Facies Analysis Research Papers - Academia.edu (original) (raw)

The digital storage and communication of significant geological data became increasingly more objective and accessible through the development of new technologies or the implementation of already well-known techniques as photogrammetry.... more

The digital storage and communication of significant geological data became increasingly more objective and accessible through the development of new technologies or the implementation of already well-known techniques as photogrammetry. Digital acquisition of geometries (both structural and depositional) of significant geological outcrops is deemed necessary, especially if the site concerned is liable to be damaged or hopelessly involved in natural processes of geological and geomorphological evolution. In this paper, we tested the performances of two different open-source software (i.e. VisualSFM and ARC3D) on a small-scale but paradigmatic outcrop in the Umbria-Marche Apennines (Italy). The test showed that ARC3D provides an high-resolution model, employing a relatively short time and requiring a not expensive hardware support for processing hundreds of photos. In the text, 3D models of the selected outcrop are reported and discussed emphasizing the potential of the method to high...

The Sandakan Formation of the Segama Gorup is exposed across the Sandakan Peninsula in eastern Sabah. This Upper Miocene part of the Segama Group unconformably overlies the Garinono Formation and is conformably overlain by the Bongaya... more

The Sandakan Formation of the Segama Gorup is exposed across the Sandakan Peninsula in eastern Sabah. This Upper Miocene part of the Segama Group unconformably overlies the Garinono Formation and is conformably overlain by the Bongaya Formation. This formation was investigated with detailed logging of outcrops and microfossils analysis in order to map the depositional facies and sedimentary environment. This study reveals the presence of seven lithofacies 1) Thick amalgamated sandstone, 2) Thin, lenticular interbedded HCS sandstones and mudstone, 3) Laminated mudstone with Rhizophora, 4) Trough Cross-bedded sandstone 5) Laminated Mudstone, 6) Strip mudstone with thin sandstone and siltstone 7) Interbedded HCS sandstone and mudstone. Based on the presence of Rhizophora, Brownlowia, Florchuetia sp., Polypodium, Stenochleana Palustris, Ascidian Spicule, low angle cross bedding, very fine grained sandstone, thin alternations of very fine sandstone, silt and clay layers showing cyclicity (muddy rhythemites), rocks in the Sandakan Formation are interpreted as mangal estuary and open marine facies. Three facies associations could be deduced from the seven lithofacies; 1) Gradual coarsening upwards shoreface, 2) abrupt change facies, and 3) prograding estuary facies association.

Lower Cretaceous sequences of the Burgan Formation are notable siliciclastic reservoirs in the Middle East. Despite of this importance, a little is known about various geological characteristics of this reservoir in Iranian northwestern... more

Lower Cretaceous sequences of the Burgan Formation are notable siliciclastic reservoirs in the Middle East. Despite of this importance, a little is known about various geological characteristics of this reservoir in Iranian northwestern part of the Persian Gulf. In this study, an integrated sedimentological and reservoir geological evaluation has been carried out on the Burgan reservoir using a complete dataset of drilled cores, core plugs, thin sections and petrophysical logs along with laboratory data including XRD analysis of all components to define grain's mineralogy and porosity – permeability data for reservoir quality evaluation. Depositional facies and environments are interpreted and correlated in sequence stratigraphic framework of targeted reservoir across the studied fields and then compared with stratigraphic equivalents in the Middle East. Seven facies types are recognized that indicate deposition in a transitional environment from siliciclastic-dominated delta setting into shallow-marine carbonate platform. Diagenesis study indicates a simple history of post-depositional events that includes near surface (marine) and shallow to deep burial realms. Diagenetic processes are grouped into two categories based on their effects on reservoir properties. They include porosity enhancing (i.e. dissolution and fracturing) and porosity reducing (compaction and cementation) diagenetic processes. Reservoir evaluation of depositional facies has been carried out by defining petrographic rock-types (PRTs) and hydraulic flow units (HFUs) and their correlation in sequence stratigraphic framework. Results showed that semi-to unconsolidated sandstone facies accumulated in Burgan-B member provides the best reservoir units in the Burgan Formation. Organic-rich (rootled) and pelagic shale facies form several intra-reservoir barriers between the reservoir units, especially in Burgan-A member. These show close correlation with reservoir descriptions of this formation reported from the neighboring areas in the Persian Gulf (i.e. Kuwait).

The facies models are the most powerful method for the genetic interpretation of the stratigraphic record, acting as syntheses of the facies relationships. Nowadays, the facies relationship interpretation is fundamented either by the... more

The facies models are the most powerful method for the genetic interpretation of the stratigraphic record, acting as syntheses of the facies relationships. Nowadays, the facies relationship interpretation is fundamented either by the Walther's Law (or Facies Correlation Law) or by the application of geostatistic tests. On the other hand, the present stratigraphic basin analysis search for stratal discontinuities (actually bedding surfaces). It is the bedding surface hierarchization, according to its physical magnitude (scale), that have revealed a usefull way for the facies association diagnosis. In accordance to this practise, it is adopted the postulate of that facies contained between bedding surfaces of the same hierarchical order, in one stratigraphic succession, without the intervenience of a bedding surface of greater magnitute, are genetically related one to each other, and may be conceived in association. This postulate differs from the universalized facies diagnosis procedures for not making use of the magnitude of the stratal discontinuities as a physical argument of the facies relationship falsification (unconformities in the Walther's Law), but as the foundation of its interpretation; furthermore, it takes away the necessity of geostatistic tests as an argument to the relationship verification, which only determines the possible and probable relations.

