9000 years of changes in peat organic matter composition in Store Mosse (Sweden) traced using FTIR-ATR

Store Mosse (the ‘Great Bog’ in Swedish) is one of the most extensive bog complexes in southern Sweden (~77 km²), where pioneering palaeoenvironmental research has been carried out since the early 20th century. This includes, for example, vegetation changes, carbon and nitrogen dynamics, peat decomposition, atmospheric metal pollution, mineral dust deposition, dendrochronology, and tephrochronology. Even though organic matter (OM) represents the bulk of the peat mass and its compositional change has the potential to provide crucial ecological information on bog responses to environmental factors, peat OM molecular composition has not been addressed in detail. Here, a 568-cm-deep peat sequence was studied at high resolution, by attenuated reflectance Fourier-transform infrared spectroscopy (FTIR-ATR) in the mid-infrared region (4000–400 cm^–1). Principal components analysis was performed on selected absorbances and change-point modelling was applied to the records to determine the timing of changes. Four components accounted for peat composition: (i) depletion/accumulation of labile (i.e. carbohydrates) and recalcitrant (i.e. lignin and other aromatics, aliphatics, organic acids and some N compounds) compounds, due to peat decomposition; (ii) variations in N compounds and carbohydrates; (iii) residual variation of lignin and organic acids; and (iv) residual variation of aliphatic structures. Peat decomposition showed two main patterns: a long-term trend highly correlated to peat age (r = 0.87), and a short-term trend, which showed five main phases of increased decomposition (at ~8.4–8.1, ~7.0–5.6, ~3.5–3.1, ~2.7–2.1 and ~1.6–1.3 ka) – mostly corresponding to drier climate and its effect on bog hydrology. The high peat accumulation event (~5.6–3.9 ka), described in earlier studies, is characterized by the lowest degree of peat decomposition of the whole record. Given that FTIR-ATR is a quick, non-destructive, cost-effective technique, our results indicate that it can be applied in a systematic way (including multicore studies) to peat research and provide relevant information on the evolution of peatlands.     

Surface wetness and mire development during the late Holocene in central Sweden

Andersson, S. & Schoning, K. 2010: Surface wetness and mire development during the late Holocene in central Sweden. Boreas, Vol. 39, pp. 749–760. 10.1111/j.1502‐3885.2010.00157.x. ISSN 0300‐9483. Late Holocene mire development and surface wetness changes have been studied in a small mixed mire located in central Sweden. Today the mire is characterized by a mainly ombrotrophic centre dominated by Sphagnum mosses, with Carex content increasing towards the more minerotrophic mire margins. Two peat sequences extracted from the central ombrotrophic part were investigated for stratigraphy, humification, testate amoebae analysis, C/N ratio and δ¹³C and δ¹⁵N stable isotopes. Three main stages of mire development are identified, with the first stage, between c. 4200 and 2600 cal. yr BP, characterized by water‐logged conditions, suggesting a minerotrophic fen stage. The second stage, between c. 2600 and 1000 cal. yr BP, is characterized by more ombrotrophic conditions and Sphagnum‐dominated vegetation. The onset of the prominent change at c. 2600 cal. yr BP could have been initiated by climate change coincident with a change in solar activity. The last stage, between c. 1000 and 50 cal. yr BP, is dominated by more ombrotrophic conditions, suggesting increased precipitation. This study shows that the response of hydrological proxies in a mixed mire during its development towards more ombrotrophic conditions might result in conflicting results, a finding that needs to be considered in palaeoenvironmental reconstructions from mires that change between ombrotrophic and minerotrophic settings.     

Late Weichselian environmental change in southern Sweden and Denmark

A synthesis is presented of the envronmental and climatic variations that are inferred to have occurred in southern Sweden (up to latitude 59°N) and Denmark during the Weichselian Late-glacial (14-9 ka BP). The chronology and characteristics of the main phases of deglaciation, sea-level change, periglacial activity, soil development, vegetation cover and climate change are summarised. A curve representing the main changes in temperature, including quantitative estimates based upon beetle data and using the ‘mutual climatic range’ method, is presented.     

