ALBERT

Description: Automatic seismic data interpretation is a significant method in the exploration of geophysics. Complexities of the subsurface structures and the subsurface wave propagation media, make the decision-making process difficult in seismic data interpretation. Nevertheless, the extent of related knowledge and using the expert system method in seismic data interpretation can mitigate this problem. An expert system is a knowledge-based system that applies its knowledge in a complex and specific area and acts as an expert end-user consultant. This study investigates the design of an ANFIS expert system for mud diapirs detection with seismic data analysis in Gorgan plain. This method was applied to seismic attributes from a complex geological mud diapir bearing structure from south of the Caspian Sea. The south of the Caspian Sea is one of the richest area as petroleum reserves, and the Gorgan plain has various mud diapirs, which act as indicators of hydrocarbon reservoirs. The expert system design process to identify mud diapirs on seismic sections was modeled in two approaches including manual and automatic seismic data interpretation. In the first approach, the experience of the expert was collected by manual interpretation of training data and used to create a knowledge base and inference of the expert system in the second approach. The validation verified the accuracy of this method with an average accuracy of 90.1% according to using minimum knowledge to develop a knowledge base of the designed ANFIS expert system.

Description: Highlights • Accurate fault model can be built even when sparse drilling wells are available. • The multiresolution fault model provides information of faults with different sizes. • Fault model provides possibility of tectonic and fluid flow analysis simultaneously. • Modelling of faults in different scales, enable more accurate well path design. • The ANN provides optimized parameters for fault detection by ant tracking algorithm. Modelling faults plays a crucial step in the chain of studies through the first phase of the hydrocarbon exploration and its following studies in reservoir engineering, simulation and field development. This study introduces an innovative and automatic integrated approach that combines seismic multi-attributes and well data for faults modelling. The proposed strategy begins with extracting fault-related seismic attributes commonly used for seismic reservoir characterization. Chaos, variance and curvature attributes, typically highlight large-scale faults that shape the structural framework of the study field. In contrast, small-scale faults, influencing subsurface fluid flow in the fractured reservoir, are modeled using the ant-tracking algorithm applied to seismic data. Small-scale and large-scale fault models, then integrated with the conventional fault model to create an integrated discrete fracture network (DFN). This DFN model incorporates information on both large-scale and small-scale faults. The proposed strategy was applied on a geologically complex petroleum field in Iran. The results, validated using Formation Micro Imager (FMI) data, demonstrate accuracy of the integrated DFN model in comparison to conventional approaches on the studied filed, particularly in capturing small-scale faults. Consequently, it can be concluded that the proposed strategy provides a viable alternative for generating accurate DFN model.

