Elisa Toivanen, Teemu Vehkamäki, Markku Väisänen
et al.
The Orijärvi area within the Paleoproterozoic Uusimaa belt contains volcanic and minor sedimentary formations, providing valuable insights into the oldest Svecofennian crust in southern Finland. Previously, felsic volcanic rocks from the Orijärvi, Kisko and Toija formations have been dated at 1895 ± 3, 1878 ± 4 and 1878 ± 4 Ma, respectively. In the present study, the Sorvasto sample from the southern boundary of the Kisko formation yields a zircon age of 1885 ± 5 Ma and a titanite age of 1800 ± 15 Ma. The zircon age falls within the interval between previously obtained age determinations and is coeval with the common Svecofennian crustal growth stage. The Kavasto sample from the western part of the area yields a zircon age of 1878 ± 6 Ma and a titanite age of 1796 ± 4 Ma. The zircon age corresponds to those obtained for similar rock types in the Toija and Ahdisto formations. Picritic interlayers occur within all these successions and are here interpreted as belonging to the same Toija formation. We tentatively infer that the Toija and Salittu formations, together with the overlying sedimentary rocks, can be traced to the West Uusimaa area in the east and the Turku area in the west. The titanite ages near 1.80 Ga reflect cooling or reheating events.
Summary: Stoneflies (order Plecoptera), one of the earliest winged insects, are ecologically vital as freshwater bioindicators. Despite their ecological and evolutionary significance, a robust phylogeny for stoneflies has remained elusive. Here, we analyzed mitogenomes from 97 species representing all 17 families, employing site-heterogeneous models to reconstruct a comprehensive phylogeny of global Plecoptera. Our results provide several key insights: 1) Scopuridae is the earliest diverging lineage within Euholognatha; 2) Taeniopterygidae and Leuctridae form sister groups, representing the second diverging clade within Euholognatha; 3) Capniidae is resolved as the sister group to Nemouridae + Notonemouridae; and 4) the phylogenetic relationships within Systellognatha are resolved. Furthermore, by integrating palaeontological and chronostratigraphic data, we selected well-vetted fossil calibrations to reconstruct a temporal framework for Plecoptera evolution. Our study identifies key periods in Plecoptera’s early divergence and the origins of extant stonefly families, establishing a foundation for future research into their biogeography, morphology, and behavioral evolution.
<p>Geothermal heat flow is an important boundary condition for ice sheets, affecting, for example, basal melt rates, but for ice-covered regions, we only have sparse heat flow observations with partly high uncertainty of up to 30 m W m<span class="inline-formula"><sup>−2</sup></span>. In this study, we first investigate the agreement between such pointwise heat flow observations and solid Earth models, applying a 1D steady-state approach to perform a statistical analysis for the entire Arctic region. We find that most of the continental heat flow observations have a high reliability and agreement to solid Earth models, except a few data points, such as, for example, the NGRIP (North Greenland Ice Core Project) point in central Greenland.</p>
<p>For further testing, we perform a conditional simulation with focus on Greenland in which the local characteristics of heat flow structures can be considered. Simple kriging shows that including or excluding the less reliable NGRIP point has a large influence on the surrounding heat flow. The geostatistical analysis with the conditional simulation supports the assumption that NGRIP might not only be problematic for representing a regional feature but likely is an outlier. Basal melt estimates show that such a local spot of high heat flow results in local high basal melt rates but leads to less variation than existing geophysical models.</p>
Wiktor Marek Luzinski, Andrew C. Morton, Andrew Hurst
et al.
