Stratigraphic Units Research Articles

The Late Devonian contraction along the Precaspian Basin north margin: Transpressional range building in the intracratonic domain

The evolution of intraplate sedimentary basins located in the vicinity of an active convergent plate boundary is often controlled by the collisional dynamics of the adjacent orogen. The transfer of compression from the orogen to the platform's interior results in the formation of complex structural geometry and kinematics that often reactivate older crustal faults, focus far-field stresses and control the evolution of associated sedimentary basins. One place where this localisation can be optimally understood is the Precaspian Basin, situated at the SE periphery of the East European Craton and bordered to the east by the Uralian orogen. The Precaspian Basin and its northern margin experienced long-term extension and subsidence interrupted by several short-lived shortening episodes. To understand the impact and role of pre-existing basement structures on the geometry and kinematics of the subsequent deformation, we analysed subsurface data from the northern margin of the Precaspian Basin by the means of 3D seismic interpretation correlated with wells and structural modelling. The analysis results provide new insights into the kinematic effects of the Late Devonian contraction event. The superposition of stratigraphic units above and below the angular unconformity suggests an intra-Famennian age of the deformation event. Steeply dipping bi-verging reverse fault zones associated with variable amounts of sinistral strike-slip movement component display an arcuate geometry, trending from WSW-ENE to NW-SE. The distribution of deformation indicates that this complex kinematic pattern was driven by a NE-SW oriented contraction and transpression, where faults show the characteristics of a restraining bend area. This area is interpreted as part of a regional transcurrent fault system developed on the northern periphery of the Precaspian Basin. Furthermore, the study results suggest that intralithospheric stress localisation transmitted by the Paleouralian subduction zone resulted in the reactivation of pre-existing basement structures, propagation of faults, and localized short-term exhumation of the Precaspian Basin north margin. Generated by the collision of Magnitogorsk volcanic arc with East European Craton, far-field stress transfer produced a zone of oblique deformation. These data and interpretation demonstrate that the northern margin of the Precaspian Basin is an excellent natural setting to investigate and better understand mechanisms of far-field strain localisation and reactivation of deformational structures in stable platform areas resulting in the intracratonic mountain building process.

Investigation and mapping of geological construction materials in parts of chemoga river sub basin, debre markos, Ethiopia

Currently the demands of geomaterials are intensively increasing all over the country regarding to the expansions of towns for the consumption of engineering structures and buildings. Therefore, searching workable, serviceable and accessible geomaterials nearby areas is a vital subject to stabilize the inflation of geomaterials. The present research was carried out in the Chemoga river sub basin in the Southern direction of Debre Markos town, North Western Ethiopia. To meet out the objectives, detailed surface explorations were carried out through systematically selected travel lines (across the strike and along streams) to detect the different lithologic formations and the contacts; A number of representative rock samples were collected for visual interpretations; GPS reading and metallic meter were the materials used in the field to quantify stratigraphic units, bedding thickness and lamination the lithologic formations; The Brunton compass was used in the field to measure the orientation (dip direction, dip amount and strikes) of geological structures. Besides to this, related literatures were reviewed to have a general background on the subject matter.Basalt and Sandstone are the dominant lithogical units in the study area and have existed with about an average thickness of 500 m and 145 m respectively. Fresh to slightly weathered basalt and columnar basalt that used as a masonry stones are ease to access, workable and the most dominant lithologic units in the study area. Fine to coarse grain reddish to light color sandstone interbedded with siltstone and mudstone is well exposed. Based on the detail field exploration and judgments, Sandstone unit has been well exposed in a desirable potential and quality. And based on the detail field investigation and researcher judgment, the sandstone resource could answer the demands of construction materials for the surrounding areas of Debre Markos town for several thousand of years. Geometrically, mostly massive and steep rock faces are well developed which are difficult for quarrying process and required high explosive materials. Generally, a sandstone rock unit is surrounded by three major normal faults and inaccessible as compared to basalt unit. Regarding to environmental influences/effects, the area is sparsely farmed and it is not common that an extractive activity does not show any environmental and social impacts. Chert is exposed on geographically limited area and rarely observed following stream cuts. Chert and basalt units are slightly to highly weathered and showed alterations on the surface. Finally, the potential and the spatial distribution of geomaterials are investigated and revealed on the map using ArcGIS software and on the basis of the findings of the present research, recommendations are forwarded.

