This study reconstructs the depositional environments that accompanied both ice advance and ice retreat of the last British–Irish Ice Sheet in NE England during the Last Glacial Maximum, and proposes three regional ice-flow phases. The Late Devensian (29–22 cal. ka BP) Tyne Gap Ice Stream initially deposited the Blackhall Till Formation during shelf-edge glaciation (Phase I). This subglacial traction till comprises several related facies, including stratified and laminated diamictons, tectonites, and sand and gravel beds deposited both in subglacial canals and in proglacial streams. Eventually, stagnation of the Tyne Gap Ice Stream led to ice-marginal sedimentation in County Durham (Phase II). During the Dimlington Stadial (21 cal. ka BP), the North Sea Lobe advanced towards the coastline of N Norfolk. This resulted initially in sandur deposition (widespread, tabular sand and gravel; the Peterlee Sand and Gravel Formation; Phase II) and ultimately in deposition of the Horden Till Formation (Phase III), a massive subglacial till. As the North Sea Lobe overrode previous formations, it thrusted and stacked sediments in County Durham, and dammed proglacial lakes between the east-coast ice, the Pennine uplands and the remaining Pennine ice. The North Sea Lobe retreated after Heinrich Event 1 (16 ka). This study highlights the complexity of ice flow during the Late Devensian glaciation of NE England, with changing environmental and oceanic conditions forcing a mobile and sensitive ice sheet.

Investigation of isolated landforms on the eastern margin of the East Anglian Fenland at Feltwell and Methwold Hythe, Norfolk has demonstrated that they represent glacifluvial delta-fan and related sediments. Section logging, borehole records and previous descriptions together indicate that the deposits were laid down as an ice-marginal delta complex and feeder channel into a proglacial lake. The internal structure and form of the delta and related feeder channel have also been determined using ground-penetrating radar. The sequence indicates deposition at the ice front, together with minor ice-front movements, a substantial discharge event and repeated solutional collapse of the underlying bedrock. Postdepositional solifluction and cryoturbation also occurred. The glaciomarginal landform complexes form part of a line of delta-fan and associated accumulations (the ‘Skertchly Line’) deposited at the margin of an ice lobe that entered the Fenland. Here the ice dammed westward-aligned rivers to form a lake, here called Lake Paterson. These observations reinforce earlier descriptions of a late Middle Pleistocene glaciation of the Fenland termed the ‘Tottenhill glaciation’. Previous research concluded that the glaciation occurred at c. 160 ka, that is, during the late Wolstonian (= late Saalian) Stage (Drenthe Substage, early Marine Isotope Stage 6), a correlation supported by evidence from the North Sea floor. The implications of these conclusions are discussed.

This paper presents a comprehensive palaeoenvironmental data set from Lake Skrzynka, northern Poland. A sediment core from the lake was investigated to reconstruct Lateglacial and Holocene environmental changes in northern Poland using a combination of palynology and stable carbon and oxygen isotope studies of carbonates and sediment geochemistry. The undisturbed sedimentation in Lake Skrzynka continues from the Allerød to the present. Our data suggest the persistence of dead ice in the Lake Skrzynka basin up to the Allerød. The sedimentary record of the lake reflects a considerable difference between the Lateglacial/early Holocene and the middle/late Holocene in terms of environmental conditions. The Lateglacial was characterized by rapid environmental changes, while climatic conditions throughout the Holocene were relatively stable. The trophic state of the lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of Lake Skrzynka. During the Lateglacial and early Holocene, as a result of predominantly open plant communities and enhanced nutrient export from the watershed, Lake Skrzynka experienced an increased trophy. The stabilization of forest cover and reduced input of nutrients resulted in the establishment of oligotrophic conditions in the lake in the early Boreal. During the late Subatlantic, the lake became eutrophic as a result of human disturbance of the local hydrological balance. The postglacial history of Lake Skrzynka can be regarded as representative of small, alkaline, through-flow lakes in temperate climates.

