A sequence stratigraphic study was conducted on the Mendi and Darai Limestone Megasequences in the foreland area of the Papuan Basin in Papuan New Guinea. It involved the integrated use of seismic, wireline log, well core and cuttings, strontium isotope age and biostratigraphic data. This study enhanced the understanding of the structure, stratigraphy and depositional architecture of the limestones, and the morphology of the basin at the time of deposition. The results of the study were integrated with published geological and tectonic models for the Papuan Basin to develop a consistent and coherent model for the depositional history of the limestones. Eleven third-order sequences were delineated within the Mendi and Darai Limestone Megasequences. Eight depositional facies were interpreted across these sequences, namely deep-shelf, shallow-shelf, backreef, reef, shoal, forereef, basin margin and submarine fan facies. Each facies was differentiated according to seismic character and geometry, well core and cuttings descriptions, and its position in the depositional framework of the sequence. Deposition of the Mendi Limestone Megasequence commenced in the Eocene in response to thermal subsidence and eustatic sea-level rise. Sedimentation comprised open-marine, shallow-water, shelfal carbonates. During the middle of the Oligocene, the carbonate shelf was exposed and eroded in response to the collision of the Australian and Pacific Plates, or a major global eustatic sea-level fall. Sedimentation recommenced in the Late Oligocene, however, in response to renewed extensional faulting and subsidence associated with back-arc extension. This marked the onset of deposition of the Darai Limestone Megasequence in the study area. The KFZ, OFZ and Darai Fault were reactivated during this time, resulting in the oblique opening of the Omati Trough. Sedimentation was initially restricted to the Omati Trough and comprised deep and shallow-marine shelfal carbonates. By the Early Miocene, however, movement on the faults had ceased and an extensive carbonate platform had developed across the Gulf of Papua. Carbonate reef growth commenced along topographic highs associated with the KFZ, and led to the establishment of a rimmed carbonate shelf margin. Shallow to locally deeper-marine, shelfal carbonates were deposited on this shelf, and forereef, submarine fan and basin margin carbonates were deposited basinward of the shelf margin. The Uramu High and parts of the Pasca High became submerged during this time and provided sites for pinnacle reef development. During the middle of the Early Miocene, a major global eustatic sea-level fall or flexure of the Papuan Basin associated with Early Miocene ophiolite obduction subaerially exposed the carbonate shelf. This resulted in submarine erosion of the forereef and basin margin sediments. Towards the end of the Early Miocene, however, sedimentation recommenced. Shallow-marine, undifferentiated wackestones and packstones were deposited on the shelf; forereef, submarine fan and basin margin sediments were deposited basinward of the shelf margin; and reef growth recommenced along the shelf margin and on the Pasca and Uramu Highs. By the end of the Early Miocene, however, the pinnacle reef on the Pasca High had drowned. During the middle of the Middle Miocene, subtle inversion associated with ophiolite obduction subaerially exposed the carbonate shelf, and resulted in submarine erosion of the forereef and basin margin sediments. Sedimentation recommenced towards the end of the Middle Miocene, however, in response to eustatic sea-level rise and flexure of the crust associated with foreland basin development. Shallow marine, undifferentiated wackestones, packstones and grainstones were deposited on the shelf; carbonate shoals were deposited along the shelf margin; and forereef, submarine fan and basin margin carbonates were deposited basinward of the shelf margin. Carbonate production rapidly outpaced accommodation space on the shelf during this time, resulting in highstand shedding and the development of a large prograding submarine fan complex basinward of the shelf margin. By the Late Miocene, carbonate deposition had ceased across the majority of the study area in response to a major global eustatic sea-level fall or inversion associated with terrain accreation events along the northern Papuan margin. Minor carbonate deposition continued on parts of the Uramu High, however, until the middle of the Late Miocene. During the latest Miocene, clastic sediments prograded across the carbonate shelf, infilling parts of the foreland basin. Plio-Pleistocene compression resulted in inversion and erosion of the sedimentary package in the northwestern part of the study area. In the southeastern part of the Papuan Basin, however, clastic sedimentation continued to the present day.