Conventional and varietal heavy mineral studies of the earliest Eocene Hermod S2 Member (Mbr) sandstones in the Greater Alvheim area of the northern North Sea have revealed marked lateral variations and more subtle vertical evolution in provenance signature. Major variations are of geographic rather than stratigraphic nature as biostratigraphy reveals that all investigated sandstones are coeval. The provenance variations show an organized pattern, with sandstones in the north showing a different signature than those in the south. The position of the sandstones relative to the East Shetland Platform (ESP) is inferred to be the main control on provenance, with sediment input from at least two different point sources. Sediment supplied from both catchments is predominantly recycled in nature, given the mineralogical maturity of the heavy mineral assemblages, consistent with the evidence for widespread Permo-Triassic and Devonian sediments on the ESP. However, some direct supply from metasedimentary (Moine and Dalradian) basement is implied by the sporadic occurrence of unstable minerals. The southern catchment incorporated a greater exposure of Permo-Triassic sandstones than the northern catchment. The Permo-Triassic part of the catchment can be reconstructed as comprising equivalents of the Foula and Otter Bank sandstones present to the west of Shetland, with the majority of the Foula section having been stripped off prior to Hermod S2 deposition, exposing Otter Bank equivalents for erosion and redeposition. However, remnant Foula-like sandstones remained exposed further south on the ESP until at least the earliest Eocene since Foula-type garnet signatures are found in the Forties Sandstone Mbr of the central North Sea. In addition to lateral differences, stratigraphic evolution of provenance can also be detected in the Hermod S2 Mbr, with variations in key provenance-sensitive parameters related to a sea-level rise that reduced the extent of alluvial storage and altered the geological framework of the hinterland.
Nikolitsa Alexandropoulou, Monica Winsborrow, Karin Andreassen
et al.
Here we present a high-resolution, continuous seismostratigraphic framework that for the first time, connects the over 1,000 km long western Svalbard-Barents Sea margin and covers the last ∼2.7 million years (Ma). By exploiting recent improvements in chronology, we establish a set of reliable age fix-points from available boreholes along the margin. We then use a large 2-D seismic database to extend this consistent chronology from the Yermak Plateau and offshore western Svalbard, southwards to the Bear Island Trough-Mouth Fan. Based on this new stratigraphic framework we divide the seismic stratigraphy along the continental margin into three seismic units, and 12 regionally correlated seismic reflections, each with an estimated age assignment. We demonstrate one potential application of this framework by reconstructing the Svalbard-Barents Sea Ice Sheet evolution from the intensification of the northern hemisphere glaciation at ∼2.7 Ma to the Weichselian glaciations. Through seismic facies distribution and sedimentation rate fluctuations along the margin we distinguish three phases of glacial development. The higher temporal resolution provided by this new framework, allows us to document a clear two-step onset to glacial intensification in the region during phase 1, between ∼2.7 and 1.5 Ma. The initial step, between ∼2.7 and 2.58 Ma shows glacial expansion across Svalbard. The first indication of shelf-edge glaciation is on the Sjubrebanken Trough-Mouth Fan, northwestern Barents Sea after ∼2.58 Ma; whilst the second step, between ∼1.95 and 1.78 Ma shows glacial advances beyond Svalbard to the northwestern Barents Sea. Phase 2 is characterized by variations in sedimentation rates and the seismic facies are indicative for a regional glacial intensification for the whole Barents Sea-Svalbard region with widespread shelf-edge glaciations recorded at around ∼1.5 Ma. During Phase 3, the western Barents Sea margin is characterized by a dramatic increase in sedimentation rates, inferring once again a regional glacial intensification. Our new stratigraphic framework allows for the first time differentiation of the sediments deposited on the slope during Early Saalian (∼0.4 and 0.2 Ma), Late Saalian (∼0.2 and 0.13 Ma), and Weichselian (<∼0.123 Ma) periods, providing new insights into the Barents Sea glaciations over the last ∼0.42 Ma.
