High vegetation and environmental diversity during the Late Glacial and Early Holocene on the example of lowlands in the Czech Republic

The diversity of vegetation and the environment in the Late Glacial period in the Elbe region is illustrated by a comparison of three palynological localities. The localities differ in their history, profile lithology and position relative to the Elbe river. The Hrabanovská ?ernava profile holds a record of the development of a shallow lake, which was surrounded by a cold continental steppe in the Early Dryas. Evidence of a pine forest in the Late Glacial period is captured in the surroundings of the profile Chrást. The Mělnický úval — P?ívory locality is an interdune infill, where marl sediments redeposited in shallow water. The surrounding vegetation was diffuse and influenced by erosion. In the Early Holocene, the landscape was covered by an open birch-pine forest. Broad-leaved woody species appeared later. Localities in the Elbe region share a high proportion of Pinus throughout the Holocene as a result of the spread of drift and terrace sands. The human impact in the mid Holocene manifests as evidence of intensive charring of localities.     

Forest Fire in Early Holocene Forest Changes at Lake Barrine,Australia

Fire is one of major factors in forest ecosystem. This paper presents results of charcoal and pollen analysis on Early Holocene sediments in Lake Barrine, Australia. Time series analysis and mathematical modeling were used to infer patterns of forest fire, relationship between fire and major vegetation elements and the roles forest fire played in forest changes. The analysis shows that in Early Holocene fire frequencies in this area decreased from one major fire in less than 50 years in the early Eucalyptus forest stage (zone S1) to one in 230 years in the later stage (zone S2). After the establishment of rainforest, fire activities were much weaker. The effects of fire on three major elements of Eucalyptus forest varied according to their different fire adaptive traits. In process of the change from Eucalyptus, forest to rainforest, fire protected-the former and delayed.the establishment of the later.     

Late Quaternary Palaeoichnological Sites from the Southern Atlantic Coast of Buenos Aires Province,Argentina: Mammal,Bird and Hominid Evidence

Palaeontological and palaeoichnological studies were made along the southeastern coast of Buenos Aires province, Argentina. Continental Late Pleistocene and continental, transitional and marine Holocene stratigraphic units were identified. The former are represented by fossil mammal bones and ichnites dated from 16,000 to 12,000 y. B.P. Continental Early Holocene beds dated circa 8,100 years B.P. contain fish, rodent and bird remains. Middle Holocene sediments 6,930 to 6,570 years B.P. are recorded by deposits bioturbated by estuarine crabs. During the Late Holocene, between 5,000 and 4,800 B.P., a marine transgression is recorded by a very rich mollusc fauna. The palaeoenvironmental variety recorded along a few tens of kilometers of the coast is a distinctive feature of this part of the Argentine coastal region. At Monte Hermoso beach, in the eastern part of the studied zone, archaeological materials were dated 7,300 years B.P., and human footprints dated 7,125 years B.P. were also recorded. In January 2005 some isolated human footprints were found at Pehuen-Co palaeoichnological site, which are older than those found at Monte Hermoso beach and of the same age as the oldest human archaeological findings in Patagonia, that is about 12,000 yeas B.P.     

Morphologic variability of the coccolithophorid Calcidiscus leptoporus in the plankton, surface sediments and from the Early Pleistocene

