Abstract In-situ stress plays a pivotal role in influencing the desorption, adsorption, and transportation of coalbed methane. The reservoir gas content represents a pivotal physical parameter, encapsulating both the coalbed methane enrichment capacity and the underlying enrichment law of the reservoir. This investigation collates, computes, and consolidates data concerning pore pressure, breakdown pressure, closure pressure, triaxial principal stress, gas content, lateral pressure coefficient, and other pertinent variables from coal reservoirs within several coal-bearing synclines in the Liupanshui coalfield, China. This study elucidates the characteristics of longitudinal stress development in the study area, the gas content of the longitudinal reservoirs and their interrelationships. The study area is situated within the middle-high stress zone, exhibiting discernible evolution patterns from reverse fault mechanism to strike-slip fault mechanism to normal fault mechanism, progressing from shallow to deep. In the deeper stratigraphy, a strike-slip-normal fault mechanism emerges. The relationship between burial depth and triaxial principal stress is subjected to linear regression, resulting in the proposal of a simplified model for vertical in-situ stress. The hyperbolic regression algorithm was employed in order to derive both the envelope and median formulas for lateral pressure coefficient (k values). The k value displays discrete behavior along the vertical axis in shallow depths, gradually converging in deeper strata and ultimately stabilising at approximately 0.65 with increasing depth. A comprehensive examination of the k value substantiates the efficacy of the simplified in-situ stress model along the vertical axis, offering profound insights into the vertical interrelationships and evolving patterns of the triaxial principal stresses. The mean gas content in the study area was found to be 11.89 m³/t, exhibiting a general increase in depth, followed by a subsequent decrease. The pore pressure (P p) displays a discernible positive correlation with gas content. This study comprehensively elucidates the developmental patterns of the stress field, the simplified model of vertical in-situ stress, the attributes of the stress ratio (K H, k h, lateral pressure coefficient k), the characteristics of reservoir gas content, and the corresponding and transformative relationships between coupled geostress field parameters and gas content. The lateral pressure coefficient conversion depth, in-situ stress conversion depth, and gas inversion depth are delineated, accompanied by a detailed exposition of their definition process, physical significance, and interrelations. Within the study area, the lateral pressure coefficient conversion depth is estimated to range between 450 and 500 m, while the critical depth for in-situ stress conversion is approximately 670 m. Moreover, the critical depth for gas content conversion falls within the range of 700–800 m. It is noteworthy that the critical depth for deep coalbed methane within the Liupanshui coalfield has been identified as approximately 800 m. Subsequently, a vertical “in-situ stress-gas content mode” relationship model for coalbed methane development was formulated, thereby providing a structured framework for understanding the dynamic interactions between vertical in-situ stress and gas content.
ABSTRACT Band pressure operation has become the main way of oil and gas well workover in the world, to solve the gel breaking problem in the gel plugging pressure technology, acrylamide and ester‐based cross‐linking agent UCL‐1 were used to synthesize a self‐degradable gel that can be used at 40°C–60°C by the one‐pot method. The cross‐linking reaction principle of the gel was analyzed by infrared spectroscopy; in addition, the degradation performance of the gel and the effects of acrylamide, UCL‐1, initiator and metal ions on the degradation performance of the gel as well as the influence law were investigated; finally, sand‐filled tubing and casing were used to simulate the stratigraphy and the wellbore, respectively, thus evaluating the sealing performance of the gel. The results showed that the cross‐linking reaction of the gel was a double‐bond copolymerization reaction; the viscosity of the gel after complete degradation in the range of 40°C–60°C was 51–450 mPa‐s, and the degradation time was 115–220 h, and the degradation time of the gel could be adjusted by changing the formulation components and the mineralization degree; moreover, the pressure‐bearing capacity of the gel in the formation at 40°C–60°C was 8.5–14.9 MPa, and the pressure‐bearing capacity of gel in wellbore is 52–73 kPa, and the blocking time is 3–6 d, which meets the construction time requirement of pressurized operation. This study extends the breaking method of gel plugging pressure technology and further promotes the development and application of pressure work technology.