In order to study the lithostratigraphy, biostratigraphy, microfacies, depositional setting and also to reconstruct the paleo-environmental conditions of the Tirgan Formation, three outcrop sections were selected in the western part of the Kopet-Daghh sedimentary basin. These sections locate at the Estarkhi village (30 km East of Shirvan city), the Jozak (40 km West of Bojnourd city) and the Zaw Mountain (45 km far from the Kalaleh city). Geographical coordinates of these outcrop sections are: 57o, 51’, 31’’ longitude and 37o, 11’, 29’’ latitude in Estrakhi section, 56o, 42’, 25’’ longitude and 37o, 24’, 55.8’’ latitude in Jozak section, and finally, 55o, 45’, 10.6’’ longitude and 37o, 31’, 20’’ latitude in Zaw section. The Tirgan Formation has a thickness of 129 m in Estarkhi, 362 m in Jozak and 639 m in Zaw section, in which measured and samples to be used in this study. A total number of 62, 102 and 226 rock samples was taken respectively from the Estarkhi, Jozak and Zaw sections, and used for the microscopic studies. Therefore, a total number of 700 thin-sections were prepared from the rock samples and studied under the microscope. In Estarkhi section, the Shurijeh Formation is overlain conformably by the Tirgan Formation. Moreover, the upper contact of the Tirgan Formation with the upper rock unit, the Sarcheshmeh Formation, is continues and conformable. In this outcrop section, the Tirgan Formation begins with siliciclastic deposits with intercalations of marls, representing a gradational passage from the continental Shurijeh Formation to the marine deposits of the Tirgan Formation. The Jozak section represents a conformable and continues contact between the Tirgan Formation with the underlying Shurijeh Formation, but, its upper contact with the overlying Abderaz Formation is cut by a fault. In Zaw section, the lower contact of the Tirgan Formation with the Zard Formation is continues and conformable, but, its upper contact with the younger deposits is covered and unclear. Based on the distribution of facies belts, three paleogeographical maps were prepared for the study area. They are: Hauterivian?-lower Barremian, lower Barremian-upper Barremian and upper Barremian-lower Aptian. Analysis of these maps shows that during the Hauterivian?-lower Barremian, in the far eastern part of the study are (e.g. Estarkhi section), the Tirgan Formation includes in siliciclastic deposits with some marine marls, in that the detrital sediments was carried to the foreland basin as a result of erosion of high structures. In the same time, the western parts of the study area was covered by deposits belonging to a tidal-flat depositional setting, representing a deepening trend from the East towards the West of the area. During the Barremian (lower Barremian-upper Barremian), a major deepening trend has occurred for the both vertical and horizontal extend regionally in the study area. Therefore, the Estarkhi area was covered by tidal-flat deposits, and in the same time, the deepening trend was continued towards the west, led to the deposition of shoal and open marine facies in the Jozak and Zaw area. Finally, in the upper Barremian-lower Aptian, a stable condition was govern for the entire area, led to the deposition of orbitolina bearing limestones totally in the study area. Vertical distribution of facies belts shows that the eastern part of the study area (e.g. Estarkhi section), represents a major deepening upward trend during the upper Barremian-lower Aptian, which is comparable with general and global transgressive trends for the Barremian-Aptian interval. But, in the western part (e.g. Jozak and Zaw areas), the bathymetry was often stable, and somehow, shows a shallowing trend, that probably belongs to the role of basement faults and local tectonic activities, creating various accommodation space on the shallow platform setting in this part of the Kopet-Daghh Basin.
Luis A. Buatois, Fernando J. Zeballo, Guillermo L. Albanesi
et al.