Analogue modelling of a Tabberabberan fold-thrust belt in the Cobar region and implications for the origin of Cobar-type mineral deposits

The Cobar Supergroup is a package of Siluro-Devonian sedimentary, volcanic and volcaniclastic rocks in central New South Wales that underwent significant deformation during the Middle Devonian Tabberabberan Orogeny. The Cobar Supergroup, particularly within the Cobar Basin, constitutes one of the most mineral-rich rock packages in New South Wales, being endowed with Au, Cu, Pb, Zn and Ag, mainly in what are commonly referred to as Cobar-type deposits. Inconsistencies in the traditional stratigraphic interpretation of the area have led to a re-evaluation of its structural history, in particular the role of the Rookery Fault, which bounds the eastern side of the basin. Evidence suggests that that structure may dip to the east, rather than the west, as is traditionally assumed, leading to the possibility that Tabberabberan deformation in the area took the form of a west-verging fold-thrust belt. Analogue modelling is employed to examine the consequences of that scenario. Such a mechanism explains the known distribution of stratigraphic units of the Cobar Supergroup and its basement, as well as observed structures, in particular a high strain zone immediately west of the Rookery Fault. The modelling indicates that deeper parts of the crust were thrust up along the Rookery Fault, which, along with substantial burial, led to perturbation of the geotherm and heating of the footwall. This accounts for the higher metamorphic grade immediately west of the Rookery Fault. Furthermore, heating and overpressuring of basement rocks in the footwall led to mobilisation of metal-bearing fluids and transport of them along the high strain zone and subsequent deposition of those metals within favourable structural traps, with variable interaction with basinal fluids, to form Cobar-type deposits. A fold-thrust mechanism with ongoing erosion of the thrust wedge can also explain the distribution of Middle to Upper Devonian rock sequences in the region. KEY POINTS A west-verging fold-thrust model is proposed to explain Tabberabberan deformation of the Cobar Supergroup and its basement. Analogue modelling is employed to demonstrate the fold-thrust model. A fold-thrust model explains the distribution of Ordovician to Upper Devonian stratigraphic units in the Cobar region, as well as associated structures, metamorphic grade distribution and the origin of syn-deformational Au, Cu, Pb, Zn, Ag mineral deposits.

Structural geology of the eastern termination of the Mt. Kumeta-Alcantara line (NE sicily, Italy)

ABSTRACT In this paper we show data from new detailed geological-structural field surveys, integrated with preliminary photogrammetric analysis, presented in a 1:10,000 scale geological map. The field-based investigations covered an area of about 60-km2, located at the southern termination of the Calabrian Forearc, in NE Sicily (Italy), at the intersection of two key regional-scale fault systems. These are represented by the Peloritani Sole-Thrust, along which the Kabilo-Calabride orogenic edifice overthrusted onto the Apenninic-Maghrebian Chain, and the Mt. Kumeta-Alcantara Line, which played a key role in the post-Oligocene evolution of the Nubia–Eurasia converging margin. The collected data permitted the recognition of a new terrigenous stratigraphic unit, the Malvagna Flysch, and the acquisition of updated structural information useful to better understand the kinematics of the easternmost portion of the Mt. Kumeta-Alcantara Line. The geological map provides new insights for the reconstruction of the geodynamic evolution of this sector of the Calabrian Forearc.

Late Quaternary slip rate of the Fengmenkou-Wuzhiling fault at the southern margin of North China block (S-NCB)

The regional crustal slipping behaviour within the interaction zone of the North China and Qinling blocks reveals the pattern of extensional grabens merging with strike-slip faults and establishes the contribution of these faults to the regional basin generation. In this study, we aimed to assess the active slipping at the Laojing Gou site along the Fengmenkou-Wuzhiling fault (FMK-WZLF), one of the main active faults at the southern margin of North China block (S-NCB), by setting a three-dimensional measurement of the offset in buried paleochannels. Mapping, trenching, and age constraints of the geomorphic and stratigraphy units illustrate three offset paleo-fluvial surfaces since the Late Pleistocene, named S1, S2, and S3, along the fault strike direction. Beneath the surface, the structure of isolated confined paleo-channels C1 and C3 was exposed on the stratigraphy profile, and they were active during 130–75 ka and 2.8–3.0 ka, respectively. We presented a set of adapted scripts for three-dimensional measurements to calculate the lateral and normal tectonic components. The left lateral slip rate for the FMK-WZLF was estimated to be 0.25–0.45 mm/a, and the long-term oblique slipping behaviour generated the scarps in a dip of 70° ± 5° across the fault plane. The oblique slip of the FMK-WZLF, together with the regional E-W and SW-NE striking normal fault system, shapes the northeastward flowing Yiluo river and the southeastward flowing Huai river at S-NCB.