Mathieu Langlais, Anthony Sécher, Guilhem Constans
et al.
The Combe-Cullier site (Lacave, Lot) is one of the few sites with a Magdalenian archaeosequence investigated using modern excavation methods. Its exceptional archaeological fill covers the entire Magdalenian period between 21,000 and 14,000 cal. BP. The cave was excavated in the early 20th century under the aegis of A. Viré, yielding remains of occupations for which no contextual data are available. Then, at the end of the 1960s, J.-F. Flies began a new operation on the slope in front of the cave, and carried out meticulous excavations using modern methodology until the mid-1970s. Most of the artefacts unearthed in the nearly five-metre-thick stratigraphic sequence are still unpublished to this day. Following academic work on elements of this collection, a multidisciplinary team was formed to re-examine all the remains in a revised chronostratigraphic framework. The results of this work are presented here by archaeostratigraphic unit (AU) and according to the different analysed artefacts (siliceous materials, bone industry, adornments, fauna). It is thus possible to track evolution at the site over nearly 7,000 years, highlighting continuities and changes. A comparison of the results obtained at Combe-Cullier with other sites in south-western France backs up the recent proposal for a new evolutionary scenario for the Aquitaine Magdalenian.
Ifeanyichukwu S. Obi, K. Mosto Onuoha, Chidozie I. Princeton Dim
The utilization of sequence stratigraphic concepts in identifying sands and their spatial continuity in distinct gross depositional settings is key, especially in frontier settings where data paucity is a common challenge. In the Baka field, onshore Niger Delta, detailed reservoir correlation guided by sequence stratigraphic framework analysis showed the distribution of sand and shale units constituting reservoir-seal pairs (RSP) correlatable across the field. Within the 3rd-order packages, it is observed that the lowstand systems tract (LST) and highstand systems tract (HST) contain more RSPs and thicker 4th- and 5th-order sands than the transgressive systems tract (TST). In terms of bathymetry, it is noted that irrespective of systems tracts, the RSP Index (RI) decreases from the proximal shallow/inner shelf settings to the more distal outer shelf areas. Amongst all three systems tracts, intervals interpreted as lowstand prograding complexes contain the best developed sands and highest RSP. Sand development within the LSTs has been controlled by a pronounced growth fault regime accompanied by high subsidence and sedimentation rates. This is linked to the basinward migration of the sands during prolonged sea-level fall, creating significant accommodation space for sand deposition. On the other hand, the TSTs known to mark periods of progressive sea-level rise and landward migration of sandy facies, show thinner sands enclosed in much thicker, laterally extensive, and better-preserved deeper marine shales. Interpreted seismic sections indicate intense growth faulting and channelization that influenced the syn- and post-depositional development of the sand packages across the field. The initial timing of deformation of sub-regional faults in this area coincides with periods of abrupt falls in sea level. This approach could be useful for predicting sand-prone areas in frontier fields as well as possible reservoir-seal parameters required for some aspects of petroleum system analysis and quick-look volume estimation.
Production of electric energy or power. Powerplants. Central stations
J. M. G. Stine, J. M. G. Stine, J. M. Feinberg
et al.