Stratigraphic exposures, fluvial archives and borehole data have been allowed to reconstruct the alluvial history of Late Pleistocene to Late Holocene and climate changes in the monsoonal wet – dry region of lower Damodar Basin (West... more

Stratigraphic exposures, fluvial archives and borehole data have been allowed to reconstruct the alluvial history of Late Pleistocene to Late Holocene and climate changes in the monsoonal wet – dry region of lower Damodar Basin (West Bengal, India). The facies architectures and climate proxies suggest that five to six climate changes occurred in between ~ 14 ka and 6 ka. Supporting evidence from the floodplain of Damodar River demonstrates that the successive phases of aggradation and incision were linked to the south-west monsoonal variability of Late Quaternary period. The onset of semi-arid climate was associated with caliches, pond and backswamp deposits of wanning low energy floods. The relatively warm-humid climate was associated with sandy bedforms, valley fills, slack water deposits and ferruginous nodules. This paper presents a synthesis of the available palaeoclimatic records from the lower Ganga Basin and the rivers of western and central India for the palaeoenvironmental significance of Late Quaternary deposits and discusses the influence of palaeoclimatic controls on the fluvial architectures and archives that developed below the floodplain of Damodar River. We have taken some representative studies from the region to reveal the spatial variability in fluvial successions in response to climate changes during this period.

This Thesis was Submitted in Partial Fulfillment of the requirements for the Master’s Degree of Science in Geology Faculty of Graduate Studies, The University of Jordan: The Triassic Period witnessed a global palaeoceanographic change... more

This Thesis was Submitted in Partial Fulfillment of the requirements for the Master’s Degree of Science in Geology Faculty of Graduate Studies, The University of Jordan: The Triassic Period witnessed a global palaeoceanographic change through the opening of Neo-Tethys Ocean, when the northern margins of Gondwana were affected by sea level fluctuations causing successive marine transgressions and regressions. The southern Mediterranean Gondwanan shelf that extended from Morocco (African plate) to Oman (Arabian sub-plate) was likewise affected by the opening of Mesozoic Neo-Tethys Ocean (Makhlouf,2006).
The Neo-Tethys shoreline approached the western shoulder of Gondwana diachronously during the middle Triassic times; Jordan was, partially, flooded by the Neo-Tethys Ocean and, as a result of this gradual transgression leading to deposition of middle and upper Triassic Formations; when Iraq el Amir and Umm Tina Formations were deposited (Makhlouf,2006).
The middle Triassic (Ladinian) strata of NW Jordan (Iraq el Amir and Umm Tina Formations) consist of medium –to-thick bedded limestones with various skeletal (bivalves, algae, corals, echinoderms, brachiopods, crinoids, ostarcods, and serpulid) and nonskeletal (peloid) components. Facies analysis documents the depositional environments, including tidal, lagoonal, barrier and open marine facies.
Four third order depositional sequences can be distinguished in each of the two stratigraphic measured outcrop sections. In the subsurface four and three third order depositional sequences are distinguished in Ajloun-1 and Northern highland-2 deep wells for the two formations respectively.
Transgressive systems tracts (TST) show deepening upward trends, in which shallow water (tidal flat and lagoonal) facies are overlain by deep water (open marine) facies, highstand systems tracts (HST) show shallowing upward trends in which relatively deep water facies are overlain by shallow water facies. All sequence boundaries in the study locality (except the top of the stratigraphic column) are of the non-erosional (SB2) type.
Correlation of depositional sequences in the studied sections shows that relatively shallow marine (tidal flat, lagoonal, sand shoal, and shallow open marine) conditions dominated in the area. These facies are alternating with deeper water open marine packstone, grainstone representing zones of maximum flooding surface (MFS).

The Lower Triassic Mineral Mountains area (Utah, USA) preserves diversified Smithian and Spathian reefs and bioaccumulations that contain fenestral-microbialites and various benthic and pelagic organisms. Ecological and environmental... more