The Cova dels Xaragalls is a small open karst system, located in the municipality of Vimbodí-Poblet (Tarragona, Catalonia, NE Spain). It is an important Holocene archaeological site that was inspected in the 1970s but from which little has been published. New excavations starting in 2008 have exposed a deep Late Pleistocene stratigraphical sequence. In this paper, we present for the first time palaeoenvironmental and palaeoclimatic reconstructions of this Late Pleistocene succession on the basis of both the small-vertebrate assemblages and the charcoals. Results from the small-vertebrate associations along the sequence indicate that the landscape had open-woodland habitats in the vicinity of the Cova del Xaragalls, with wet points in the surrounding area. Woodland habitats were dominant throughout the sequence, as evidenced by the abundance of the species Apodemus sylvaticus, but were better developed during warm periods (layers C5 and C8), whereas during cold periods (layers C4 and C3) the environment was slightly more humid in response to higher mean annual precipitation and the opening of the landscape. The charcoal analysis indicates that the woodland surrounding the cave was composed mainly of Pinus (more than 90% was identified as Pinus), but that during the cold period (C3–C4) it incorporated some Quercus ilex/coccifera and Angiosperm indet., probably linked with greater precipitation. Comparisons are made with other long palaeoenvironmental sequences from the northeastern Iberian Peninsula and with global marine isotopic curves, providing a scenario for the palaeoclimatic and palaeoenvironmental changes that occurred during the Late Pleistocene in the woodland areas surrounding the Cova dels Xaragalls.

Two glacial deposits in the Gesso valley (Maritime, Alps) have been ¹⁰Be-dated at 20 140±1080 (weighted mean±SD) and 16 590±970 years, respectively, thus constraining the Last Glacial Maximum (LGM) and Gschnitz stadials in the southwestern part of the Alps. The LGM age is chronologically coherent with MIS 2 and synchronous with most other LGM moraines in the Alps. The Gschnitz stadial also appears to be in agreement with the ages obtained from other Alpine sites and with Heinrich Event I. This suggests that the Alpine glaciers reacted simultaneously and essentially synchronously with the climate change associated with Heinrich Event 1. The Equilibrium Line Altitudes (ELAs) of the LGM and Gschnitz reconstructed palaeoglaciers are 1850 and 1910 m a.s.l., respectively. The ELA comparison across the Alps indicates that the palaeoclimate of the Maritime Alps during the LGM was rather different from that of other Alpine sectors. However, the similar Gschnitz ELA value between the Gesso valley and other sites across the mountain chain indicates that Alpine glaciers responded with the same intensity to the climate change associated with Heinrich Event I. Overall, these results suggest that the interaction between the atmospheric circulation of air masses and local Alpine orography was more complex than has previously been argued.

A multiproxy study of Eemian Stage sediments in two core records, Licze and Obrzynowo, in the Gulf of Gdańsk area of northern Poland, shows that the brackish-marine interglacial conditions were determined partly by regional environmental changes and partly by local changes of the river outflow from the Vistula into the southern Baltic Sea. Correlation of the sediments with the Eemian is based on pollen analysis of the Obrzynowo record, showing the presence of regional pollen zones (RPAZ) E2–E6, combined with previously published pollen analyses from Licze (RPAZ E1–E7). A floating chronology is established on the basis of correlation with the annually laminated Bispingen sequence. Diatoms, foraminifera and ostracods are used as marine environmental proxies at both sites. An indication of marine conditions as early as pollen zone E1 or E2 at Licze and close to the E2–E3 boundary at Obrzynowo reflects the rapid relative sea-level rise in the area, which proceeded through ∼3000 years. A major salinity increase c. 1100 years after the beginning of the Eemian (early pollen zone E4) at both sites may be related to the opening of the Danish Straits. The Obrzynowo site became isolated from the sea at c. 3500 years (early pollen zone E5), whereas marine conditions continued at Licze until c. 7000 years, that is, throughout pollen zone E5. Gradually shallower water after c. 5000 years presumably resulted from progradation of the rivers combined with isostatic rebound of the area before final isolation from the sea at c. 7000 years.