<p>The upper Paleozoic Cutler Group of southern Utah, USA, is a key sedimentary archive for understanding the Earth-life effects of the planet's last pre-Quaternary icehouse–hothouse state change: the Carboniferous–Permian (C–P) transition, between 304 and 290 million years ago. Within the near-paleoequatorial Cutler Group, this transition corresponds to a large-scale aridification trend, loss of aquatic habitats, and ecological shifts toward more terrestrial biota as recorded by its fossil assemblages. However, fundamental questions persist. (1) Did continental drift or shorter-term changes in glacio-eustasy, potentially driven by orbital (Milankovitch) cycles, influence environmental change at near-equatorial latitudes during the C–P climatic transition? (2) What influence did the C–P climatic transition have on the evolution of terrestrial ecosystems and on the diversity and trophic structures of terrestrial vertebrate communities?</p>
<p><span id="page110"/>The Paleozoic Equatorial Records of Melting Ice Ages (PERMIA) project seeks to resolve these issues in part by studying the Elk Ridge no. 1 (ER-1) core, complemented by outcrop studies. This legacy core, collected in 1981 within what is now Bears Ears National Monument, recovered a significant portion of the Hermosa Group and the overlying lower Cutler Group, making it an ideal archive for studying paleoenvironmental change during the C–P transition. As part of this project, the uppermost <span class="inline-formula">∼</span> 450 m of the core were temporarily transferred from the Austin Core Repository Center to the Continental Scientific Drilling Facility at the University of Minnesota for splitting, imaging, and scanning for geophysical properties and spectrophotometry. Here we (1) review the history of this legacy core, (2) introduce recently obtained geophysical and lithologic datasets based on newly split and imaged core segments to provide a sedimentological and stratigraphic overview of the Elk Ridge no. 1 core that aligns more accurately with the currently recognized regional lithostratigraphic framework, (3) establish the position of the boundary between the lower Cutler beds and the overlying Cedar Mesa Sandstone in the core, and (4) outline our ongoing research goals for the core.</p>
<p>In-progress work on the core aims to refine biostratigraphic and chemostratigraphic age constraints, retrieve the polarity stratigraphy, interrogate preserved cyclostratigraphy, analyze sedimentary structures and paleosol facies, investigate stable isotope geochemistry, and evaluate elemental abundance data from X-ray fluorescence (XRF) scanning. Together with outcrop studies throughout Bears Ears National Monument and its vicinity, these cores will allow the rich paleontological and paleoenvironmental archives recorded in the continental Carboniferous–Permian transition of western North America to be confidently placed in a robust chronologic context that will help test hypotheses relating ecosystem evolution to the Carboniferous rainforest collapse, initial decline of the Late Paleozoic Ice Age, and long-wavelength astronomical cycles pacing global environmental change.</p>
<p>Understanding the underlying mechanisms of strain localization in the Earth’s lithosphere is crucial for explaining the mechanics of tectonic plate boundaries and various failure-assisted geophysical phenomena, such as earthquakes. Geological field observations suggest that shear zones are the most important lithospheric structures demonstrating intense shear localization at plate boundaries, accommodating a major portion of tectonic deformations. Despite extensive studies over the past several decades, the factors governing how shear zones accommodate bulk shear, whether via distributed strain (i.e. the development of macroscopic S (schistosity) foliations normal to the principal shortening strain axis) or via localized shearing (i.e. the formation of shear-parallel C bands, where C refers to the French “cisaillement” (shear)), remain largely unexplored. This study aims to address this gap in knowledge by providing observational evidence of varying S and C development in crustal shear zones from two geological terrains in eastern India. These field observations are complemented by 2D viscoplastic numerical simulations within a strain-softening rheological framework to constrain the factors controlling two competing shear accommodation mechanisms: distributed strain accumulation and shear band formation. The model-based analysis recognizes the bulk shear rate <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>(</mo><msub><mover accent="true"><mi mathvariant="italic">γ</mi><mo mathvariant="normal">˙</mo></mover><mi mathvariant="normal">b</mi></msub><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="21pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="28d0c96574bcde5f5a559f93eb3f1999"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-15-1281-2024-ie00001.svg" width="21pt" height="13pt" src="se-15-1281-2024-ie00001.png"/></svg:svg></span></span>, initial viscosity (<span class="inline-formula"><i>η</i><sub>v</sub></span>), and initial cohesion (<span class="inline-formula"><i>C</i><sub>i</sub></span>) of a shear zone as the