DNA from pollen: principles and potential

This paper describes our recent extraction of ancient DNA (aDNA) from Holocene pollen and discusses the potential of the technique for elucidating timescales of evolutionary change. We show that plastid DNA is recoverable and usable from pollen grains of Scots pine Pinus sylvestris from 10 ka and 100 years ago. Comparison of the ancient sequences with modern sequences, obtained from an extant population, establish a first genetic link between modern and fossil samples of Scots pine, providing a genetic continuity through time. One common haplotype is present in each of the three periods investigated, suggesting that it persisted near the lake throughout the postglacial. The retrieval of aDNA from pollen has major implications for palaeoecology by allowing (i) investigation of population level dynamics in time and space, and (ii) tracing ancestry of populations and developing phylogenetic trees that include extinct as well as extant taxa. The method should work over the last glacial oscillation, thus giving access to ancestry of populations over a crucial period of time for the understanding of the relationship between speciation and climate change.

Forest fires and insects: palaeoentomological research from a sub-fossil burnt forest.

The role of fire within Pinus-mire ecosystems is explored by focusing on a palaeoentomological investigation of the extensive burnt fossil forest preserved within the basal deposits of the raised mires of Thorne and Hatfield Moors, Humberhead Levels, eastern England. Remains of charred tree macrofossils (roots, stumps and trunks) are widely distributed across both sites, mainly comprising Pinus and Betula. Evidence from this research and elsewhere suggest fires were a common event on Pinus mires, and may indicate that such episodes played an important role in the development of raised bogs. A fire-loving (pyrophilous) insect fauna appears to have been attracted to the burnt areas and the decline and extirpation in Britain of a number of pyrophilous species (e.g. Stagetus borealis Isrealsson) suggests the former importance of this type of habitat within British Pinus-mire systems. The lack of consideration given to the role of natural fires within the British landscape is questioned and the interpretation of charcoal within mire deposits as a possible anthropogenic indicator is highlighted as an area that would benefit some reconsideration.

Palaeoclimate change recorded in Upper Cretaceous (Albian-Cenomanian) Kazhdumi Formation Borehole spectral Gamma-Ray Logs, South Pars Gas field, Persian Gulf

Th/U and Th/K data from spectral gamma-ray logs obtained from outcrop successions have been used as a rapid and inexpensive proxy for determining possible episodes of humid-arid palaeoclimate change. Such outcrop-based measurements have never been tested using spectral gamma-ray data obtained from wireline logs in subsurface boreholes. Th/K and Th/U ratios have traditionally been used to decipher sequence stratigraphic patterns, at outcrop and in borehole. The possible influence of palaeoclimate on such ratio changes has yet to be proven, especially from borehole data. In this work, we compare borehole-derived Th/K (and to a lesser extent Th/U) to palaeoenvironmental changes inferred from palynology and deduce that both sea level and changing hinterland weathering regimes caused discrete fluctuations observed in the spectral gamma-ray logs. This is the first time such subsurface information has been used in this way. Interpretation of wireline logs in terms of palaeoclimate as well as sea level may now be considered, and the use of such logs in palaeoclimate reconstruction is strengthened.

Palaeobiology of an extinct Ice Age mammal: Stable isotope and cementum analysis of giant deer teeth

The extinct giant deer, Megaloceros giganteus, is among the largest and most famous of the cervids. Megaloceros remains have been uncovered across Europe and western Asia. but the highest concentrations come from Irish bogs and caves Although Megaloceros has enjoyed a great deal of attention over the centuries, paleobiological study has focused oil morphometric and distributional work until now. This paper presents quantitative data that have implications for understanding its sudden extirpation in western Europe during a period of global climate change approximately 10.600 C-14 years ago (ca 12,500 calendar years BP). We report here the first stable isotope analysis of giant deer teeth. which we combine with dental cementum accretion in order to document age, diet and life-history seasonality from birth until death Enamel delta C-13 and delta O-18 measured in the second and third molars from seven individual giant deer Suggest a grass and forbbased diet supplemented with browse in a deteriorating. possibly water-stressed, environment, and a season of birth around spring/early summer Cementurm data indicate that the ages of the specimens ranged from 6.5 to 14 years and that they possessed mature antlers by autumn, similar to extant cervids. In addition. the possibility for combining these two techniques in future mammalian paleoccological studies is considered. The data presented in this study imply that Megoloceros would have indeed been vulnerable to extirpation during the terminal Pleistocene in Ireland. and this information is relevant to understanding the broader pattern of its extinction.

Geological fakes and frauds

Some geological fakes and frauds are carried out solely for financial gain (mining fraud), whereas others maybe have increasing aesthetic appeal (faked fossils) or academic advancement (fabricated data) as their motive. All types of geological fake or fraud can be ingenious and sophisticated, as demonstrated in this article. Fake gems, faked fossils and mining fraud are common examples where monetary profit is to blame: nonetheless these may impact both scientific theory and the reputation of geologists and Earth scientists. The substitution or fabrication of both physical and intellectual data also occurs for no direct financial gain, such as career advancement or establishment of belief (e.g. evolution vs. creationism). Knowledge of such fakes and frauds may assist in spotting undetected geological crimes: application of geoforensic techniques helps the scientific community to detect such activity, which ultimately undermines scientific integrity.