The ages of nine alluvial units, identified by the integration of data obtained from five trenches at the southern termination of the Alhama de Murcia Fault (AMF) (eastern Betics, Spain), are constrained using luminescence dating based on the Optically Stimulated Luminescence (OSL) from quartz, Infrared Stimulated Luminescence (IRSL) at 50°C, and post-IR elevated temperature (225°C) IRSL signals from K-feldspar. All signals pass the routine tests associated with the Single Aliquot Regenerative (SAR) protocol, including the recycling ratio, recuperation, and dose recovery tests. The equivalent doses (D_e), residual doses and anomalous fading rates (‘g’-values) of the IRSL at 50°C (IR₅₀) and post-IRIRSL at 225°C (pIRIR₂₂₅) from K-feldspar are compared for 16 samples. The residual doses in laboratory-bleached samples suggest that there is no significant unbleachable residual dose using these signals; the residual doses are 0.17±0.15 Gy and 0.93±0.80 Gy, respectively. For both signals, the residual doses appear to depend on the corresponding natural doses; that is, the larger the natural doses, the larger the residuals, an observation made for the first time for IRSL signals. The average fading rate for the pIRIR₂₂₅ (0.94±0.07%/decade, n = 48) is markedly lower than that for IR₅₀ (2.08±0.16%/decade, n = 48), indicating that the age correction for the pIRIR₂₂₅ is much smaller than that for IR₅₀. The agreement between the quartz OSL, corrected IR₅₀, and corrected pIRIR₂₂₅ for the two youngest samples suggests that the pIRIR₂₂₅ is an accurate dating signal in this age range (<25 ka). The oldest age obtained using the corrected pIRIR₂₂₅ signal is 320±20 ka for sample 098807; the corrected IR₅₀ age is only 154±15 ka. Although this suggests that the pIRIR₂₂₅ signal circumvents the effect of anomalous fading to a great extent, the resulting age cannot be regarded as necessarily accurate because of the limitations of the fading correction model used, and the absence of independent age control for the old samples. Nevertheless, our luminescence ages provide the first age constraints on the seismic activity of the southern termination of the AMF.

Core 86027-144 (74°15.56′N, 91°14.21′W) represents a rare, continuous record of Late Pleistocene to Holocene sediments from High Arctic Canada extending from the end of the Last Glaciation. Based on microfossils (dinocysts, non-pollen palynomorphs, benthic and planktonic foraminifera), foraminiferal δ¹⁸O and δ¹³C, and sedimentology, seven palaeoenvironmental zones were identified. Zone I (>10.8 cal. ka BP) records deglaciation, ice-sheet destabilization, float-off and subsequent break-up. Zone II (c. 10.8–10.4 cal. ka BP) shows ice-proximal to ice-distal glaciomarine conditions, interrupted by pervasive land-fast sea-ice marked by a hiatus in coarse sediment deposition. Significant biological activity starts in Zone III (10.4–9.9 cal. ka BP), where planktonic foraminifera (Neogloboquadrina pachyderma) suggest early oceanic throughflow. Surface waters flowed NW–SE; however, the deep-water origin remains unclear (potentially NWArctic Ocean or Baffin Bay). Postglacial amelioration (open-water season greater than present) in Zone IV (9.9–7.8 cal. ka BP) perhaps corresponds to the regional ‘Holocene Thermal Maximum’ previously proposed. A transitional period (Zone V; 7.8–6.7 cal. ka BP) of rapid environmental change fluctuating on a scale not observed today is marked by increasing sea-ice and reduced oceanic influence. This probably signals the exclusion of deeper Atlantic water owing to the glacio-isostatic shallowing of inter-island sills, coupled with generally cooling climate. Conditions analogous to those at present, with increased sea-ice and modern microfossil assemblages, commence at c. 6.7 cal. ka BP (zones VI–VII). Although climate ultimately forces long-term environmental trends, core 86027-144 data imply that regional dynamics, especially changes in sea-level, exert a significant control on marine conditions throughout the Canadian Arctic Archipelago.