The Upper Cambrian-Tremadocian rocks exposed in the Alfarcito area of Cordillera Oriental, northwest Argentina reveal a series of transgressive-regressive cycles punctuated by incision of fluvio-estuarine valleys. An integrated sedimentologic, biostratigraphic and sequence stratigraphic study permits characterization of the sedimentary facies and stratal stacking patterns, and a revision of the stratigraphic framework of this succession. The Upper Cambrian-Tremadocian succession is included within the existing Santa Rosita Formation, which is formally subdivided here into six units, the Tilcara, Casa Colorada, Pico de Halcón, Alfarcito, Rupasca and Humacha members. This scheme recognizes the internal complexities of the formation, in that the Tilcara and Pico de Halcón members record sedimentation in areally-restricted incised valleys and contain structures indicative of tidal dominance, whereas the Casa Colorada, Alfarcito and Rupasca members typify wave-dominated open-marine environments, where background suspension-fallout was punctuated by oscillatory flows during storms. The Tilcara Member is incised into the underlying Mesón Group. The Casa Colorada Member reflects a basinwide Late Cambrian transgression and subsequent progradation and consists of lower to upper offshore deposits. The Pico de Halcón Member is incised into the Casa Colorada Member. The Alfarcito Member is divided into three distinctly upward-coarsening and-thickening intervals. The sandstone-dominated intervals are composed of lower to middle shoreface deposits with minor amounts of offshore transition and upper shoreface deposits. The heterolithic, fine-grained intervals record more distal deposition, ranging from the lower offshore to the offshore transition. The Rupasca Member is a dominantly fine-grained unit that records a major late early to early late Tremadocian transgression. The lower interval of this member consists of lower offshore to offshore-transition deposits, while the upper part is made up of shelf to lower offshore deposits. The Humacha Member is not exposed in the study area. The importance of integrating biostratigraphy within a sedimentologic and sequence-stratigraphic framework is underscored here, in that it enables us to construct a more accurate stratigraphic framework which permits a clear understanding of the sedimentary dynamics of this system.
<p>This work explores a probabilistic modeling workflow and its implementation targeting CO<span class="inline-formula"><sub>2</sub></span> generation rate and CO<span class="inline-formula"><sub>2</sub></span> source location by the occurrence of carbonate–clay reactions (CCRs) in three-dimensional realistic sedimentary basins.
We ground our study on the methodology proposed for a one-dimensional case study and a single CCR formulation by <span class="cit" id="xref_text.1"><a href="#bib1.bibx8">Ceriotti et al.</a> (<a href="#bib1.bibx8">2017</a>)</span> which includes a framework to account for thermodynamic parameter uncertainties.
This methodology is here extended to a realistic three-dimensional sedimentary basin setting and transferred to encompass different types of CCRs, including two newly formulated CCRs which account for minerals typically observed in sedimentary environments.
While testing the ability of the selected procedure to model diverse CCRs in three-dimensional realistic subsurface sedimentary systems, we quantitatively compare the impact of CCR formulation on the spatial distribution of CO<span class="inline-formula"><sub>2</sub></span> source location, temperature and pressure compatible with CO<span class="inline-formula"><sub>2</sub></span> gaseous generation, and CO<span class="inline-formula"><sub>2</sub></span> generation rate in three-dimensional environments characterized by complex and non-uniform stratigraphy. The application of the procedure to various types of CCRs enables us to provide an insight into the impact of mineralogical composition on the activation temperature and pressure and the amount of CO<span class="inline-formula"><sub>2</sub></span> released by the different CCR mechanisms. Finally, we show the implementation of the proposed probabilistic framework to define scenarios associated with various levels of probability to be used as the input and boundary conditions for CO<span class="inline-formula"><sub>2</sub></span> migration and transport models in the subsurface.</p>
Erik Tihelka, Michael S. Engel, Diying Huang
et al.
Summary: Mimicry is ubiquitous in nature, yet understanding its origin and evolution is complicated by the scarcity of exceptional fossils that enable behavioral inferences about extinct animals. Here we report bizarre true bugs (Hemiptera) that closely resemble beetles (Coleoptera) from mid-Cretaceous amber. The unusual fossil bugs are described as Bersta vampirica gen. et sp. nov. and Bersta coleopteromorpha gen. et sp. nov. and are placed into a new family, Berstidae fam. nov. The specialized mouthparts of berstids indicate that they were predaceous on small arthropods. Their striking beetle-like appearance implies that they were either involved in defensive mimicry or mimicked beetles to attack unsuspecting prey. The latter would represent the first case of aggressive mimicry in the invertebrate fossil record. These findings enrich our understanding of the paleoecological associations and extinct behavioral strategies of Mesozoic insects.
