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1.
Data on types of Holocene sediments overlying the Upper Pleistocene glacial sediments and constituting the Curonian (Kurshskaya) Spit are summarized to assess its geological stability. The data made it possible to define and describe four main types of sections: (1) peaty, (2) peaty-sandy, (3) gravelly-sandy, (4) muddy-sandy-sapropelic. These spit sections are correlated with the counterparts in adjacent areas of the Baltic Sea and Curonian Lagoon (Kurshskaya Bay). The role of different sources is elucidated for sedimentary material in the spit. Data on recent processes of erosion and accumulation in coastal areas of the spit are compared with types of sediments and sections in the spit and adjacent areas of the sea and lagoon. It is established that paleostraits filled with peat and sapropel represent low-stability areas of the spit. Various scenarios of the spit evolution in response to high sea-level rise are considered. 相似文献
2.
Anne Marie de Grosbois 《Environmental Earth Sciences》2012,65(6):1727-1736
The investigations were carried out in order to evaluate change of the beaches profile during the period 1993–2008 and to
elucidate main trends of the coastal dynamics. Morphometric indicators (beach width, height and inclination) were measured
every year during the period 1993–2008 in 70 measuring stations located along the coastline. It was determined that the dynamic
shoreline of the mainland during 1993–2008 receded by 10.2 m and the dynamic shoreline of the Curonian Spit advanced into
the sea by 8.3 m. The different morphometric beach indicators changed to varying extents over the period 1993–2008, but comparison
of values for 1993 and 2008 showed that those changes were small. The average beach width increased by 1.2 m on the mainland
coast and by 0.5 m on the Curonian Spit coast. The average beach height also increased negligibly: by 0.5 m on the mainland
coast and by 0.1 m on the Curonian Spit coast. The average beach slope inclination increased by 0.012 (from 0.065 to 0.077)
on the mainland coast and by 0.005 (from 0.073 to 0.078) on the Curonian Spit coast. The measurements show that, despite being
the most dynamic elements in the coastal system, these beaches managed to retain their morphometric indicators almost unchanged
during the period of observation. 相似文献
3.
A quantitative analysis of historical aerial photographs and maps coupled with detailed field surveys provided the data necessary
to assess the importance of overwash processes and vegetative recovery on Nauset Spit, Cape Cod, Massachusetts Development
of all plant communities and physiographic features is extremely rapid on the spit. Dunes are evident from aerial photographic
analysis in as little as three years after overwash; salt marshes are apparent in only ten years. Classical ecological succession
does not appear to occur on Nauset Spit, since environments are periodically altered by overwash processes. Most dominant
species on the barrier can grow in bare sandy substrate. Migration of the Nauset Spit, system proceeds by a cyclic series
of events, involving inlet dynamics, overwash processes, and dune building 相似文献
4.
Geological-geophysical methods were applied to provide deeper insight into the nature of unique relict lagoonal sediments exposed on the underwater slope of the Curonian Spit. The study of textural features and morphology of the deformed lagoonal sediments indicates a similarity of their formation mechanism with clay diapirism. Analysis of seismoacoustic data and side scan sonar survey allowed us to establish the configuration of paleolagoon and to determine the direction of dune migration in the past. 相似文献
5.
Spit systems are seldom recognized in the pre‐Quaternary sedimentary record compared to their common occurrence along present‐day coasts and in Quaternary successions. This lack of recognition may partly be due to the lack of widely accepted depositional models describing the facies characteristics of spit systems and their subaqueous platforms in particular. The Skagen spit system is a large active system that began to form 7150 yr bp and from 5500 bp to Recent times it has prograded 4 m year?1 and accumulated 3·5 × 109 m3 of sand. The spit system provides a unique opportunity for establishing a well‐constrained depositional model because uplift and erosion have made large windows into the preserved facies, while active spit‐forming processes can be examined at the young prograding end of the same system. The depositional model presented here thus builds on excellent outcrops, surface morphology, a well‐defined palaeogeography and detailed C14 age control supplemented with observations from continuous well cores and profiles obtained by ground‐penetrating radar and transient electromagnetic surveys. The factors that have governed the development of the spit system, such as relative sea‐level change, wave and current climate, tidal range, sediment transport and depositional rates are also well‐understood. The sedimentary facies of the spit system are grouped into four principal units consisting from below of thick storm sand beds, dune and bar‐trough deposits, beach deposits and peat beds. These four units form a coarsening and shallowing upward sand‐dominated succession, up to 32 m thick, which overlies offshore silt with a transition zone and is topped by a diastem overlain by young aeolian dune sand. The sedimentary structures and depositional processes are described in detail and integrated into a depositional model, which is compared to other spit systems and linear shoreface models. 相似文献
6.