Most studies of late Holocene sea-level changes generally assume stable tectonic conditions. However, unrecognized neotectonic ‘noise’, even the small rates of passive continental margins, can severely distort sea-level reconstructions of the late Holocene. The detailed sea-level curve proposed here is reconstructed by identification of an area (Læsø archipelago in the Kattegat Sea) where small neotectonic level changes and other kinds of ‘background noise’ can be precisely quantified by advanced LiDAR techniques. We show that the absolute (‘eustatic’) sea level of Kattegat has risen by 110±14 cm since AD 1300 and that the Little Ice Age lowstand occurred between 1250 and 1750. Thereafter, four oscillations with a cyclicity of ∼70 years peaked around 1790, 1860, 1920–1950 (double peak), and at the present. We discuss the global implications of the curve, for example that the acceleration in the present sea-level rise may be part of this 70-year cyclicity, and that the non-anthropogenic sea-level rise between 1700 and 1790 seems faster than the present and projected sea-level rise for the 21st century. Moreover, the conspicuous sea-level fall at the beginning of the Little Ice Age confirms that ice-cap growth can be faster than ice-cap melting. By comparison with 29 long-term tide gauge measurements of the region we show that the isostatic implications of the sea-level curve are in nearly perfect agreement with Peltier's global isostatic VM2 model (applied by IPCC and PSMSL) and yield a 3–4 times smaller spread of isostatic rates. Owing to this higher precision it is possible to produce a reliable isostatic map of SWScandinavia, Denmark, NGermany and NWPoland. This new map identifies an isostatic jump by ∼0.6 mm a⁻¹ at the Ringkøbing-Fyn Basement High, separating the isostatic pattern of the North German Basin from the isostatic pattern of the Danish Basin and the Scandinavian Peninsula.

In Gästrikland in central Sweden, deglaciation took place c. 11 000 cal. a BP. In the present study the shore displacement during the earliest ice-free period is investigated by the ¹⁴C dating of sediment from isolated lake basins. The shore displacement in Gästrikland includes an initial phase (∼500 years) of rapid regression, followed by a slowing of the relative sea level (RSL) fall to a rate similar to that of the remaining Holocene c. 9250 cal. a BP. The Ancylus Lake stage of the Baltic Sea belongs to the analysed interval. The RSL curve and glacial unloading history are used to separate and quantify elements of isostatic uplift. The postglacial uplift is ∼260 m, of which ∼45 m forms a rapid initial rise, which can be treated as qualitatively separate from the later, slower rise. There is considerable glacial unloading just prior to the deglaciation, but calculations suggest that only a small part of this relates directly to the rapid early Holocene rebound: most unloading is transferred either to uplift immediately prior to the deglaciation or to subsequent Holocene or future uplift. The isostatic rise in Gästrikland occurring between the end of the Younger Dryas stadial and the deglaciation, c. 11 500–11 000 cal. a BP, is estimated to be 100–110 m. Observations and estimations are incompatible with a Weichselian maximum ice thickness much smaller that 3000 m. The lack of glacial unloading during the Younger Dryas has a measurable impact on the Holocene isostatic rebound in Gästrikland, reducing it by an estimated 20–25 m.

