. Although the climate remained warm and wet after 7400 cal yr BP, local sea-level rise possibly led to the termination of earlier rice exploitation at this site of the northern Yangtze Delta.

The Homo erectus cranium, mandible and hundreds of associated lithic artifacts found in Lantian (central China) in the 1960s demonstrate that the area was important for hominin habitation during the early to middle Pleistocene. However, the region, which was not adequately researched until the early 2000s, still poses several questions regarding hominin behavior and lithic technology development. In this study, three loess-paleosol sequences (the Jijiawan, Ganyu and Diaozhai sites), from which in situ stone artifacts were recovered, are investigated and dated by optically stimulated luminescence (OSL), magnetostratigraphy and stratigraphic correlation. The results demonstrate that the artifacts are located within paleosol layers S4 (correlative with marine oxygen isotope stage (MIS) 11), S3 (MIS 9), S2 (MIS 7), and S1 (MIS 5); and within loess layer L1 (MIS 2-4). The main stone-knapping technique used was direct hard hammer percussion. In addition, the technological features of the stone tools found at these sites exhibit little variation, indicating the presence of a long-established, stable technology in the Lantian area. Our observations show that the ancient humans lived episodically on the terraces of the Bahe River from the early Pleistocene, indicating a long history of hominin occupation of the region.

The Weihe River in central China is the largest tributary of the Yellow River and contains a well-developed strath terrace system. A new chronology for the past 1.11 Ma for a spectacular flight of strath terraces along the upper Weihe River near Longxi is defined based on field investigations of loess—paleosol sequences and magnetostratigraphy. All the strath terraces are strikingly similar, having several meters of paleosols that have developed directly on top of fluvial deposits located on the terrace treads. This suggests that the abandonment of each strath terrace by river incision occurred during the transition from glacial to interglacial climates. The average fluvial incision rates during 1.11—0.71 Ma and since 0.13 Ma are 0.35 and 0.32 m/ka, respectively. These incision rates are considerably higher than the average incision rate of 0.16 m/km for the intervening period between 0.71 and 0.13 Ma. Over all our results suggest that cyclic Quaternary climate change has been the main driving factor for strath terrace formation with enhanced episodic uplift.

Su Fossu de Cannas (SFC) cave is one of several known cavities in the Sadali plateau in Sardinia, Italy. The evolution of the cave is the result of complex erosional and deposital processes that occurred during the Neogene and Quaternary. A fossiliferous cemented conglomerate, containing various deer remains, now forms the ceiling of a cavity (tunnel). The faunal remains belong to a large cervid, which show some morphological affinity with large deer that have an endemic Sardinian lineage (Praemegaceros sardous — Praemegaceros cazioti). Palaeoecological data based on some peculiar features and the large size of the SFC deer suggest that it is the most primitive Megacerine found in Sardinia to date, and the first representative of the endemic lineage. The 450 ka U—Th age for the flowstone capping the fossiliferous layer defines: the end of sedimentation in which Sadali deer remains are preserved; and the dispersal from the mainland of the ancestor of the endemic Sardinian Megacerini. Stratigraphic and micromorphological analyses of the cave deposits allow the reconstruction of the timing of the cave’s development throughout the Pliocene to the Holocene.

Anisotropy of magnetic susceptibility (AMS) is a frequently applied method in sedimentology, especially in the determination of the orientation of transport processes. We present an analysis of magnetic fabric (MF) studies on loess. New aspects of fabric development reveal: i) The deposition of the aeolian sediments was controlled by gravity, low-energy transport and local geomorphology, hence no clarified wind direction can be defined. ii) The influence of phyllosilicates is also significant among the magnetic components. iii) While the primary MF is relatively well-defined, the secondary MF is influenced by several processes. The analysis of stereoplots combined with the q—β diagram and photostatistics showed encouraging results during the characterization of various secondary MF such as redeposited MF and pedogenic fabric. iv) Changes in processes from aeolian to water-lain deposition and the increasing transportation energy were reflected by the connection between AMS and observed micro-scale sedimentary features. v) A relationship was obvious between the degree of pedogenesis and the transformation of sedimentary MF into a vertical MF typical for paleosols. vi) The significant role of very fine grained magnetite on the formation of inverse MF could not be excluded.

A 25 m-thick outcrop section exposed at Torre Mucchia, on the sea-cliff north of Ortona, eastern central Italy, comprises a rare Middle Pleistocene succession of shallow-water and paralic sediments along the western Adriatic Sea. An integrated study of the section, including facies and microfacies analyses, and characterization of paleobiological associations (mollusks, fishes, ostracods, foraminifers and pollen), enable a detailed reconstruction of the paleoenvironmental and paleoclimatic conditions during deposition. The shallow-water deposits include a transgressive, deepening- and fining-upward shoreface to offshore-transition facies succession overlain by a regressive shoreface-foreshore sandstone body with an erosive base and a rooted and pedogenically altered horizon at the top that imply deposition during sea-level fall. This forced regressive unit is overlain by paralic strata forming a transgressive succession comprising palustrine carbonates and back-barrier lagoonal mudstones. The palustrine carbonates exhibit some of the typical features encountered in palustrine limestones deposited within seasonal freshwater wetlands (marl prairies). Following the sea-level rising trend, the freshwater marshes were abruptly replaced by a barrier-lagoon system that allowed deposition of the overlying mud-rich unit. Within these deposits, the faunal assemblages are consistent with a low-energy brackish environment characterized by a relatively high degree of confinement. The pollen record documents the development of open forest vegetation dominated by Pinus and accompanied by a number of mesophilous and thermophilous tree taxa, whose composition supports a tentative correlation with Marine Oxygen Isotope Stage 17. The new pollen record from Torre Mucchia improves our understanding of the vegetation development in the Italian Peninsula during the Middle Pleistocene and sheds new light on the role played by the most marked glacial periods in determining the history of tree taxa.

Climatic variability of Marine Isotope Stage (MIS) 11 is examined using a new high-resolution direct land—sea comparison from the SW Iberian margin Site U1385. This study, based on pollen and biomarker analyses, documents regional vegetation, terrestrial climate and sea surface temperature (SST) variability. Suborbital climate variability is revealed by a series of forest decline events suggesting repeated cooling and drying episodes in SW Iberia throughout MIS 11. Only the most severe events on land are coeval with SST decreases, under larger ice volume conditions. Our study shows that the diverse expression (magnitude, character and duration) of the millennial-scale cooling events in SW Europe relies on atmospheric and oceanic processes whose predominant role likely depends on baseline climate states. Repeated atmospheric shifts recalling the positive North Atlantic Oscillation mode, inducing dryness in SW Iberia without systematical SST changes, would prevail during low ice volume conditions. In contrast, disruption of the Atlantic meridional overturning circulation (AMOC), related to iceberg discharges, colder SST and increased hydrological regime, would be responsible for the coldest and driest episodes of prolonged duration in SW Europe.