7.
《Journal of South American Earth Sciences》1999,12(3):325-331
The Atlantic shoreline in Patagonia, southernmost South America, is a paraglacial coast that has undergone extensive erosion and retreat since the late Pleistocene, releasing a large volume of sand and gravel to southward littoral drift. Despite regional erosive conditions, accretionary landforms developed during the Holocene in three coastal reentrants. These are, from north to south along a 200 km long shoreline stretch: (1) the cuspate foreland that underlies Bustamante Point, in the Rı́o Gallegos Estuary; (2) the cuspate foreland with incipient spit underlying Dungeness Point, in the eastern Strait of Magellan; (3) the San Sebastián Bay tidal flat; and (4) the El Páramo Spit, partly enclosing the San Sebastián Bay. These accretionary landforms contain a record of relative sea level changes for approximately the past 7 ka, and indicate a tectonically driven drop of about 3 m during growth of Bustamante Point and of 1–2 m in the other areas. Differential sea level fall influenced development of the landforms, with slower rates favoring spit development in the south. 相似文献
8.
E. A. Rogozhin N. K. Kapustian G. N. Antonovskaya Ya. V. Konechnaya 《Geotectonics》2016,50(3):238-243
Based on seismological monitoring data specifying earthquake epicenters, a new map is made for the Western sector of the Russian Arctic region. The seismicity data is reworked in detail by specifying the epicentral positions of earthquakes and adding data on weak seismicity for areas which were earlier insufficiently studied, including those at the boundary of the Arctic Shelf of the Russian Federation. The fundamental possibility of applying seismological observations to construct a regional geodynamic map is discussed (in particular, the important role of island-based seismic stations). The possibility of specifying the nature of seismicity in terms of spectral-temporal analysis (STAN) of waveforms based on data from the new seismic station on the Franz Josef Land is considered. Possible application of the character of seismicity obtained from geophysical data to specify the geodynamic nature of events accompanying interaction of the ridge and shelf spreading is discussed. 相似文献
9.
The paper concerns issues of geology and metallogeny of the Russian Arctic, namely, (i) limits of the Russian oceanic Arctic in the context of the continental origin of territories under jurisdictional dispute; (ii) geology and tectonic history of the region; (iii) distribution of mineral deposits; (iv) outlook for diamond, PGE, Ni, rare metals, gold, and bauxite resources development.Advanced diamond exploration and development can be expected proceeding from geology of new potentially diamondiferous areas, the Phanerozoic history and composition of lithospheric mantle beneath the Siberian craton which were controlled by the Siberian superplume at the Permian–Triassic boundary, and from new exploration approaches adapted to the prospecting conditions of Arctic Siberia.According to the available knowledge of Ni and PGE mineralization in the Noril’sk region, it is reasonable to develop depleted ores and tailings (mining dumps at the Noril’sk and Talnakh deposits). However, the key solution consists in new large discoveries within the Dzheltula and Kharaelakh volcanic and plutonic complexes.Gold production enhancement may be associated with black shale-hosted Au-As mineralization in the northeastern Russian Arctic, but the problem is in the lack of efficient and environmentally safe dressing technologies for these ores.Most of rare metals in the area (Nb, Sc, Y, and other elements) are stored in the giant Tomtor field, which has a complex structure and history. A special technology designed for the Tomtor ores ensures more than 60% extraction of ore components.Good prospects for the bauxite potential are expected from the Timan district where bauxite may occur in Vendian and Early Carboniferous formations.It is suggested to include the development of the Russian Arctic as a priority target in the national economic strategy. 相似文献
10.