most critical factors determining the dominance of one mechanism over the other. For a given <span class="inline-formula"><i>C</i><sub>i</sub></span> value, low <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mover accent="true"><mi mathvariant="italic">γ</mi><mo mathvariant="normal">˙</mo></mover><mi mathvariant="normal">b</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="13pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="4644dd3d742379793344dfe157cb4220"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-15-1281-2024-ie00002.svg" width="13pt" height="13pt" src="se-15-1281-2024-ie00002.png"/></svg:svg></span></span> and <span class="inline-formula"><i>η</i><sub>v</sub></span> values facilitate the formation of S foliation (uniformly distributed strain), which transitions to a C-dominated shear accommodation mechanism as <span class="inline-formula"><i>η</i><sub>v</sub></span> increases. However, increasing <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mover accent="true"><mi mathvariant="italic">γ</mi><mo mathvariant="normal">˙</mo></mover><mi mathvariant="normal">b</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="13pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="db38185590a90eb3deb07c1663154ae5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-15-1281-2024-ie00003.svg" width="13pt" height="13pt" src="se-15-1281-2024-ie00003.png"/></svg:svg></span></span> facilitates shear accommodation through a combination of the two mechanisms, leading to S–C structures. The article finally discusses the conditions under which shear zones can significantly intensify rates of localized shear, producing rapid slip events, such as frictional melting and seismic activities.</p>
Saif Ullah, Mohammed Y. Ali, Muhammad A. Iqbal
et al.
Abstract The United Arab Emirates (UAE) is dependent on desalinated water and shallow aquifers to satisfy its freshwater requirements. Despite the paramount importance of understanding the depth and spatial extent of these aquifers, comprehensive investigations into the properties of these aquifers, as well as the underlying subsurface structures and stratigraphy, have been conspicuously lacking. This study presents the findings of integrated geophysical and borehole investigations conducted in the Al Jaww Plain, southeastern Al Ain, UAE, focusing on the properties of groundwater aquifers, the Semail ophiolite contact, and subsurface structures and stratigraphy. Through the analysis of groundwater borehole data, three interconnected types of groundwater aquifers have been identified, and characterized by their hydrogeological properties. The near-surface Quaternary unconfined aquifer, with an average thickness of 25 m, represents a fresh groundwater aquifer. The second aquifer, with an average thickness of 110 m, is connected to the upper Quaternary freshwater aquifer and is interpreted as part of the surficial aquifer system. The third aquifer has an average thickness of 200 m. By employing electrical resistivity tomography, the depth of the water table and groundwater potential in the shallow unconfined Quaternary aquifer near Jabal Mundassa have been estimated, aligning with the properties observed in the unconfined Quaternary aquifer across the entire Al Jaww Plain as depicted in the groundwater borehole cross section. In addition, this study provides insights into subsurface structures and stratigraphic features, revealing the westward extension of the Hawasina thrust sheet within the plain. Gravity and magnetic data analyses in the southeastern region of the Al Jaww Plain delineate the extent of the Semail ophiolite. Notably, magnetic data reveals the presence of an NW–SE-oriented magnetic anomaly detached from the main ophiolite thrust, which corresponds to the interpretation of the Semail ophiolite contact with sedimentary carbonate rocks on the Bouguer gravity map.
Ranko Biondić, Lucija Plantak, Ana-Maria Radovan
et al.
Numerous coastal karst springs of the Mediterranean region have problems with salinization. Salinization usually occurs during summer dry periods as a result of long droughts and excessive pumping for water supply. The Boljkovac water supply pumping station has slightly increased parameters that indicate the possibility of salinization during the dry summer periods, but the main salinization occurs post heavy rains which appear after long dry periods in the fall, winter, and spring. Due to the occasional occurrence of salinization, continuous monitoring of the aquifer by depth was set up at the piezometric well drilled near the water supply pumping station. The results of the monitoring were analyzed in relation to external factors that can negatively affect the disruption of the labile dynamic balance of salt and fresh water. The analyzed external factors are the pumping rate for the water supply, the amount of precipitation, surface flow and the interaction of surface water and groundwater, as well as the sea level changes. In Croatia, and the wider Mediterranean area, there are a large number of springs and water wells that have the same or similar problems, so the results of this analysis can be used in designing monitoring and setting up management systems for these coastal aquifers.
