Hasil untuk "Stratigraphy"

Andreev Konstantin M. , Andreeva Olga V., Burygin Maxim A. et al.

The paper deals with the results of study of the Chernovka I campsite located in the Sergiyevsk district, Samara region. The topography of site, the history of its study, information about stratigraphy and planigraphy of archaeological material location are considered. The characteristics of pottery assemblage of site and technology of pottery making are discussed. The detail description of the stone inventory and the main types of tools are presented. It characterizes the identified objects and burials studied within the excavation site. The materials from the site can be divided into several cultural-chronological groups, marking short-term phases of anthropogenic activity. The earliest is associated with the Mesolithic period and dates back to the beginning of the second quarter of the VIII millennium BC. Most of the morphologically marked tools, primarily the asymmetric trapezoid, find direct analogies in assemblages of the Yangelka culture from the Southern Trans-Urals. The next episode of visitation at the campsite dates back to the end of the second quarter of the VI millennium BC and records the economic activity of Neolithic groups there. Equally short-term was the presence at the site of bearers of the Early Eneolithic Khvalynsk culture. Another rather expressive group of artifacts may be associated with the late Eneolithic (Chekalino-type ceramics). Finally, the site was visited episodically in the late Bronze Age and the late Middle Ages; two burials are associated with this last phase.

Zlatozar Boev

A first attempt has been made to systematically present the achievements of several archaeozoological fields in Bulgaria: archaeomalacology, archaeoichthyology, archaeoherpetology, archaeornithology, and archaeomammalogy. The main results and some of the more significant studies in each of these fields are presented. In summary, archaeozoological studies began in the first decade of the 20th century. A list of established authors of archaeozoological publications in Bulgaria has been compiled. Of the identified species, four species of birds and six species of mammals have disappeared from the modern fauna of the country. Two species have completely disappeared globally.

Miklós Kázmér, Petra Jamšek Rupnik, Krzysztof Gaidzik

Searching for unknown earthquakes in Slovenia in the first millennium, we performed archaeoseismological analysis of Roman settlements. The <i>Mesto pod mestom</i> museum in Celje exhibits a paved Roman road, which suffered severe deformation. Built on fine gravel and sand from the Savinja River, the road displays a bulge and trench, pop-up structures, and pavement slabs tilted up to 40°. The city wall was built over the deformed road in Late Roman times, supported by a foundation containing recycled material (<i>spolia</i>) from public buildings, including an emperor’s statue. We hypothesize that a severe earthquake hit the town before 350 AD, causing widespread destruction. Seismic-induced liquefaction caused differential subsidence, deforming the road. One of the nearby faults from the strike-slip Periadriatic fault system was the seismic source of this event.

T. J. Dunai, S. A. Binnie, A. Gerdes

<p>Analysis of cosmogenic nuclides produced in surface rocks and sediments is a valuable tool for assessing the rates of processes and the timing of events that shaped the Earth surface. The various nuclides that are used have specific advantages and limitations that depend on the time range over which they are useful, the type of material they are produced in and not least the feasibility of the analytical effort. Anticipating novel applications in Earth surface sciences, we develop in situ-produced terrestrial cosmogenic krypton (Kr<span class="inline-formula">_it</span>) as a new tool, the motivation being the availability of six stable and one radioactive isotope (<span class="inline-formula">⁸¹</span>Kr, half-life 229 kyr) and of an extremely weathering-resistant target mineral (zircon). We provide proof of principle that terrestrial Kr<span class="inline-formula">_it</span> can be quantified and used to unravel Earth surface processes.</p>

Antonio Jorge Campos Magalhães, Daniel Galvão Carnier Fragoso, Guilherme Pederneiras Raja Gabaglia et al.