The Lower Triassic Mineral Mountains area (Utah, USA) preserves diversified Smithian and Spathian reefs and bioaccumulations that contain fenestral-microbialites and various benthic and pelagic organisms. Ecological and environmental changes during the Early Triassic are commonly assumed to be associated with numerous perturbations (productivity changes, acidifica-tion, redox changes, hypercapnia, eustatism and temperature changes) post-dating the Permian–Triassic mass extinction. New data acquired in the Mineral Mountains sediments provide evidence to decipher the relationships between depositional environments and the growth and distribution of microbial structures. These data also help to understand better the controlling factors acting upon sedimentation and community turnovers through the Smithian–early Spathian. The studied section records a large-scale depositional sequence during the Dienerian(?)–Spathian interval. During the transgression, depositional environments evolved from a coastal bay with continental deposits to intertidal fenestral–microbial limestones, shallow subtidal marine sponge–microbial reefs to deep subtidal mud-dominated limestones. Storm-induced deposits, microbialite–sponge reefs and shallow subtidal deposits indicate the regression. Three microbialite associations occur in ascending order: (i) a red beds microbialite association deposited in low-energy hypersaline supratidal conditions where microbialites consist of microbial mats and poorly preserved microbially induced sedimentary structure; (ii) a Smithian microbialite association formed in moderate to high-energy, tidal conditions where microbialites include stromatolites and associated carbonate grains (oncoids, ooids and peloids); and (iii) a Spathian microbialite association developed in low-energy offshore conditions that is preserved as multiple decimetre thick isolated domes and coalescent domes. Data indicate that the morphologies of the three microbialite associations are controlled primarily by accommodation, hydrodynamics, bathymetry and grain supply. This study suggests that microbial constructions are controlled by changes between trapping and binding versus precipitation processes in variable hydrodynamic conditions. Due to the presence of numerous metazoans associated with microbialites throughout the Smithian increase in accommodation and Spathian decrease in accommodation, the commonly assumed anachronistic character of the Early Triassic microbialites and the traditional view of prolonged deleterious conditions during the Early Triassic time interval is questioned.

A cross-disciplinary (sedimentological, geochemical, micropalaeontological and archaeological) examination of 12 continuous cores, up to 20 m long, integrated with stratigraphical, geomorphological and historical investigations, allows... more

A cross-disciplinary (sedimentological, geochemical, micropalaeontological and archaeological) examination of 12 continuous cores, up to 20 m long, integrated with stratigraphical, geomorphological and historical investigations, allows for reliable delineation of the middle–late Holocene environmental evolution in the Pisa old town area, with special emphasis on the Etruscan age transition. Depositional facies were identified through integration of sedimentological and micropalaeontological (benthic foraminifers, ostracods, phytoclasts and palynomorphs) data, while sediment dispersal patterns were reconstructed on the basis of geochemical analyses. Facies architecture was chronologically constrained by combined archaeological and radiocarbon dating. The turnaround from early Holocene, transgressive conditions to the ensuing (middle–late Holocene) phase of sea-level highstand is witnessed by a prominent shallowing-upward succession of lagoonal, paludal and then poorly drained floodplain deposits supplied by two river systems (Arno and Serchio). This ‘regressive’ trend, reflecting coastal progradation under nearly stable sea-level conditions, was interrupted by widespread swamp development close to the Iron–Etruscan age transition. The expansion of vast, low-lying paludal areas across the alluvial plain was mostly induced by the intricate, short-term evolution of the meandering Arno and Serchio river systems. These changes in the fluvial network, which occurred during a period of variable climate conditions, strongly influenced the early Etruscan culture (7th–5th century BC) in terms of human settlement and society behaviour. Conversely, a strong impact of human frequentation on depositional environments is observed at the transition to the Roman age (from the 1st century BC onwards), when the wetlands were drained and the modern alluvial plain started to form. The palaeoenvironmental reconstruction fits in with the original geographical descriptions mentioned in Strabo's Chronicles, and provides chronologically constrained data of fluvial evolution from the Pisa old town area.

North Sea oil is overwhelmingly generated in shales of the Upper Jurassic e basal Cretaceous Kimmer-idge Clay Formation. Once generated, the oil is expelled and ultimately migrates to accumulate in sandstone or carbonate reservoirs. The... more

North Sea oil is overwhelmingly generated in shales of the Upper Jurassic e basal Cretaceous Kimmer-idge Clay Formation. Once generated, the oil is expelled and ultimately migrates to accumulate in sandstone or carbonate reservoirs. The source rock shales, however, still contain the portion of the oil that was not expelled. As a consequence such shales and juxtaposed non-source lithofacies can form the targets for the exploration of 'unconventional oil'. In this paper, we examine part of the Kimmeridge Clay Formation as a hybrid shale resource system within which 'Hot Shale' and organic-lean sandstone and siltstone intervals are intimately interbedded. This hybrid system can contain a greater volume of oil because of the increased storage capacity due to larger matrix porosities of the sand-silt interbeds, together with a lower adsorptive affinity in the interbedded sandstone. The relationship between the estimated volume percentages of sand and mudstone and free oil determined from Rock-Eval ® S1 yields is used to place limits on the drainage of oil from source mudstone to reservoir sand at the decimeter scale. These data are used to determine oil saturations in interbedded sand-mudstone sequences at peak oil maturity. Higher values of free hydrocarbon (as evidenced by the S1 value in mudstone) suggest that more oil is being retained in the mudstone, while higher S1 values in the interbedded sands suggest the oil is being drained to saturate the larger pore spaces. High silica content in the interbeds confirms the brittleness in this mudstone esandstone lithofacies e an important factor to be considered for fracture stimulation to successfully work in a hybrid system. The key points of this hybrid unconventional system are the thickness, storage capacity and the possibility to capture a portion of the expelled, as well as retained oil.