On a global scale, morphological variability of the extant coccolithophorid Calcidiscus leptoporus (Murray and Blackman, 1898) Loeblich and Tappan was investigated in surface sediments and plankton samples and from an Early Pleistocene time-slice (1.8 Ma to 1.6 Ma). In the bivariate space coccolith diameter versus number of rays in the distal shield, Holocene samples follow a single, unimodal morphocline. Sample means of coccolith size and number of elements group in three clusters, I, II and III, which are of biogeographic significance. Clusters II and III coccoliths (mean coccolith size of 5.0 μm and 20.9 elements, and 6.6 μm and 25.6 elements, respectively) are found in a tropical belt extending from 11 °N to 17 °S with an annual minimum sea-surface temperature above 23.5 °C. Cluster I coccoliths (5.8 μm, 20.7 elements) are found in samples outside that belt. The distribution of coccoliths in the surface sediments is tentatively interpreted to be a result of mixing to a varying degree of at least three different morphotypes (‘small’, ‘intermediate’ and ‘large’), which were identified in the living plankton, and which are separated from each other at 5 μm and 8 μm mean coccolith diameter, respectively. A comparison of the surface sediments with the Early Pleistocene assemblages revealed that between 1.6 Ma and 1.8 Ma two morphoclines A and B existed, the first of which persisted until the Holocene in the form of C. leptoporus, while the second comprises only extinct morphotypes including Calcidiscus macintyrei as one end-member. During the Early Pleistocene morphocline A was more homogeneous and no clusters were evident.Morphocline B shows a clear bimodality with a separation of morphotypes at 9.5 μm. Our observations suggest that morphoclines are subsets within the total stratigraphical range of a single species, and represent the global variability of that species in a particular time interval. Morphotypes, which belong to a morphocline, represent the infra-specific variability of that species within the biogeographic and stratigraphic limits of that species.     

青藏高原冬给措纳湖畔新发现的细石器及其同周边地区的技术关系

青海玛多冬给措纳湖畔新发现的海拔超过4000 m的全新世中期细石器对于我们认识青藏高原细石器乃至中国全新世的细石器的技术特点与分布格局提供了新的材料,其典型器物组合包括楔形细石核、柱形细石核、端刮器和锯齿刃器等。青藏高原全新世早中期的细石器组合中楔形细石核-柱形细石核-锥形细石核的技术传统是相对稳定的,但缺乏典型船形细石核和小型两面器等华北地区旧石器晚期细石器组合中常见的重要石器类型。通过进一步比对显示,青藏高原全新世早中期细石器的直接来源可能并非直承华北旧石器晚期的细石器传统,而与青藏高原邻近地区(我国西北地区、西南西区)全新世早中期的细石器工业具有更为密切的联系。     

Non-pollen palynomorphs in the Black Sea corridor

There have been few studies of non-pollen palynomorphs (NPP) in Holocene brackish water environments. The Black Sea is one of the world’s largest and deepest bodies of stable brackish water and a natural laboratory for study of marine carbon cycling to anoxic sediments. The main NPP in the modern sediments of this brackish water sea are dinoflagellate cysts (dinocysts), acritarchs (mainly the prasinophytes Cymatiosphaera, Micrhystridium, Sigmopollis and Pseudoschizaea) and diverse fungal remains. Other NPP include colonial algae, tintinnids, copepod and cladoceran egg covers, testate amoebae and microforaminiferal linings. These NPP assemblages are similar to those in the marginal marine environment of the Pliocene St. Erth Beds (England), but have more abundant NPP, and virtually lack scolecodonts. In the Black Sea corridor, modern assemblages from areas with salinity >22‰ have higher percentages of microforaminiferal linings and fewer prasinophytes, colonial algae and fungal spores. Prasinophytes dominate only in mid-Holocene sediments, during a 2000 years interval of sea level transgression and sapropel deposition. Early Holocene sediments have lower dinocyst diversity, increased fresh–brackish water colonial algae (Pediastrum spp. and Botryococcus braunii), zygnemataceous spores and desmids (including Zygnema, Cosmarium), ostracod linings and fewer foraminiferal linings. These assemblages are similar to those in the Baltic Sea where the annual salinity is about 6–8‰.     