Formation of a string and pool topography as expressed by morphology, stratigraphy and current processes on a mire in Kuusamo, Finland

A review is made of earlier work and theories on a formation of string mires, together with a report on detailed investigations carried out over seven years on a small string ( aapa ) mire in eastern Finland, to determine the applicability of earlier hypotheses on the explanation of string and pool patterning. Attention is paid to the topography of the surface and bottom of the mire and to the peat and pollen stratigraphy. Results are presented of year-round temperature measurements and long sequences of snow and frost depth readings from both pools and strings. Snow depth is shown to be a decisive factor in ground frost formation. The strings are shown by a series of repeated Geodimeter measurements to move partly upslope, partly downslope and partly in a sideways direction. The maximum cumulative movement recorded was about 1 m in seven years. Some of the pools remained unfrozen even in midwinter because of groundwater flow. Uneven retention and discharge of the surface water causes the strings to be in a labile state and promotes their movement. The initial formation of the string and pool topography is dated to 2,000–3,000 radiocarbon years B.P. and attributed to a rise in the groundwater table due to climatic change. The resulting fluviodynamics of the mire surface led to the accumulation of loose material into ramparts at the spring flood season and led in time to differential peat formation conditions, progressive peat accumulation on the strings, and regressive peat degradation in the pools. Thus the strings became higher and the pools deeper. The authors believe the importance of frost action, ice expansion and solifluction on the development of string and pool patterns is frequently overestimated.     

皖南地区奥陶系层序地层学分析

皖南东至地区奥陶系在地层分区上可以分为下扬子地层分区、过渡地层分区和江南地层分区 ,在沉积相上可分为台地、斜坡与盆地沉积。通过对位于台地、斜坡和盆地露头层序地层的研究 ,分别将奥陶纪地层自下而上划分为 3个Ⅰ类沉积层序和 2个Ⅱ类沉积层序 ,并详细分析了每个沉积层序各体系域的特征。区内的奥陶系总体为一向上变深的沉积层序 ,经历了镶边陆棚—淹没台地—浅海盆地 3个演化阶段 ,其盆地呈北西浅、南东深的沉积构造格局     

Holocene peatland development and hydrological variability inferred from bog‐pine dendrochronology and peat stratigraphy – a case study from southern Sweden

Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726‐year ring‐width chronology was developed and assigned an absolute age of 7233–6508 cal a BP (5284–4559 BC) through cross‐dating with German bog‐pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog‐surface wetness. A major establishment phase at 7200–6900 cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog‐pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long‐term palaeoclimatic context. Copyright © 2012 John Wiley & Sons, Ltd.     

第四纪地层学发展的大趋势——以蓝田第四纪地层的研究为例

<正> 1963—1964年,在陕西蓝田第四纪地层内发现了猿人化石,吴汝康(1964、1966)命名为蓝田猿人。化石采自两个不同的地点:头盖骨、上颌骨及3颗牙齿产于公王岭(34°11′06″N,109°29′22″E),下颌骨则采自陈家窝(34°14′05″,109°15′07″E)。     

Environmental history of southern Patagonia unravelled by the seismic stratigraphy of Laguna Potrok Aike