The digital storage and communication of significant geological data became increasingly more objective and accessible through the development of new technologies or the implementation of already well-known techniques as photogrammetry.... more

The digital storage and communication of significant geological data became
increasingly more objective and accessible through the development of new technologies or the
implementation of already well-known techniques as photogrammetry. Digital acquisition of
geometries (both structural and depositional) of significant geological outcrops is deemed
necessary, especially if the site concerned is liable to be damaged or hopelessly involved in natural
processes of geological and geomorphological evolution. In this paper, we tested the performances
of two different open-source software (i.e. VisualSFM and ARC3D) on a small-scale but
paradigmatic outcrop in the Umbria-Marche Apennines (Italy). The test showed that ARC3D
provides an high-resolution model, employing a relatively short time and requiring a not expensive
hardware support for processing hundreds of photos. In the text, 3D models of the selected outcrop
are reported and discussed emphasizing the potential of the method to highlight structural,
sedimentological and paleontological details.
As a result, 3D photogrammetry proved to be a powerful and effective tool to digitally conserve and
objectively communicate important geological observations and to facilitate accessibility and
dissemination of the collected data within the scientific community.

The Strzelecki Group incorporates Berriasian to Albian, fluvial sediments deposited in the Gippsland Basin during initial rifting between Australia and Antarctica. Neocomian strata of the lowermost Strzelecki Group are assigned to the... more

The Strzelecki Group incorporates Berriasian to Albian, fluvial sediments deposited in the Gippsland Basin during initial rifting between Australia and Antarctica. Neocomian strata of the lowermost Strzelecki Group are assigned to the Tyers River Subgroup (exposed in the Tyers area) and the Rhyll Arkose (exposed on Phillip Island and the Mornington Peninsula). The Tyers River Subgroup incorporates two formations: Tyers Conglomerate and Rintoul Creek Formation. The latter is subdivided into the Locmany and Exalt Members. Ten fluvial sedimentary facies are identified in the lowermost Strzelecki Group: two gravelly facies; four sandy facies; and four mudrock facies. Associations of these facies indicate: (i) prevalence of gravelly braided-river and alluvial-fan settings during deposition of the Tyers Conglomerate; (ii) more sluggish, sandy braided to meandering fluvial systems during Locmany Member sedimentation; and (iii) a return to active, sandy, braided-river settings for deposition of the Exalt Member. The Tyers Conglomerate and Rhyll Arkose rest on an irregular erosional surface incised into Palaeozoic rocks of the Lachlan Fold Belt. The overlying Rintoul Creek Formation incorporates more mature sediments where lithofacies associations varied according to base-level change, variations in subsidence rates, and/or tectonic uplift of the principal sediment source terranes to the northwest.

Ancient deltaic facies are difficult to differentiate from tidally influenced shallow-marine facies. The Wagad Sandstone Formation of the Wagad Highland (eastern Kachchh Basin) is typified by offshore and deltaic facies with sedimentary... more

Ancient deltaic facies are difficult to differentiate from tidally influenced shallow-marine facies. The Wagad Sandstone Formation of the Wagad Highland (eastern Kachchh Basin) is typified by offshore and deltaic facies with sedimentary characteristics that represent different conditions of hydrodynamics and related depositional processes. The study area, the Adhoi Anticline, constitutes a ~154-m-thick, shale-dominated sequence with progressive upward intercalations of bioturbated micritic sandstone and quartz arenite. Two thick Astarte beds (sandy allochemic limestone), with an erosional base and gravel blanketing, illustrate tidal amplification and high-energy stochastic events such as storms. Sedimentological characteristics document three depositional facies: an offshore, shale-dominated sequence prograding to proximal prodeltaic micritic sandstone and quartz arenite with sandy allochemic limestones, further prograding to mouth bars and abandoned channel deposits. The Wagad Sandstone Formation displays depositional environmental conditions that are dissimilar from those of coeval deposits in Kachchh sub-basins as well as on regional and global
scales. This is attributed to a reactivation of the Kachchh Mainland and South Wagad faults which resulted in detachment and uplift of the Wagad block which then experienced prograding deltaic conditions.

The Madneuli polymetallic deposit is the major deposit of the Bolnisi ore district in the southeastern part of Georgia, which is in production since the 70's. The Bolnisi district is part of the Lesser Caucasus; it extends towards the... more

The Madneuli polymetallic deposit is the major deposit of the Bolnisi ore district in the southeastern part of Georgia, which is in production since the 70's. The Bolnisi district is part of the Lesser Caucasus; it extends towards the west in the Eastern Pontides, Turkey. The origin of the Madneuli deposit is still controversial. Our study is based on physical volcanology and sedimentary basin analyses. Eleven principal volcanic and volcano-sedimentary facies types were identified within the Madneuli open pit based on their composition, texture, volcanic and sedimentary structures. The presence of various submarine sedimentary structures, hyaloclastite and turbiditic rocks and Radiolaria described for the first time within the host rocks of the Madneuli open pit, supports the submarine depositional setting for the volcano-sedimentary succession hosting the Madneuli deposit.