Claudia Bertoni, Johanna Lofi, Aaron Micallef
et al.
There is growing evidence that passive margin sediments in offshore settings host large volumes of fresh and brackish water of meteoric origin in submarine sub-surface reservoirs. Marine geophysical methods, in particular seismic reflection data, can help characterize offshore hydrogeological systems and yet the existing global database of industrial basin wide surveys remains untapped in this context. In this paper we highlight the importance of these data in groundwater exploration, by reviewing existing studies that apply physical stratigraphy and morpho-structural interpretation techniques to provide important information on—reservoir (aquifer) properties and architecture, permeability barriers, paleo-continental environments, sea-level changes and shift of coastal facies through time and conduits for water flow. We then evaluate the scientific and applied relevance of such methodology within a holistic workflow for offshore groundwater research.
Seismicity is frequently used to deduce the tectonics of a region. The study of earthquakes as a tectonic component, seismotectonics, has grown as one of the key research areas on active tectonics, especially from the analysis of earthquake focal mechanisms. FMC computes the different earthquake parameters that can be obtained from focal mechanism data, classifies the rupture type of each focal mechanism, performs a clustering analysis of the data if required by the user, outputs the parameters in different formats and generates a classification diagram from the input data. Keywords: Earthquake, Focal mechanism, Clustering
Reinaldo Rojas, Manuel Iturralde-Vicent, Peter W. Skelton
Along the NE flank of Cuba, parts the Bahamian carbonate platform are exposed, while in the central part of the island a Cretaceous volcanic arc sequence is present. Rudist assemblages are found in both of these major tectonic settings… in order to continue, download the full paper in PDF.
Mehdi Sarfi, Amin Navidtalab, Ebrahim Ghaseminejad
et al.
Micropalaeontological study based on planktonic foraminifera in the Cenomanian - Turonian succession of the Holul section, located in the Lurestan geological province (west of the Kermanshah City), resulted in distinction of Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica biozones. Whiteinella archaeocretacea biozone globally defines the Cenomanian - Turonian transition. Detection of this biozone in the Holul section could be a clue for continuous sedimentation of the Cenomanian - Turonian transition in the studied stratigraphic section. Elongated chambers planktonic foraminifera such as Muricohedbergella simplex are relatively common during time span of Whiteinella archaeocretacea biozone in the Holul stratigraphic section. Results of the isotopical analysis in the studied section indicates an increasing - decreasing trend from the top of Rotalipora cushmani to the base of Helvetoglobotruncana helvetica biozones including two positive shifts before and after Whiteinella archaeocretacea biozone that can be correlated with carbon isotope peaks of OAE2 in the Neotethys Basin.
Soil acidity has become a principal constraint in dry land
crop production systems of acidic Ultisols in tropical and subtropical
regions of southern China, where winter wheat and canola are cultivated as
important rotational crops. There is little information on the determination
of critical soil pH as well as aluminium (Al) concentration for wheat and
canola crops. The objective of this study is to determine the critical soil
pH and exchangeable aluminium concentration (Al<sub>KCl</sub>) for wheat and
canola production. Two pot cultures with two Ultisols from Hunan and Anhui
(SE China) were conducted for wheat and canola crops in a controlled growth
chamber. Aluminium sulfate (Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>) and hydrated lime
(Ca(OH)<sub>2</sub>) were used to obtain the target soil pH levels from 3.7
(Hunan) and 3.97 (Anhui) to 6.5. Plant height, shoot dry weight, root dry
weight, and chlorophyll content (SPAD value) of wheat and canola were
adversely affected by soil acidity in both locations. The critical soil pH
and Al<sub>KCl</sub> of the Ultisol from Hunan for wheat were 5.29 and 0.56 cmol kg<sup>−1</sup>, respectively. At Anhui, the threshold soil pH and Al<sub>KCl</sub> for
wheat were 4.66 and 1.72 cmol kg<sup>−1</sup>, respectively. On the other hand,
the critical soil pH for canola was 5.65 and 4.87 for the Ultisols from
Hunan and Anhui, respectively. The critical soil exchangeable Al for canola
cannot be determined from the experiment of this study. The results
suggested that the critical soil pH and Al<sub>KCl</sub> varied between different
locations for the same variety of crop, due to the different soil types and
their other soil chemical properties. The critical soil pH for canola was
higher than that for wheat for both Ultisols, and thus canola was more sensitive
to soil acidity. Therefore, we recommend that liming should be undertaken to
increase soil pH if it falls below these critical soil pH levels for wheat
and canola production.
