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The Buton Island is located in the the subduction zone between the Eurasian, Indo-Australian, and Pacific Plates. This island is exposed at the most southern part of southeast Sulawesi, adjacent to the Muna and the Tukang Besi Islands. Recent investigations have suggested that the Buton Island had experienced multiple tectonic events during the Neogene period, with the first collision occurred between Southeast Sulawesi/Muna and Buton and the second collision occurred between Buton and Tukang Besi. The objective of this study is to present the Neogene history of the Buton Island based on identification of the Tondo Formation. This study investigated the clastic of Tondo Formation in the Wakoko River (South Buton) and the Wambona River (North Buton) to identify the strata of stratigraphy, age and depositional environment, provenance, and evolution of the Tondo Formation in the Buton Island.

Cretaceous strata are widely distributed across China and record a variety of depositional settings. The sedimentary facies consist primarily of terrestrial, marine and interbedded marine-terrestrial deposits, of which marine and interbedded facies are relatively limited. Based a thorough review of the subdivisions and correlations of Cretaceous strata in China, we provide an up-to-date integrated chronostratigraphy and geochronologic framework of the Cretaceous system and its deposits in China. Cretaceous marine and interbedded marine-terrestrial sediments occur in southern Tibet, Karakorum, the western Tarim Basin, eastern Heilongjiang and Taiwan. Among these, the Himalayan area has the most complete marine deposits, the foraminiferal and ammonite biozonation of which can be correlated directly to the international standard biozones. Terrestrial deposits in central and western China consist predominantly of red, lacustrine-fluvial, clastic deposits, whereas eastern China, a volcanically active zone, contains clastic rocks in association with intermediate to acidic igneous rocks and features the most complete stratigraphic successions in northern Hebei, western Liaoning and the Songliao Basin. Here, we synthesise multiple stratigraphic concepts and charts from southern Tibet, northern Hebei to western Liaoning and the Songliao Basin to produce a comprehensive chronostratigraphic chart. Marine and terrestrial deposits are integrated, and this aids in the establishment of a comprehensive Cretaceous chronostratigraphy and temporal framework of China. Further research into the Cretaceous of China will likely focus on terrestrial deposits and mutual authentication techniques (e.g., biostratigraphy, chronostratigraphy, magnetostratigraphy and cyclostratigraphy). This study provides a more reliable temporal framework both for studying Cretaceous geological events and exploring mineral resources in China.

Fluid modification critically affects the quality of clastic rock reservoirs. At present, the mechanism of multistage fluid alteration in clastic rock reservoirs under deep burial conditions is still a matter of debate. To solve this problem, this study focuses on the deep clastic reservoirs of the Zhuhai Formation in the Wenchang A Sag of the Zhujiangkou Basin as an example and conducts a series of petrological and geochemical analyses. The results indicate that the fluids that primarily affect reservoir development are hydrothermal fluids and organic acids, and the hydrothermal fluid activity occurred over multiple stages, leading to a diagenetic environment with alternating acidic and alkaline conditions. In this low-permeability reservoir, hydrothermal fluids under acidic conditions were favorable for reservoir development. However, these fluids gradually became alkaline as the reaction proceeded, and under alkaline conditions, carbonate precipitation blocked the pores. In contrast, organic acids had a very positive effect on improving the reservoir. Thus, in this relatively sealed low-permeability reservoir, regions with significant hydrothermal development typically exhibit poor reservoir quality, whereas areas with substantial influxes of organic acids exhibit better porosity and permeability. Furthermore, the order of fluid injection caused substantial variations in reservoir properties. Reservoir areas that first experienced strong hydrothermal injection tend to have very poor properties. In contrast, reservoir areas that first experienced weak hydrothermal fluid influence followed by strong organic acid activity exhibit better properties. The reservoir areas initially improved by organic acids show good connectivity, and any precipitates from later hydrothermal fluids did not accumulate in reservoir pores. As a result, these reservoirs display the best reservoir characteristics. This study defines a model of reservoir development under the combined effects of multiphase fluids and diagenetic environments, which is highly important for evaluating the exploration potential of deep clastic rock reservoirs.

