Academic literature on the topic 'Fluvial sediments; Quaternary deposits'

The lithostratigraphic classification of the Quaternary deposits is based on the genesis of the sediments. The distinguished environments are marine - estuarine, fluvial, eolian and slope. The marine - estuarine deposits are restricted to certain time-intervals within the Quaternary and are limited to the northern part of Belgium. Fluvial deposits are found throughout the Quaternary. On the basis of the sedimentological - lithological differentials within the Meuse basin and the Schelde basin a bipartite subdivision of the fluvial deposits is introduced. Eolian deposits are differentiated on the basis of their grain size distribution, namely sand and silt. The sandy deposits are accumulated in the northern part of Belgium, whereas loess is deposited in the more southern part of the country. Slope deposits are not restricted regionally neither temporally.

Offshore areas, along the North Shore of the St. Lawrence Estuary, have major lithostratigraphic and seismostratigraphic units that relate to the advance or retreat of the Late Wisconsinan Ice Sheet, subsequent marine transgression or regression, and reworking of postglacial deposits. Glacial diamicton and glaciomarine units (acoustic units 1 and 2) were emplaced between >18 and 14.5 ka, by basal meltout or ice-marginal sedimentation; they reflect ice-proximal sedimentation associated with ice-terminal stillstands. Deep-water muds (acoustic unit 3) represent ice-distal accumulation of glaciomarine sediment from glaciofluvial plumes between 13.5 and 11 ka. After this time exceptionally thick nearshore coarse-grained deltaic and estuarine successions (acoustic unit 4) were deposited. The uppermost postglacial sediment (acoustic unit 5) forms the seabed and reflects a reworking phase concomitant with a lowering sea level and ablating Late Wisconsinan ice sheets.Glacioisostatic rebound, which occurred about 23 ka to the present, uplifted glacial and marine deposits and resulted in extensive reworking and production of modern placers. Heavy-mineral concentrations vary as follows: terrestrial tills, 9–20%; modem storm-berm and delta top deposits, 43–60%; delta slope deposits, 25–55%; and deep (170+ m) offshore sediments, 0–2%. Three stages occurred in marine placer formation: (1) 6700 BP, fluvial discharge was high, and fluvial-dominated deltas were built; marine limit was 30 m asl, with progradation of deltas and delivery of sediments with at most 2% heavy minerals; (2) 5200 BP, fluvial discharge was reduced; marine limit was 15 m asl, deltaic sediments were reworked, increasing heavy mineral concentration to 2–8%; (3) 2800 BP, fluvial input was greatly reduced, waves and tides were more influential, a strong littoral current system developed, causing significant reworking of nearshore sediments, heavy mineral concentrations increased, with values exceeding 20% locally. Mass budget calculations show that the second-cycle reworked sediment (acoustic unit 5) is a potential economic target (1 km3, or 1700 Mt). If 7% (using atomic weights) of this target sediment is ilmenite (FeTiO3). then 27 Mt of titanium may be available.

AbstractThere is a considerable Variation in the lithology and thickness of glacial and fluvial Sediments in Western Europe. This wide range of materials is associated with significant engineering problems and considerable economic interest from the extractive industries.Geophysical techniques are widely applied to map and investigate areas with glacial deposits and fluvio-glacial sands and gravels. There are sheet-like outwash deposits, some with buried and therefore unpredictable Channels, and smaller fissure and pocket deposits in rock. An assessment of the geometry of a deposit can be accurately achieved with geophysical methods, and electrical techniques have been particularly successful. The nature of the deposit, layering within the deposit, lateral Variation of lithology, thickness and depth to bedrock may all be established quickly and with great cost effectiveness.Numerous other problems occur with Quaternary environments particularly alteration and contamination of rock masses. Electrical techniques are also a powerful investigative tool in these situations.The success of these techniques depends upon the geophysical properties of the material to be investigated and the geophysical properties of the underlying sediment or bedrock, the technique actually selected, professional field practice and interpretation. These factors will be discussed and illustrated with reference to a number of case studies.

Palynologic and Lithostratigraphic Research of Lacustrine, Marsh and Fluvial Quaternary Deposits in Rašica Dolina and Mišja Dolina, and on Radensko Polje The article deals with the results of palynological and stratigraphical research of lacustrine, marsh and fluvial Quaternary deposits in the Rašica dolina and Mišja dolina, and on Radensko polje. Correlation with equivalent Quaternary deposits and their palynoflora from the Grosuplje polje area was also performed. In the study area, Mesozoic, predominantly carbonate rocks are transgressively covered by Quaternary deposits which are in general composed of five lithostratigraphic units (from bottom to top): 1. gravel, 2. grey lacustrine clay, 3. reddish brown loam, 4. light grey marly clay and 5. alluvial marsh deposits. On the basis of pollen analysis the Quaternary sediments of the study area are chronostratigraphically classified to the Late or Middle Pleistocene and Holocene.