Duarte, Luís Vítor, Silva, Ricardo Louro, Azerêdo, Ana Cristina
et al.
An integrated stratigraphic analysis of the Coimbra Formation was performed in the S. Pedro de Moel outcrops of the Lusitanian Basin (Portugal). This unit is dated from the lower–upper (Oxynotum Chronozone) Sinemurian and is subdivided into eight informal subunits. Except for its base, consisting of dolostones and microbialites, much of the succession consists of bioclastic and bioturbated micritic centimetric–decimetric limestones (sometimes rich in benthic macrofauna) alternating with millimetric–centimetric marly layers, all deposited in shallow-water carbonate ramp environments. Organic-rich sediments occur throughout, with total organic carbon reaching up to 12 wt%. At a broader scale, the Coimbra Formation is transgressive and part of a long-lasting 2nd-order transgressive–regressive facies cycle ending around the Sinemurian–Pliensbachian boundary. The vertical variation of $\delta ^{13}\mathrm{C}$ determined in bulk carbonate is characterized by relatively normal marine values ($0$–$2.5‰$); however, several negative shifts are associated with the organic-rich sediments, with a maximum amplitude of ${\sim }8‰$ in the Obtusum Chronozone. These shifts in bulk carbonate $\delta ^{13}\mathrm{C}$ are interpreted to be of diagenetic origin and, therefore, of local significance. However, it cannot be discarded that a regional/global signal is imprinted on the observed trends.
This study employs the tool of sequence stratigraphy to evaluate Day Field, in the Onshore Niger Delta of Nigeria for hydrocarbon predictions using six (6) well logs displayed at standard scales to enhance log trends for lithologic and stratal package delineation. The identified key stratigraphic bounding surfaces were tied to well-defined palynological (P) zone and foraminiferal (F) zones with the aid of the biostratigraphic data and calibrated using the Niger Delta Chronostratigraphic chart. Five (5) MFSs (34.0, 33.0, 31.3, 28.1, and 26.2 Ma) and six (6) SBs (35.4, 33.3, 32.4, 29.3, 27.3, and 24.9 Ma) were delineated. The stratigraphic surfaces were matched with the palynological (P480– P580) and foraminiferal zones (P20/N1–P22/N3) encountered. The results indicate that the study area is of Late Eocene to Late Oligocene age (26.2–35.9 Ma). The key stratigraphic surfaces also reflect a series of relative sea-level falls (regressive episodes) and sea-level rises (transgressive episodes) that are regionally extensive and correlated across the wells. Five sequences (SEQ1–SEQ5) were recognized, SEQ1 and SEQ5 comprising three system tracts (LST, TST, and HST) revealing four third-order depositional sequences (classified as type 1 sequence), while SEQ2-SEQ4 comprises two system tracts (TST and HST). Two depositional environments were interpreted from the log trends; the Fluvial (shoreface) and Tidal environments. The hydrocarbon exploration prospects identified are the sand units of the LST and HST combining with the shale units of the TST offering good reservoir and seal/source rocks respectively.
Ruslan Suleymanov, Gulnara Obydennova, Andrey Kungurtsev
et al.