Stratigraphy of the western Mediterranean and southern Calabrian ridges,eastern Mediterranean

The present paper illustrates the stratigraphic results of a transponder-navigated coring program carried out in 1978 on the southern Calabrian Ridge (Cobblestone Area 4) and western Mediterranean Ridge (Cobblestone Area 3).Semi-quantitative investigations of over 600 foraminiferal samples and 450 nannofossil slides from forty cores, with a total recovery of 333 m, comprise the data base of the study.Most of the sediments recovered are Late Pleistocene or Holocene in age. The high-resolution nannofossil biostratigraphic scheme recently proposed for the Quaternary, coupled with sapropel stratigraphy and with tephrachronology resulted in precise correlation of the cores.Mid-Pleistocene sediments were recovered in a single core from Area 4, and in one core from Area 3, both located on basin walls. Four cores from basin walls in Area 4 yielded Pliocene sediments. No sediments older than approximately 3 m.y. (foraminiferal Zone M Pl 4, Reticulofenestra pseudoumbilica nannofossil Zone) are exposed on the explored walls from the southern Calabrian Ridge. Early and Late Pliocene sediments were recovered from the walls of the deepest crater-like basin explored in Area 3, but only in dredges. In this latter area also two peculiar lithologies were cored, basically unfossiliferous, but thought to be pre-Pliocene in age: a mud breccia whose clasts yield a sparse assemblage of mid-Cretaceous planktonic foraminifera, and a dolomitic mudstone, which is attributed to the Late Messinian on the basis of correlation with a similar lithology cored at DSDP Site 374, and substantiated by analogy in X-ray controlled mineralogical composition.The fairly complete record of Late Pleistocene and Holocene sapropels recovered in the southern Calabrian Ridge discards the hypothesis that the southern part of the Ionian Sea did not undergo stagnant cycles during the ice ages.Another hypothesis relating the origin of Cobblestone topography to olistostromes is also considered untenable on the basis of the new data. The large number of cores, precisely located on a previously mapped, highly irregular bottom physiography, disproves that large-scale chaotic sedimentation occurred: debris flows recorded in base-of-slope cores document local slope failures.     

Changes in the relative abundance of Polyarthra vulgaris and P. dolichoptera,following the elimination of fish

In the last decade palynological investigations of the sediments of large lakes in the USSR (Ladoga, Onega, Kubenskoye, Vozhe, Lacha, Beloye) and the Baltic Sea have been carried out. Limnic and marine sediments are notable for their high pollen and spore concentrations and pollen diagrams from these deposits have a regional significance. The diagrams from Lakes Onega and Ladoga belong to the Kola-Karelian type while the sediments of Lacha, Vozhe, Kubenskoye and Beloye belong to the North-Russian type (Neustadt 1957). Three types of Holocene pollen diagrams are registered for the Baltic Sea. Modern and fossil pollen spectra reflect the composition of the zonal vegetation. Late-glacial sediments are found in several profiles of lake and sea deposits. Holocene deposits are divided into eight stratigraphic zones: Late-glacial sediments (DR₂-Al-DR₃) and Post-glacial sediments (PB, BO, AT, SB, SA). The zonations of lake and sea sediments can be clearly correlated.     

