Complex Geological History Research Articles

Tectonic evolution and structural geology of the Jurassic succession in the Zubair oil field, southern Iraq

This study investigates the structural style and tectonic evolution of Jurassic succession in southern Iraq, within the Zubair oil field, which are crucial for charging oil to the Cretaceous reservoirs, utilized 3-D seismic reflection data to explore its complex geological history. The field is located in the Mesopotamian plain on the northeast Arabian Plate in southern Iraq. Four folds recognized: Hammar, Shuaiba, Rafdyia, and Safwan, each shaped by specific geodynamic processes. Hammar, Shuaiba, and Safwan are characterized as salt-related folds, influenced by salt tectonics. Rafdyia is identified as a compression-related fold formed due to the convergence of the Arabian and Eurasian plates. Forty-seven faults were identified, with diversity patterns and spatial distributions suggesting a tectonic history marked by three distinct phases: extensional tectonics, extensional with concurrent salt activity, and plate convergence. These phases have created a series of graben structures that, along with the identified folds, highlight the role of three primary tectonic processes: basement tectonics, salt dynamics, and plate interactions in shaping the structural style of the Zubair oil field during the Jurassic time.

Vilyui and Priverkhoyansk Composite Tectono-Sedimentary Elements, Northeastern East Siberia

A vast region of the Northeastern Siberia west of the Verkhoyansk Range includes two large sedimentary basins, Vilyui and Priverkhoyansk. Combined, these basins constitute the Lena-Vilyui Petroleum Province, which contains the largest gas reserves in the northeastern Asia. Both basins have a long and complex geological history that resulted in the accumulation of over 14 km-thick succession of Upper Proterozoic, Paleozoic, Mesozoic and Cenozoic sedimentary rocks. According to the volume's terminology, we subdivide this sedimentary body into two composite tectono-sedimentary elements (CTSE), the Vilyui and Priverkhoyansk (VI CTSE and PV CTSE), which closely correspond to the same-named basins. The CTSEs consist of ten distinct tectono-sedimentary elements (TSEs), each representing a distinct tectonic setting. This region has been studied very irregularly. In total, more than 400 deep wells have been drilled, mostly within the VI CTSE and only a few tens - in the PV CTSE. Eleven gas and gas condensate accumulations have been discovered in the VI CTSE. The PV CTSE remains poorly explored with only two commercial discoveries made as of the present-day.

Geotourism and Geoeducation: A Holistic Approach for Socioeconomic Development in Rural Areas of Los Santos Municipality, Santander, Colombia

This study emphasizes the untapped geotourism and geoeducation potential in the Mesa de Los Santos region, situated within the Chicamocha Canyon in Colombia, renowned for its abundant geoheritage. Despite the region's geological richness, geotourism development opportunities have been overlooked, leaving its geoheritage largely unexplored for tourism. Focused on the georoute Refugio La Roca—Los Santos, the study identifies key geosites with significant potential for future geotourism endeavors. The Mesa de Los Santos region boasts a complex geological history and diverse geodiversity shaped by various natural phenomena. However, its full geotourism potential remains undiscovered. The georoute, incorporating natural and cultural heritage, is strategically designed for geotourism and geoeducation, aiming at fostering geoconservation in rural areas. Educational and interpretive panels are employed as didactic resources to enlighten tourists about the natural phenomena shaping the landscape, enhancing their overall experience and understanding. By integrating geoethical considerations into geosite management, the study proposes achieving sustainable geoconservation in the Chicamocha Canyon territory. This approach not only contributes to preserving the region's geological uniqueness but also provides a platform for socio-economic development in rural areas. The study envisions creating meaningful experiences that attract tourists while benefiting local communities, thereby promoting holistic and sustainable rural development.