The Flagstone Bench Formation ranges in age from earliest Triassic to Norian (Late Triassic) and is exposed in the Beaver Lake area of the northern Prince Charles Mountains. This sandstone-dominated formation rests conformably on the... more

The Flagstone Bench Formation ranges in age from earliest Triassic to Norian (Late Triassic) and is exposed in the Beaver Lake area of the northern Prince Charles Mountains. This sandstone-dominated formation rests conformably on the Bainmedart Coal Measures and represents the upper part of the Permian–Triassic Amery Group. It is divisible into three members: the Ritchie, Jetty and McKelvey members (in ascending order). Nine sedimentary facies assignable to three facies associations (major channel, crevasse/fan and flood-basin deposits) are recognized within the formation. Ritchie Member sedimentation took place during a transition from consistently hygric to seasonally dry conditions and the unit comprises sandstone-dominated, sheet-like channel deposits interspersed with few, thin, mottled, haematite-rich floodbasin siltstones. Deposition took place under fluctuating discharge conditions chiefly within the channel tracts of axially (northwesterly/northeasterly) flowing, low-sinuosity braided rivers. The Jetty Member shows a gross upward-fining profile dominated in the lower part by poorly sorted pebbly sandstones and in the upper part by ferruginous mudcracked siltstones, mottled palaeosols, calcrete and thin massive sandstone sheets. This unit reflects deposition of easterly directed alluvial fans and extensive flood-basin silt under a semi-arid climatic regime. The Upper Triassic sandstone-dominated McKelvey Member shows a return to axial drainage along the Lambert Graben with sedimentation occurring primarily within lowsinuosity braided channel tracts under wetter climatic conditions.

Carbonate mud that accumulated in the deep parts of a late Kimmeridgian carbonate ramp (Iberian Basin, NE Spain) was partly derived by resedimentation from shallow water production areas. High-frequency sea- level changes, probably driven... more

Carbonate mud that accumulated in the deep parts of a late Kimmeridgian carbonate ramp (Iberian Basin, NE Spain) was partly derived by resedimentation from shallow water production areas. High-frequency sea- level changes, probably driven by climatic changes in tune with precession and short-eccentricity cycles, affected carbonate production and the amount of exported sediment. Facies analysis and correlation of three outcrops located in middle and outer ramp settings allows a comparison of high-order sequences (bundles of beds and sets of bundles) across a ramp transect and an assessment of the carbonate factory. Analysis of the storm deposits found in middle ramp settings identifies deepening to shallowing high-frequency cycles based on the level of exported carbonate. In outer ramp areas, many of the bundles exhibit a thinning trend, indicating a progressive decrease of carbonate production and hence, carbonate export during periods of high- frequency sea-level rise. δ13Ccarb values show a gradual increase through the studied long-term transgressive interval ranging from 1.5‰ to 2.8‰. Within this long-term evolutionary trend, short-term δ13Ccarb fluctuations occur that correspond with some of the high-order cycles defined from sedimentary facies analysis. These short-term δ13Ccarb shifts are interpreted as shifts in carbonate export from shallow reef regions to the outer ramp. A consequence of this study is that variation in δ13Ccarb can be used for correlation in outer ramp successions, at least on a basin-wide scale.

L'étude céramologique du site d'Arancou – Las Courrèges (Pyrénées‐Atlantiques, France), outre corroborer les données archéologiques ayant révélé une occupation datant de la seconde moitié du Ier s. ‐ IIème s. de notre ère, vient offrir de... more

L'étude céramologique du site d'Arancou – Las Courrèges (Pyrénées‐Atlantiques, France), outre corroborer les données archéologiques ayant révélé une occupation datant de la seconde moitié du Ier s. ‐ IIème s. de notre ère, vient offrir de nouvelles données et correspondances statistiques sur le faciès de consommation ainsi que de nouveaux profils, notamment une

During the past decade, the size of 3D seismic data volumes and the number of seismic attributes have increased to the extent that it is difficult, if not impossible, for interpreters to examine every seismic line and time slice. To... more

During the past decade, the size of 3D seismic data volumes and the number of seismic attributes have increased
to the extent that it is difficult, if not impossible, for interpreters to examine every seismic line and time
slice. To address this problem, several seismic facies classification algorithms including k-means, self-organizing
maps, generative topographic mapping, support vector machines, Gaussian mixture models, and artificial neural
networks have been successfully used to extract features of geologic interest from multiple volumes. Although
well documented in the literature, the terminology and complexity of these algorithms may bewilder the average
seismic interpreter, and few papers have applied these competing methods to the same data volume. We have
reviewed six commonly used algorithms and applied them to a single 3D seismic data volume acquired over the
Canterbury Basin, offshore New Zealand, where one of the main objectives was to differentiate the architectural
elements of a turbidite system. Not surprisingly, the most important parameter in this analysis was the choice of
the correct input attributes, which in turn depended on careful pattern recognition by the interpreter. We found
that supervised learning methods provided accurate estimates of the desired seismic facies, whereas unsupervised
learning methods also highlighted features that might otherwise be overlooked.