The Late Neogene sedimentary sequence of the Murray Basin provides an excellent opportunity to examine paleoenvironmental change across southeastern Australia. A detailed stratigraphic analysis of sediments deposited within the basin in the last 10 Ma was undertaken to assess the influence of tectonic and eustatic processes on deposition. / Stratigraphic observations and radiogenic isotope analysis reveals the onset of deposition by 7.2 Ma with a transgressive episode that deposited the marine marls of the Bookpurnong Beds. Deposition was restricted to the central and eastern parts of the basin due to the Hamley Fault. In the west, subsurface elevation contours indicate the presence of incised paleodrainage channels above Miocene limestones, which facilitated the formation of a large estuary system at 5.3 Ma. The sediments of the Norwest Bend Formation were deposited within this western region, while further east, the Loxton-Parilla Sands strandplain deposited over 214 coastal ridges. The basal parts of this unit occur as lateral equivalents to the sediments of the Lower Norwest Bend Formation (in the west). Topographic and magnetic data reveal that tectonism was active during this period and resulted in the erosion and truncation of strandlines. / Tectonic evidence and an estimated minimum 28,037 year cyclicity between strandline sets, suggests that the Loxton-Parilla Sands strandlines do not represent an unbroken record of glacioeustatic change. The subaerial exposure of these sediments at approximately 3.0 Ma caused the formation of a calcareous karst above the Norwest Bend Formation and a ferruginous and/or silicious cap (the Karoonda Surface) above the Loxton-Parilla Sands. The stratigraphic position of these surfaces are indicative of a regional widespread unconformity. / The Douglas-Blackburn paleodrainage system in western Victoria was dammed during the Mid-Late Pliocene by uplift associated with the Padthaway High, which caused the formation of a 400,000 km2 lacustrine system, known as Lake Bungunnia. Topographic analysis indicates that Lake Bungunnia comprised at least four distinct sub-basins with water depths of up to 30 metres, with lake shorelines indicating that active tectonism occurred during this period. The resulting lack of sediment input to the coast caused the formation of the Kanawinka Escarpment, a large erosional scarp along the southern margin of the Padthaway High. / The geomorphology of the modern Murray Basin can be directly attributed to the demise of the Lake Bungunnia system. Movement along the Morgan Fault in the west at approximately 700 Ka, resulted in the draining and progressive drying of Lake Bungunnia as a breach was created along the Padthaway High. The Murray River gorge as observed today was incised following this episode. The modern Murray River (and playa lakes such as Lake Tyrell) occupy the lowest elevations along the former sub-basins of Lake Bungunnia. / The Late Neogene sedimentary sequence across the Murray Basin illustrates a complex interaction of eustatic and tectonic processes on deposition. Sedimentation within strandline, estuarine and lacustrine systems, particularly in the western Murray Basin, display evidence of significant tectonic control. This highlights the important role that neotectonic processes have played in shaping southeastern Australia.

Cette thèse étudie la boutonniére d'Ifni dans son cadre général : Anti-Atlas, strtigraphique et tectonique. Une approche géochronologique la compléte.

Ce travail repose sur l'approche géologique et métallogénique du massif des Grandes Rousses.

Entre la plate-forme urgonienne et la bordure septentrionale du bassin vocontien, les assises barrémo-bédouliennes du Vercors, de la zone de Borne et du Dévoluy sont caractérisées par des variations constantes d'épaisseur et de faciès dues à une évolution paléogéographique complexe. L'étude stratigraphique est basée sur la répartition des Orbitolinidés et des Ammonites d'une part, sur l'analyse séquentielle d'autre part. Du point de vue paléontologique, les associations d 'Ammoni tes, plus riches en grandes espèces circalittorales que les successions pélagiques de la coupe stratotypique d'Angles, de même que les Orbitolinidés representés par 43 espèces, permettent de définir trois périodes de stabilité de faune (Barrémien inférieur, Barrémien supérieur, Bédoulien) séparées par trois périodes de renouvellement de durée apparemment plus courte (Bil, Bi6 sommital-Bs1, BsAi-Ai1 basal). Les périodes de stabilité du Barrémien inférieur et du Barrémien supérieur ont été elles-mêmes subdivisées en deux niveaux grâce à l'examen du degré d'évolution des Orbitolinidés et du contenu spécifique des associations tant d'Orbitolinidés que d'Ammonites. Du point de vue séquentiel, la succession Hauterivien terminal - Bédoulien inférieur a été découpée dans toute cette région en 38 séquences de deuxième ordre regroupées en 13 séquences de troisième ordre (= membres) et quatre