Abstract Sequence stratigraphy is a method that unravels the evolution of sedimentation through time and space within sedimentary basins. Nowadays, the exploration and production of natural resources generated by or related to sedimentary processes depend on constructing a chronostratigraphic framework to identify sequences of distinct hierarchies. In clastic and carbonate successions, exploratory studies focus on higher-rank sequences to evaluate the potential of natural resources and to make discoveries. Conversely, lower-rank (i.e. high-frequency) sequences characterize and highlight the spatial and temporal occurrence of natural resource deposits and heterogeneities, necessary for optimizing production. For instance, high-resolution sequence stratigraphic surfaces may indicate the location of placer deposits or coal seams. In the petroleum industry, high-resolution sequence stratigraphy is applied in reservoir zonation and characterization, which are the stratigraphic essence of 3D geological and fluid flow models. Thus, this methodology can guide reservoir management, forecast and optimize production, and increase the ultimate recovery factor. Recent technological innovations such as virtual outcrop models and Ground Penetration Radar have promoted a significant advance in the visualization of surfaces and stacking patterns, making stratigraphic analysis more accurate and efficient than the traditional use of analogs.

C. Aichholzer, Ph. Duringer, A. Genter

Abstract In the 1950s, a petroleum well in Soultz-sous-Forêts (no 4589; Upper Rhine Graben, France) reached the Lettenkohle (Triassic) at 830 m depth. During the exploration phase at Soultz-sous-Forêts, the first enhanced geothermal system pilot project in the world, the well was core-deepened up to 2227 m into the granitic basement (then renamed EPS-1). The objectives of this deeper well were (i) to explore the granitic fractured reservoir and (ii) provide a precise geological characterization of the Soultz-sous-Forêts horst. This paper presents the first complete core analysis of the sedimentary formations observed in the EPS-1 cores (from the middle Muschelkalk to the Permian) in conjunction with the gamma-ray log description and field works. The detailed descriptions of the geological formations encountered in the well are presented with photo boards displaying the most characteristic facies of each formation, since the wells are rarely cored, especially in the Muschelkalk. This study also aims to describe the gamma-ray log to provide a strong baseline for future geothermal well exploration in this area (or old well reinterpretations). At this time, it is the only available reference for the complete section: Muschelkalk to Permian sedimentary formations.

Jun-Long Liu, Wei Yin, You-Liang Ji et al.

Abstract The Middle Jurassic Shaximiao Formation encompasses tens of meters of thick lowstand meandering valley (LMV) strata in the western Sichuan foreland basin. Ancient LMVs newly discovered in this area were further studied based on sequence stratigraphy and seismic sedimentology. The aim of the present study was to investigate the sedimentary characteristics, sequence architecture, and the controls on LMV deposition in this tectonically active basin using field survey data, seismic sections, seismic amplitude imaging, core description, and comprehensive application of drilling data. The results show the following: (1) Three regional sequence boundaries and two flooding surfaces were recognized, and the Shaximiao Formation was divided into two-third-order sequences and four systems tracts. (2) Three sedimentary facies associations were identified: incised valley-fill, tributary channel, and overbank facies. Incised valleys are 5–17 km wide, 20–60 m deep and traceable for 120 km along their axes. (3) In the downstream segment, the role of tectonism gradually diminishes, and periodic base-level changes control the form and evolution of the incised valleys. Three types of LMVs—A1, A2, and A3—developed with changes in base level (lake level); of these types, the base level of the A3 LMV was likely the lowest.

Stefano Cremonini

The main duties of the geologist’s contribution to the field work in the archaeological excavation sites are briefly recalled. The need for a preliminary conceptual and pragmatic approach for a correct understanding of the local context of each field campaign is stressed. Furthermore, as an example of the importance of the stratigraphic understanding in “delayed” field-microenvironment, a microstratigraphic sequence is proposed concerning the sedimentation that can occur in some ancient grave-coffin in an open alluvial environment and the problems related to the processes involved in such a restricted environment. Finally some peculiar, unusual study-settings are shown that may bring about mistakes or misunderstanding of the stratigraphic themes and therefore can be of interest for both the soil scientists and archaeologists as well as for geologists.