ABSTRACT Thick Quaternary sediments at Quesnel, British Columbia, provide a record of the late Quaternary history of an area near the centre of the former Cordilieran Ice Sheet. These sediments, in part, fill stream valleys that were cut sometime prior to the Late Wisconsinan Fraser Glaciation. Of special note are (1) fluvial or glaciofluvial sand and gravel deposited by aggrading streams, perhaps in part during early Fraser time; (2) thick glaciolacustrine mud, sand, and diamicton laid down later as glaciers advanced across central British Columbia; and (3) glaciolacustrine sediments similar to (2), but deposited in an ice-dammed lake at the end of the Fraser Glaciation. The stratigraphy is punctuated by colluvial deposits that are products of landslides from valley walls at various times during the late Quaternary; this process continues to the present. During the Fraser Glaciation, glaciers from the Coast and Cariboo Mountains coalesced and flowed north over central British Columbia. Fraser Glaciation advance sediments and older Pleistocene deposits were partially removed by this ice sheet and the eroded remnants mantled with till. At the end of this glaciation, the Cordilieran Ice Sheet downwasted and receded southward along an irregular front across the study area. Large amounts of sediment were deposited in glacial lakes dammed by the southward-retreating ice. With complete déglaciation of the interior, glacial lakes drained and the present drainage system was established. At first, valleys were partially aggraded with sand and gravel, but later, streams dissected valley fills to produce a series of terraces at successively lower levels.

Abstract The composition of the transparent heavy-mineral assemblages (0.25-0.1 mm) in Quaternary slope, karst, glacial, fluvioglacial and fluvial deposits with different parent material was investigated in the Kielce-Łagów Valley (the central part of the Palaeozoic core of the Holy Cross Mountains). For the purpose, 93 samples of mostly sandy sediments were examined. Some marker and some supporting minerals can be distinguished. Slope and karst deposits are dominated by the abrasion-resistant minerals zircon, tourmaline, staurolite and rutile. This assemblage points at a source consisting of strongly weathered pre-Quaternary bedrock. Glacial and fluvioglacial deposits are dominated by medium-resistant and non-resistant minerals (garnet, amphibole, pyroxene and biotite). The two types of parent material of the heavy minerals are typical of the Quaternary deposits in the Polish uplands. The two sources are most clear in the younger (Vistulian and Holocene), mostly fluvial sediments. The results of the analysis imply that the impact of Pleistocene glaciers on the central part of the Holy Cross Mountains was neither large enough to hide the local mineralogical background, nor sufficient to dominate over the main processes transforming the mineral composition under the variable climatic conditions of the Quaternary, including aeolian processes and chemical weathering.

AbstractThe Pliocene and Quaternary unconsolidated sediments of the Upper Rhine Graben (URG) were petrographically analysed in numerous high quality drill cores. The heavy mineral composition of the Graben sediments was compared to those from the Graben margins. In addition, the sedimentary lithofacies were investigated. The chronological classification of the sedimentary successions was established by the interpretation of sporadic palaeontological and palaeomagnetic data.Within the Pliocene sediments, two distinguishable heavy mineral assemblages indicate different source areas of the Graben fill. At first, a heavy mineral assemblage of stable minerals (turmaline, zircon and anatase) indicates a contribution of debris supplied from Buntsandstein areas at the Graben margins. Secondly, a mixed association of stable minerals in combination with unstable (garnet, hornblende, less epidote) and distinct rare minerals (e.g. monazite, xenotime) can be traced back to debris derived from the crystalline rocks of the southern Graben margins (Black Forest, Vosges). The distribution of sediments with this mixed heavy mineral assemblage proves the fluvial sediment transport from south to north and therefore the course of the Pliocene proto-Rhine along the Graben.The correlation between the Quaternary sediment successions in the south and the north of the Graben is problematic due to their variable thicknesses as well as their changing lithofacies.In the southern URG, the Quaternary strata could be subdivided into the older Breisgau Formation and the younger Neuenburg Formation based on characteristic lithofacies. Within this succession, the lower part of the Breisgau Formation (lower Breisgau beds) can be distinguished by noticeable lower contents of hornblende, which probably reflects the effects of weathering and solution of these unstable minerals due to repeated discontinuities during the sediment accumulation. The sediments of the upper part of the Breisgau Formation (upper Breisgau beds) and of the Neuenburg Formation contain a heavy mineral assemblage of garnet, epidote and hornblende, which is typical for Rhine deposits with Alpine contribution. This probably unaffected composition indicates a more unvaried and rapid accumulation of predominantly Alpine debris. In the northern URG, the Quaternary strata are subdivided into three aquifers and intercalated fine-grained horizons. Here, the Quaternary sediments can be petrographically classified into Rhine deposits (garnet, epidote and hornblende) and local accumulations contributed from the Graben margins (turmaline, zircon and anatase) without contemporaneous influence of the Rhine. The analytical results obtained from several drill cores in the northern URG provide evidence for the spatial and temporal variability of the course of the Rhine during the Quaternary.

AbstractBioclastic carbonate deposits that formed because of a combination of nearshore marine, fluvial, and aeolian processes, occur along the Saurashtra coast and in the adjacent interior regions of western India. Whether these carbonates formed by marine or aeolian processes has been debated for many decades. The presence of these deposits inland poses questions as to whether they are climate controlled or attributable to postdepositional tectonic uplift. In particular, the debate centres on chronologic issues including (1) appropriate sampling strategies and (2) the use of 230Th/234U and 14C ages on the bulk carbonates. Using traces (<1%) of quartz grains trapped in carbonate matrices, optically stimulated luminescence (OSL) dating of quartz grains, deposited along with the carbonate grains, provides ages for the most recent deposition events. The OSL ages range from >165 to 44 ka for the shell limestones, 75–17 ka for the fluvially reworked sheet deposits, and 80–11 ka for miliolites deposited by aeolian processes. These are younger than the 230Th/234U and 14C ages and suggest that the inland carbonate deposits were reworked from older carbonate sediments that were transported during more arid phases.