mégaséquences. Ces dernières permettent la définition de trois formations carbonatées superposées : les calcaires bioclastiques de Borne,* les calcaires à débris de Glandasse et les calcaires urgoniens. L'étude sédimentologique aboutit à la mise en évidence de deux modèles de sédimentation carbonatée - haut-fond et plate-forme - ainsi qu'à la description des remaniements synsédimentaires sur la bordure du bassin vocontien. Les hauts-fonds, de surface restreinte, sont caractérisés par une sédimentation bioclastique et oolitique de milieux marins modérément à fortement agités, non confinés, appartenant au moins à l'étage infralittoral (hauts-fonds du Trièves et du Vercors méridional entre l'Hauterivien terminal et le Barrémien supérieur basal). La plate-forme, d'une superficie souvent très importante, se distingue du haut-fond par la présence d'un domaine interne généralement très développé, caractérisé par des milieux temporairement émergés (médio- à supralittoral) ou marins peu profonds (médio- à infralittoral), mais toujours parfaitement protégés et fréquemment confinés (plate-forme urgonienne au Barrémien supérieur et au Bédoulien inférieur). Dans les deux cas les faciès à Cnidaires peu développés ne constituent pas de barrière morphologique entre le domaine interne et le talus externe. Les remaniements gravitaires affectent principalement les faciès bioclastiques du talus externe des hauts-fonds ou de la plate-forme urgonienne. Resédimentés dans le bassin vocontien, ils correspondent principalement à des coulées sableuses dans lesquelles se distinguent des séquences proximales d'épaisseur plurimétrique et des séquences distales décilnétriques, semblables à des turbidites. Plus rarement s'observent des coulées boueuses dans lesquelles le mélange vase autochtone-sable allochtone est complet. L'importance croissante de ces remaniements synsédimentaires entre la base et le sommet de chaque membre et, surtout, de chaque mégaséquence paraît indépendante de la mobilité du socle et témoigne d'une instabilité croissante des dépôts bioclastiques sur le talus externe pendant les périodes de progradation des faciès de plate-forme. L'étude paléogéographique a permis de détailler les trois grandes étapes de l'évolution de ce secteur entre le sommet de l'Hauterivien et l'Aptien. De l'Hauterivien terminal au Barrémien basal (membres HsBi-Bi1, sommet de la mégaséquence 5) les coulées sableuses constitutives des calcaires bioclastiques de Borne proviennent d'un haut-fond, apparu et développé à cette époque dans le Trièves méridional le long de la faille de Menée (haut-fond du Trièves), mais dont on ne connaît pas les caractères sédimentologiques en raison de l'érosion des assises correspondantes. Du Barrémien basal au Barrémien supérieur basal (membres Bi2-Bs1, mégaséquence 6) le Vercors méridional est caractérisé, au voisinage de la faille de Menée et sur la bordure septentrionale du bassin vocontien, par l'apparition, puis le développement du haut-fond du Vercors méridional. Outre les faciès bioclastiques qui dominent, ce haut-fond est caractérisé par l'importance des faciès oolitiques et l'existence de nombreuses petites bioconstructions à Cnidaires. La progradation des faciès, faible vers le SE, est au contraire très importante vers le NW. Du Barrémien supérieur au Bédoulien (membres Bs2-Ai2, mégaséquences 7 et 8) la superficie couverte par la sédimentation carbonatée s'accroît considérablement tandis que les faciès se différencient. Les faciès à Rudistes qui étaient absents sur les hauts-fonds, caractérisent le domaine interne de la plateforme. Développée d'abord à partir du haut-fond du Vercors méridional,la plateforme urgonienne englobe rapidement d'autre hauts-fonds apparus à cette époque plus au Nord en bordure de la basse Isère et enfin s'anastomose aux platesformes voisines pour constituer une vaste plate-forme urgonienne péri-vocontienne. Cette évolution est perturbée au début du Bédoulien par des arrivées massives de matériel terrigène, responsables de l'individualisation d'une sédimentation localement détritique (marnes inférieures à Orbitolines). Une deuxième perturbation, beaucoup plus importante (transgression du Bédoulien terminal , interrompt définitivement cette évolution de la sédimentation carbonatée. D'un point de vue plus général, deux types de passages latéraux ou verticaux de faciès ont été reconnus entre le domaine interne de la plate-forme (ou le sommet des hauts-fonds) et le talus externe : - à l'Est et au SE le premier est caractérisé par la prépondérance des faciès bioclastiques grossiers et l'absence généralisée des bioconstructions à Cnidaires conservées (secteur "au vent" situé face à la houle mésogéenne) ; - au Sud, le second est caractérisé par l'importance des bioconstructions à Cnidaires, la prépondérance des faciès bioclastiques fins et la rareté des faciès bioclastiques grossiers (secteur relativement protégé, situé "sous le vent"). L'étude paléostructurale a montré que deux