We defined extreme cold winter events as those with occurrence probabilities lower than the 10th percentile of the probability density function, based on observed winter temperatures in southern China since 1951. Subsequently, we constructed impact severity levels using documentary evidence for those events during 1951–2000, considering three indexes for the freezing of rivers/lakes, widespread snow/ice storms, and cold damage to subtropical/tropical crops. Using these criteria we identified 50 extreme cold winters for the period AD 1650–1949 based on ∼4000 pieces of comparable information extracted from local gazettes in southern China, after verification using data from three weather stations with long records. It was found that the frequencies of the extreme cold winter events since 1650 varied over time. The most frequent occurrences were found during AD 1650–1699 and in the first and second halves of the 19th century, with frequencies twice as high as in the second half of the 20th century. In contrast, the frequencies of extreme winters during the 18th century were close to that in the second half of the 20th century. High frequencies of extreme cold winters in AD 1650–1720 and AD 1795–1835 occurred during the sunspot Maunder and Dalton Minima. The intensities of some historical cold events, such as those during 1653–1654, 1670, 1690, 1861, 1892 and 1929, exceeded those of the coldest winter events since 1951.

Two peat cores from two neighbouring bogs in Lofoten, northern Norway were densely AMS dated and analysed for humification. The two cores have been influenced by human agricultural impact, especially c. 1600 cal. a BP, which may have affected the local hydrology of the bogs. From 7400 cal. a BP onwards, 19 distinct wet-shifts are recorded in the two cores. Eight or nine of these correspond chronologically to periods of low solar activity. This correlation is most convincing during the last 2000 years. Some wet-shifts are connected with a solar low-activity period during the Subboreal/Subatlantic transition, which in central Europe is dated at 2750–2565 cal. a BP. For Lofoten, the corresponding Subboreal/Subatlantic transition – or the wet-shift marking this transition – is dated at c. 2600 cal. a BP. Some wet-shifts occur just before or just after solar low-activity periods, but only four of the nineteen wet-shifts are clearly not temporally connected with periods of low solar activity. Compared with the wet-shifts in NW European (mainly British Isles) bogs, there are more frequent wet-shifts in northern Norway. Compared with other peat cores in northern Norway, especially for the interval 6500–5000 cal. a BP, Lofoten deviates by its lack of wet-shifts. As in England, Scotland and Ireland, there is regional variability in the temporal formation of wet-shifts in northern Norway.

Thick, relatively homogeneous basal tills exposed in the drumlins and flutes of the Weedsport drumlin and flute field in New York State exhibit anisotropy of magnetic susceptibility (AMS) and pebble fabrics that are consistently oriented parallel to the streamlined bedforms. The pebble fabrics and AMS fabrics are concordant. In this study, six drumlins and five flutes were sampled. Thermally induced, incremental reduction of isothermal remanent magnetization indicates that AMS is caused by primarily elongate maghaemite grains. The orientations of principal axes of maximum susceptibility (k₁) are generally parallel to pebble long-axis orientations, and tend to plunge mildly up-glacier. Fabric directions are generally parallel to drumlin long-axis orientations, but deviate by 12°–23° from flute directions. Fabrics of the flutes are stronger and more unidirectional than those of the drumlins. These results support the use of AMS as a fast and objective method for characterizing fabrics in tills, and suggest hypotheses about basal processes linked to glacially streamlined landforms.

Limestone and dolomite bedrock surfaces, together with blocks derived from these underlying bedrocks, at Basissletta, NE Spitsbergen, contain Late Pleistocene–early Holocene, shallow-marine, spionid polychaete borings Caulostrepsis taeniola Clarke, Caulostrepsis contorta Bromley & D'Alessandro, and Maeandropolydora isp. The borings occur about 9–78 m above present sea level, and this is the northernmost known occurrence of these trace fossils. ¹⁴C dating of wood, whalebone and bivalves in the vicinity and in neighbouring areas indicates that the borings have a radiocarbon age spanning from about 7 to 11 ka. Recent borings of these ichnotaxa have not been found in the sea around Spitsbergen. The presence of the fossil borings indicates that invasion of boring polychaetes to the northern part of the Barents Sea region was limited to a Late Pleistocene–early Holocene temperature optimum. The presence of Caulostrepsis and Maeandropolydora on subaerially exposed shallow-water Pleistocene–Holocene bedrock surfaces in arctic areas can be a valuable tool with which to evaluate both postglacial emergence and climatic oscillations because they indicate a summer surface water temperature of at least 8 °C.