SEBASTIAN LINDHORST JÖRN FÜRSTENAU H. CHRISTIAN HASS CHRISTIAN BETZLER 《Sedimentology》2010,57(4):935-955
A sedimentary model for hooked spit depositional systems based on ground‐penetrating radar and sedimentological data is presented. The recurved main spit of Sylt Island (southern North Sea) is dominated by migrating sand dunes; the investigated hooked spit exhibits a system of foredune ridges, oriented perpendicular to the dunes of the recurved spit. The development of the hooked spit is related closely to the presence of an adjacent tidal inlet, where strong tidal currents and a steep bathymetry prevent a further northward progradation of the main spit and trigger a deflection from northerly‐directed to easterly‐directed net sediment transport. Ground‐penetrating radar data and shallow sediment cores reveal the sedimentary architecture of the hooked spit in high resolution and allow the proposition of a genetic stratigraphic model. It is shown that the growth of the hooked spit is controlled by the interplay of alongshore migrating foreshore beach drifts under fair‐weather conditions and strong erosional events, interpreted as the result of rare severe storms. These storms may excavate scarps in the backshore, which play an important role in the development of foredune ridges. Accelerator mass spectrometry 14C ages indicate an absolute age of at least 1300 years for the hooked spit, which possibly correlates with strengthened erosion of the main spit. In contrast to the main spit, where the sediment budget is negative nowadays, growth of the hooked spit beach accelerated significantly during the last decades. This effect can probably be attributed to enhanced beach‐nourishments updrift along the main spit and makes the investigated hooked spit a natural laboratory to study the influence of increasing sediment supply into a system developing under the conditions of sea‐level rise. The study shows that the same external forces lead to distinct progradational processes along one barrier‐spit system. 相似文献
11.
《《幕》》2005,28(1):61-63
The IUGS Executive Committee (EC) met (55th meeting) March 19-22, 2005, in Vilnius, Lithuania, a city with a storied history that dates from the year 1323. The meeting was jointly hosted by the Geological Survey of Lithuania, Vilnius University, and the lUGS Commission on Geoscience for Environmental Management. Prior to the formal meeting, EC members and meeting observers were conducted on a superb field excursion to view aspects of the Quaternary geology and environmental history of the Lithuanian maritime region. 相似文献
12.
I. F. Jefferson D. Evstatiev D. Karastanev N. G. Mavlyanova I. J. Smalley 《Engineering Geology》2003,68(3-4):333-351
Loess and loess-like deposits were much studied in the Soviet Union, and are currently under investigation in Russia and surrounding countries. There is a vast literature in Russian, which touches on all aspects of loess science and technology. In particular, the studies of the origin of collapsibility are almost totally in Russian, and of course studies on the various regions of Russia and the countries of the Former Soviet Union FSU appear in Russian. This review looks at the literature in Russian and attempts to pick out key contributors, major topics and works and to identify the critical regions and zones of investigation. Because so many regions of the FSU had people living on loess ground, there is a vast literature on engineering geology and ground engineering topics, and this tends to dominate all the literature on loess in Russian. Following Russian practice, the fine-grained deposits under consideration are divided into loess and loess-like deposits. Three main topics are recognised across the whole spectrum of loess research: formation and distribution of loess deposits; stratigraphy, cyclicity and palaeoclimatology; and engineering topics, in particular hydrocollapse and subsidence, and we concentrate on the engineering geology topics. An attempt is made, based on the map of Abelev and Abelev [Abelev, Yu.M., Abelev, M.Yu., 1968. Fundamentals of design and construction on collapsible macroporous soils, 2nd ed. Stroiizdat, Moscow, 431 pp. (in Russian)] of collapsing loess deposits, to define seven loess regions within the geographical limits of the old USSR. The seven regions are those where geotechnical problems might be expected. 相似文献
13.