Late Pleistocene history of turbidite sedimentation in a submarine canyon off the northern Great Barrier Reef, Australia

Cores from slopes east of the Great Barrier Reef (GBR) challenge traditional models for sedimentation on tropical mixed siliciclastic-carbonate margins. However, satisfactory explanations of sediment accumulation on this archetypal margin that include both hemipelagic and turbidite sedimentation remain elusive, as submarine canyons and their role in delivering coarse-grained turbidite deposits, are poorly understood. Towards addressing this problem we investigated the shelf and canyon system bordering the northern Ribbon Reefs and reconstructed the history of turbidite deposition since the Late Pleistocene. High-resolution bathymetric and seismic data show a large paleo-channel system that crosses the shelf before connecting with the canyons via the inter-reef passages between the Ribbon Reefs. High-resolution bathymetry of the canyon axis reveals a complex and active system of channels, sand waves, and local submarine landslides. Multi-proxy examination of three cores from down the axis of the canyon system reveals 18 turbidites and debrites, interlayered with hemipelagic muds, that are derived from a mix of shallow and deep sources. Twenty radiocarbon ages indicate that siliciclastic-dominated and mixed turbidites only occur prior to 31 ka during Marine Isotope Stage (MIS) 3, while carbonate-dominated turbidites are well established by 11 ka in MIS1 until as recently as 1.2 ka. The apparent lack of siliciclastic-dominated turbidites and presence of only a few carbonate-dominated turbidites during the MIS2 lowstand are not consistent with generic models of margin sedimentation but might also reflect a gap in the turbidite record. These data suggest that turbidite sedimentation in the Ribbon Reef canyons, probably reflects the complex relationship between the prolonged period (> 25 ka) of MIS3 millennial sea level changes and local factors such as the shelf, inter-reef passage depth, canyon morphology and different sediment sources. On this basis we predict that the spatial and temporal patterns of turbidite sedimentation could vary considerably along the length of the GBR margin.

Development of an Arcellacean (testate lobose amoebae) based transfer function for sedimentary phosphorous in lakes.

Arcellacea (testate lobose amoebae) communities were assessed from 73 sediment-water interface samples collected from 33 lakes in urban and rural settings within the Greater Toronto Area (GTA), Ontario, Canada, as well as from forested control areas in the Lake Simcoe area, Algonquin Park and eastern Ontario. The results were used to: (1) develop a statistically rigorous arcellacean-based training set for sedimentary phosphorus (Olsen P (OP)) loading; and (2) derive a transfer function to reconstruct OP levels during the post-European settlement era (AD1870s onward) using a chronologically well-constrained core from Haynes Lake on the environmentally sensitive Oak Ridges Moraine, within the GTA. Ordination analysis indicated that OP most influenced arcellacean assemblages, explaining 6.5% (p < 0.005) of total variance. An improved training set where the influence of other important environmental variables (e.g. total organic carbon, total nitrogen, Mg) was reduced, comprised 40 samples from 31 lakes, and was used to construct a transfer function for lacustrine arcellaceans for sedimentary phosphorus (Olsen P) using tolerance downweighted weighted averaging (WA-Tol) with inverse deshrinking (RMSEPjack-77pp; r2jack = 0.68). The inferred reconstruction indicates that OP levels remained near pre-settlement background levels from settlement in the late AD 1970s through to the early AD 1970s. Since OP runoff from both forests and pasture is minimal, early agricultural land use within the lake catchment was as most likely pasture and/or was used to grow perennial crops such as Timothy-grass for hay. A significant increase in inferred OP concentration beginning ~ AD 1972 may have been related to a change in crops (e.g. corn production) in the catchment resulting in more runoff, and the introduction of chemical fertilizers. A dramatic decline in OP after ~ AD 1985 probably corresponds to a reduction in chemical fertilizer use related to advances in agronomy, which permitted a more precise control over required fertilizer application. Another significant increase in OP levels after ~ AD 1995 may have been related to the construction of a large golf course upslope and immediately to the north of Haynes Lake in AD 1993, where significant fertilizer use is required to maintain the fairways. These results demonstrate that arcellaceans have great potential for reconstructing lake water geochemistry and will complement other proxies (e.g. diatoms) in paleolimnological research.

Identification of last interglacial deposits in eastern Beringia: a cautionary note from the Palisades, interior Alaska

Last interglacial sediments in unglaciated Alaska and Yukon (eastern Beringia) are commonly identified by palaeoecological indicators and stratigraphic position ~2-5m above the regionally prominent Old Crow tephra (124±10ka). We demonstrate that this approach can yield erroneous age assignments using data from a new exposure at the Palisades, a site in interior Alaska with numerous exposures of last interglacial sediments. Tephrochronology, stratigraphy, plant macrofossils, pollen and fossil insects from a prominent wood-rich organic silt unit are all consistent with a last interglacial age assignment. However, six 14C dates on plant and insect macrofossils from the organic silt range from non-finite to 4.0 14C ka BP, indicating that the organic silt instead represents a Holocene deposit with a mixed-age assemblage of organic material. In contrast, wood samples from presumed last interglacial organic-rich sediments elsewhere at the Palisades, in a similar stratigraphic position with respect to Old Crow tephra, yield non-finite 14C ages. Given that local permafrost thaw since the last interglaciation may facilitate reworking of older sediments into new stratigraphic positions, minimum constraining ages based on 14C dating or other methods should supplement age assignments for last interglacial sediments in eastern Beringia that are based on palaeoecology and stratigraphic association with Old Crow tephra.