Goldina Rimma D. , Bernts Veronika A.

The article focuses on the chronology of graves dating back to the early (1st – 2nd centuries AD) – Nyrgynda stage of the 1st – 5th century Tarasovo burial ground, a classical monument attributed to the Cheganda culture of the Pyany Bor cultural-historical community. Cultural stratigraphy is applied as a research method. Artifacts from the early stage were correlated for 37 male and 102 female complexes, separately. The analysis of grave goods from male burials showed the following three chronological groups, that can be distinguished at the Nyrgynda stage: 1st century (group 1), 2nd century (group 2) and 1st – 2nd centuries AD (group 3). The goods from female graves are more representative and various, so three more groups with shorter chronological lives can be singled out: the fi rst half of the 2nd century (group 2а), the second half of the 2nd century (group 2б) and the 1st – fi rst half of the 2nd century (group 4). Certainly, the suggested chronology leaves room for any eventual corrections subject to new findings.

Gregor Kovačič, Špela Habič

Prispevek obravnava značilnosti 17 kraških presihajočih jezer Zgornje Pivke. V času dolgotrajnega deževja v novembru 2000, ko je izmerjena količina dežja več kot trikrat presegala povprečno mesečno količino padavin, se je voda, po več desetletjih, pojavila v vseh jezerih. Izjemoma so bile poplavljene tudi številne druge manjše kraške globeli, kjer ojezeritve še niso bile dokumentirane. S pomočjo terenskih meritev in interpretacijo letalskih posnetkov so bili izmerjeni vodostaji in površine jezer ter prostornina vode v njih.   The article presents the characteristics of the 17 intermittent karst lakes of Upper Pivka. During the extended precipitation in November 2000, when the amount of precipitation was more than three times the average, all the lakes were flooded for the first time in several decades. Also several additional small karst depressions were flooded, where overflowing had never been recorded before. By combining field observations with the interpretation of aerial photographs the water level, the extent of the lakes and the volumes of containing water were calculated.

Larry G. Marshalli, R. Hoffstetter, R. Pascual et al.

M. Clarke

Jalil Jafari, Asadollah Mahboubi, Mohammad Khanehbad et al.

The Oligo- Miocene Asmari Formation is one of the most important reservoir units of the Marun Oilfield in Dezful Embayment SW Iran, deposited in Zagros foreland basin. The goal of this study is to interpret depositional environment and sequence stratigraphy of lower zones of the Asmari Formation in Well No.281, 342 and 312in Marun Oilfield based on changes in the shape of γ- Ray, isolith maps and microfacies properties. Accordingly, identification of 9 carbonate microfacies and 2 siliciclastic petrofacies were identified that are deposited in four depositional environment including open marine, barrier, lagoon and tidal flat in a homoclinal ramp (consisting of outer, middle and inner ramp). Also, based on the shape of γ- Ray log, There sediment were deposited in marine environment. In open marine and barrier environments, The shape of γ- Ray log is serrated bell-shaped, serrated funnel-shaped, left bow-shaped, serrated shape and right boxcar shape, Whole in the beach environment it is cylinder and funnel shape and in lagoon and tidal flat environment can be seen on right bow to cylinder-shaped. Based on the isolith maps, sandstone of lower zones of the Asmari Formation in Marun Oilfield expanded by deltaic system along the southwestern margin of the basin and influenced by changes in sea level constantly. Sequence stratigraphic analysis led to identification of three third- order (DS1, DS2 and DS3) depositional sequences.