Absolute dating methods have been used in chronological studies of geological processes and sedimentary units of Quaternary age in Central Amazonia, Brazil. Although radiocarbon dating has been very useful in archaeological research and soil studies, the temporal interval of this method is inefficient in evaluating the sedimentation aspects and geological events from the beginning of the Quaternary in the Amazon basin. The use of crystal luminescence dating has been one of the most promising tool for determining the absolute dating of Quaternary deposits in the Amazonian region. Optically stimulated luminescence (OSL) dating, following the MAR and SAR protocols, in a tectonic-sedimentary study of Quaternary fluvial deposits in the confluence area of the Negro and Solimões rivers, indicated ages from 1.3 (Holocene) to about 67.4 kyears (Late Pleistocene) for these sediments. Low radioactive isotope concentrations were found about 2ppm for 235U and 238U; 5ppm for 232Th; and the 40K concentrations were almost zero. A comparison was made between MAR and SAR protocols taking into account the fluvial depositional process.

The buried Paleozoic bedrock surface of southern Ontario is dissected by an interconnected system of valleys. These buried valleys are infilled with thick successions of glacial, interglacial, and fluvial sediments that contain a lengthy record of changing environmental conditions during the late Quaternary. Detailed logging of over 500 m of sediment recovered from 11 continuously cored boreholes provides the basis for this study. The boreholes were drilled within two poorly defined bedrock valleys located east of the Niagara Escarpment in southern Ontario as part of a groundwater exploration program. Six distinct facies types were identified within the cores: sand, gravel, fine-grained sediment, and sand-rich, mud-rich, and clast-rich diamict. Textural characteristics of the cored sediments and vertical changes in facies types were used to identify six stratigraphic units (SU I through SU VI) within the valley-infill deposits. These units are interpreted to record fluvial or colluvial (SU I), lacustrine (SU II), fluvial, glaciofluvial or deltaic (SU III), subglacial (SU IV), glaciofluvial (SU V) and subglacial or ice marginal (SU VI) conditions. Sediment characteristics and stratigraphic relationships allow tentative correlation with known surficial deposits. Analysis of the subsurface characteristics and geometries of this stacked succession of coarse- and fine-grained stratigraphic units also allows identification of the geometry of potential aquifers.