The origin of two distinct diagenetic depth zones in hydrocarbon-bearing sediments of Huanghekou Sag, offshore Bohai Bay Basin, China

Formation waters from the Huanghekou Sag, offshore Bohai Bay Basin, exhibited two depth zones with elevated total dissolved solid (TDS) composition. The shallow diagenetic zone at a depth of ∼1200–2000 m (∼45–70 °C) and the deep diagenetic zone at a depth of ∼3000–4000 m (∼100–130 °C) have TDS concentrations exceeding 70,000 mg/L, while the depth interval in between the two zones has TDS concentrations lower than 35,000 mg/L. Isometric log-ratio interpretations of the reconstructed formation water compositions, crude oil compositions, stable hydrogen and oxygen isotopes, light microscopy and clay mineral analysis were used to interpret the origins of the two diagenetic depth zones. Formation waters within each stratigraphic unit were dominantly composed of Na–K–Cl type. Processes affecting the deep diagenetic zone were attributed to (1) the dissolution of halite, albite and albitization, which predominantly caused the TDS enrichment, and (2) the dilution of TDS caused by the inter-layer H2O released from the transformation of smectite to illite (salinity reversal at depths > ∼3500 m). In comparison, the enrichment in TDS in the shallow diagenetic zone was attributed to hydrocarbon biodegradation, which consumed free water. The crude oil composition indicates severe hydrocarbon biodegradation. Biodegradation of low-molecular-weight organic carbons such as hexadecane (through methanogenesis) and benzene (through microbial sulfate reduction) could consume sufficient H2O to enrich TDS to the observed levels. At the same time, relatively constant Na/Cl and Ca/Cl ratios versus TDS can be explained by water consumption as well. This work could serve as a reference for the interpretation of two diagenetic zones characterised by distinct TDS enrichments in other hydrocarbon-bearing sedimentary basins.

Synchronous exhumation episodes across Arctic Canada, North Greenland and Svalbard in relation to the Eurekan Orogeny

The sedimentary record across the Canadian High Arctic, North Greenland and Svalbard is fragmentary, making regional correlation difficult. We seek new insights by integrating information from the preserved geological section with evidence of former stratigraphic units that are no longer present (missing section), using paleo-thermal methods to define episodes of deeper burial and subsequent exhumation. Parts of the region were affected by deformation induced by the Paleocene–Eocene movement of Greenland relative to the North American and Eurasian plates (the Eurekan Orogeny). However, our results indicate four discrete episodes of kilometre-scale exhumation before, during and after the Eurekan Orogeny that led to disruption of sedimentary basins across the region. (1) Regional Maastrichtian exhumation possibly reflects doming above the rising Iceland Plume. The plume impact at the base of the lithosphere contributed to the onset of mid-Paleocene sea-floor spreading west of Greenland that provided the driving force for the Eurekan Orogeny. (2) Localized Paleocene exhumation was caused by inversion of fault zones in the initial stage of the Eurekan Orogeny due to compression that also formed foreland basins and caused the West Spitsbergen Fold Belt. (3) Regional exhumation that began at the end of the Eocene postdates sea-floor spreading west of Greenland and thus represents post-Eurekan tectonics. This episode, which also affected regions far from the Eurekan Orogen, coincided with a major change in the North-East Atlantic spreading system. Transmission of stress from a shift in the motion of Africa relative to Europe may have contributed to these changes. (4) Regional, late Miocene uplift and erosion initiated the development of present-day landscapes. Our results show both local uplift events within the Eurekan Orogen and synchronous effects over large regions that require new ideas about the stresses driving horizontal and vertical movements of the earth’s crust.