《Gondwana Research》2014,25(1):358-367
The ice shield of Antarctica, which measures several kilometers in thickness, presents a challenge when attempting to unravel the subglacial geology. Here, we report about systematic airborne magnetic surveys conducted over the last decade, which investigated a significant part of Dronning Maud Land (DML), imaging for the first time the crustal architecture of the interior of this sector of East Antarctica. High-resolution data reveal parallel, elongated magnetic anomalies in southeastern DML. These NW–SE trending anomalies can be traced farther east into sparser Russian magnetic data sets. Several high amplitude magnetic anomalies with values above 400 nT have been observed in southwestern DML and Coats Land. They differ clearly in wavelength and amplitudes from the magnetic pattern found in the east and do not show any evidence of a Pan-African orogenic belt or suture zone connecting the Shackleton Range with eastern DML, as hypothesized in several studies. This leads to the assumption of the existence of a hitherto unrecognized large tectonic province in southeastern DML. Whereas an over 100 km long magnetic lineament in the interior of the Dronning Maud Land may reflect a major shear zone akin to the Pan-African age Heimefrontfjella shear zone. Both findings bring new evidences to the still open question about the amalgation of East and West Gondwana. In addition, the magnetic data allow mapping the eastern extent of the presumable cratonic province of Coats Land, a region considered as a key piercing point for reconstructions of Rodinia. Furthermore, the Beattie Magnetic Anomaly in southern Africa is assumed to continue into East Antarctica. Two magnetic highs in western DML are identified as possible eastward continuation of this prominent anomaly. 相似文献
14.
Lithuania, in the Baltic region of northern Europe, is heavily dependent on groundwater resources for its public water supply,
with a large proportion, especially in rural areas, derived from shallow Quaternary aquifers. A national groundwater-vulnerability
methodology, based upon the UK approach, has been developed on behalf of the Lithuanian Ministry of Environmental Protection
as a possible basis for the future protection of shallow groundwater resources for the rural inhabitants.
Some modifications to the UK methodology were required to enable archive data to be used. The four aquifer classes depicted
on the final groundwater vulnerability map are based upon the assessed relative permeabilities of the uppermost Quaternary
deposits. The derivation of the classification of soil-leaching potential required a reassessment of Soviet-based soil wetness
and particle-size classes and a calculation of subsoil-saturated hydraulic conductivity. A preliminary validation of the final
maps against available shallow groundwater samples suggests that the methodology satisfactorily predicts the intrinsic groundwater
vulnerability.
The final methodology, based upon its low-cost approach using archive data, is relevant to the current needs of Lithuania
and can be applied in other regions of similar geology and climate.
Electronic Publication 相似文献
15.
Timing of the last deglaciation in Lithuania 总被引：1，自引：1，他引：0
VINCENT R. RINTERKNECHT ALBERTAS BITINAS PETER U. CLARK GRANT M. RAISBECK FRANÇOISE YIOU EDWARD J. BROOK 《Boreas: An International Journal of Quaternary Research》2008,37(3):426-433
Boulders from the Grūda Moraine, which is associated with the maximum extent of the Scandinavian Ice Sheet (SIS) during the last glaciation, and the Baltija (also referred to as the South Lithuanian), the Middle and North Lithuanian moraines, which are associated with recessional stages of the SIS, were sampled for surface exposure dating using 10 Be. By combining these data with existing radiocarbon ages, we developed a chronology for the retreat of the SIS margin in Lithuania. Our new 10 Be ages suggest that the SIS margin began to retreat from its maximum extent at 18.3 ± 0.8 10 Be kyr. Based on a probable correlation of the Baltija Moraine with the Pomeranian Moraine in Poland, we infer that the Baltija Moraine was formed following a re-advance of the SIS margin. The ice margin retreated from the Baltija position at 14.0 ± 0.4 10 Be kyr. The SIS-margin retreat paused at least two more times to form the Middle Lithuanian Moraine at 13.5 ± 0.6 10 Be kyr and the North Lithuanian Moraine (tentatively correlated to the Pajūris Moraine) at 13.3 ± 0.7 10 Be kyr. Subsequent ice-margin retreat from the North Lithuanian Moraine represented the final deglaciation of Lithuania. Direct dating of these moraines better constrains the relation of ice-margin positions in Lithuania to those in adjacent countries as well as the SIS response to climate change. 相似文献
16.
The first results of SHRIMP dating of magmatic complexes and associated gold–silver deposits and ore occurrences (Kupol, Dvoinoe, Moroshka, and others) in the Chukotka sector of the Russian Arctic coast are discussed. The petrological and isotopic–geochronological data are used for reconstructing their formation conditions. 相似文献
17.
18.