Orientador: Francisco Sérgio Bernardes Ladeira
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
Made available in DSpace on 2018-08-18T07:37:54Z (GMT). No. of bitstreams: 1 Celarino_AndreLuizdeSouza_M.pdf: 6577902 bytes, checksum: d76059e9c39490c344571bfeab4259c6 (MD5) Previous issue date: 2011
Resumo: O rio Mogi Guaçu apresenta, no trecho próximo a Estação Ecológica de Jataí, em Luis Antônio-SP, elevada sinuosidade do canal e inúmeros meandros abandonados causados pela migração lateral e posterior avulsão do curso principal. Essa situação proporcionou uma configuração específica para os solos localizados no terraço e na planície aluvial do rio. Para entender melhor a morfopedogênese desse local, foi feita uma sequência de perfis e tradagens para a investigação da continuidade lateral dos horizontes pedológicos, para depois serem realizadas análises químicas, granulométricas, mineralógicas, micromorfológicas e datações. Identificou-se horizontes ricos em matéria orgânica que ocupam toda a várzea e antigo terraço fluvial, que estão se desenvolvendo sobre um depósito residual de 130.000A.P, conforme datação realizada em um dos perfis. Esses horizontes possuem gêneses diferentes. Um deles, classificado como hístico (H), se desenvolveu preenchendo um antigo meandro abandonado, enquanto os horizontes acima dele, compostos por uma sequência de horizontes A húmicos, foram depositados posteriormente em ambiente de maior energia do rio, num dado momento onde ele já tinha incidido seu talvegue em alguns metros e se deslocado no sentido contrário ao de sua planície aluvial. Esse horizonte foi enterrado por sedimentos aluviais e a preservação da matéria orgânica foi eficiente, apesar de apresentar menores quantidades de carbono orgânico que o horizonte H. A mineralogia mostrou que a Caulinita é o mineral predominante na fração argila, apesar de ocorrerem também Gibbsita e VHE. Esta última seria resultado de neoformação, indicando atual situação de drenagem livre, ou, sua presença é de origem alóctone. A micromorfologia mostrou feições redox ainda preservadas na base do perfil 3, porosidades fissurais associadas à processos de perda de água pela superfície e grandes diferenças granulométricas entre os perfis apresentados, a principal delas se refere à diminuição latente do grau de seleção dos grãos do esqueleto no sentido da vertente para a planície aluvial. As razões molares apontaram para descontinuidades no horizonte 2A em P5 e P3, e entre os horizontes Ah e H, no perfil 4, mostrando distintas condições de pedogênese dentro dos perfis. Os processos de formação desses horizontes estão ligados à migração lateral do rio Mogi Guaçú e incisão do seu talvegue, que proporcionaram condições redutoras para o acúmulo de matéria orgânica, resultando em momentos de maior e menor acúmulo. Com as datações foi possível propor a cronologia da formação do paleoterraço e da planície aluvial nos últimos 130.000 anos e dos solos associados, no entanto, as considerações feitas a respeito da influência do paleoclima e de fatores estruturais não são conclusivas, devido à dinâmica geológica e geomorfológica da área, que é bastante específica
Abstract: The Mogi Guaçu river, near to Estação Ecológica de Jataí (Luis Antônio-SP), shows high sinuosity on its channel and many abandoned meaders caused by lateral migration and main course's avulsion. This situation is responsible by a specific configuration for the soils which are localized at terrace and at the river's alluvial plain. For a better understanding of the local morphopedogenesis, a profiles' sequence and some boreholes were made in order to investigate the lateral continuity of the soil horizons, and then perform chemical analysis, particle size distribution, mineralogy, micromorphology and datings.This process enabled the identification of horizons rich in organic matter which fills the lowland and the old's alluvial plain, which are developing above residual deposits of 130.000B.P, in according to the dating of one of the profiles. These horizons have different genesis. One of them, classified as histic horizon (H), developed filling an older abandoned meander, while the horizons above, compound by a sequence of humic A horizons, were deposited later on high energy river environment, at some point where it has been cut its thalweg in some meters and moved away of the alluvial plain. This horizon was buried by alluvial sediments and the preservation of organic matter was efficient, despite of showing lower amounts of organic carbon than H horizon.The mineralogy has shown that Caulinite is the predominant mineral in clay fraction, although Gibbsite and HIV also exist. HIV may be the result of neoformation, indicating an actual situation of free drainage, or, its presence is allochthounous. The micromorpholy has shown preserved redox lineament on the bottom of profile 3, porosities associated to water loss processes by surface and big granulometric differences between the profiles. One of the biggest differences refers to the grain selection's reduction of the skeleton in the direction of the slope to the alluvial plain. The molar ratios indicated gaps on 2A horizon in the P5 and P3, and between Ah and H horizons, on profile 4, showing different profile conditions of soil forming. The formation process of those horizons is linked with lateral migration of the river Mogi Guaçu and incision of its thalweg, which provides reducing conditions for the amount of organic matter, resulting in higher and lesser moments of accumulation.By datings was possible propose paleoterrace and alluvial plain formation chronology of last 130.000 years and associated soils, although, the considerations made about paleoclimate and structural factors influence aren't conclusive, due to geologic and geomorphologic dynamic of area, that is much specific
Mestrado
Análise Ambiental e Dinâmica Territorial
Mestre em Geografia

[Truncated abstract] Detailed sedimentological, petrographical, geochemical and palynological studies have provided insight into the source rocks and the processes that operated during formation of the Tertiary Yandi channel iron deposit (CID) of the eastern Pilbara, Western Australia. Yandi is the largest and most valuable CID in the world, accounting for more than 2.5% of global iron production in 2003, and is the type-example of CID. The Yandi CID occupies the palaeo-Marillana Creek in the central Hamersley Ranges. It is near-coincident-with the modern Marillana Creek which incised Proterozoic bedrock of the Weeli Wolli Formation (Hamersley Group) and associated dolerite intrusions. Three lithostratigraphic units fill the palaeo-Marillana Creek and comprise the Marillana Formation. The units in stratigraphic order are the: (1) Munjina Member; (2) Barimunya Member, which hosts the majority of the iron resource; and (3) Iowa Eastern Member. Fossil pollen and spores in organic-rich claystones in the Munjina Member indicate that deposition of the Marillana Formation most likely commenced in the Early Oligocene in response to erratic seasonal flows with high energy flood events and intervening quiescent suspension settling of clays. The Marillana Formation consists of twelve facies. These conglomerate and clay facies form three facies associations. The basal facies association is composed of polymictic conglomerate, clay and interbedded CID that represents a lag deposit along the base of the palaeochannel. This facies association characterises the Munjina Member. The second facies association consists of iron-rich conglomerate sheets, bars and subordinate scour-fills and characterises the Barimunya Member. Channel iron deposits of the overlying Iowa Eastern member consist of reworked Barimunya Member iron conglomerates. The upper facies association is polymictic conglomerate with clay that characterises the remainder of the Iowa Eastern Member. Polymictic iron conglomerate in the Munjina and Barimunya Members contains Weeli Wolli Formation and dolerite clasts indicating local derivation. Rare earth element profiles of the other iron conglomerate facies indicate derivation of the Barimunya and Iowa Eastern CID from a different source. These iron conglomerates are characterised by relatively flat LREE profiles. The LREE exhibit an enriched profile approaching the MREE [(average La/Nd)N = 0.7], and the HREE profile shows minor enrichment approaching ytterbium [(average Dy/Yb)N = 0.9]. Comparison of iron conglomerate REE profiles to those of the bedrock indicates that these conglomerates were most probably derived from the Joffre Formation BIF of the Hamersley Group

The purpose of this study is to assess the engineering geological and geotechnical characteristics and to perform seismic hazard studies of the Upper Pliocene and Quaternary deposits located towards the west of Ankara. Based on a general engineering geological and seismic characterization of the site, site classification systems are assigned for seismic hazard assessment studies. The objective of the research is to determine the regional and local seismic soil conditions, predominant periods and ground amplifications, and to idealize the soil profile of the sites by the aid of surface geophysical methods. These studies are combined and integrated with the geotechnical database from a variety of in-situ and laboratory studies that are compiled from present and previous studies regarding the project area and then transferred to an analytical environment for creating relevant information for our site. Then, engineering geological and geotechnical seismic characterization along with seismic zoning map preperation is accomplished. Finally, based on a general engineering geological and geotechnical site characterization, site classification systems are assigned to account for site effects in seismic hazard assessments along with the assessment of mitigation and remediation of seismic hazards.