Resistivity anomalies in the shallow and deep crust beneath West Tasmania from a broadband magnetotelluric 2D transect

West Tasmania has a complex geological history, including a Cambrian tectonic collision and related orogenesis, which formed ore deposits in a volcanic hosted massive sulfide (VHMS) setting. While the topography and dense vegetation covering the area presents challenges for on-ground investigations, the area is relatively well-studied such that 3D geological models are available. This contribution presents results of a broadband magnetotelluric (MT) 2D transect across the area (∼30 stations over a ∼ 80 km line, deployed in early 2016) that enables a combined interpretation of regional-scale geoelectric and geological structures. After accounting for noise, distortion and geoelectric strike; we produce 2D resistivity models using OCCAM2D inversion. We infer low resistivity anomalies in the shallow ( < 3 km ), mid (3–8 km) and deeper crust. Along this MT transect the shallow and mid crust low resistivity zones correspond to major crustal faults. Deep low resistivity features in the east of the transect suggest fluid pathways associated with metamorphism along the western boundary of the Tyennan block during the Cambrian Tyennan Orogeny, while others potentially represent the metasomatism of lower crustal rocks and fluid pathways converging into the mid crust.

Miocene magmatism in Northern Tunisia and its geodynamic implications

The Nefza igneous rocks in Northern Tunisia belong to the Miocene magmatic belt extending from Northern Tunisia to Morocco and consist mainly of Serravallian–Tortonian granodiorite and rhyodacite (~ 14–8 Ma) and Messinian basalts (~ 8–6 Ma). Differences in geochemical composition between units have been interpreted to be the result of geodynamic processes in the upper mantle below the Western Mediterranean area, but their implications for Northern Tunisia are unclear due to limited data. In this contribution, we present an updated geodynamic model for Northern Tunisia based on new petrographic and whole-rock geochemical results from the Nefza magmatic suite from outcrop and OB45 drill core samples. Petrographic observations show that rhyodacites display a microlithic texture with quartz, plagioclase, K-feldspar, biotite, and glass, whilst granodiorite contains plagioclase, quartz and exhibits fine-grained texture with a 2–3 mm crystal size. The Nefza magmatic rocks are overprinted by multiple weathering and alteration processes with loss of ignition (LOI) ranging between 0.88 and more than 5 wt%. The linear relationships between mobile elements (Ca, Na, P, K, Mg, Si), large-ion lithophile elements (LILE), and LOI suggest element mobilisation during alteration. Major and trace element compositions show the Nefza magmatic rocks plot in the rhyolite, dacite, and trachydacite fields for felsic rocks and plot in the basalt and trachybasalt fields for mafic rocks. Granodiorite and rhyodacite rocks exhibit negative Eu anomalies and a LILE enrichment (Rb, Ba, Pb) relative to high-field-strength elements (HFSE: Nb, Ta, Hf, Zr, REE). Mafic rocks enriched in LILE show geochemical characteristics between calc-alkaline and alkaline trends. Comparison with nearby regions suggests that the generation of calc-alkaline magmas resulted from the partial melting of the lithospheric mantle due to slab break-off or tearing in Eastern Algeria. The upward flow of asthenospheric material through the widening tear in the sinking slab leads to partial melting of the mantle and shallowing of the lithosphere–asthenosphere boundary, ultimately leading to the formation of alkaline magma. The Nefza geochemical variations underscore Mediterranean upper mantle heterogeneity, offering crucial insights into Mediterranean geodynamics. More studies are needed to constrain mantle dynamics and the region’s complex geological history.

Assessment of river ecological status in the French West Indies based on diatom flora

The Water Framework Directive (WFD) requires member states to routinely assess the river ecological status using community-based indices. However, there is still a lack of published WFD-compliant methods for the French West Indies, especially using diatom-based indices. Martinique and Guadeloupe exhibit diverse landscapes shaped by their complex geological history and tropical climatic conditions. These strong particularities make the existing indices developed for the European mainland unusable. Based on diatom sampling from to 2013 (607 samples) and through multivariate analyses, we developed the Indice Diatomique des Antilles (IDA). We first identified the key abiotic factors influencing diatom communities on both islands, and then characterized taxon sensitivity by considering their presence probability along a pressure gradient.. The index was based on the presence and relative abundance of these taxa in each sample. The last step consisted of using new data from the 2014–2022 sampling surveys (457 samples) as a validation dataset to verify IDA accuracy. Our results suggest that the IDA methodology is well designed to assess the ecological status of rivers in the West Indies.