This paper presents the results of studying the soils at the archeological site of the Tyater-Araslanovo-II settlement located in the Republic of Bashkortostan, eastern European Russia. The settlement functioned in the 15th–12th centuries BCE (the Late Bronze Age). We compared the soil properties at four sites in the study area: archeological (1), buried (2), affected by long pyrogenic exposure (3), and background site (4). In soil samples, the total carbon content, the fractional composition of humus and organic matter characteristics, alkaline hydrolyzable nitrogen, total phosphorus, mobile phosphorus, potassium, absorbed calcium and magnesium, pH, particle size distribution, basal soil respiration, and optical density were estimated. The study results showed the anthropogenic impact on the archeological site’s soils. The newly formed AU horizon at the archeological site (1), affected by the cattle summer camp, was richer in soil nutrients and agrochemical properties, namely, the content of exchangeable and gross forms of phosphorus, alkaline hydrolyzable nitrogen, and exchange cations of the soil absorbing complex compared to the reference soil (4). For the pyrogenic layer (AU[hh]<sub>pyr</sub>) from the ancient furnace (fireplace) (3), the mobile and total forms of phosphorus were several times higher than those in the reference soil (4) but inferior regarding other agrochemical parameters. Thus, the activities of ancient people (especially cattle breeding) greatly influenced the properties of the soil.
J. E. Cunningham, J. E. Cunningham, N. Cardozo
et al.
<p>Five seismic interpretation experiments were conducted on an area of
interest containing a fault relay in the Snøhvit field, Barents Sea,
Norway, to understand how the interpretation method impacts the analysis of
fault and horizon morphologies, fault lengths, and throw. The resulting
horizon and fault interpretations from the least and most successful
interpretation methods were further analysed to understand their impact on
geological modelling and hydrocarbon volume calculation. Generally, the
least dense manual interpretation method of horizons (32 inlines and 32 crosslines; 32 ILs <span class="inline-formula">×</span> 32 XLs, 400 m) and faults (32 ILs, 400 m) resulted in inaccurate
fault and horizon interpretations and underdeveloped relay morphologies and
throw, which are inadequate for any detailed geological analysis. The
densest fault interpretations (4 ILs, 50 m) and 3D auto-tracked horizons (all
ILs and XLs spaced 12.5 m) provided the most detailed interpretations, most
developed relay and fault morphologies, and geologically realistic throw
distributions. Sparse interpretation grids generate significant issues in
the model itself, which make it geologically inaccurate and lead to
misunderstanding of the structural evolution of the relay. Despite
significant differences between the two models, the calculated in-place
petroleum reserves are broadly similar in the least and most dense
experiments. However, when considered at field scale, the differences in
volumes that are generated by the contrasting interpretation methodologies
clearly demonstrate the importance of applying accurate interpretation
strategies.</p>
The Chinese Chang'e-3 mission landed close to the eastern rim of the ~450 m diameter Ziwei crater. Regional stratigraphy of the landing site and impact excavation model suggest that the bulk continuous ejecta deposits of the Ziwei crater are composed by Erathothenian-aged mare basalts. Along the traverse of the Yutu rover, the western segment features a gentle topographic uplift (~0.5 m high over ~4 m), which is spatially connected with the structurally-uplifted crater rim. Assuming that this broad topographic uplift has physical properties discontinuous with materials below, we use data returned by the high-frequency lunar penetrating radar onboard the Yutu rover to estimate the possible range of relative permittivity for this topographic uplift. Only when the relative permittivity is ~9 is the observed radar reflection consistent with the observed topography, suggesting that the topographic uplift is composed of basaltic blocks that were excavated by the Ziwei crater. This result is consistent both with the impact excavation model that predicts deeper basaltic materials being deposited closer to the crater rim, and with observation of numerous half-buried boulders on the surface of this hill. We note that this study is the first to use topography and radargram data to estimate the relative permittivity of lunar surface uplifts, an approach that has had many successful applications on Mars. Similar approaches can apply other ground penetrating radar data for the Moon, such as will be available from the ongoing Chang'e-4 mission.