Holocene persistence of wooded steppe in the Great Hungarian Plain

Aim We used a combination of new and previously published palaeoecological data to test three hypotheses: (1) that wooded steppe persisted in the Great Hungarian Plain throughout the Holocene; (2) that wooded steppe and steppe were most extensive between c. 9900 and 8300 cal. yr bp (the ‘Boreal steppe’ period); and (3) that Southern Continental, Pontic and Eastern Sub‐Mediterranean steppe species reached the region during the early Holocene via the ‘Lower Danube Corridor’. Location Sarló‐hát oxbow lake, Hungary and the Eastern European wooded steppe zone. Methods Holocene sediments deposited in the Sarló‐hát oxbow lake were subjected to pollen and microcharcoal analyses. Twelve radiocarbon age estimates were obtained to determine sediment chronology. In addition, previously published palaeoecological data from the Great Hungarian Plain were compiled, analysed and compared with previous studies in other regions of steppe and wooded steppe in eastern Europe. Results Palynological data from two sediment cores extending to c. 11,400 cal. yr bp indicate the persistent dominance of the landscape by temperate deciduous wooded steppe throughout the Holocene, although with varying canopy composition. Warm‐continental steppe grasslands and saline tall‐grass meadows developed on edaphically constrained areas, which remained steppe‐dominated throughout the Holocene. The extent of steppe grasslands did not increase between 9900 and 8300 cal. yr bp . After c. 3100 cal. yr bp , anthropogenic activities led to the development of cultural steppe. Thermophilous steppe species of the Southern Continental, Pontic and Sub‐Mediterranean floristic elements probably reached the Great Hungarian Plain principally via the Lower Danube Corridor during the late glacial interstadial and Holocene. Eurythermic members of these elements, however, probably survived the Last Glacial Maximum in favourable microsites, extending their ranges during the Holocene from these local sources. Main conclusions Our results confirm the Holocene persistence of wooded steppe in the Great Hungarian Plain, disprove the ‘Boreal steppe’ theory, and suggest an Early Holocene period of greater vegetation openness between 11,400 and 9900 cal. yr bp . Evidence for the post‐glacial immigration of south‐eastern steppe elements into the Carpathian Basin is equivocal: the last glacial/interglacial presence of several southern steppe species suggests that the Hungarian Plain hosted suitable habitats for them during warm and cold phases alike.     

The Holocene climatic optimum at the southern coast of the Sea of Japan

Palynological spectra were studied from piston-cores of bottom sediments in the southwestern part of the Sea of Japan and the East Korea Bay. Five palynological assemblages were revealed in the sediments of the deep core and three, in the shelf core. The palynological assemblages were formed during different climatic phases and reflect main stages in the development of the vegetation of the region. The Holocene optimum was determined for the southern coast of the Sea of Japan.     

The significance of the oil palm (Elaeis guineensis Jacq.) in the late Holocene environments of west and west central Africa: A further consideration

Abundant archaeological evidence of the occurrence of the endocarp of the oil palm,Elaeis guineensis, in the rain forest and woodland savanna zones of west and central Africa from about 5000 B.P. has shown the tree to be an important element in the subsistence economy of the region; its pollen also has been recorded in most of the regional terrestrial sediments studied so far. The distinct and consistently sudden and more marked increases in this pollen during the late Holocene when compared with the late Tertiary and late Pleistocene frequencies strongly indicate that the late Holocene upsurges were due to both natural and human factors favourable for the expansion of this heliophytic tree. Reasons are given for suggesting that upsurges in oil palm pollen during the late Holocene period in this region can be used as indices of plant cultivation. While the oil palm is known from early Tertiary deposits in west Africa, its earliest palynological record from terrestrial sediments in the west central part dates back only to the early Holocene. More palynological studies of Tertiary and Quaternary terrestrial cores are required to establish with more certainty the antiquity ofE. guineensis in west central Africa.     

Further discussion of Phyllocladus and its pollen in Victoria during the Holocene

Phyllocladus pollen was not identified in mid-late Holocene sediments in the Otway Ranges but has been found, in western Victoria, in a surface sample and in lake sediments probably younger than 1100 BP. These results refute the view of Churchill and Dodson (1980) that Phyllocladus was present in western Victoria (probably in the Otway Ranges) through the Holocene until dry conditions caused its extinction about 1100 BP. It is concluded that the Phyllocladus pollen in western Victorian Holocene deposits is derived from sources in Tasmania and/or New Zealand.     

Carotenoids in bottom sediments of lake Shira as a paleoindicator for reconstruction of Lake States in Khakassiya,Russia

The concentrations of carotenoids buried in the bottom sediments of Lake Shira (Siberia, Khakassiya) have analyzed for the period of the last 2300 years. The bottom sediments were found to contain carotenoids, which are molecular markers of the corresponding groups of Phototrophic organisms. The bottom sediments of Lake Shira were shown to be a promising object for climate reconstructions of the Late Holocene in southern Siberia.     