The gas hydrate system of the western Black Sea Basin

The basin-scale distribution of gas hydrates and methane migration pathways in the western Black Sea remains enigmatic, owing to the region's complex geological history. Characterizing the abundant gas hydrate accumulations across temporal scales poses significant challenges. In this study, we developed and applied a 3D large-scale numerical model to study the formation, development, and fate of natural gas hydrate systems in the western Black Sea sub-basin. Our model enables us to simulate the dynamic evolution of basin geometry and facies distribution over the last 98 million years and under dynamically changing boundary conditions, e.g. due to sea-level changes. Our study estimates the total volume of gas hydrates stored within western Black Sea sediments at ∼14,607 MtC, equivalent to ∼30,073 × 1011 m3 of CH4 (at STP conditions) which is about 5 times higher than average gas hydrate density at continental margins. Our findings reveal three distinct mechanisms driving gas hydrate reservoir formation within the reconstructed sub-basin: gas hydrate recycling zones, chimney-like structure formation, and gas hydrate deposits associated with paleo-deep sea fans. We identified and simulated key controlling parameters, related to methane migration pathways and regional geomorphology, governing each type of hydrate formation. Subsequently, we conduct a detailed analysis of regional gas hydrate systems, focusing on the Dniepr paleo-fan system, the Danube paleo-fan region, multiple offshore locations near Turkey, and the central Black Sea area. Furthermore, we investigate various biogenic methane formation kinetics and their impact on basin-scale methane generation. Our sensitivity studies enable us to predict the optimal temperature range for microbial activity driving methanogenesis in the Black Sea sediments at 30 °C–40 °C. Overall, our study provides a novel understanding and quantitative correlation between methane generation, migration, and storage in the form of gas hydrates on a basin-scale in the western Black Sea.

Two stages of gold mineralization in the Hebaoshan deposit: Evidence from the U-Pb dating and trace element geochemistry of rutile, monazite and apatite

The Hebaoshan gold deposit (41.5 t Au @ 3.5 g/t) is located in the southeastern region of the South China Block, central part of the Wuyishan metallogenic belt. The ore-hosting rocks in this area are predominantly Precambrian metasedimentary rocks and Caledonian granitic rocks. Two hydrothermal mineralization stages can be distinguished: a quartz-sericite-pyrite-native gold (stage I) and a chlorite-quartz-sericite-chalcopyrite-electrum (stage II), with hydrothermal monazite and rutile are firstly identified in separate stages. The complex geological history of the region has resulted in ongoing debates regarding the age of gold mineralization and the genesis of the major gold deposits in this area. In order to precisely constrain the mineralization age of the deposit and further establish a genetic model for the ore deposit, LA-ICP-MS U-Pb dating and trace element analysis on accessory minerals were conducted. Based on the textures mineral assemblages, and geochemical features of the accessory minerals, magmatic apatite, hydrothermal rutile, and both magmatic and hydrothermal monazite were identified. The U-Pb ages of magmatic apatite and monazite are determined to be 445.3 ± 15.80, 441.3 ± 15.10 Ma and 446.57 ± 1.03 Ma, respectively, suggesting that these ages represent the emplacement ages of the Caledonian intrusive rocks. The ages of hydrothermal monazite and hydrothermal rutile are determined to be 238.46 ± 2.01 Ma (single-mineral analysis), 238.46 ± 2.01 Ma (in-suit analysis) and 179.54 ± 7.28 Ma, respectively, suggesting that represent two mineralization events during the Late Triassic to early Jurassic in the Hebaoshan area. These data provide new constraints on the mineralization process in the Hebaoshan deposit and excludes the link between gold mineralization and the intrusion of the Caledonian granites. Regionally, It is speculated that the two mineralization events at Hebaoshan are respectively associated with intracontinental orogenic movements between the Yangtze Block and Cathaysia Block, the flat-slab subduction of the Paleo-Pacific Plate (stage I), and the subsequent extensional tectonics related to the collision between the Yangtze Block and Cathaysia Block (stage II).Our study indicates that the timing of multiple episodic mineralization can be constrained by analysis of accessory minerals, which provides a geological basis for better genetic model for the deposit and provide geological evidence for unraveling the relationships between magmatic activities and mineralization events in the region.