Trilobites achieved their maximum generic diversity in the Cambrian, but the peak of morphological disparity of their cranidia occurred in the Middle to Late Ordovician. Early to middle Cambrian trilobites with a specialized cephalon are rare, especially among the ptychoparioids, a group of libristomates featuring the so-called “generalized” bauplan. Here we describe an unusual ptychopariid trilobite Phantaspis auritus gen. et sp. nov. from the middle Cambrian (Miaolingian, Wuliuan) Mantou Formation in the Shandong Province, North China. This new taxon is characterized by a cephalon with an extended anterior area of double-lobate shape resembling a pair of rabbit ears in later ontogenetic stages; a unique type of cephalic specialization that has not been reported from other trilobites. Such a peculiar cephalon as in Phantaspis provides new insights into the variations of cephalic morphology in middle Cambrian trilobites, and may represent a heuristic example of ecological specialization to predation or an improved discoidal enrollment.
Editorial is a privilege of the editors to share their opinions and news with the readers. It’s been a while since the last editorial was published in Acta Carsologica. In the following, I present my opinion on some issues related to our work and publishing. It was provoked by the Opinion, written by Wolfgang Dreybrodt and published in this issue. We are all aware that the way we do and publish scientific work has been changing fast and dramatically. Rapid progress, broad and productive collaborations, ever better access to sophisticated research equipment, the need for publishing and the search for funds sometimes distract us from deep thinking on the research questions that should be the key element of scientific work. The somehow provoking Opinion opens up many concerns that we all face. It does not reflect the opinion of the editorial board, although I agree with most of them. At some point one might say that times have changed, we need to collaborate and promote our work in order to be seen. However, basic scientific ethics as stressed in the Opinion, should not suffer from the changes. One ethical question facing the editors is whether we should publish in our own journals. A principle answer would be no. Acta Carsologica has an inherent interest in the research at Classical Karst, where most of our editors work. Therefore, we publish in our journal, but we do not interfere into the editorial process of our manuscripts. In times when you have to pay either to read and/or publish a manuscript, new opportunities arise for journals like ours. These journals can attract authors who, for whatever reason, cannot or do not want to spend money on publication and want to keep their work open. However, authors and readers should be aware that publishing is not our main task and that it is difficult to offer such good services as in journals belonging to the large publishing groups. In addition to managing reviews and making decisions, the editors’ tasks often include providing funds for layout and printing, reporting, website maintenance, proofreading, translation, transport, packaging and dispatch of issues. Surely this should not be an excuse for the delays in publication or the long editorial process, but I hope for some understanding of those waiting. We can of course improve. The whole system of scientific publishing is dependent on the review process. The everlasting problem of this and other journals is to get reviewers and then the timely reviews. Looking at the number of publications processed at any time, even in a “narrow” field like ours, we can imagine how many reviewers are needed. Most potential reviewers are busy, active researchers who are aware of the importance of the reviews, but are unable to respond to the requests. If a review takes one day, how many reviews per year can one accept? And, when it comes to selection, why not do a review for a high-ranking journal in which you want to publish your own work. Journals like ours therefore depend on a strong community interested in ensuring that their research field vivid and recognised. Small focused journals provide such a platform. I am asking you all to consider your own role in the karst community and accept the review from our and other karst science journals. This will keep us well and alive, and your work published and seen as well.