Integration of Sequence Stratigraphic Analysis and 3D Geostatistical Modeling of Pliocene–Pleistocene Delta, F3 Block, Netherlands

AbstractThis research is focused on the analysis of the sequence stratigraphic units of F3 Block, within a wave‐dominated delta of Plio–Pleistocene age. Three wells of F3 block and a 3D seismic data, are utilized in this research. The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section. Integration of seismic sequence stratigraphic interpretation, using well logs, and subsequent 3D geostatistical modeling, using seismic data, aided to evaluate the shallow hydrocarbon traps. The resulting models were obtained using System Tract and Facies models, which were generated by using sequential stimulation method and their variograms made by spherical method, moreover, these models are validated via histograms. The CDF curve generated from upscaling of well logs using geometric method, shows a good relation with less percentage of errors (1 to 2 for Facies and 3 to 4 for System Tract models) between upscaled and raw data that complements the resulted models. These approaches help us to delineate the best possible reservoir, lateral extent of system tracts (LST and/or HST) in the respective surface, and distribution of sand and shale in the delta. The clinoform break points alteration observed on seismic sections, also validates the sequence stratigraphic interpretation. The GR log‐based Facies model and sequence stratigraphy‐based System Tract model of SU‐04‐2 showed the reservoir characteristics, presence of sand bodies and majorly LST, respectively, mainly adjacent to the main fault of the studied area. Moreover, on the seismic section, SU‐04‐2 exhibits the presence of gas pockets at the same location that also complements the generated Facies and System Tract models. The generated models can be utilized for any similar kind of study and for the further research in the F3 block reservoir characterization.

Fault reactivation potential in a carbonate field in Brazil based on geomechanical analysis

The reactivation of faults may directly modify their permeability and the integrity of the petroleum system seal. Thus, this understanding is fundamental for decision-making in the petroleum industry at different levels while developing, for example, hydraulic fracturing projects, fracture networking, Enhanced Hydrocarbon Recovery (EOR), and CO2 storage. The identification of the stress field based on elastic properties, failure criterion, rock strength, and in-situ principal stresses allow to understand the geomechanical behavior of stratigraphic units. This process becomes complex in carbonate reservoirs because they present high geomechanical variability related to the sedimentary and diagenetic processes they undergo. In this context, the present work aims to study the potential for fault reactivation in the pre-salt Barra Velha and Itapema Formations and in the Camboriu Formation in the study area, Santos Basin, Brazil, based on geomechanical modeling. Data from 28 wells with basic geophysical well-logs and wellbore image logs, absorption and formation pressure tests, and 3D pre-stack seismic data were used. The results indicate an abnormally high fluid pore pressure (9.49 ppg) concerning hydrostatic pressure (8.34 ppg). Three structural compartments delimited by interpreted seismic horizons and faults were defined. Three fault regimes were defined based on minimum and maximum horizontal stresses gradients: a double normal-transcurrent regime for the Barra Velha and Itapema Formations; a normal regime for the Piçarras Formation; and a double transcurrent-inverse regime for the Camboriu Formation. Finally, based on the stress polygon, scenarios of fault reactivation in the structural compartments were estimated. With increases between 16% and 28.1% of the pore pressure by fluid injection, the transcurrent movement of the faults can be generated. The reverse faults of a shallower structural compartment have the highest probability of reactivation and movement.

Stratigraphy of the Cenozoic succession in eastern Azerbaijan: Implications for petroleum systems and paleogeography in the Caspian basin