Thesis (PhD)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: The discovery of lucrative diamond deposits along the west coast of Southern Africa about 1200 kilometres from the Kimberley region during the period 1908 to 1927, gave rise to a number of different theories with respect to their possible provenance. These included the transportation of diamonds from unknown sources in southern Namibia by south-flowing rivers, hidden on- and off-shore kimberlites along the coast, and transportation by west-bound rivers from the hinterland. Subsequent research has shown that the latter is the only plausible theory. The discovery of marine and coastal diamond deposits as far south as the Olifants River estuary showed that the Vaal-Orange drainage in its current form could not have been the only conduit for diamonds to the coast, and the drainage evolution of southern Africa was interpreted as comprising essentially the following two main palaeo-fluvial systems active in the formation of the world's only known diamond mega-placer deposit:  The Karoo River with its headwaters similar to those of the modern Orange and Vaal Rivers and entering the Atlantic Ocean via the present-day Olifants River;  The Kalahari River that drained southern Botswana and followed the route of the modern-day Molopo River, entering the Atlantic Ocean in the vicinity of the present Orange River mouth. An important shortcoming of the above model is that it could not account for the fact that diamond distribution along the west coast shows a marked increase in grade and average stone size at the estuaries of all the major rivers draining from the escarpment to the Atlantic between the Olifants and the Orange Rivers. The presence of fluvial diamond deposits along the courses of the Buffels, Swartlintjies, Spoeg, Horees and Groen Rivers confirms that the increased grade and diamond size at their estuaries is not a function of large bays and rougher bottom topography associated with the rivers, although these could have contributed to this phenomenon. This proves that the catchments of the rivers between the Olifants and Orange Rivers also had access to diamondiferous debris, although they were not in contact with these two major drainages. A number of researchers proposed that diamonds liberated from pre-Karoo kimberlites were moved from their primary hosts to the south-western parts of the subcontinent by Dwyka glacials. From the above it is clear that nearly a century after the discovery of diamonds along the west coast of southern Africa consensus regarding their origin had not been reached. The aim of this study was therefore to establish a model explaining the most likely sources and distribution history of the more important alluvial diamond deposits in southern Africa. The methodology comprised a study of 1878 diamonds collected from 25 alluvial and two kimberlitic sources for comparison with known similar data from 12 kimberlitic populations in southern Africa. The diamond study was supplemented by a study of sedimentary clasts from bulk gravel samples taken along the Middle and Lower Orange River as well as Scanning Electron-microscope (SEM) Analyses of garnet grains and zircon geochronology. The evidence from the study does not support the postulated existence of a former Karoo River. The surface features of diamonds, notably brown spots indicating – in the context of southern Africa - liberation from pre-Karoo kimberlites, as well as the results of Fourier Transform Infrared analyses revealed that the populations at Kwaggaskop along the Sout River, previously considered an erosion remnant of the Lower Karoo River and those occurring south of Brandvlei and Van Wyksvlei in the valley of the Sak River, previously considered to have been reworked from the Middle Karoo River, differ profoundly from each other. In addition, the surface feature studies and Fourier Transform Infrared Analyses clearly show major distinctions between the diamond populations from the Sout River-Olifants River estuary and those from the Kimberley kimberlite province which was said to have supplied diamonds in large quantities to the Olifants River estuary via the postulated Karoo River. Furthermore the idea of a palaeo-Gamoep River playing a significant role in the transportation of diamonds to the west coast is favoured by the presence of brown-spotted diamonds and diamonds with Platelet Preservation Indices revealing severe platelet destruction that could be traced through Bosluispan in the Koa River valley, the Buffels River valley, the Buffels River estuary and to the shallow marine environment north of the Buffels River. Zircon geochronology confirmed the role of the Orange River in the denudation of the sub-continent. With respect to the drainage evolution and diamond distribution in southern Africa the results of this study indicate a complex diamond dispersal model that differs in some respects from prevailing theories. It shows that diamonds liberated from pre- Karoo kimberlites in the north-eastern part of the sub-continent were initially moved in a south-westerly direction by pre-Karoo drainages, then by Dwyka glaciers and ice sheets. Ultimately, after liberation from exhumed glacial and fluvial deposits and together with diamonds subsequently liberated from Jurassic and Cretaceous kimberlites, Cretaceous and younger drainages provided the transport toward the Atlantic Ocean where the diamonds were concentrated along shorelines and in bedrock trap sites. Significant quantities did not reach the coast, but were locked up in fluvial sediments in erosion remnants like terraces, karstic depressions and other segments of palaeo-channels along the way. The presence of diamonds with FTIR characteristics reminiscent of those from Orapa and Jwaneng in the Orange River deposits as well as in a raised marine terrace in southern Namaqualand and in marine deposits north of Concession 12A, also negates the possible existence of a palaeo-Kalahari River, unless it was a very young system that did not interrupt the south-bound dispersal of Botswana diamonds during the Late Oligocene-Early Miocene. The study also included microscopic examination of a parcel of diamonds from the enigmatic Skeleton Coast deposits, north-western Namibia. These results confirmed the conclusion based on geological and geomorphic grounds that these diamonds cannot be linked to the Oranjemund deposits, while their surface features showed that pre-Karoo sources comprise the most likely provenance for the Skeleton Coast diamonds. Thus the combination of FTIR analyses and surface feature studies of diamonds, zircon geochronology and SEM analyses of garnets allowed the formulation of a revised model for the distribution of alluvial diamonds and the drainage history of the sub-continent since the Middle Cretaceous, while the study of sedimentary clasts confirmed the repeated occurrence of high energy fluvial conditions – especially evident in the palaeo-Orange River sediments – that contributed to the high percentage of gem stones in the surviving alluvial diamond populations due to the destruction of poor quality diamonds.