grands accidents NE-SW paraissent avoir fonctionné à cette époque: les failles de l'Isère au NW et de Menée au SE. Traduite par l'effondrement de leurs compartiments SE et la stabilité ou la surrection de leur compartiment NW, cette mobilité tectonique paraît responsable : - de la création des hauts-fonds du Trièves et du Vercors méridional à l'Hauterivien terminal et au Barrémien basal; - de l'inversion régionale des vitesses de subsidence au début du Barrémien supérieur (crise du Barrémien supérieur basal), phénomène ayant permis le développement de la plate-forme urgonienne ; - de l'effacement progressif de la sédimentation carbonatée dans le Vercors SE entre le Barrémien supérieur et l'Aptien terminal. La coïncidence des paroxysmes relatifs de la mobilité du socle, des limites des mégaséquences et des périodes de renouvellement des faunes d'Orbitolinidés et d'Ammonites n'est probablement. pas un effet du hasard. Il semble qu'elle soit due à l'influence d'événements géologiques majeurs agissant sur la sédimentation et les peuplements de la plate-forme urgonienne et de la bordure nord-vocontienne. Ces derniers pourraient appartenir à deux catégories : - des événements atectoniques, d'origine eustatique, tel que la transgression du Bédoulien terminal responsable des lacunes finibédouliennes du Vercors, du développement des faciès urgoniens dans les Pyrénées et surtout de la disparition des faciès à Rudistes sur les plates-formes urgoniennes du SE de la France ; - des événements tectoniques, locaux ou régionaux, échos possibles des vicissitudes de l'expansion océanique dans l'Atlantique (crises de la limite Hauterivien - Barrémien, du Barrémien supérieur basal, de la limite BS3-BsAi).

<p>In order to explore site formations and reconstruct environmental development in Medieval and Post-Medieval towns, urban occupational strata in Norrköping and Karlstad were studied according to biostratigraphy, sedimentology and pedology. New field procedures including continuous pilot sampling, parallel archaeological and geological stratigraphic interpretation, and on-site analysis of plant macrofossils were developed and applied at archaeological excavations in both towns. Representation of both disciplines in the field during excavations greatly contributed to more complete field interpretations.</p><p>Stratigraphical analyses indicate that geological processes have been active in both towns, and reveal similarities in site formation. The earliest proto-urban phase is represented by the presence of dark earths, formed by the combination of alluvial processes and cattle tramping. Alluvial processes were common in Karlstad due to the flooding of the river delta, and in Norrköping due to the sloping topography. Both situations were enhanced by human activity, which caused drainage problems. A significant change in composition and origin of house foundation fill was also noted. The oldest foundations contained fine-grained material of local origin in contrast to younger foundations, which contained coarser material, sometimes of regional origin. This is interpreted as a professionalisation of the urban building tradition, which in Norrköping occurred during the 16th century and in Karlstad during the 18th century. Site formations of urban strata are regulated by three major factors: deposition, post-depositional soil formation and erosion/truncation, which all may occur both culturally and naturally.</p><p>Plant macrofossil analyses in Norrköping and Karlstad resulted in a fossil record with a total amount of 203 and 169 different types of plant species and taxa respectively. The records indicate that site formation processes seem to have been inhibited during wintertime. The results also confirm the idea of the early Scandinavian towns as rural, also during the Post-Medieval time. The finds of cultural plants in Karlstad indicate 18th century cultivation of Fragaria moscata and 17th century import of Pimento officinalis. In Norrköping remains of beer additives confirm that the tradition of combining Humulus lupulus and Myrica gale disappeared after the 15th century, but also indicate a the use of Filipendula ulmaria as a beer addative. Finds of seeds from Nicotiana rustica suggests that tobacco cultivation occurred in Norrköping 1560-1640, which is some decades earlier than known so far in Sweden.</p>