The Cenozoic succession in the Lower Kura Basin includes largely uniform, often carbonate-free mudstones. Because age dating of these sediments has proved difficult, the stratigraphy of the Cenozoic succession and the distribution of organic-rich strata are poorly known. A better understanding of the Cenozoic succession is not only important for petroleum-systems-analysis, but also for the understanding of the Cenozoic evolution of the Caucasus region. Therefore, bulk geochemical data (carbonate, TOC, sulphur, Rock-Eval) of 885 samples and biostratigraphic data were collected along seven outcrop profiles. This enabled the establishment of a continuous stratigraphic record from the Middle Eocene to the Late Miocene (Pontian). The study results show that potential source rocks are present in three stratigraphic units: the Middle Koun (Middle Eocene), Maikop Group (Oligo-Miocene) and Diatom Formation (Upper Miocene). The Middle Koun is about 100 m thick near the Caspian Sea and contains highly oil-prone sediments (2–24 wt% TOC; HI 300–577 mgHC/gTOC), which may generate 1.5 tHC/m2. The Maikop Group contains on average 1.8 wt% TOC, but is often gas-prone. Highly oil prone layers (2–5 wt% TOC; HI 300–450 mgHC/gTOC) are rare. Nevertheless, the Upper Maikop Formation may generate ∼2 tHC/m2. The Diatom Formation contains paper shales with high TOC contents (3–22 wt%) and HI values (350–770 mgHC/gTOC). The paper shale unit is more than 60 m thick near the Caspian Sea and can generate 3.8 tHC/m2. Previously it was thought that the Maikop Group had the highest petroleum potential, whilst Upper Miocene and Middle Eocene source intervals were overlooked. The Middle Eocene to Lower Oligocene succession in the Kura Basin is largely carbonate-free. In contrast, coeval successions elsewhere in the Caucasus region contain sediments with varying, but often high carbonate contents. Differences in carbonate content imply greater water depth during deposition in the Kura Basin.

Quaternary Stratigraphy and Geomorphic History of the Flatwoods Region of Owen and Monroe Counties, Indiana

The Flatwoods region of Owen and Monroe Counties, Indiana is an archetype of late Quaternary history of the southern Midwest. We compile decades of field observations and sampling, including soil cores, a deep test hole, and hundreds of water well, seismic, and other data sources, to construct a detailed Quaternary stratigraphy and geomorphic history of the region, including a model of the preglacial bedrock topography. Optically stimulated luminescence (OSL) techniques provide the first numerical ages of the sediments and reveal the Illinois Episode glacier advanced into the region between 111-175 ka. Gray, calcareous Illinois Episode sediments dominate the valley fill, but highly weathered red glaciogenic sediments in the eastern part of the region may be related to a pre-Illinois Episode glacial event. Fine-grained stratified lake sediments indicate the southwestward draining bedrock valley was flooded as glacial ice entered the drainage basin. Sandy outwash covers the lake sediment marking the advance of glacier ice that ultimately crossed the basin and deposited till. Till is found in several ice-marginal ridges interpreted to be moraines marking the glacial limit. The Flatwoods valley routed water to the east end of the region where it spilled over one or more cols into Raccoon Creek, then continued toward the Ohio River in a glacial drainage system developed along the glacier margin. The Sangamon Geosol is a pervasive soil stratigraphic unit developed into Illinois Episode sediments, eroded only in modern stream valleys. The Geosol is well expressed morphologically, noted mostly by deep leaching of carbonates, red colors, and weathered mineralogy. Wisconsin Episode glaciation is represented by eolian sediments, including a thin increment of silty sediment incorporated into the upper solum of the Sangamon Geosol. Windblown Peoria Loess, deposited between ~27-16 ka, blankets the entire Flatwoods region, with greatest thicknesses preserved on flat lake or outwash plain landforms. Supplemental DataGeodatabase: The geodatabase includes locations of water-well records, borehole and outcrop sites, geophysical (gamma-ray) logs, refraction seismic surveys, passive seismic (horizontal-to-vertical spectral ratio [HVSR]) surveys, and data from the geological literature.Metadata: FGDC-compliant metadata for geodatabase.Data: Analytical data and other geological information include: a downhole geophysical (gamma-ray); data from the 2019 test hole, including clay mineralogy, core photographs, a downhole gamma-ray log, and particle size analysis; Indiana Geological and Water Survey (IGWS) archive data, which is comprised of borehole descriptions; a copy of Jacobs' (1994) Ph.D. dissertation; scanned profile description sheets and core stratigraphy from Jacobs (1994); and supplementary optically stimulated luminescence (OSL) data.ReadMe: Detailed file directory explaination of items within each of the supplemental data item ZIP files.