The study of palaeosols, coupled with the classical methods of process sedimentology, is increasingly becoming a powerful tool for palaeoenvironmental reconstructions. The intrinsic complementarity of these two methods, which record the... more

The study of palaeosols, coupled with the classical methods of process sedimentology, is increasingly becoming a powerful tool for palaeoenvironmental reconstructions. The intrinsic complementarity of these two methods, which record the effects of processes developing over different periods of time, allows to improve the detail of facies analysis. This type of approach has actually never been adopted for the Upper Valdarno Basin, which is one of the best-known continen- tal Plio-Pleistocene basins of the Northern Apennines. The aim of this paper is to document the existence of pedogenized intervals within the Upper Valdarno basin fill and to describe and charac- terize them in terms of sedimentary and pedogenic processes. Thus we tested this approach on four stratigraphic intervals, selected within the whole succession because of their particular significance in the basin history. Deposits have been described and interpreted in terms of sedimentary facies and pedologic characteristics, with par- ticular attention on the inferred relative temporal relationships between sedimentary and pedogenic processes. This led to several considerations about landscape stability and evolution, accommoda- tion and sedimentation rates, which are not commonly possible with the analysis of single-event deposits.

Sedimentological and palynological studies have been undertaken on a sequence of Permian rocks exposed in the vicinity of Fairbairn Dam, near the town of Emerald in central Queensland. The rocks represent part of the fill of the northern... more

Sedimentological and palynological studies have been undertaken on a sequence of Permian rocks exposed in the vicinity of Fairbairn Dam, near the town of Emerald in central Queensland. The rocks represent part of the fill of the northern Denison Trough, a north-south elongate feature on the western margin of the Bowen Basin. The present investigation sheds new light on the depositional environment and stratigraphic context of the exposed sequence. The section is interpreted as the product of coastal environments of deposition. Five lithofacies are recognized and interpreted as: (1) major distributary channel fill: thick, erosively based, cross-bedded sandstone; (2) interdistributary bay deposits: thinly interbedded sandstone, siltstone and claystone with carbonaceous shale; (3) tidal inlet and tidal delta deposits: erosively based, bimodally cross-bedded sandstones; (4) beach ridge deposits: massive, quartzose sandstone beds; and (5) middle-upper shoreface (i.e. inner marine shelf) facies: amalgamated units of hummocky cross-stratified sandstones. Evidence for tidal flux and the importance of wave-generated structures suggests that the coastal complex was of mixed-influence, affected by a balance between fluvial outflow, waves and tides. Regional correlations suggest that the exposed section represents an eastward prograding coastal plain without any pronounced deltaic depocentres. Palynological assemblages from four samples support an interdistributary bay interpretation for the thinbedded facies, and indicate a Late Permian age for the exposed sequence. Palynofloras, which are dominated by pterophyte spores and disaccate gymnosperm pollen in three samples, and algae and acritarchs in the fourth, are characteristic of the upper stage 5 palynozone of Price (1983). The age and lithostratigraphic correlation suggest that the rocks exposed in the vicinity of the dam spillway are part of the Freitag Formation.

Abstract The Eocene transgressive deposits of the Acıgöl, Burdur and Isparta basins are the best exposed of the SW Turkey and shed light on one of the outstanding problems of the tectono- sedimentary evolution during paleotectonic and... more

Abstract
The Eocene transgressive deposits of the Acıgöl, Burdur and Isparta basins are the best exposed of the SW Turkey and shed light on one of the outstanding problems of the tectono- sedimentary evolution during paleotectonic and neotectonic period. In the present paper we describe a tectonic model of the
progressive foreland migration of the allochthonous units such as Lycian and Antalya nappes, initial
emplacement onto stable carbonate platform in the Early Oligocene, carrying piggy-back basins and
incorporating from alluvial fan to deep-marine deposits recognized in these terrigenous successions.
In general, the facies and structural observations on the overall Mid-Late Eocene clastic sequences,
outcropping in behind the Lycian nappes, indicate: i) the alluvial fan to shallow marine settings of the
Başçeşme Fm in Acıgöl, ii) the Varsakyayla Fm in Burdur and iii) proximal to distal flysch facies
trend of the Kayıköy Fm in Isparta. The collected data allow us to hypothesize that the Mid-Late Eocene tectono-sedimentary history was characterized by a terrigenous clastics, probably lying on the constructing tectonic edifice and then deformed and covered by a piggy-back like sequence. The
tectono-sedimentary evolution of the Eocene transgressive in SW Turkey has been probably developed through a progressive migration towards the foreland basin.

Classification of different lithofacies and petrotypes is one of the main objectives of modern quantitative seismic interpretation. In this study, we present preliminary results of the application of a proximal support vector machine... more

Classification of different lithofacies and petrotypes is one
of the main objectives of modern quantitative seismic
interpretation. In this study, we present preliminary results
of the application of a proximal support vector machine
(PSVM) classification algorithm to seismic data. In this
application we illustrate the PSVM method to differentiate
limestone from shale in a Barnett Shale gas play. The
PVSM’s low complexity feature compared to the standard
vector machines could be well exploited in a data intensive
computation such as the 3D seismic lithofacies
classification. The paper reports two applications of this
technique one for waveform classification and the other for
the classification of well data. In both these applications
PSVM classification results showed strong agreement with
structural and stratigraphic interpretation results.