The Danube / Kisalföld Basin is the north-western sub-basin of the Pannonian Basin System. The lithostratigraphic subdivision of the several-km-thick Upper Miocene to Pliocene sedimentary succession related to Lake Pannon has been developed independently in Slovakia and Hungary. A study of the sedimentary formations across the entire basin led us to claim that these formations are identical or similar between the two basin parts to such an extent that their correlation is indeed a matter of nomenclature only. Nemčiňany corresponds to the Kálla Formation, representing locally derived coarse clastics along the basin margins (11- 9.5 Ma). The deep lacustrine sediments are collectively designated the Ivanka Formation in Slovakia, while in Hungary they are subdivided into Szák (fine-grained transgressive deposits above basement highs, 10.5 - 8.9 Ma), Endrőd (deep lacustrine marls, 11.6 -10 Ma), Szolnok (turbidites, 10.5 - 9.2 Ma) and Algyő Formations (fine-grained slope deposits, 10 - 9 Ma). The Beladice Formation represents shallow lacustrine deltaic deposits, fully corresponding to Újfalu (10.5 - 8.7 Ma). The overlying fluvial deposits are the Volkovce and Zagyva Formations (10 - 6 Ma). The synoptic description and characterization of these sediments offer a basin-wide insight into the development of the basin during the Late Miocene. The turbidite systems, the slope, the overlying deltaic and fluvial systems are all genetically related and are coeval at any time slice after the regression of Lake Pannon initiated about 10 Ma ago. All these formations get younger towards the S, SE as the progradation of the shelf-slope went on. The basin got filled up to lake level by 8.7 Ma, since then fluvial deposition dominated.

The latest exploration developments and discoveries from the eastern Mediterranean documented that Neogene formations can act as source-rocks for hydrocarbon generation and their exploitation delivered large amounts of mostly biogenic gas to the market. Examples of such offshore gas-fields include the Zohr-Egypt, Leviathan/Tamar-Israel, and Aphrodite-Cyprus. Having attracted the oil majors’ attention for hydrocarbons exploration in southern Greece (e.g., Exxon-Mobil, Chevron), by using onshore geologic analogs, we suggest relevant perspectives in the country’s offshore sector. Our study focuses on Miocene marine deposits exploration, from Gavdos Island, southern Greece, evaluating their characteristics as potential source-rocks affected by a paleodepositional framework. By integrating fieldwork, organic (Rock-Eval VI-pyrolysis, CHNS) and inorganic geochemical data (XRF), the current results indicate gas-prone organic matter with variable preservation status, reflecting a few oxidation episodes during deposition under generally dysoxic-to-suboxic conditions. Paleoclimatic weathering indices (CIA, C.I., Sr/Cu, Rb/Sr) suggest predominantly arid to semi-arid regimes punctuated by short-lived humid phases that locally enhance organic accumulation and nutrient supply. Variations in paleosalinity and stratification, particularly within the Messinian section, are interpreted as precursors to the Messinian Salinity Crisis. Our findings highlight the potential for hydrocarbon-prone intervals in the deeper-offshore Eastern Mediterranean basins, where most favorable conditions for organic-carbon preservation and maturation are documented by the discoveries.

The purpose of this study was to investigate the stability of rocky slopes largely formed of sandstone and claystone clastics along Highway 80-2 in Mosul City, northern Iraq. Seven separate stations along the route were covered by the investigation, and each station included two to five study locations. Field studies were used to identify both man-made and natural slope failures caused by building a residential complex. The identification of these slopes' sliding surfaces was done using a user-friendly, contemporary method, with the potential for future advancements in measuring safety parameters. According to the analysis, the sliding potential is raised, especially during rainy seasons, by geotechnically weak rocks. Examples of these rocks include sandstone and claystone. The most important assumption underlying the suggested approach is a circle-shaped arch that is centered at the point where a vertical line from the slope's toe intersects the upper slope level. The sliding base is represented by the diagonal line inside the effective range of the slope, which relies on the angle of internal friction and is equal to the horizontal distance twice the vertical height of the slope. The angle of internal friction for most clastic slope materials was determined to be 27°. The slope inclination was used to determine the shape and sequence of sliding surfaces. As a result of the study's findings, it can be concluded that the suggested model accurately predicts the slides seen in the study area.

The Upper Eocene San Martí Xic Formation (Orís, Vic, SE Ebro basin, Spain) shows coralgal buildup developed in mixed carbonate siliciclastic deposits. During the upper Eocene, the sedimentation in the Orís area was strongly influenced by global and local factors associated with the Ebro Basin evolution. In particular, from the early Eocene to the Oligocene, the south-eastern margin of the Ebro Basin was affected by the uplift of the Catalan Range thrust. The central part of this zone shows the most pronounced deformation associated with a sin-sedimentary evolution of fan and delta fan depositional systems. These deposits gradually evolved into basin sedimentation with shallow water limestones and clastic sediments corresponding to the last marine event of the Ebro Basin. The stratigraphical series in Orís corresponds to two cycles. A first transgressive sedimentary cycle is characterized by floatstone to rudstone with Discocyclina and Nummulites, developed in a deeper and oligophotic environment associated with more humid conditions. The subsequent regressive cycle shows aggradational and progradational deltaic sediments with Nummulites developed in more arid conditions. Coralgal buildups occur interdigitated with these aggradational and progradational deltaic sediments. Facies analysis allows to better constraining the paleoenvironment where coralgal buildup developed, characterized by high sedimentation rate, mesotrophic conditions and turbid waters. The coralgal buildups of San Martí Xic Formation were thus influenced by both climatic changes and the local detrital input from delta fan system associated with the uplift of the Catalan Range thrust, showing the resilience of Eocene corals to climate changes and related clastic inputs.