Revisiting the late Quaternary fossiliferous infills of Cathedral Cave, Wellington Caves (central eastern New South Wales, Australia)

ABSTRACTThe Wellington Caves were the first Australian locality from which Europeans collected and analysed vertebrate fossils. Within this system, Cathedral Cave contains Australia's stratigraphically deepest sequence of fossil‐bearing infill sediments, the age and depositional history of which has been poorly understood. Here we present results from a new excavation of the upper 4.2 m of the deposit, reanalysing the stratigraphy, petrography, sedimentology and geochemistry, and employing optically stimulated luminescence dating, radiocarbon dating and Bayesian age modelling to establish a robust chronology. We recognise 13 sedimentary layers and sublayers in two stratigraphic units. Unit 2 accumulated between 72 000 ± 5000 and 38 000 ± 7000 years ago as sediments and animals entered through a now‐blocked ceiling hole. Accumulation halted for around 30 000 years when the hole closed. Unit 1 accumulated when deposition was reinitiated around 7000 ± 2000 years ago, continuing through to a few hundred years ago. Our chronology refutes earlier dating of the deposit, which suggested that extinct Pleistocene megafauna taxa persisted locally until the Last Glacial Maximum. It confirms the deposit as one of the few in Australia that formed during the interval of major environmental upheaval marked by the arrival of humans, variable climate and the extinction of many megafaunal species.

Overlapping Histories: A Stratigraphical Approach to the Walls of Theban Tomb 123 (Luxor, Egypt)

ABSTRACT Currently, the walls of the Theban Tomb 123 (Luxor, Egypt) are the result and evidence of diverse histories developed over a span of 3400 years. They encapsulate, as overlapping layers, material and intangible transformations that reveal multiple uses, meanings, and ontologies which converged in the necropolis of Thebes. At this tomb, originally built for a scribe named Amenemhet, a detailed study of the stratigraphic matrix of one of the walls was undertaken. Forty-eight stratigraphic units have been documented and arranged in a Harris matrix through an exhaustive survey of the macroscopic evidence about the historical changes on the wall. The analysis performed reveals the complexity of these spaces and their multiple occupations across thousands of years and sheds light on the unambiguous visions of these places regarded as pristine relics of the pharaonic past.

Spatial distribution of Mesozoic deposits and their temperature ranges within the Weser-Wiehengebirge Syncline of the inverted Lower Saxony Basin, Minden area, Germany

Abstract. The provision of climate-neutral, sustainable, and independent heat sources is an essential part of the ongoing transformation of heating systems in Germany. The city of Minden, located at the junction of the river Weser and the Middleland Canal, with its strong industrial sector, faces a massive transition of how heat and energy will be provided for industrial processes as well as heating in the commercial and residential sectors. In our study, we evaluate the structural requirements for the exploitation and utilization of deep geothermal energy from regional Mesozoic rocks, which are known to source thermal springs in the greater Minden area, and geothermal projects in other parts of the North German Basin. The compilation of geological data, seismic data, and rock properties from wells is used to construct a regional structural model as well as temperature distributions based on depth uncertainties of the respective stratigraphic units. Our investigations indicate several stratigraphic units ranging from the Middle Jurassic, Keuper, and Muschelkalk to the Middle Bunter at depths greater than 4100 m below mean sea level with suitable temperatures greater than 150 ∘C. Seismic data reveal the presence of faults, which may act as a conduit for thermal waters in the northern part of Minden. Our study also provides a basis for further geothermal exploration and exploitation south of Minden, where an operating geothermal system has already been established in the city of Osnabrück and further north, where the potential reservoirs are located at greater depths as shown by hydrocarbon exploration data. First estimations of the geothermal power output for two selected reservoir horizons yield up to 11.3 and 14.3 MW (10 % probability to yield these or higher values), respectively. We conclude that the subsurface of the inverted part of the Lower Saxony Basin principally fulfills the requirements (formation temperatures) for deep geothermal production not only for residential and commercial use but also for industrial processes. However, future detailed reservoir analyses and thermo-hydraulic investigations on a regional scale require additional exploration work like newly acquired seismic surveys and deep exploration wells.