Environmental changes in the northeast of the Buryat Republic during the Holocene post-Optimum: First results

The results of a high-temporal-resolution geochemical and pollen analysis of bottom sediments in Lake Baunt (55°11′15″ N and 113°01′45″ E), located within the continuous permafrost zone, have made it possible to reconstruct the environmental and climate changes in northern Buryatia during the Holocene post-Optimum for the first time. Over the last almost 7000 years, the natural and climatic conditions in the northeast of Buryatia have not remained homogeneous. A relatively warm and dry climate occurred here at the end of the Holocene Optimum between 6900 and 6000 BP. Later, about 6000–1500/1000 BP, the climate became colder, long-term permafrost activated, and chemical weathering attenuated. The climate over the last 1500–1000 years was colder in general than the modern climate. The environmental indices have different values in sediments with respect to warm and cold intervals and reflect the sedimentation conditions what were controlled by climate changes.     

Characterization of the depth-related changes in the microbial communities in Lake Hovsgol sediment by 16S rRNA gene-based approaches

The undisturbed sediment of Lake Hovsgol (Mongolia) is scientifically important because it represents a record of the environmental changes that took place between the Holocene (the present age) and Pleistocene (the last ice age; 12,000 14C years before present day). Here, we investigated how the current microbial communities change as the depth increases by PCR-denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes of the microbial communities. The microbial diversity, as estimated by the Shannon index, decreased as the depth increased. In particular, significant changes in archaeal diversity were observed in the middle depth (at 39-42 cm depth of total 60 cm depth) that marks the border between the Holocene and Pleistocene. Phylotype belonging to Beta-and Gamma-Proteobacteria were the predominant bacteria and most of these persisted throughout the depth examined. However, as the depth increased, some bacteria (some genera belonging to Beta-Proteobacteria, Nitrospira, and OP8-9) were not detectable while others (some genera belonging to Alpha-, Beta-, Gamma-Proteobacteria) newly detected by DGGE. Crenarchaea were the predominant archaea and only one phylotype belonging to Euryarchaea was found. Both the archaeal and bacterial profiles revealed by the DGGE band patterns could be grouped into four and three subsets, respectively, subsets that were largely divided by the border between the Holocene and Pleistocene. Thus, the diversity of the current microbial communities in Lake Hovsgol sediments decreases with increasing depth. These changes probably relate to the environmental conditions in the sediments, which were shaped by the paleoclimatic events taking place between the Holocene and Pleistocene.     

宁波沿海平原Z02孔第四纪地层及古环境演变

宁波沿海平原第四纪沉积物属于海陆交互沉积,记录了良好的古气候变化信息,是研究古气候冷暖变化、沉积物沉积特征的良好载体.对位于宁波沿海平原东南部的Z02孔进行14C和古地磁测年,根据钻孔岩性、孢粉组合、有孔类和介形类组合、粒度等环境替代指标特征,确定了 Z02孔第四纪地层划分,揭示了研究区第四纪以来的古环境演变信息.结果...     

Climate, human palaeoecology and the use of fuel in Wadi Sana, Southern Yemen

This study integrates analysis of wood charcoal assemblages with climate proxies, palaeoenvironmental and archaeological data sets in hyper-arid Wadi Sana, Yemen, to address the availability and use of wood fuels by South Arabian hunter-herder groups from the Early Holocene (8000–7700 cal. b.p.) to Middle Holocene (6900–4800 cal. b.p.) periods. The Early Holocene environment, regulated by a stronger Southwest Asian monsoon, was moister than the present, providing a marshy winter grazing area for cattle herders, whose construction of hearths and food preparation strategies changed over time. This study provides an insight into long term stability of land cover and use as well as the dynamics of human contributions to landscape change. We suggest that complex environmental and cultural processes affect species availability, fuel choice and land use management. Despite environmental and economic changes in Wadi Sana, our dataset does not show changes in fuel choice from the Early to Middle Holocene.     