Ongoing climatic changes potentially affect tree-line ecosystems, but in many regions the observed changes are superimposed by human activities. We assessed how the forest-tundra ecotone has changed during the last century in the Putorana Mountains, northern Siberia, an extremely remote and untouched area in Eurasia. A space-for-time approach was used to determine the spatio-temporal dynamics of forest structure and biomass along an altitudinal transect. From the closed larch forest to the upper tree line, the mean age of Larix gmelinii (Rupr.) decreased considerably from 220 to 50 years ago. At the current upper species line, there is a strong and successful germination of larch, with 1500 saplings per hectare, indicating an ongoing filling-in, a densification of a formerly open forest and an upslope shift of the tree-line position (approximately 30 to 50 m in altitude during the last century). The forest expansion coincided with large increases in winter precipitation during the 20th century. In contrast, tree growth rates were significantly positively related to summer temperatures, neither of which increased markedly. The total aboveground biomass decreased from approximately 40 t ha⁻¹ in the closed larch forest to 5 t ha⁻¹ at the tree line. Our study demonstrates that ongoing climatic changes lead to an upslope expansion of forests in the remote Putorana Mountains, which alters the stand structure and productivity of the forest-tundra ecotone. These vegetation changes are very probably of minor importance for aboveground carbon sequestration, but soil carbon data are needed to estimate the impact of the forest expansion on the total ecosystem carbon storage.

Here we document late-Holocene climate variability in West Greenland as inferred from a marine sediment record from the outer Disko Bay. Organic-walled dinoflagellate cysts and other palynomorphs were used to reconstruct environmental changes in the area through the last c. 1500 years at 30–40 years resolution. Sea ice cover and primary productivity were identified as the two main factors driving dinoflagellate cyst community changes through time. Our data provide evidence for an opposite climate trend in West Greenland relative to the NE Atlantic region from c. AD 500 to 1050. For the same period, sea-surface temperatures in Disko Bay are out-of-phase with Greenland ice-core reconstructed temperatures and marine proxy data from South and East Greenland. This is probably governed by an NAO-type pattern, which results in warmer sea-surface conditions with less extensive sea ice in the area for the later part of the Dark Ages cold period (c. AD 500 to 750) and cooler conditions with extensive sea ice inferred for the first part of the Medieval Climate Anomaly (MCA) (c. AD 750 to 1050). After c. AD 1050, the marine climate in Disko Bay becomes in-phase with trends described for the NE Atlantic, reflected in the warmer interval for the remainder of the MCA (c. AD 1050–1250), followed by cooling towards the onset of the Little Ice Age at c. AD 1400. The inferred scenario of climate deterioration and extensive sea ice is concomitant with the collapse of the Norse Western Settlement in Greenland at c. AD 1350.

Seismic records and evidence from sediment cores at Chilliwack Lake provide the basis for a long-term (postglacial) sediment budget for a 324-km² Cordilleran catchment. Chilliwack Lake (11.8 km² surface area), situated in the North Cascade Mountains, near Chilliwack, British Columbia, was formed behind a valley-wide recessional moraine in the final phase of post-Fraser alpine glaciation. Seismic surveys highlight the postglacial lacustrine record, which is underlain by a thick layer of sediments related to deglacial sedimentation. Sediment cores provide details of grain-size fining from the delta to the distal lake basin. The cores also show a record of intermittent fire and debris flows. Magnetic measurements of lake sediments provide information on grain size, as well as a dating framework. The total postglacial lake-floor deposit volume is estimated to be 397 ± 27 × 10⁶ m³. Including estimates of fan and delta deposition, the specific postglacial yield to the lake is calculated to be ∼86 ± 13 Mg km² a⁻¹. The sediment volume in the uppermost (Holocene) lacustrine layer is 128 ± 9 × 10⁶ m³, representing ∼41 ± 4 Mg km² a⁻¹ in the Holocene. Compared with other Cordilleran lakes of similar size, particularly those with glacial cover in the watershed, Chilliwack Lake has experienced relatively modest rates of sediment accumulation. This study provides an important contribution to a growing database of long-term (postglacial) sediment yield data for major Cordilleran lakes, essential for advancing our understanding of the pace of landscape evolution in formerly glaciated mountainous regions.