A Cepstral Technique for Unmasking Vital Sub-Seismic Stratigraphic Details Embedded in Dense 3D Seismic Data from Niger Delta

Seismic visibility is enhanced through the change of the seismic data outlook from the standard amplitude measurement to a new domain in order separate fact from artifact in seismic processing and interpretation. General seismic data interpretation involves direct fault and horizon mapping, sequence stratigraphy and seismic modeling to produce structural, stratigraphic and reservoir maps for the delineation, exploration and production of hydrocarbon in oil fields. These methods operate on stacked and migrated data and without adequate calibration. Besides, final stacks are inadequately displayed, processing is coarse and in time domain. Actual hydrocarbon entrapments are rarely detailed well enough to permit reliable location of wells from these studies alone owing to noise. This paper presents the results of the application of Cepstral transform (CT) in the interpretation of the 3D seismic data in the Niger Delta. The aim of the study was to develop a robust technique for mapping subtle stratigraphic units which are usually masked during normal data interpretation using Cepstral algorithm. The Cepstrum is the Fourier transform of the log of the spectrum of the data. The transform filters the field data recorded in time domain, and recovers lost sub-seismic geologic information in quefrency domain. Cepstral domain analysis separates source and transmission path effects. The algorithm is based on fast Fourier transform technique and was developed within Matlab software. The results of the Cepstral decomposition yielded gamnitude, saphe and quefrency maps of the reservoir and revealed sub-seismic faults, differences in lithology and better reservoir delineation and delimitation.

Magnetostratigraphy of the Oligocene and Miocene of the Linxia Basin, northwestern China

The Cenozoic biochronology framework for northern China has been based on few vertebrate fossil localities with unverified age constraints. The Linxia Basin, located on the northeastern margin of the Qinghai-Tibetan Plateau, northwestern China, preserves thick, successive terrestrial sequences with an enormous quantity of vertebrate fossils of ages spanning the Late Oligocene to Early Pleistocene. This record has bearing on the definition of Cenozoic mammalian biochronology of North China, and its better dating. However, our understanding of detailed mammalian evolution and infilling history of the Linxia Basin has been hampered by poor age constraints and disagreement with new paleontological findings. To clarify the age range of the fluvial-lacustrine deposits and their faunas in the lower part of the succession, we present here a revised magnetostratigraphy and its chronology obtained from three well-correlated and overlapping sections in the eastern Linxia Basin. Magnetite and hematite were identified as the main ChRM (characteristic remanent magnetization) carriers in the sediments. Reliable specimens from 1142 sampled layers representing a total thickness of 484.4 m from the three sections yielded 28 normal and 23 reversed polarities. With the aid of updated biochronological constraints, the fluvial-lacustrine sequence of five stratigraphic units (Tala, Jiaozigou, Shangzhuang, Dongxiang, and Liushu/Hujialiang formations), was successfully correlated to chrons of the GPTS (geomagnetic polarity timescale). These represent the top of Chron C13r (ca. 33.8 Ma) to lower Chron C5n.2n (ca. 10.8 Ma). The recalibrated basin-infilling history shows response to episodic growth of topographic highs during these time intervals. Moreover, this new age model yields an estimated age of ca. 27 Ma (within Chron C9n of early Late Oligocene) for the paracerathere fauna from the eastern Linxia Basin, which is in accordance with other biochronological findings. The new age estimate for the paracerathere fauna supports a proposal for relocating the basal boundary of the Chinese Tabenbulukian Land Mammal Stage/Age to Chron C9r.

Carnivores from the late Pleistocene locality Melitzia Cave (Mani peninsula, Greece)

ABSTRACT Mani peninsula is considered an important region for the Palaeolithic research of Greece. A considerable number of sites have been excavated to date, containing deposits with cultural remains from the Middle Palaeolithic, the Upper Palaeolithic, and the Neolithic period. Melitzia Cave is a cave locality filled with Upper Pleistocene deposits, yielding in the upper stratigraphic units fossil remains of numerous large mammals and small vertebrates along with cultural remains, indicating that the cave was inhabited by both humans and carnivores. The layers date to the Upper Pleistocene, and more specifically between 46,448–44,553 BP and 11,150–10,680 BP. The present study focuses on the recovered carnivore assemblage of Melitzia Cave, which has revealed the presence of Crocuta spelaea, Vulpes vulpes, Felis silvestris, Meles meles, Mustela nivalis, Martes sp., ?Ursus sp., and Carnivora indet., described in detail herein. This species composition is typical for the late Pleistocene of Southeastern Europe.