AFRIKAANSE OPSOMMING: Die ontdekking van ryk alluviale diamantafsettings aan die suider-Afrikaanse weskus, meer as 1200 kilometer van die Kimberley-omgewing af tussen 1908 en 1927, het 'n aantal teorieë omtrent moontlike provenansgebiede vir hierdie afsettings tot gevolg gehad. Dit het gewissel van die suidwaartse vervoer van diamante vanaf bronne in suidelike Namibië, diamantdraende kimberliete in die kusvlaktes of op die vastelandstoep onder huidige seevlak, tot die vervoer van diamante deur weswaarts-vloeiende riviere vanuit die binneland. Geen ontdekkings wat eersgenoemde teorie kon ondersteun is in Namibië gemaak nie. Verder, namate meer gevorderde navorsingsresultate aan die lig gekom het, het dit duidelik geword dat kimberliete wat weg van 'n antieke kraton geleë is, grootliks sonder diamante is, en gevolglik het die idee van nabygeleë diamantdraende kimberliete in die kusvlakte of op die seebodem as bron, onaanvaarbaar geword. Grootskaalse wes- tot suidweswaartse vervoer van diamante het gevolglik die enigste aanvaarbare alternatief gebied. Die ontdekkiing van aan- en aflandige mariene afsettings tot so ver as suid van die Olifantrsrivier het getoon dat die Vaal-Oranjestelsel in sy huidige vorm nie die enigste vervoerkanaal vir diamante na die weskus kon wees nie. Die dreineringsgeskiedenis van suidelike Afrika was gevolglik vertolk aan die hand van twee voorgestelde groot oer-rivierstelsels, naamlik: - Die Karoorivier met sy bolope naastenby soortgelyk aan dié van die moderne Oranje- en Vaalriviere, en wat langs die huidige Olifantsrivier uitgemond het; - Die Kalaharirivier wat die suide van Botswana gedreineer het, en min of meer die roete van die huidige Moloporivier gevolg het, met sy monding baie naby aan dié van die moderne Oranjerivier. 'n Belangrike tekortkoming in bogenoemde model is die feit dat dit nie 'n verduideliking bied vir die volgende feit nie: Diamant-produksiedata van die Suid-Afrikaanse weskus toon 'n skielike toename in graad (karaat per 100 ton) en gemiddelde steengrootte van diamante by die monding van al die belangrike riviere tussen die Olifants- en Oranjeriviere, wat vanaf die platorand na die Atlantiese Oseaan dreineer. Die feit dat fluviale diamantvoorkomste in die valleie van die Bufffels-, Swartlintjies-, Spoeg-, Horees- en Groenriviere aangetref word, bevestig dat hierdie verskynsel nie net aan die teenwoordigheid van kus-inhamme en ruwer vloertopografie wat met die riviermondings geassosiëer is, toegeskryf kan word nie, alhoewel dit wel „n bydrae tot hierdie waarneming kon maak. Dit bevestig dat hierdie riviere wel in hul opvang-gebiede ook toegang tot diamanthoudende puin gehad het, sonder enige kontak met die Olifants- of Oranjeriviere. 'n Aantal navorsers het die gedagte geopper dat diamante wat uit voor-Karoo kimberliete vrygestel was, deur bewegende ysplate en/of gletsers vanaf hul provenansgebiede na die suidweste van die subkontinent vervoer is. Uit die voorafgaande paragrawe is dit duidelik dat, ongeveer ʼn eeu ná die ontdekking van diamante langs die suider-Afrikaanse weskus, daar nog nie eenstemmigheid bereik is oor die oorsprong van hierdie diamante nie. Die doel van hierdie studie was gevolglik die daarstelling van „n model wat „n aanvaarbare verduideliking bied vir die verspreiding en afsetting van sommige voorkomste van spoeldiamante in suidelike Afrika soos tans waargeneem. Vir hierdie doel is 1878 diamante afkomstig vanuit 25 alluviale en twee kimberlietvoorkomste ondersoek. Die resultate is vergelyk met soortgelyke inligting wat bekend is vir diamantpopulasies vanuit 12 suider-Afrikaanse kimberliete. Die diamantstudie is aangevul met die ondersoek van spoelklippe vanuit gruismonsters wat langs die Middel- en Benede Oranjerivier versamel is asook Skanderings-elektron Mikroskoop-analises (SEM) van granaatkorrels en sirkoon-geokronologie. Die resultate van hierdie studie ondersteun nie die hipotese van „n eertydse Karoorivier nie. Die teenwoordigheid van bruin spikkels op diamante wat – in die konteks van die geologiese geskiedenis van suidelike Afrika – vrystelling vanuit vóór- Karoo kimberliete impliseer, asook die resultate van FTIR-analises dui op „n komplekse model wat „n alternatief bied vir bestaande sienswyses. Dit toon dat die diamantpopulasies by Kwaggaskop langs die Soutrivier wat veronderstel was om die Benede Karoorivier te verteenwoordig, en dié wat suid van Brandvlei en Van Wyksvlei in die vallei van die Sakrivier aangetref word en veronderstel was om afkomstig te wees uit die Middel Karoorivier, drasties van mekaar verskil. Dit openbaar ook beduidende verskille tussen die diamantpopulasies van die Olifantsriviermonding en dié van die Kimberley-omgewing waarvandaan die veronderstelde Karoorivier groot hoeveelhede diamante aan die Sout-Olifantsrivier sou gelewer het. Verder verskaf die teenwoordigheid van diamante met bruin spikkels en diamante met eienskappe wat toon dat hul stikstofplaatjies vernietig is, „n skakel tussen Bosluispan in die vallei van die Koarivier en die seegebied noord van die Buffelsrivier, via die Buffelsriviervallei en die Buffelsriviermonding, en hierdie feite ondersteun gevolglik eerder die voorstel dat groot hoeveelhede diamante deur die paleo-Gamoeprivier na die weskus vervoer is. Die teenwoordigheid van diamante met FTIR-kenmerke soortgelyk aan dié van Orapa en Jwaneng in die Mid-Oranje afsettings, 'n mariene terras in die suide van Namakwaland en in mariene konsessies noord van Seegebied 12A, opponeer ook die gedagte van 'n paleo-Kalaharirivier, tensy laasgenoemde 'n baie jong stelsel was wat nie die suidwaartse beweging van Botswana-diamante gedurende die Laat Oligoseen tot Vroeg Mioseen verhinder het nie. Die resultate van die sirkoon-geokronologie het die rol van die Oranjerivier in die afplatting van die subkontinent bevestig. Die volgende model tree uit bogenoemde waarnemings na vore: diamante wat in die noordooste van die subkontinent uit kimberliete met „n voor-Karoo inplasingsouderdom vrygestel is, is aanvanklik suidweswaarts vervoer deur voor-Karoo riviere. Daarna is die diamante deur gletsers en ysplate gedurende die Dwyka-tydperk, en uiteindelik ná vrystelling vanuit ontblote glasiale en paleo-fluviale afsettings tesame met diamante wat intussen vanuit Jura- en Krytouderom kimberliete vrygestel is, deur die dreineringstelsels in die Kryt-tydperk en later, verder suidweswaarts vervoer. Sommige het onderweg in fluviale sedimente (terrasse, karstholtes en ander reste van paleokanale) agtergebly, terwyl „n beduidende hoeveelheid tot in die Atlantiese Oseaan vervoer is waar hulle deur mariene prosesse in ou strandlyne en bodemrots opvangstrukture gekonsentreer is. Die studie het ook die mikroskopiese ondersoek van 'n pakkie diamante afkomstig vanuit die enigmatiese afsettings aan die noordelike Skedelkus van Namibië ingesluit. Op grond van geologiese en geomorfologiese getuienis word die afleiding gemaak dat die Skedelkusdiamante nie met die Oranjemund-afsettings verbind kan word nie, terwyl die mikroskopiese oppervlakteksture toon dat bronne met 'n voor-Karoo inplasingsouderdom die mees waarskynlike provenans vir hierdie diamante is. Die kombinasie van FTIR-analises en oppervlaktekstuur-studies van diamante, sirkoongeokronologie en SEM-analises van granate het die formulering van „n hersiene model vir die subkontinent se dreineringsgeskiedenis sedert die Middel-Kryttydperk en diamantverspreiding moontlik gemaak terwyl die studie van sedimentêre klaste getoon het dat hoë-energietoestande, waardeur diamante van swak gehalte vernietig sou word, herhaaldelik voorgekom het, veral in die paleo-Oranjerivier. Die afleiding word gemaak dat hierdie aspek „n bydrae gelewer het tot die hoë persentasie juweelstene in die oorblywende alluviale diamantpopulasies.