<p>This study deals with the influence of topography on glacial dynamics and the genesis of till in an area of moder-ate bedrock relief. An area 25 km west of Lycksele, northern Sweden, was investigated using geomorphological and sedimentological methods. The bedrock is dominated by coarse-grained granites and the topography, ranging in altitude between 310 and 490 m. a.s.l., is characterized by relatively wide, free-lying hills.</p><p>The erosional and depositional features provide evidence of several glacial events, with regional ice flows from approximately the same direction (NW-NNW). The gravel fraction of the till is dominated by material transported more than 10 km. However, the total glacial erosion has been modest, as indicated by the frequent occurrence of residual pre-glacial weathering features. There is no evidence of warm-based conditions during the period when the ice divide of the Late Weichselian ice sheet was situated E-SE of the study area. The major mor-phological impact is most likely by pre-Late Weichselian ice sheets.</p><p>The general stratigraphy at the valley floors is a complex sequence of heterogeneous till and beds of sorted sediments with some evidence of glacial deformation covered by an up to 2.5-m-thick, texturally homogeneous till layer with distinct fissility structure and clast fabric orientation. The lower unit is interpreted as pre-Late Weichselian marginal deposits, and the upper till as mainly formed during rigid-bed conditions, i.e. by lodgement, during the last deglaciation. The role of pervasive deformation and melt-out in the formation of the upper till are discussed. Inferred mainly from till fabrics it is evident that the ice flow was strongly topographically controlled within a relatively wide marginal zone of the retreating ice.</p><p>At the summits of the hills there are only signs of very weak glacial abrasive and depositional activity, sug-gesting frozen based conditions over the summits until a very late stage of the deglaciation. The very thin till at the summits, which also lay as a drape over the thick lee-side deposits, consists of a mixture of relatively fine-grained, distantly derived debris and of local bedrock fragments entrained during a very late phase of plucking.</p><p>On the stoss- and lateral slopes of the hills the till is thin and discontinuous. The irregular bedrock surface in these areas created a “mosaic” of small-scale subglacial depositional environments, which were superimposed on the changes in the conditions for deposition along the hillslope. This till is comparatively coarse-grained, which is interpreted as an effect of syn-depositional winnowing of fines, and locally also because of the incorporation of local bedrock material largely from pre-glacially weathered zones.</p><p>On the lee-sides of the hills the deposits are considerably thicker than on slopes facing other directions. They are characterized by highly variable texture and structure, suggesting a depositional environment characterized by large temporal and spatial variations in meltwater activity and stress/strain conditions. The lee-side tills are inter-preted as mainly pre-Late Weichselian in age.</p><p>The overall conclusion is that the local topography strongly controlled the basal ice flow and produced a com-plex pattern of thermal variations within a relatively wide marginal zone of the ice sheet during the last deglacia-tion. The study supports the view that there are complete transitions between the different genetical types of sub-glacial tills, although the role of deformation by pervasive shearing is uncertain in this type of coarse-grained till.</p>

<p>Organic-walled microfossils are abundant and taxonomically diverse in Cambrian-Ordovician strata; some are important for biostratigraphy and for the correlation of geological successions. New assemblages of Cambrian-Ordovician acritarchs from Kolguev Island, Arctic Russia and Middle Cambrian ichnofossils of endoliths from Peary Land, North Greenland are studied. Twenty-seven acritarch species are described in detail and 10 taxa are left under open nomenclature. The diagnosis of one genus is restricted, and two other are emended. New combinations are proposed for three species and one new species is recognised. The studied acritarch assemblages are taxonomically rich and age-diagnostic and used to recognise Upper Cambrian and Tremadoc strata on Kolguev Island. The sedimentologically continuous successions provide for the first time palaeontological evidence of Cambrian strata in the north-eastern sector of Europe. The exact level of the Cambrian-Ordovician boundary was distinguished together with stratigraphic intervals equivalent to the <i>Peltura</i> and <i>Acerocare</i> zones of the Upper Cambrian of Baltica. The newly established relative age of the lowermost sedimentary succession overlying the Timanian unconformity allows verification of the minimum age of the Timanian deformation and the time-span of the hiatus bound to this unconformity. Endoliths occur in the fossil record from the Early Archean and they played an important role in the formation of stromatolites and the process of bioerosion and biodegradation. Endoliths that have actively bored into brachiopod shells or carbonate grains (euendoliths), and some that inhabited the cavities inside brachiopod shells (cryptoendoliths) are described. Borings within the carbonate grains extended with a dentritic pattern, whereas those within the brachiopod shells were formed by a multifilamentous euendolith which produced characteristic longitudinally ridged galleries. The cryptoendolithic morphologies include indeterminate coccoid masses and at least two filamentous forms. However, considerable variation in the dimensions of the currently phosphatised diagenetic crusts of the cryptoendoliths hinders discrimination.</p>