From pilot knowledge via integrated reservoir characterization to utilization perspectives of deep geothermal reservoirs: the 3D model of Groß Schönebeck (North German Basin)

The Groß Schönebeck site in the North German Basin serves as research platform to study the geothermal potential of deeply buried Permian reservoir rocks and the technical feasibility of heat extraction. The structural setting of the site was investigated in more detail by a newly acquired 3D-seismic survey to improve the former conceptual model that was based on several old 2D seismic lines. The new data allow a revision of the geological interpretation, enabling the setup of a new reservoir model and providing base information for a possible further site development of Permo-Carboniferous targets. The 3D seismic allows for the first time a consistent geological interpretation and model parameterization of the well-studied geothermal site. Main reflector horizons and the corresponding stratigraphic units were mapped and the structural pattern of the subsurface presented in the 8 km × 8 km × 4 km large seismic volume. Attribute analysis revealed some fracture and fault patterns in the upper Zechstein and post-Permian units, while formerly hypothesized large offset faults are not present in the Rotliegend reservoir. However, a well-established graben-like structure at the top of the Zechstein succession is most likely related to broken anhydritic brittle intra-salt layers of some meter of thickness. Most reflectors above the salt show a rather undisturbed pattern. The main reservoir sandstone of the Dethlingen Formation (Rotliegend) was mapped and characterized. The base of the underlying Permo-Carboniferous volcanic rock sequence and hence its thickness could not be depicted reliably from the geophysical data. Based on the seismic data and the available reconnaissance drilling, logging, and laboratory data of the Groß Schönebeck research site, the thickness and distribution of the sedimentary Rotliegend (with emphasis of the sandy reservoir section) and of the volcanic rock sequence was modelled and stochastically parameterized with petrophysical properties guided by seismic facies pattern correlation, providing a more realistic reservoir description. Properties include total and effective porosity, permeability, bulk density, thermal conductivity, thermal diffusivity, and specific heat capacity. The data and interpretation constitute the basis for a better understanding of the thermo and hydromechanical processes at the site and for future measures. Further site development could include a deepening of one well to provide evidence on the volcanic rock sequence and consider deviated wells into favourable zones and the design of a fracture-dominated utilization approach.

Building a silicic effusive volcano: Geology, structure, and tectonics of Monte Amiata (Middle Pleistocene, Italy)

Monte Amiata (305–231 ka; Italy) is an uncommon example of completely effusive silicic (trachydacite) composite volcano. We applied the Unconformity Bounded Stratigraphic Unit criteria, volcanic facies analysis, and structural analysis to decipher its geological evolution and structure, and to infer the relations between regional tectonics and the shallow plumbing structure. Based on the occurrence of a first-order geological unconformity representing a paleoweathering surface of paleoclimatic significance, we recognize two major volcanic stratigraphic units and seven phases of activity. Monte Amiata emplaced in the releasing step-over of a large NE-SW striking oblique shear zone, which (a) favored the emplacement at 5–6 km depth of a silicic intrusion during Pliocene, (b) promoted the rising of deeper mafic magmas and the formation of an apical dike-rift zone during Pleistocene, and (c) accounts for the effusive eruptions of degassed magmas and the growth of the volcano.

Prehistoric Mining Data: How to create Open Data from archaeological research for the ARIADNE community and beyond

Making archaeological data available for the scientific community received a major boost through the ARIADNE Infrastructure projects that began in 2013. The purpose of this article is to present a methodology for converting excavation and field survey documentation from its original source into a format that corresponds to the FAIR principles and commits to the ARIADNE guidelines, with the ultimate goal to make the data publicly available and incorporating them into the ARIADNE portal. The methodology is illustrated by excavation and field survey reports that have been created according to the requirements of the Austrian Federal Monuments Office and document the archaeological investigations undertaken in the project 'Prehistoric copper production in the eastern and central Alps'. These were further processed in an Open Research Data pilot project, which initiated the development of the methodology. This consists of a pipeline to convert excavation and field survey reports to lasting file formats and extract information on sites, archaeological structures, stratigraphic units and finds from the reports to create CIDOC CRM encoded RDF data. The goal of the pipeline is to lower the entry threshold for creating such data by making data entry easy, using spreadsheets and applying easy to install and open-source (at least freely available) tools. All components of the pipeline are freely available, and detailed documentation with installation instructions and sample data can be downloaded for those who wish to test the methodology and try it out using their own data.