Variation of upwelling/oceanic conditions during the latest Pleistocene through Holocene off the central Peruvian coast: A diatom record

Diatoms are well preserved in partly laminated Holocene and late Pleistocene sediments on the upper continental slope of central Peru. Accumulation rates of diatom species previously recognized as tropical (oceanic, warm water) and subtropical (neritic, cooler water, upwelling) changed markedly downcore in Kasten cores obtained at 11°15′S, 12°58′S, and 13°37′S latitude. Subtropical species (e.g., Thalassiosira eccentrica “group”, Thalassiothrix frauenfeldii, Chaetoceros spp. resting spores, Delphineis spp.) predominated in late Pleistocene sediments of the two southern cores. A mix of tropical and subtropical diatom assemblages occurred in latest Pleistocene sediments, while tropical species (e.g., Coscinodiscus nodulifer/radiatus, Pseudoeunotia doliolus, Thalassionema nitzschioides var. parva) predominated in the late Holocene sediments. In the northern core latest Pleistocene sediments also contained a mix of tropical and subtropical species. Similarly, late Holocene sediments contained predominately tropical species of diatoms. Neoglacial periods (200–400 yr B.P., 2000–2700 yr B.P.), however, were sometimes characterized by a greater abundance of subtropical species and punctuated periodically with blooms of Skeletonema costatum and Rhizosolenia shrubsolei. It is proposed that during times of Southern Hemisphere cooling, Peruvian coastal waters north of 12°S were subjected to episodic mixing with warmer water masses before being overwhelmed by tropical waters that may have either passed southward across a weakened Equatorial Front or arose from intensified offshore countercurrents. Coastal waters south of 12°S latitude were probably unaffected by the tropical influence. Rather, these waters may have undergone intensified upwelling during the last Glacial epoch.     

Preliminary study of the calcareous taphocoenoses in Late Quaternary glacial marine sequences of the Ross Sea (Antarctica)

Three gravity cores were collected in north-western Ross Sea (Coulman Island and Cape Adare areas) during 1998 and 1999 “Progetto Nazionale Ricerche in Antartide”. Several carbonate-rich levels, from Late Pleistocene to Holocene in age, interbedded with glacial marine sequences were recovered. Examination of the compositional characters (X-ray structure, texture, water, TOC and CaCO₃ contents) and taphonomic data (fabric of the fossil concentration, degree of preservation of foraminifers and bryozoans, together with paleoecological inferences) has allowed the preliminary documentation of oscillations of the ice-shelf front in this area. Benthic foraminifer tests in glacial marine sediments older than the Last Glacial Maximum are often badly preserved (abraded and broken), testifying to the persistent transport of these sediments. In the younger sediments, an increased concentration of Neogloboquadrina pachyderma occurs, indicating more open water conditions. The occurrence of a mainly autochthonous fauna in muddy sediments in between two volcanic events in the Coulman Island area could indicate stable environmental conditions. The occurrence of limited % of fragmented foraminifers indicates the decreasing influence of glacial reworking. In the Cape Adare area, mass flow events were common during the Holocene retreat of the ice shelf. Several bioclastic-rich deposits (stylasterids and bryozoans assemblage) in the studied core with interbedded muddy sediments could indicate mass transport events from neighboring shallow environments. During undisturbed open-marine conditions, represented by muddy sedimentation, foraminifers and other calcareous taxa colonized the previous coarse-textured skeletal substratum.     

Late Quaternary diatoms in the sediments of Przedni Staw Lake (Polish Tatra Mountains)

The paper presents a diatom succession in the Late Glacial and Holocene sediments of the Przedni Staw lake in the Pie Stawów Polskich Valley High Tatra Mts. Ten diatom phases are distinguished and presented against a pollen diagram from the analyzed core showing continuous sedimentation from the Oldest Dryas to the Subatlantic period. The diatom flora in the Late Glacial sediments is predominantly littoral — Fragilaria, Navicula, Nitzschia, Diploneis, Pinnularia and Amphora species. The Holocene sediments enclose more abundant planktonic species such as Cyclotella quadriiuncta, Asterionella formosa and Melosira distans.