Abstract The Pliocene climate is one of the best analogs for the climate of a globally warmer future. Here, we present a new Pliocene integrated chronostratigraphy from the Anno Formation in the uppermost Awa Group, which is distributed throughout the Boso Peninsula, central Japan, based on paleomagnetic and benthic foraminiferal oxygen isotope records. This new chronostratigraphy provides valuable constraints for paleoceanographic and paleoclimatic studies in the northwestern Pacific Ocean, where the number of paleoceanographic records is limited due to the lack of calcareous microfossils from deep-sea sediment cores, with the exception of some plateaus at water depths above the calcite compensation depth (CCD). Paleomagnetic results indicate that the Anno Formation corresponds to the period extending from the Nunivak normal polarity subchronozone (4.493–4.631 Ma) to Chron C2An.2n (3.116–3.207 Ma), which is just above the Mammoth reversed polarity subchronozone. Although foraminifera are not found in the middle Anno Formation, our oxygen isotope records from the upper and lower Anno Formation demonstrate the recording of glacial–interglacial cycles. However, the amplitude of our δ18O profile is much larger than that of the LR04 stack, with similar to slightly lower glacial values and much lower interglacial values. This observation implies that the bottom water had lower δ18O values and/or a warmer water mass during interglacials compared with global average deep-water regions.
The results of the palynological investigations of the Miocene sediments of the Tyulgan brown coal mine are summarized and discussed in this paper. Seven pollen complexes have been established according to the pollen analysis of the Tyulgan, Kuyurgaza, and Voroshilovka horizons (Cis-Uralian Superhorizon, Lower-Middle Miocene). The less informative pollen complexes have been discovered from the deposits of the Ushkatly horizon (Middle-Upper Miocene). Six sections of the Tyulgan brown coal mine have been stratified and correlated on the basis of the palynological data. New data on the vegetation evolution, main sources of coal, sedimentation, and climate changes of the Southern Urals during the Miocene have been obtained. It has been revealed that the Tyulgan time was characterized by the warmest (subtropical) climate when Taxodiaceae forests developed. During the Kuyurgaza time, the climate changed from cool to warm and back to cool at the end. The Voroshilovka time is characterized by warm climate conditions. In summary, vegetation of the studied area during the Miocene changed in the following way: 1) coniferous-broadleaved forest with significant participation of the subtropical elements; 2) mixed broadleaved forests, 3) coniferous forests with admixture of small- and broadleaved trees, 4) small-leaved forests and mixed small- and broadleaved forests with admixture of the subtropical elements. Two types of sediment accumulation conditions have been established – low swamps developed during the Tyulgan and Kuyurgaza time and transitional swamps that existed during the Voroshilovka time. According to the palynological analysis, Taxodiaceae, Nyssa sp., Alnus sp., Sphagnum sp., and Polypodiaceae were the main coal-forming plants.
The mountainous and ice-free terrains of the
maritime Antarctic generate complex mosaics of snow patches, ranging from
tens to hundreds of metres. These can only be accurately mapped using
high-resolution remote sensing. In this paper we evaluate the application of
radar scenes from TerraSAR-X in High Resolution SpotLight mode for mapping
snow patches at a test area on Fildes Peninsula (King George Island, South
Shetlands). Snow-patch mapping and characterization
of snow stratigraphy were conducted at the time of image acquisition on 12
and 13 January 2012. Snow was wet in all studied snow patches, with
coarse-grain and rounded crystals showing advanced melting and with frequent
ice layers in the snow pack. Two TerraSAR-X scenes in HH and
VV polarization modes were analysed, with the former showing the best results
when discriminating between wet snow, lake water and bare soil. However,
significant overlap in the backscattering signal was found. Average wet-snow
backscattering was −18.0 dB in HH mode, with water showing −21.1 dB and
bare soil showing −11.9 dB. Single-band pixel-based and object-oriented
image classification methods were used to assess the classification potential
of TerraSAR-X SpotLight imagery. The best results were obtained with an
object-oriented approach using a watershed segmentation with a support vector
machine (SVM) classifier, with an overall accuracy of 92 % and Kappa of 0.88. The main
limitation was the west to north-west facing snow patches, which showed
significant error, an issue related to artefacts from the geometry of
satellite imagery acquisition. The results show that TerraSAR-X in SpotLight
mode provides high-quality imagery for mapping wet snow and snowmelt in the
maritime Antarctic. The classification procedure that we propose is a simple
method and a first step to an implementation in operational mode if a good
digital elevation model is available.