Laguna Potrok Aike, located in southernmost Patagonia (Argentina, 52°S) is a 100 m deep hydrologically closed lake that probably provides the only continental southern Patagonian archive covering a long and continuous interval of several glacial to interglacial cycles. In the context of the planned ‘International Continental Scientific Drilling Program’ initiative ‘Potrok Aike Maar Lake Sediment Archive Drilling Project’, several seismic site surveys that characterize in detail the sedimentary subsurface of the lake have been undertaken. Long sediment cores recovered the material to date and calibrate these seismic data. Laguna Potrok Aike is rimmed steeply, circular in shape with a diameter of ∼3·5 km and is surrounded by a series of subaerial palaeoshorelines, reflecting varying lake-level highstands and lowstands. Seismic data indicate a basinwide erosional unconformity that occurs consistently on the shoulder of the lake down to a depth of −33 m (below 2003 ad lake level), marking the lowest lake level during Late Glacial to Holocene times. Cores that penetrate this unconformity comprise Marine Isotope Stage 3-dated sediments (45 kyr bp ) ∼3·5 m below, and post-6800 cal yr bp transgressional sediments above the unconformity. This Middle Holocene transgression following an unprecedented lake-level lowstand marks the onset of a stepwise change in moisture, as shown by a series of up to 11 buried palaeoshorelines that were formed during lake-level stillstands at depths between −30 and −12 m. Two series of regressive shorelines between ∼5800 to 5400 and ∼4700 to 4000 cal yr bp interrupt the overall transgressional trend. In the basin, mound-like drift sediments occur after ∼6000 cal yr bp, documenting the onset of lake currents triggered by a latitudinal shift or an increase in wind intensity of the Southern Hemispheric Westerlies over Laguna Potrok Aike at that time. Furthermore, several well-defined lateral slides can be recognized. The majority of these slides occurred during the mid-Holocene lake-level lowering when the slopes became rapidly sediment-charged because of erosion from the exposed shoulder sediments. Around 7800 and 4900 cal yr bp , several slides went down simultaneously, probably triggered by seismic shaking.     

New discoveries of the Vedde Ash in southern Sweden and Scotland

The Vedde Ash (c. 10 300 ¹⁴ C BP) provides a key time-parallel marker horizon within the Younger Dryas chronozone or GS-1 event of the GRIP stratigraphy. Until recently, the known distribution of wind-blown Vedde Ash outside Iceland was restricted to the west coast of Norway, off-shore sequences close to the Outer Hebrides and the Greenland summit GRIP ice core. The first discoveries of the Vedde Ash in Scotland were reported in 1997, following the development of a new technique for extracting rhyolitic micro-tephra particles from minerogenic deposits. Here we report on the discovery of the Vedde Ash at additional sites in Scotland and at sites in southern Sweden. The concentration of tephra particles in sediments is highest in sites in western Norway, but is also relatively high in sites in southwestern Sweden, suggesting that the main ash cloud travelled eastwards from its volcanic source of Katla, in southern Iceland. Electron microprobe analyses do not indicate any clear geochemical evolution within the samples reported here.     

Late Weichselian-Holocene foraminiferal stratigraphy and palaeohydrogrphic changes in the Gothenburg area, southwestern Sweden

Marine clay from two cores (50 and 36m deep) from Gothenburg, southwestern Sweden, have been analysed using different stratigraphic methods. Foraminiferal stratigraphy complemented withe lithostratigraphy, pollen and mollusc analyses show an environmental succession from arctic conditions with water depths up to 100m during Late Welchselian time, to a boreal shallow water environment in early Holocene time. A comparison of the foraminiferal faunas with those from corresponding investigations from southern Bohuslän, NW of Gothenburg, shows a similar development in the two areas. The sudden environmental change around the Pleistocene/Holocene boundary (10,000 years B.P.) along the Swadish west coast is attributed to changes of the hydrographic patterns; a general shift of the circulation pattern of the Skagerrak/ Kattegat at that time and or a large supply of fresh water flowing into the area from the Lake Vanern basin.     

Crustal development in the Agnew region,Western Australia,as shown by Rb/Sr isotopic and geochemical studies

Rb/Sr geochronology on a folded greenstone-granitoid complex in the Agnew area, Western Australia, yields four distinct ages of igneous activity that conform with stratigraphic and intrusive relationships. They are (using $\text{λ}{}^{87}\text{Rb}\text{= 1.42 · 10}{}^{\mathrm{?11}}\text{a}{}^{\mathrm{?1}}$, NBS 70A = 522 ppm Rb and 65.3 ppm Sr):

     

14.