Description: Highlights • New geophysical data and samples redefine submarine volcanism in Sicilian Channel. • Three dominant bands of volcanism are distinguished. • Ancient, eroded structures aligned at 120° are tied to faulted banks in the north. • Younger band of similarly aligned volcanism in the south is linked to grabens. • Youngest structures comprise small, dispersed volcanoes with distinct orientation. Abstract The origin and role of volcanism in continental rifts remains poorly understood in comparison to other volcano-tectonic settings. The Sicilian Channel (central Mediterranean Sea) is largely floored by continental crust and represents an area affected by pronounced crustal extension and strike-slip tectonism. It hosts a variety of volcanic landforms closely associated with faults, which can be used to better understand the nature and distribution of rift-related volcanism. A paucity of appropriate seafloor data in the Sicilian Channel has led to uncertainties regarding the location, volume, sources and timing of submarine volcanism. To improve on this situation, we use newly acquired geophysical data (multibeam echosounder and magnetic data, sub-bottom profiles) and dredged seafloor samples to: (i) re-assess the evidence for submarine volcanism in the Sicilian Channel and define its spatial pattern, (ii) infer the relative age and style of magmatism, and (iii) relate this to the dominant tectonic structures in the region. Quaternary rift-related volcanism has been focused at Pantelleria and Linosa, at the northwest boundaries of their respective NW-SE trending grabens. Subsidiary and older volcanic sites potentially occur at the Linosa III and Pantelleria SE seamounts, collectively representing the only sites of recent volcanism that can be directly related to the main rift process. These long-lived polygenetic volcanic landforms have been shaped by magmatism that is directly correlated with extensional faulting and buried igneous bodies. Older volcanic landforms, sharing a similar scale and alignment, occur to the north at Nameless Bank and Adventure Bank. These deeply eroded volcanoes have likely been inactive since the Pliocene and are probably related to earlier stages of crustal thinning and underlying feeder structures in the northern region of the Sicilian Channel. Along a similar alignment, Pinne Bank, SE Pinne Bank and Cimotoe in the northern Sicilian Channel lack a surface volcanic signature but are associated with intrusive bodies or deeply buried volcanic rock masses. Terrible Bank, in the same region, also shows evidence of ancient, polygenetic magmatism, but was subject to significant erosion and lacks a prominent alignment. The much younger volcanism at Graham Volcanic Field and along the northern Capo-Granitola-Sciacca Fault Zone differs markedly from that observed in the other study areas. Here, the low-volume and scattered volcanic activity is driven by shallow-water mafic magma eruptions, which gave rise to small individual cones. These sites are associated with large fault structures away from the main rift axis and may have a distinct magmatic origin. Dispersed active fluid venting occurs across both ancient and young volcanic sites in the region and is directly associated with shallow magmatic bodies within tectonically-controlled basins. Our study provides the foundation for an updated tectonic and magmatic framework for the Sicilian Channel, and for future detailed chronological and geochemical assessment of the sources and evolution of magmatic processes in the region.

Description: Highlights • Ankaramites are Ca-rich and Ni-poor porphyritic basalts that are common in oceanic arcs. • Melt inclusions from Kibblewhite Volcano show similar compositions to ankaramites. • Ankaramite is a primary magma component in oceanic arcs. • Interaction between melt and mantle can produce ankaramitic melts. • Harzburgite formed by melt-mantle interactions is the source of high-Mg andesites. Abstract Ankaramites, which are clinopyroxene-rich basalts with primitive whole-rock compositions (Mg# 〉65), are common in oceanic arcs and are characterized by high whole-rock CaO/Al2O3 (〉1.0) ratios and olivine crystals with anomalously low nickel contents (〈0.2 wt% NiO). These geochemical characteristics cannot be explained by the melting of ordinary mantle peridotite. However, their origin is critical for understanding the formation of primary magmas in oceanic arcs. Here, we investigated olivine-hosted melt inclusions (MIs) from ankaramites and magnesian andesites of the Kibblewhite Volcano in the Kermadec arc. The MIs from the ankaramites have similar major and trace element characteristics to the host rocks, indicating that the ankaramites did not result from an accumulation of mafic minerals but rather represent the primary magma in the Kibblewhite Volcano. The MIs from the magnesian andesites were hosted in forsteritic olivine xenocrysts with a wide range of NiO contents (Fo90–92; 0.13–0.39 wt% NiO) and have similar major element compositions to the ankaramites but exhibit a wide range of CaO/Al2O3 (0.85–1.54). The trace element characteristics of the MIs from the magnesian andesites do not match those of the host rocks, indicating that they are not primary melts of the magnesian andesites but primitive basaltic melts generated before the magnesian andesites formed. Interestingly, the CaO/Al2O3 ratio of MIs from the magnesian andesites was negatively correlated with the NiO content of their host olivines. This correlation suggests that the composition of the primary basaltic magmas of the Kibblewhite Volcano changed continuously from peridotite-derived to ankaramitic. This correlation could not be explained by grain-scale process, crustal anatexis, or contribution of slab-derived carbonate-rich fluids. Instead, we propose that this correlation can be explained by the interaction of the ascending primary basaltic melts with the lithospheric mantle. During melt-mantle interaction, the assimilation of clinopyroxene and fractionation of olivine and orthopyroxene caused the CaO/Al2O3 ratio to increase in the melt and the Ni content to decrease. Furthermore, because the magnesian andesites have low CaO/Al2O3 ratios and could be derived from a clinopyroxene-poor mantle lithology, the interaction between the melt and mantle may also be closely related to the origin of the magnesian andesites at Kibblewhite Volcano. This interpretation provides a new perspective on the origin of the oceanic arc ankaramites and why primary andesitic and basaltic magmas coexist in the Kibblewhite Volcano.