This article investigates how, where, and to what extent the mineralogical and chemical composition of sand-sized sediments is modified by extreme weathering in modern equatorial settings, with the ultimate goal of learning to read climate from the sedimentary record. To single out the weathering effect, we studied the compositional trends of fluvial sands along the western branch of the East African Rift between 5°S and 5°N. The relative durability of different detrital components, as well as potential hydraulic-sorting and grain-size effects, were assessed by comparing samples with similar provenances in different climatic and environmental conditions or of different size classes within the same sample. Sands of equatorial central Africa at the headwaters of the Congo and Nile basins display the full spectrum of petrologic suites characterizing rift-shoulder and volcanic rift provenances. Unlike in arid Arabia, quartzose sands are not restricted to areas where detritus is recycled from prerift sedimentary covers. In a hot humid climate, weathering can effectively obliterate the fingerprint of parent rock lithology and produce a nearly pure quartz residue even where midcrustal basement rocks are being actively uplifted and widely unroofed. In such settings garnet is destroyed faster than hornblende, and zircon faster than quartz. Weathering control on detrital modes is minor only in the rain shadow of the highest mountains or volcanoes, where amphibole-dominated quartzofelicdspathic metamorphiclastic sands (Rwenzori Province) or clinopyroxene-dominated feldspatholithic volcaniclastic sands (Virunga Province) are generated. Our detailed study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than of progressive maturation in temporary storage sites during stepwise transport and shows that the transformation of diverse parent rocks into a quartzose \"white sand\" may be completed in one sedimentary cycle in hydromorphic soils of subequatorial lowlands. Micas and heavy minerals, which are less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behavior of chemical indexes such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands.

The type sections of the Lower Riphean Burzyan Group (Ai, Satka, and Bakal formations) are located in the northeast part of the Bashkirian meganticlinorium. In its central and southern regions, the above formations are traditionally compared with the Bolshoi Inzer, Suran, and Yusha formations. Our studies whose results are discussed herein were centered on trends in the indicator ratios of trace elements in clay rocks of the six formations to obtain arguments in support of certain variants of their correlations. The trends in the average geochemical characteristics of clay rocks of the Burzyan Group in the northeastern and central + southern regions of the meganticlinorium, reflecting the composition of their parental rocks, were found out to be notably different. This does not necessarily indicate that individual correlations between the Burzyan Group rocks in various regions should be incorrect but rather highlights the necessity to revisit this problem.

This study investigates the petrographic, mineralogical, geochronological, and geochemical signatures of river sands across southern Africa. We single out the several factors that control sand generation, including weathering and recycling, and monitor the compositional changes caused by chemical and physical processes during fluvial transport from cratonic sources to passive-margin sinks. Passive-margin sands have two first-cycle sources. Quartz and feldspars with amphibole, epidote, garnet, staurolite, and kyanite are derived from crystalline basements exposed at the core of ancient orogens and cratonic blocks (dissected continental block provenance). Volcanic rock fragments, plagioclase, and clinopyroxene are derived from flood basalts erupted during the initial phases of rifting (volcanic rift provenance). First-cycle detritus mixes invariably with quartzose detritus recycled from ancient sedimentary successions (undissected continental block provenance) or recent siliciclastic deposits (e.g., Kalahari dune sands; recycled clastic provenance). U-Pb ages of detrital zircons mirror the orogenic events that affected southern Africa since the Archean. Damara (0.5-0.6 Ga) and Namaqua (1 Ga) age peaks are prominent throughout Namibia, from the Orange mouth to the Namib and Skeleton Coast Ergs, and also characterize Kalahari dunes and sands of the Congo, Okavango, and Zambezi Rivers. Instead, sharp old peaks at 2.1 Ga and 2.6 Ga characterize Limpopo and Olifants sands, matching the age of the Bushveld intrusion and the final assembly of the Zimbabwe and Kaapvaal Cratons, respectively; discordant ages indicate Pb loss during the Pan-African event. Chemical indices confirm that weathering is minor throughout the tropical belt from South Africa and Zimbabwe to Namibia and coastal Angola but major for quartzose sands of the Congo, Okavango, and upper Zambezi Rivers, largely produced in humid subequatorial regions. Recycling of quartzose sediments is extensive in all of these catchments. From Congo to Mozambique, along the >5000-km Atlantic and Indian Ocean rifted margins, polycyclic detritus reaches commonly 50% and locally up to 100%, in line with the estimated incidence of recycling worldwide. Quantitative information provided by provenance studies of modern sands helps us to better understand the relationships between sediment composition and plate-tectonic setting and to upgrade the overly simplified and often misleading current provenance models. This is a necessary step if we want to decipher the stratigraphic record of ancient passive margins and reconstruct their paleotectonic and paleoclimatic history with greater accuracy.