V. I. Velichkin 《Geology of Ore Deposits》2007,49(5):372-377
The outstanding contribution of Professor F.I. Wolfson to the origination and development of Russian science and practice in the field of geology of uranium deposits is emphasized. Under his guidance, a team of highly skilled specialists on uranium deposits was gathered at the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences, in Moscow. Owing to their efforts, all significant uranium deposits in the former Soviet Union and socialist bloc countries have been studied comprehensively. A theory of uranium ore formation was developed on this basis, and elaborated practical recommendations promoted the creation in the Soviet Union of the world’s largest uranium resource sources. Today, Wolfson’s ideas and works are widely used in planning and carrying out complex investigations at operating uranium deposits and in new promising uranium districts. 相似文献
19.
Gravelly spit deposits in a transgressive systems tract: the Pleistocene Higashikanbe Gravel, central Japan 总被引：1，自引：0，他引：1
The Pleistocene Higashikanbe Gravel, which crops out along the Pacific coast of the Atsumi Peninsula, central Japan, consists of well‐sorted, pebble‐ to cobble‐size gravel beds with minor sand beds. The gravel includes large‐scale foreset beds (5–10 m high) and overlying subhorizontal beds (0·5–3 m thick), showing foreset and topset structure, from which the gravel has previously been interpreted as deposits of a Gilbert‐type delta. However, (1) the gravel beds lack evidence of fluvial activity, such as channels in the subhorizontal beds; (2) the foresets incline palaeolandwards; (3) the gravels fill a fluvially incised valley; and (4) the gravels overlie low‐energy deposits of a restricted environment, such as a bay or an estuary. The foresets generally dip towards the inferred palaeoshoreline, indicating landward accretion of gravel. Reconstruction of the palaeogeography of the peninsula indicates that the Higashikanbe Gravel was deposited as a spit similar to that developed at the western tip of the present Atsumi Peninsula, rather than as a delta. According to the new interpretation, the large‐scale foreset beds are deposits on the slopes of spit platforms and accreted in part to the sides of small islets that are fragments of the submerging spit during relative sea‐level rise. The subhorizontal beds include nearshore deposits on the spit platform topsets and deposits of gravel shoals or bars, which are reworked sediments of the spit beach gravels during a transgression. The lack of spit beach facies in the subhorizontal beds results from truncation by shoreface erosion. Dome structure, which is a cross‐sectional profile of a recurved gravel spit at its extreme point, and sandy tidal channel deposits deposited between the small islets were also identified in the Higashikanbe Gravel. The Higashikanbe Gravel fills a fluvially incised valley and occupies a significant part of a transgressive systems tract, suggesting that gravelly spits are likely to be well developed during transgressions. The large‐scale foreset beds and subhorizontal beds of gravelly spits in transgressive systems tracts contrast with the foreset and topset beds of deltas, characteristic of highstand, lowstand and shelf‐margin systems tracts. 相似文献
20.
Curt D. Peterson Scott S. Williams Kenneth M. Cruikshank John R. Dub 《Geoarchaeology》2011,26(2):219-244
A coincidence of the Beeswax galleon shipwreck (ca. A.D. 1650–1700) and the last Cascadia earthquake tsunami and coastal subsidence at ∼A.D. 1700 redistributed and buried wreck artifacts on the Nehalem Bay spit, Oregon, USA. Ground‐penetrating radar profiles (∼7 km total distance), sand auger probes, trenches, cutbank exposures (29 in number), and surface cobble counts (49 sites) were collected from the Nehalem spit (∼5 km2 area). The field data demonstrate (1) the latest prehistoric integrity of the spit, (2) tsunami spit overtopping, and (3) coseismic beach retreat since the A.D. 1700 great earthquake in the Cascadia subduction zone. Wreck debris was (1) initially scattered along the spit ocean beaches, (2) washed over the spit by nearfield tsunami (6–8 m elevation), and (3) remobilized in beach strandlines by catastrophic beach retreat. Historic recovery of the spit (150 m beach progradation) and modern foredune accretion (>5 m depth) have buried both the retreat scarp strandlines and associated wreck artifacts. The recent onshore sand transport might re‐expose heavy ship remains in the offshore area if the wreck grounded in shallow water (<20 m water depth of closure). © 2011 Wiley Periodicals, Inc. 相似文献