The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 boundary. Like many other crises, it coincided with a negative carbon isotope excursion but the associated palaeoenvironmental changes remain... more

The mass extinction of the olenellid trilobites occurred around the Cambrian Series 2–Series 3 boundary. Like many other crises, it coincided with a negative carbon isotope excursion but the associated palaeoenvironmental changes remain unclear. To investigate the causal mechanism for this event, we report facies changes, pyrite framboid petrography and carbon isotope values from Cambrian Series 2–Series 3 (traditionally Early–Middle Cambrian) boundary strata of the Carrara Formation (Death Valley region, California) and Pioche Formation (Nevada). These data reveal regionally changing water depths from high-energy, nearshore facies (oolitic grainstone) to more offshore silty marl and finer-grained carbonate mudstone. In the Carrara Formation, the series boundary occurs within a deepening succession, transitioning from high-energy, nearshore facies (oolitic grainstone and oncolitic packstone) to offshore marl, the latter of which contains pyrite framboid populations indicative of low-oxygen (dysoxic) depositional conditions. Intermittent dysoxia persisted below sub-wave base settings throughout the early and middle Cambrian, but did not intensify at the time of extinction, arguing against anoxia as a primary cause in the olenellid trilobite extinction. Within both field areas, the extinction interval coincided with a minimum in δ 13 C carb values, which we interpret as the regional manifestation of the Redlichiid-Olenellid Extinction Carbon isotope Excursion (ROECE). The Series 2–Series 3 boundary is reported to closely coincide with a large-amplitude sea-level fall that produced the Sauk I/II sequence boundary, but the placement of the Series 2–Series 3 boundary within a transgressive interval of the Carrara Formation shows that this is not the case.The main sequence boundary in the succession occurs much lower in the succession (at the top of the Zabriskie Quartzite) and therefore precedes the extinction of the olenellids and ROECE.

The studied area is located in the NW of Moldavian Platform, the oldest platform unit of the Romanian territory, representing the western margin of the East European Platform. The integrated analysis and correlation of seismic reflection... more

The studied area is located in the NW of Moldavian Platform, the oldest platform unit of the Romanian territory, representing the western margin of the East European Platform. The integrated analysis and correlation of seismic reflection surveys and wireline logs, together with mud logging and additional geological data, allow a better delineation and characterization of the Sarmatian (Middle–Late Miocene) gas reservoirs from this area. A gradually decreasing reservoir quality and, most likely, hydrocarbon potential from NW towards SE is suggested, related to sedimentary facies changes. Thermal maturation models indicate that two hydrocarbon systems are present in the Moldavian Platform: a thermogenic hydrocarbon system of Paleozoic age and a biogenic hydrocarbon system of Miocene age. This analysis is focused on the biogenic hydrocarbon system of Miocene age, which contains significant gas fields. The gas is represented by more than 98% methane and is reservoired especially in the lower part of the Sarmatian deposits, where suitable conditions for accumulation and sealing are encountered. The hydrocarbon entrapment is in structural traps of faulted monocline type and in sands/sandstones that pinch out forming lithostratigraphic traps.

Three outcrops of the Silurian Sharawra Formation at its type locality in Old Qusaiba Village in Central Saudi Arabia were studied for lithofacies distribution, petrographical, and geochemical characteristics. The outcrops were logged and... more

Three outcrops of the Silurian Sharawra Formation at its type locality in Old Qusaiba Village in Central Saudi Arabia were studied for lithofacies distribution, petrographical, and geochemical characteristics. The outcrops were logged and nine different lithofacies were identified in the field. Petrographic analysis shows the Sharawra Formation to be mainly subarkosic associated with increasing mica content near to its contact with the underlying Qusaiba Shale Formation. Major and trace element geochemistry indicates that the sediments of the formation were deposited in a passive continental margin. The source area discriminating plots reveal acidic or felsic rocks such as granites as the probable provenance of the Sharawra sediments. The Chemical Index of Alteration (CIA) and Chemical Index of Weathering (CIW) indicate a moderate degree of weathering in the source area of these Silurian sediments. This study provides a baseline for future characterization studies of Paleozoic siliciclastic formations in Saudi Arabia and neighbouring countries.

Clastic-carbonate succession which including the Nahr Umr and Mauddud Formations are represented a part of Albian-Early Turonian Sequence (Wasi`a Group). The present study includes Petrography, microfacies analysis, depositional... more