The focus of this study is to investigate the arsenic movement and impacts on the residual concentrations on groundwater pollution load. The Gangetic plain area in the Ballia, Uttar Pradesh is selected as study area, which is also reported to extreme arsenic pollution in soil-water system. A modelling approach is developed to assess the arsenic flux in partially saturated zone using data of soil texture, soil hydraulic properties and stratigraphy. Soil type, slope, and land-use cover is considered for estimating the transient flux at the top boundary from daily precipitation and evapotranspiration data of the study area. Solute transport in the subsurface is predicted by the mass transfer equation, which is derived by integrating Darcy's law with the equation of mass balance. The arsenic profiles of varying hydrogeological conditions associated with different locations in the study area are presented as breakthrough curves. The results shows that the arsenic transport is dominated by the advective flux and strongly depends on the soil-moisture flow conditions. Which may increases the arsenic load to underlaying groundwater resources. The simulated results suggest that mobility plays a vital role arsenic transport as well as on adsorbed arsenic concentration in subsurface. Likewise, the adsorption isotherms show that the high peak curve for Bairai and low at Sikarderpur. A higher pollution risk is observed in the Belthara Road, whereas a lower vulnerability is computed in the north and northeast regions. This study can help in strategising sustainable groundwater management and protection planning of identified regions of India. Keywords: Arsenic transport, Adsorption, Subsurface, Sustainable groundwater management
Some basic characteristics of the alpine karst waters in Slovenia are presented. By the method of hydrological balance it was estimated that their groundwater reserves can supply a spring with an average discharge 115 m3/s. According to the comparison between the extent of the alpine karst and the EIONET-SI data base on springs it was stated, that for approximately 1200 alpine karst springs the total capacity (not the average discharge, but the amount of water that can be captured at low waters) is around 15 m3/s. At present only some 25% of these reserves is exploited for the water supply of around 240.000 inhabitants. Due to high vulnerability and different human impacts the quality of these water resources is endangered. Therefore it is necessary to protect them with adequate measures planned on the basis of accurate hydrogeological data. Present level of protection is unsatisfactory, as the water protection decree was accepted only for one quarter of captured springs. Additionally, the expert basis for such decree was prepared for a little less than one fi fth of captured springs.
Predstavljene so osnovne značilnosti alpskih kraških voda v Sloveniji. Z metodo vodne bilance sem ocenila, da njihove zaloge zadoščajo za napajanje izvira s povprečnim pretokom 115 m3 /s. Po primerjavi obsega alpskega krasa s podatki o izvirih iz baze EIONET-SI je bilo ugotovljeno, da je skupna izdatnost (ne povprečni pretok, ampak količina vode, ki jo je možno zajemati ob nizkem vodostaju) približno 1200 alpskih kraških izvirov okrog 15 m3 /s. Za vodooskrbo je trenutno izkoriščenih le okrog 25 % teh zalog, z njimi pa se oskrbuje okrog 240.000 prebivalcev. Zaradi velike ranljivosti kraških vodonosnikov in različnih človekovih vplivov je ogrožena kakovost teh vodnih virov. Nujna je zato njihova ustrezna zaščita, ki pa mora temeljiti na kakovostnih hidrogeoloških podatkih. Trenutna stopnja zaščite je nezadovoljiva, saj ima le približno četrtina zajetih izvirov sprejet odlok o varovanju, še za nekaj manj kot petino pa so že pripravljene ustrezne strokovne podlage.