Azadeh Bordbar, Mehdi Najafi, Mohammad nabi Gorgij

  Introduction   The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001) stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1) describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2) interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3) dividing the section based on lithostratigraphic principles and (4) recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.       Material and Method   The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68) were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962) and Embry and Klovan (1971) for carbonate rocks and for samples descriptions from Flugel (2004) and Wilson (1974) methods were used.     Discussion of Results and Conclusions   The Basiran section predominantly composed of limestone - marl in the middle and upper part and conglomerate – sandstone in the lower part. The most prominent component of carbonate sediments are larger foraminifera such as Orbitoides, Lepidorbitiodes, Siderolites, Omphalocyclus and some of pelagic foraminiferas. Systematic determination of those benthic foraminiferas suggests Late Campanian-Maastrichtian age for Basiran section. Microfacies analysis led to the   Recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. With respect to gradual shallow water facies changes, absence of barrier reef, sliding and slumping structure, cortoids, oncoids, pisoids and aggregate grains, that are abundant in rimmed shelves, several evidences shows that above mentioned carbonate are deposited in the ramp environment (Burchette & Wright 1992) . Furthermore, based on high diversity and abundance of benthose foraminiferas this environment can be considered as foram dominated carbonate ramp system ( Boxton & Pedley 1989 ) . Based on field observation, microfacies analysis and sequence stratigraphic studies, fourth third order depositional sequence (DS) in the Basiran section are identified. These depositional sequences are separated by type1 sequence boundary (lower boundary of first depositional sequence and upper boundary of fourth depositional sequence) and type 2 sequence boundary (lower boundary of 2 nd and 3 rd depositional sequence). First depositional sequence consists of LST, TST and HST and contains tidal flat, lagoon, shoal, shallow open marine and deep open marine microfacies. Lower boundary is of type 1 sequence boundary (SB1). 2 nd and 3 rd depositional sequences consist of TST and HST. Therefore contains shallow open marine and shoal microfacies and have been separated by sequence boundary type 2 (SB2). Fourth depositional sequence contains of TST and HST. Upper boundary is of type 1 sequence boundary (SB1) and terminates to with clear unconformities to Paleocene conglomerate. It is seems that both local tectonic activity and global eustasy may have controlled the third and forth order sequences and cyclicities of the Upper Cretaceous sediments in Basiran section. The SB1 in the top of the fourth depositional sequence ,which shows subaerially exposed the carbonate platform, possibly related to the widespread glacio-eustasy sea-level drop could be linked to the cooling event in the Cretaceous-Tertiary boundary(KTB). Â

T. Hergert, O. Heidbach, K. Reiter et al.

The stress field at depth is a relevant parameter for the design of subsurface constructions and reservoir management. Yet the distortion of the regional stress field due to local-scale features such as sedimentary and tectonic structures or topography is often poorly constrained. We conduct a stress sensitivity analysis using 3-D numerical geomechanical modelling with an elasto-plastic material law to explore the impact of such site-specific features on the stress field in a sedimentary sequence of the Swiss Alpine foreland. The model's dimensions are 14 × 14 × 3 km³ and it contains 10 units with different mechanical properties, intersected by two regional fault zones. An initial stress state is established involving a semi-empirical relationship between the ratio of horizontal to vertical stress and the overconsolidation ratio of argillaceous sediments. The model results indicate that local topography can affect the stress field significantly to depths greater than the relief contrasts at the surface, especially in conjunction with horizontal tectonic loading. The complexity and frictional properties of faults are also relevant. The greatest variability of the stress field arises across the different sedimentary units. Stress magnitudes and stress anisotropy are much larger in stiffer formations such as massive limestones than in softer argillaceous formations. The stiffer formations essentially carry the load of the far-field forces and are therefore more sensitive to changes of the boundary conditions. This general characteristic of stress distribution in the stiff and soft formations is broadly maintained also with progressive loading towards the plastic limit. The stress field in argillaceous sediments within a stack of formations with strongly contrasting mechanical properties like in the Alpine foreland appears to be relatively insensitive to changes in the tectonic boundary conditions and is largely controlled by the maximum stiffness contrast with respect to the load-bearing formations.

G. Kocurek, K. Havholm

T. Jerzykiewicz, D. Russell

Cemile Solak, Kemal Taslı, Sacit Özer