Description: Highlights • Alkaline magmas of the TLTF island chain result from a subduction-modified mantle source and two-stage partial melting. • The role of mantle source and parental melt composition for high Cu-Au mineral potentials is important but limited. • A shallow crustal magma reservoir is key for epithermal ore formation. Abstract The Tabar-Lihir-Tanga-Feni (TLTF) island chain in northeastern Papua New Guinea formed by tectonic and alkaline to shoshonitic magmatic activity since the Pliocene. Several volcanic centers are Cusingle bondAu mineralized including the world-class Ladolam Au deposit and Conical Seamount south of Lihir. The latter has been recognized as a juvenile analogue to the Ladolam deposit located on-shore. Whereas the mineralization at Conical Seamount is reasonably well studied, the specific magmatic processes that promote epithermal mineralization at this seamount but not at others are poorly understood. Here, we present new petrological and geochemical data from Conical Seamount, and compare them with those from the barren (unmineralized) Edison, Tubaf and New World seamounts nearby. We focus on whole rock compositions and major and trace element analysis of melt inclusions and minerals including clinopyroxene, sulfide and magnetite. We combine our observations with modelled constraints on mantle source composition and partial melting as well as magma evolution. A first-stage melting leaves a residual mantle source enriched in Au. Second-stage melting of a previously subduction-metasomatized mantle generally promotes the transfer and concentration of metals and volatiles in the ascending melts. These magmas are unlikely to control ore formation as all seamounts show evidence for similar mantle sources and parental melt composition. However, the presence of a shallow crustal magma chamber is unique to Conical Seamount. It is characterized by frequent melt replenishments and extensive magma fractionation leading to sulfide and magmatic volatile saturation. These specific magma chamber processes lead to the pre-enrichment of the magma in chalcophile elements including Au, while sulfide saturation coeval with magmatic volatile exsolution provide the way for an effective Au transfer from the magmatic to the epithermal system.

Description: Highlights • First successful in situ DGT application in the deep ocean. • DGT-lability of dissolved (〈0.2 μm) Cu, Ni, Cd, Mn, As, V, REY differs depending on chemical speciation. • REY in deep ocean water can be almost quantitatively assessed with DGT. • Low Cu availability reflects dominating organic speciation. Abstract Geochemical behaviour and bio-availability of trace metals are closely related to their physical fractionation and chemical speciation. The DGT speciation technique allows the challenging assessment of labile concentrations of Mn, Cd, Cu, Ni, V, As, and REY in ocean waters. In this first deep-water in situ study of DGT-lability, we demonstrate the approach in bottom waters of the Clarion-Clipperton Zone in the central NE Pacific. In the dissolved fraction (〈0.2 μm), 70% to 100% of Cd, Ni, V, and REY, but only 25% of Cu and less than 50% of As were determined, reflecting their prevailing dominance of organic vs. inorganic complexation. This study demonstrates the applicability and sensitivity of DGT-passive samplers for trace metals as a suitable technique in monitoring of anthropogenic activities, such as deep seabed mining, as well as for natural process studies in abyssal environments.