Bulk organic δ¹³C values of sediment sequences are commonly used to indicate past climatic changes, although the causes and mechanisms leading to the observed organic carbon isotope responses are presently not fully understood. Based on two sedimentary sequences, namely a peat profile and a fluvial and swamp sequence from the tropical NW Leizhou Peninsula in South China, we interpret more negative bulk organic δ¹³C values to suggest wetter and warmer conditions, implying a stronger East Asian (EA) summer monsoon, and less negative δ¹³C values to indicate drier and cooler conditions, reflecting a weakening of the EA summer monsoon. A warm and wet period occurred between c. 48.0 and 28.0 cal. ka BP. In the study region, a climate shift occurred at c. 22.0 (or 20.0) cal. ka BP, and the driest and coldest period occurred between c. 19.0 and 16.0 cal. ka BP. After c. 12.0 cal. ka BP, the climate changed towards wetter and warmer conditions. Several possible millennial-scale dry and cold oscillations characterized possibly by C4 plants, or by more positive organic δ¹³C values during the period when C3 plants dominated, are cautiously and tentatively interpreted as showing a similarity with Heinrich events and other cold millennial-scale oscillations evidenced from a Greenland ice core and Chinese stalagmite. We demonstrate that bulk organic δ¹³C records of sedimentary sequences in the study region have potential for indicating the changes in vegetation composition that were closely associated with climate variation during the last glacial period.

Stalagmites from Xianren Cave in Yunnan Province, SW China have visible bands of alternating compact and porous sub-layers, which have recently been demonstrated to be annual: the compact sub-layer consists of elongated columnar aragonites with a general longitudinal orientation (parallel to the vertical growth axis), while the porous sub-layer is composed mainly of needle aragonites forming radiating masses. In order to understand the growth mechanism of this type of stalagmite laminae, factors that could determine the growth rate and crystal structures of modern carbonates, such as cave-air temperature, CO₂ concentration, drip rate and the hydrochemical parameters of drip water, have been monitored systematically. In this study, we selected five active drip sites to monitor for two years at a monthly frequency. Based on the monitoring results and the analyses of stalagmite laminae, we conclude that the compact sub-layer forms in winter, when the drip rate is moderate and the degassing is slow, continuous and prolonged. The porous sub-layer forms in early spring, when the drip rate is lower and Mg/Ca is higher than that during the formation of the compact sub-layer. We also found exceptionally some calcite laminae. Furthermore, we discovered modern calcites precipitating at all study sites in the first hydrologic year when the rainfall was very abundant. Therefore, it is suggested that the occurrence of localized calcites in an aragonitic stalagmite indicates an interval of higher rainfall.

We evaluate the glacial dynamics and subglacial processes of the Apriķi glacial tongue in western Latvia during the Northern Lithuanian (Linkuva) oscillation of the last Scandinavian glaciation. The spatial arrangement of glacial bedforms and deformation structures are used to reconstruct the ice dynamics in the study area. The relationship between geological structures at the glacier bed and the spatial distribution of drumlins and glacigenic diapirs, on the one hand, and the permeability of sediment and bedrock, on the other, is ascertained. Drumlins are found in the upper part of the Apriķi glacial tongue area and are composed of soft deformable sediments overlying highly permeable Devonian dolomite. The soft deformable clayey silty bed with low hydraulic conductivity is conducive to the development of diapirs. The occurrence of diapirs and drumlins is controlled by the fluctuation of pore-water pressure at the glacier bed and is considered to be an indicator of fast ice flow of the Apriķi glacial tongue during its reactivation at the end of the Oldest Dryas (18–15 ka BP).