A reappraisal of the stratigraphy and depositional development of the Upper Greensand (Late Albian) of the Devizes district,southern England     

M.A. Woods  I.P. Wilkinson  G.K. Lott  K.A. Booth  A.R. Farrant  P.M. Hopson  A.J. Newell 《Proceedings of the Geologists' Association. Geologists' Association》2008,119(3-4):229-244

     

15.

Echinoid distribution and sequence stratigraphy in the Cenomanian (Upper Cretaceous) of southern England     

Andrew B. Smith  Andrew S. Gale 《Proceedings of the Geologists' Association. Geologists' Association》2006,117(2):207-217

     

16.

Sedimentology and depositional environments of the Lund Diamicton, southern Sweden     

KÄRSTIN MALMBERG PERSSON  ERIK LAGERLUND 《Boreas: An International Journal of Quaternary Research》1990,19(2):181-199

The Lund Diamicton (earlier named Lund Till) in SW Skåne, S. Sweden, is a glacioaquatic sediment consisting of clay and massive and laminated diamictons. It is characterized by clasts derived from the Baltic depression and its depositional history can be summarized as follows: After deglaciation, large fields of stagnant ice remained in the area and a periglacial land surface with ice-wedge polygons and wind-abraded clasts was developed in ice-free areas. A transgression followed and a clay/diamicton sediment was deposited, partly on top of stagnant ice and against a coastal barrier of stagnant ice along large parts of the basin boundary. This sediment is the Lund Diamicton. The main depositional processes were: fall-out of clay from suspension, sediment gravity flow from stagnant ice and icebergs and rain-out of debris from floating icebergs. The unit was extensively deformed by escaping pore water, loading, flow and due to melting of buried ice. The Lund Diamicton is the equivalent in this area of the classical 'Low Baltic till', which has been interpreted as a basal till deposited by the 'Low Baltic ice stream'. The present study concludes that this unit is instead a glacioaquatic sediment deposited during a transgression in the Öresund area. Its boundary represents the highest coastline and not the margin of a glacier.     

17.

The age,stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District     

K. J. McNamara 《Geological Journal》1979,14(1):41-68

The Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.     

18.

The age,stratigraphy and genesis of the coniston limestone group in the southern lake district     

K. J. McNamara 《Geological Journal》1979,14(2):41-68

The Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.     

19.

Formation conditions and stratigraphy of Carboniferous coal deposits of the Siberian Platform     

《International Geology Review》2012,54(4):429-440

Litbological, paleogeographic, and paleontologic characteristics of the Siberian Platform indicate three stages in the geological development of the region and evolution of its organic world: Early, Middle, and Late Carboniferous, corresponding to the Lower, Middle, and Upper series of the Carboniferous system. Deposits of the lower series, separated as the Anganehan horizon. Include the Anganchan, Kazach'ya, and Krasnognr'yevka suites and lower portions of the Apsekan, Brus, Fat'yanikha, and Kondromo suites. Deposits of the middle series are assigned to the Tushama horizon, which includes the Tushama, Yangoto, Miirma, and Khattynngynakh suites and the Upper portions of the Apsekan, Brus, Fat'yanikha, and Kondromo suites. Formations of the upper series (the Kata horizon) include the Rudnaya, Anaklt, Listvyazhnoye, Kata, and Chokhchuolu suites.—Authors.     

20.

Microfaunas,microfloras and the environmental stratigraphy of the Late Glacial and Holocene in Cardigan Bay     

J. R. Haynes  R. J. Kiteley  R. C. Whatley  P. J. Wilks 《Geological Journal》1977,12(2):129-158

The distribution of foraminifers, ostracods, diatoms and pollen is studied in cores from submarine boreholes. This reveals that the history of the Flandrian transgression is largely the record of the infilling of meltwater channels cut during the early Late Glacial with transgressive estuarine and finally marine deposits. It also supports the idea of the ‘climatic earliness’ of the Welsh seaboard at all stages. Estuarine deposits in excess of —51 m O.D. suggest that Late Glacial sea levels were initially as low as —60 m O.D. and support the idea that the Welsh ice withdrew before 14,000 years B.P. The sea-level rise plots as a smooth curve but was probably episodic in its early phases.     