<p>Development of a predictive model for the distribution of diagenetic alterations and related evolution of reservoir quality of sandstones was achieved by integrating the knowledge of diagenesis to sequence stratigraphy. This approach allows a better elucidation of the distribution of eogenetic alterations within sequence stratigraphy, because changes in the relative sea level induce changes to: (i) pore water chemistry, (ii) residence time of sediments under certain near-surface geochemical conditions, (iii) variations in the detrital composition, and (iv) amounts and type of organic matter.</p><p>This thesis revealed that eogenetic alterations, which are linked to sequence stratigraphy and have an impact on reservoir quality evolution, include formation of: (i) pseudomatrix and mechanically infiltrated clays in fluvial sandstones of the lowstand and highstand systems tracts (LST and HST, respectively), (ii) kaolinite in tide-dominated deltaic and foreshore-shoreface sandstones of HST, Gilbert-type deltaic sandstones of LST and fluvial deltaic sandstones of LST, (iii) kaolinite and mechanically infiltrated clays in sandstones lying below sequence boundary, (iv) K-feldspar overgrowths in fluvial deltaic LST, (v) glaucony towards the top of fluvial deltaic LST immediately below and at transgressive surface (TS) and in foreshore and shoreface transgressive systems tracts (TST) below parasequence boundaries (PB) and maximum flooding surface (MFS), (vi) framboidal pyrite and extensive cementation by calcite and dolomite in foreshore and shoreface and tide-dominated deltaic TST, and shoreface and tidal flat HST bioclastic-rich arenites particularly in the vicinity of PB, TS and MFS, (vii) pervasive cementation by iron oxide in shoreface-offshore and shoreface sandstones of TST immediately below the MFS, (viii) zeolites and palygroskite in shoreface sandstones of TST and HST, particularly above PB, and (ix) cementation by siderite in Gilbert-type deltaic sandstones of LST, tide-dominated deltaic and foreshore-shoreface sandstones of HST and in tide-dominated deltaic sandstones of TST, particularly at MFS. Moreover, this thesis revealed that the distribution of eogenetic alterations strongly control, and thus provide information for constraining the distribution patterns of mesogenetic alterations, such as illitization of mechanically infiltrated clays and dickitization of kaolinite, and hence of related reservoir quality evolution of sandstones during progressive burial.</p>

<p>This thesis constrains the distribution of diagenetic alterations and their impact on reservoir-quality and heterogeneity evolution pathways in relation to depositional environments and sequence stratigraphy (systems tracts and key sequence stratigraphic surfaces) of four selected paralic and shallow marine siliciclastic successions. </p><p>Typical eogenetic alterations encountered include the dissolution and kaolinitization of framework silicates, which are closely associated to shoreface facies of forced regressive systems tract (FRWST), lowstand systems tract (LST), upper part of the highstand systems tract (HST), and below the sequence boundary (SB). These alterations are attributed to incursion of meteoric water owing to rapid and considerable fall in the relative sea level. Extensive carbonate cementation is most evident below marine and maximum flooding surfaces (MFS), whereas dissolution of carbonate cement and detrital dolomite occur in LST, HST and below SB. Parameters controlling the patterns and texture (microcrystalline vs. poikilotopic) of calcite cement have been constrained within sequence stratigraphic framework of the sandstones. Coarse crystalline to poikilotopic calcite textures of meteoric water origin are thus closely linked to the FRWST, LST and upper part of the HST sandstones and occur mainly as stratabound concretions, whereas microcrystalline calcite, which was precipitated from marine porewaters, occurs as continuously cemented layers in the transgressive systems tract (TST) and lower part of the HST sandstones.</p><p>Eogenetic alterations impose, in turn, profound control on the distribution pattern of mesogenetic alterations, and hence on reservoir quality evolution (destruction vs. preservation) pathways of sandstones. Eogenetic infiltrated clays, which occur in the tidal estuarine TST and HST sandstones, have helped preserving porosity in deeply buried sandstone reservoirs (≈ 5 km) through inhibition of extensive cementation by quartz overgrowths. Other essential findings of this thesis include deciphering the control on the formation of authigenic illite and chlorite by ultra-thin (≤ 1 µm thick), grain-coating clay mineral substrate. </p>