Description: A revaluation of the relative sea-level (RSL) indicators in the Baia di Infreschi (Cilento, Southern Italy) supported by new 30 U/Th dating on speleothems indicates that the upper level of Lithophaga burrows identified by Bini et al. (2020) at ~9 m a.s.l. and correlated to the Last Interglacial (LIG) highstand should be referred to the highstand of the MIS 9e, whereas the local RSL for the highstand of the LIG is now reassessed at 5.3 ± 0.18 m a.s.l. The upper level of the Lithophaga marker can be followed for ~12 km along the coast, suggesting a substantial absence of important relative tectonic movements. In the Baia di Infreschi an additional marine indicator, a notch sealed by a flowstone dated ~110 ka, indicates several phases of RSL stationing below the maximum highstand of the LIG. The presence of flowstones as low as 2 m a.s.l. dated to the MIS 7 shows that the highstand of MIS 7 was probably below the present sea level. All these evidences allow us to reassess the stratigraphy of some archaeological caves in the area, indicating that the sedimentary successions preserved there are older than what was previously believed.

Description: Published

Description: 100212

Description: OSA2: Evoluzione climatica: effetti e loro mitigazione

Description: JCR Journal

Description: Earth System Literacy offers a rich matrix of narratives about (planet) Earth, World and Humans when interwoven with cultural artefacts (e.g. arts, history). Anthropogenic global change locks them together in a unifying framework. By making a distinction between reproduction, work (ergon, Greek) and civicness, there are narratives that convey what characterises the human condition today, including the material, social and historic settings of the Anthropocene.

Description: Published

Description: 445–449

Description: Animals have a deep evolutionary relationship with microbial symbionts, such that individual microbes or an entire microbial community can diverge alongside the host. Here, we explore these host-microbe relationships in Echinometra, a sea urchin genus that speciated with the Isthmus of Panama and throughout the Indo-West Pacific. We find that the eggs from five Echinometra species generally associate with a species-specific bacterial community and that the relatedness of these communities is largely congruent with host phylogeny. Microbiome divergence per million years was higher in more recent speciation events than in older ones. We, however, did not find any bacterial groups that displayed co-phylogeny with Echinometra. Together, these findings suggest that the evolutionary relationship between Echinometra and their microbiota operates at the community level. We find no evidence suggesting that the associated microbiota is the evolutionary driver of Echinometra speciation. Instead, divergence between Echinometra and their microbiota is likely the byproduct of ecological, geographic, and reproductive isolations.

Description: The Red Sea is an important example of a continental rift transitioning slowly to an oceanic basin. However, structures that can inform us of how that transition occurred have been poorly reported because deep seismic reflection data capable of imaging basement under the rift sediments are generally lacking publicly. Three lines of multichannel seismic reflection data have recently been published revealing structures on the Nubian side of the central part of the basin. In this study, we reassess these data in the light of recent studies of the central Red Sea. Over continental crust, the data reveal reflection sequences likely due to strata at or near the base of the evaporites, in two cases with varied dips suggesting the presence of syn-rift growth stratigraphy. Almost all of those reflections dip downwards towards the rift axis, not away as would be expected from tilted fault blocks of bookshelf faulting types. That observation, and low relief of basement, confirm inferences made earlier based on gravity anomalies that this part of the Red Sea lacks large-relief fault escarpments and is most likely a syn-rift sag basin. In the transition to oceanic crust, an abnormally broad magnetic anomaly of estimated Chron 5 age is found not to be associated with structures such as sills, so it likely arises from deeper sources. One of the seismic lines traverses a ridge in Bouguer gravity anomalies that runs across the axis. This feature has previously been interpreted as a volcanic ridge similar to those observed at other ultra-slow spreading ridges. The seismic data reveal diffuse basement reflections and confirm that the record immediately above basement lacks reflections typical of sedimentary strata. Both observations are consistent with the presence of oceanic crust. Modelling of gravity anomalies suggests the ridge is likely underlain by igneous intrusive rocks displacing mantle rocks, as expected for a volcanic ridge. The seismic data, combined with recently updated multibeam and high-resolution sparker seismic results, further suggest how the evaporite movements have been modulated by basement topography. These results add to our knowledge of the evaporite movements and continent-ocean transition structures in the central Red Sea.