	Ma	87Sr/86Sr initial (IR)
(1) Differentiated gabbro-granophyre from a stratigraphically old (Kathleen Valley) greenstone sequence	$\text{> 2718 ± 50}$	$\text{0.7007 ± 0.0004}$
(2) Voluminous tonalite, the Lawlers Tonalite	$\text{2652 ± 20}$	$\text{0.70152 ± 0.00012}$
	$\text{2576 ± 14}$	$\text{0.70218 ± 0.00021}$
(3) A less voluminous leucogranite, and a large complex pegmatite cutting the Perseverance nickel orebody	$\text{2588 ± 18}$	$\text{0.7624 ± 0.0068}$
(4) Aplitic leucotonalite (very minor volumes but widespread)	$\text{2474 ± 14}$	$\text{0.70193 ± 0.00012}$

Sedimentology and depositional environments of the Lund Diamicton, southern Sweden

The Lund Diamicton (earlier named Lund Till) in SW Skåne, S. Sweden, is a glacioaquatic sediment consisting of clay and massive and laminated diamictons. It is characterized by clasts derived from the Baltic depression and its depositional history can be summarized as follows: After deglaciation, large fields of stagnant ice remained in the area and a periglacial land surface with ice-wedge polygons and wind-abraded clasts was developed in ice-free areas. A transgression followed and a clay/diamicton sediment was deposited, partly on top of stagnant ice and against a coastal barrier of stagnant ice along large parts of the basin boundary. This sediment is the Lund Diamicton. The main depositional processes were: fall-out of clay from suspension, sediment gravity flow from stagnant ice and icebergs and rain-out of debris from floating icebergs. The unit was extensively deformed by escaping pore water, loading, flow and due to melting of buried ice. The Lund Diamicton is the equivalent in this area of the classical 'Low Baltic till', which has been interpreted as a basal till deposited by the 'Low Baltic ice stream'. The present study concludes that this unit is instead a glacioaquatic sediment deposited during a transgression in the Öresund area. Its boundary represents the highest coastline and not the margin of a glacier.     

The age,stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District

The Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.     

The age,stratigraphy and genesis of the coniston limestone group in the southern lake district

The Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.     

Formation conditions and stratigraphy of Carboniferous coal deposits of the Siberian Platform

Litbological, paleogeographic, and paleontologic characteristics of the Siberian Platform indicate three stages in the geological development of the region and evolution of its organic world: Early, Middle, and Late Carboniferous, corresponding to the Lower, Middle, and Upper series of the Carboniferous system. Deposits of the lower series, separated as the Anganehan horizon. Include the Anganchan, Kazach'ya, and Krasnognr'yevka suites and lower portions of the Apsekan, Brus, Fat'yanikha, and Kondromo suites. Deposits of the middle series are assigned to the Tushama horizon, which includes the Tushama, Yangoto, Miirma, and Khattynngynakh suites and the Upper portions of the Apsekan, Brus, Fat'yanikha, and Kondromo suites. Formations of the upper series (the Kata horizon) include the Rudnaya, Anaklt, Listvyazhnoye, Kata, and Chokhchuolu suites.—Authors.     

Microfaunas,microfloras and the environmental stratigraphy of the Late Glacial and Holocene in Cardigan Bay

The distribution of foraminifers, ostracods, diatoms and pollen is studied in cores from submarine boreholes. This reveals that the history of the Flandrian transgression is largely the record of the infilling of meltwater channels cut during the early Late Glacial with transgressive estuarine and finally marine deposits. It also supports the idea of the ‘climatic earliness’ of the Welsh seaboard at all stages. Estuarine deposits in excess of —51 m O.D. suggest that Late Glacial sea levels were initially as low as —60 m O.D. and support the idea that the Welsh ice withdrew before 14,000 years B.P. The sea-level rise plots as a smooth curve but was probably episodic in its early phases.