Archaeological site investigations on the South Atlantic Coastal Plain have revealed stratified cultural remains in sand deposits of mixed aeolian and fluvial origins, aeolian sand sheets and dunes, alluvial terraces, and Carolina Bay rims. These sites are typically shallow but have yielded discernible archaeostratigraphy within sand dominated deposits by using luminescence dating (OSL), AMS radiocarbon dating, and close interval sediment sampling. Periods of site burial are linked to regional and global paleoclimate records, including Bond events, and provide broader reconstructions for human ecology and periods of site burial.

Linking river behaviour and drainage basin evolution to Quaternary environmental change, most notably the effects of climatic variability, tectonics, and human activity on runoff and sediment delivery, has a long history of research in the Mediterranean areas of Europe, North Africa, and the Near East. This field of research was initially stimulated by the (re)discovery at the beginning of the twentieth century of many Classical Period remains buried by river alluvium; perhaps the best known of which is the site of Olympia in western Greece (Huntington 1910). The widespread evidence for large-scale shifts in river channel positions and the rapid growth of deltas and coastal alluvial plains in historical times (Judson 1963; Raphael 1973; Kraft et al. 1980; and Chapter 13) also provided much impetus for this research. In addition, archaeological investigations carried out soon after the Second World War in Algeria (Gaucher 1947), Italy (Selli 1962), Libya (McBurney and Hey 1955) and Spain (Gigout 1959) resulted in the recovery of large numbers of Palaeolithic stone tools from Pleistocene fluvial deposits. These early examples of what has now become more widely known as ‘geoarchaeology’ (Davidson and Shackley 1976; Butzer 1977) or ‘alluvial archaeology’ (Macklin and Needham 1992) were, with their strong interdisciplinary focus, highly innovative and ahead of their time in the way they integrated archaeology, geomorphology, and geochronology. Building on this theme, the principal aim of this chapter is to consider how river systems in the Mediterranean region have responded to the environmental changes that took place during the Late Quaternary–a time interval corresponding approximately to the last 130,000 years. There are a number of reasons for choosing this period for reviewing river-environment interactions in the Mediterranean: 1. It encompasses the last glacial–interglacial cycle (c.130 to 10 ka) for which there is now abundant global evidence from polar ice cores, speleothem records, and lake and marine sediments, for both longand short-term changes in climate. These changes included massive reorganizations of the atmosphere-ocean-cryosphere systems—often over timescales of less than 100 years (Lowe and Walker 1997)—and they are clearly recorded in the Mediterranean region (see Allen et al. 1999 and Chapter 4).