Clastic-carbonate succession which including the Nahr Umr and Mauddud Formations are represented a part of Albian-Early Turonian Sequence (Wasi`a Group). The present study includes Petrography, microfacies analysis, depositional environment, digenetic development, and reservoir characterization for seven boreholes (Lu-2, Lu-4, Lu-5, Lu-8, Lu-13, Lu-14 and Lu-39) within Luhais Oil field South Iraq.
There are six type of carbonate microfacies were recognized in the Mauddud Formation:- Orbitolina - Milliolids wackestone to packstone Orbitolina wackestone to packstone, miliolids wackestone, Peloidal wackestone to packstone, Ooides to Peloids grainstone and bioclastic Wackestone - Packstone. These microfacies are represented three depositional environments: restricted shallow marine environment, semi-restricted shallow marine environment and Shoal environments. While the Nahr Umr Formation characterized by six lithofacies; Lithofacies I (Mudstone), Lithofacies II (Siltstone - Claystone), Lithofacies III (Lenticular Bedded Sandstone-Mudstone), Lithofacies IV (Falser Bedded Mudstone - Sandstone), Lithofacies V (Parallel Lamination Sandstone - Siltstone) and Lithofacies VI (Well sorted sandstone). These lithofacies are suggested four depositional environment of Nahr Umr Formation: Active channel environment, channel fill environment, delta plain environment and delta front and shore face environment.
The most common diagenetic features observed and distribution in the studied sections includes Micritization, Cementation, Leaching (dissolution), dolomitization and Compaction fabrics. The most effective diagenetic processes were cementation, dissolution and dolomitization processes which have direct affect upon the study sections.
The Nahr Umr and Mauddud sequence can be divided by the gamma ray and shale value into three zones (A, B and C); therefore we have interpretation of the logs porosity and porosity evaluation according to these divisions.
Keywords: Facies Architecture, Diagenetic Development, Albian-Early Turonian and Luhais Oil field

"Thecideid brachiopods are poorly known brachiopods of debated phylogenetic relationships which occur from the Late Triassic to the Recent. Although well known in encrusting communities of Jurassic and Cretaceous cryptic habitats, they... more

"Thecideid brachiopods are poorly known brachiopods of debated phylogenetic relationships which occur from the Late Triassic to the Recent. Although well known in encrusting communities of
Jurassic and Cretaceous cryptic habitats, they have received less attention in Cenozoic environments. Extensive thin section analysis of circumalpine Paleogene carbonates (Late Eocene of
Austria as well as the Early Oligocene of Slovenia, the Inntal Valley and Northern Italy) has revealed the presence of thecideid brachiopods allowing for the analysis of their taphonomy,
component relationships and facies distribution. The complex morphology of the valves enables these brachiopods to be readily identified in thin section, even if highly fragmented or encrusted.
Component analyses using semi-quantitative and quantitative methods reveal that these brachiopods are most commonly associated with corals and coralline algae. The brachiopods are often included within complex encrustation sequences. Their palaeoecology thus closely mirrors that of Recent and fossil thecideid species which are characteristics of cryptic habitats in tropical and warm temperate seas. The potential of these minute brachiopods as palaeoecological indicators has been underestimated especially considering their ease of recognition in thin section not only of complete valves, but also of highly fragmented material. "

We studied mollusk-dominated multispecies assemblies from the south Pyrenean foreland in Spain by using relative abundance data in a framework of high-frequency depositional sequences for an in- terval spanning 2 myr across the early... more

We studied mollusk-dominated multispecies assemblies from the south Pyrenean foreland in Spain by using relative abundance data in a framework of high-frequency depositional sequences for an in- terval spanning 2 myr across the early Eocene climatic optimum. The sequences are part of the Figols (middle Ypresian) and Castigaleu (upper Ypresian) allogroups and together document environmental changes influenced by tectonics at the lower frequency and driven by sea level and climate at the high-frequency temporal scale. We ap- plied ordination through multidimensional scaling and other tech- niques to explore the structure of the data set. Six Figols and eight Castigaleu communities, linked along onshore-offshore gradients, were interpreted on uniformitarian grounds. Paleoenvironments ranged from mangrove forest to tidal flat, tidal creek, estuary, delta front, shoreface, carbonate ramp, and inner shelf. Some habitats were represented throughout the interval, allowing examination of the ef- fect on coastal ecosystems of environmental disturbances tied to sea- level lowstands, as deduced from the sequence stratigraphic analysis. These disturbances presumably amounted to extirpation by river floods, burial, increased turbidity, high river-derived nutrient input, and decreased ecospace availability. The major effect on the man- grove-estuary-delta gradient was coincident with the unconformity separating the two allogroups. Mangrove communities suffered a change in rank of dominating species and a turnover of rare species. Subtidal estuarine and delta communities were affected in their rel- ative abundances, but we observed no change in rank or turnover. We suggest that the different niche breadth of organisms leads to different responses to perturbation of several scales. Many intertidal cerithioidean gastropods went extinct, whereas subtidal turritelline gastropods were unchanged, during the major environmental varia- tion. Mangrove gastropods experienced increased originations in the upper Ypresian. The carbonate ramp heterotrophs did not change across the Figols-Castigaleu perturbation, although throughout the early Eocene the phototroph guild within the same ecosystem was undergoing frequent turnover events. All studied associations showed significant changes in the relative abundances of constituent species across unconformities of minor entity, proving that soft-bottom ma- rine communities conform to an open-membership model of ecosys- tem recruitment, as suggested by studies of past open marine eco- systems. Persistence to a degree is suggested by mangrove commu- nities, indicating a slightly more limited membership in low-nutrient estuarine habitats, a response more similar to that of coral reef trop- ical ecosystems. This study confirms the idea that different species and communities may experience opposite effects from the same events and shows that faunal distributions in estuarine and deltaic systems reflect more than just bathymetric change. High onshore origination also conforms to the theory of onshore-offshore faunal change.

Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope... more

Globally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary and Olenellus biostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to r...