Results of the study of Neogene-Quaternary deposits of Sardakh Island (the Lena Delta) are described here. Taxonomic composition and spore-pollen spectra structure analysis indicated that sandstones, which are located in the section bottom have middle-late Miocene age. The middle part of the studied section has a Pliocene - early Pleistocene age. The upper part has a late Pleistocene age. We assume that sediments were deposited in the river environments.

The Ivar Aasen (IA) oilfield is located on the Gudrun Terrace on the eastern flank of the Viking Graben in the Norwegian North Sea. The field was discovered in 2008. The reservoir is located within a sedimentary sequence of Mid-Jurassic to Late-Triassic age, which consists of shallow marine to fluvial, alluvial, floodplain and lacustrine deposits overlying a regionally extensive, fractured calcrete interval. The sequence exhibits a complex mineral composition and is heterogeneous at a scale below that of a logging sensor. Shale layers, re-deposited shale and what was first believed to be redeposited calcrete fragments present in various forms throughout the sequence. Looking more in depth to XRD and XRF data and contrasting Fe concentration in the dolomite, it is also possible to explain some of the carbonate deposits through other processes. Extensive data acquisition in the form of advanced wireline logs and coring with analysis performed in “geopilot” wells before production start, enabled a novel thin bed formation evaluation technique based on the modified Thomas-Stieber method (Johansen et al. 2018). The method increased the in-place oil volumes within the Triassic reservoir zone internally named Skagerrak 2. This led to several improvements and a modified drainage strategy of Ivar Aasen. Several good producers were placed in the complex net of the Skagerrak 2 Formation. Results from these producers have encouraged development of an even more marginal and complex net, deeper into the Triassic sedimentary sequence. Therefore, another “geopilot” was drilled into the deeper Triassic sediments, internally named as the Alluvial Fan. This zone exhibits conglomerate clasts in a matrix varying between clay, silt, feldspars, and very fine to very coarse sand fractions, grading towards gravel. Previously, this zone was considered to be mostly non-net. Applying the same interpretation method as for Skagerrak 2, the Alluvial Fan promised economic hydrocarbon volumes. The latest geopilot proved producible hydrocarbons, and subsequently a producer was also successfully placed in this part of the reservoir. Production data and history matching from the beginning of production have for a long while established the previous increase of IA Triassic oil volumes published in 2018. Advanced studies of mineralogy and spectroscopy (Johansen et al. 2019) have indicated that a significant amount of the previously interpreted dolomite, could be reinterpreted as ferroan dolomite. The latter is a heavier mineral that increases the matrix density, hence also the total porosity. The additional findings described provided another necessary first-order correction to further enhance the evergreen geomodel. This paper describes this methodology which resulted in improved petrophysics and reservoir properties of the Alluvial Fan, yet again demonstrating the value of advanced wireline logs and detailed analysis that in total impacts the IA reserve volumes in a significant manner. Repeated success with the applied spectroscopy data and the thin bed methodology used today (Johansen et al. 2018), has resulted in even the deeper Braid Plain Formation becoming of economic interest. It is expected to lie within the oil zone in an upthrow block in the northern part of the IA field and could be developed into the next target.