Geologic History of the Amundsen Crater Region Near the Lunar South Pole: Basis for Future Exploration

We provide the first detailed 1:100,000 scale geomorphologic map of the ∼100 km Amundsen crater region, which is of high scientific relevance for future exploration, e.g., NASA’s VIPER mission, the Artemis program, and the Chinese International Lunar Research Station. We investigated the complex geological history of the region before and after the formation of Amundsen crater on the rims of the South Pole–Aitken (SPA) and Amundsen–Ganswindt basins. We present a new Amundsen crater formation age of ∼4.04 Ga, which, in contrast to previously derived ages, is based on non-light-plains terrain. The estimated maximum excavation depth for Amundsen crater is ∼8 km, and elevated concentrations of FeO near the crater suggest that Amundsen may have redistributed SPA-derived materials. Plains materials of various kinds were observed both inside and outside Amundsen crater and are estimated to be up to 350 m thick and ∼3.8 Ga old. A less cratered, tens of meters thick mantling unit indicates a resurfacing event ∼3.7 Ga ago. We highlight five potential exploration sites that satisfy technical constraints (such as shallow slopes, solar illumination, and Earth visibility), provide materials that can be sampled, and are capable of addressing multiple science objectives. Due to its accessibility and traversability, combined with its geologic diversity, proximity of permanently shadowed regions for studying volatile processes, and ability to address multiple science objectives, we confirm and reinforce the Amundsen crater region as a high-priority landing and exploration site.

Marine introgressions and Andean uplift have driven diversification in neotropical Monkey tree frogs (Anura, Phyllomedusinae).

The species richness in the Neotropics has been linked to environmental heterogeneity and a complex geological history. We evaluated which biogeographic processes were associated with the diversification of Monkey tree frogs, an endemic clade from the Neotropics. We tested two competing hypotheses: the diversification of Phyllomedusinae occurred either in a "south-north" or a "north-south" direction in the Neotropics. We also hypothesized that marine introgressions and Andean uplift had a crucial role in promoting their diversification. We used 13 molecular markers in a Bayesian analysis to infer phylogenetic relationships among 57 species of Phyllomedusinae and to estimate their divergence times. We estimated ancestral ranges based on 12 biogeographic units considering the landscape modifications of the Neotropical region. We found that the Phyllomedusinae hypothetical ancestor range was probably widespread throughout South America, from Western Amazon to Southern Atlantic Forest, at 29.5 Mya. The Phyllomedusines' ancestor must have initially diverged through vicariance, generally followed by jump-dispersals and sympatric speciation. Dispersal among areas occurred mostly from Western Amazonia towards Northern Andes and the South American diagonal of dry landscapes, a divergent pattern from both "south-north" and "north-south" diversification hypotheses. Our results revealed a complex diversification process of Monkey tree frogs, occurring simultaneously with the orogeny of Northern Andes and the South American marine introgressions in the last 30 million years.

A Tilted Broad Plume Underneath the Greenland Cratonic Keels

AbstractTo advance our comprehension of the complex geological history and mantle dynamics in the North Atlantic region, we employ all available broadband seismic data recorded in Greenland to reveal an abnormal mantle transition zone (MTZ) structure. Central and eastern Greenland exhibits depressed 410 and 660 km discontinuities (d410 and d660, respectively) bordering the MTZ, indicative of a substantial thermal anomaly associated with an underlying plume, surpassing the 1,800°C threshold for post‐garnet phase transitions at the d660. Variations in MTZ thickness across Greenland stem from differing temperature anomalies at the d410 and d660, possibly linked to a tilted plume within the MTZ. These findings corroborate geodynamic models, elucidating the interaction between post‐garnet phase transitions and upwelling plumes. The results shed light on the origin of the enigmatic Icelandic hotspot track and its influence on the thermal and lithospheric structures beneath Greenland.

Ancient diversity within Diporodrilus (Crassiclitellata, Annelida) clarify the historical biogeography of Corso-Sardinian earthworms

Corsica and Sardinia are amongst the largest islands of the Western Mediterranean. Their complex geological history included belonging to the European–Iberian continental margin (close to current-day Catalonia and Provence) and varying degrees of isolation for the last 30 million years, leading to peculiar, highly endemic faunas and floras. This is especially true for their earthworm faunas, which include endemic species of several Lumbricoidea genera and the endemic family (or subfamily) Diporodrilidae. Only three species have been described for the morphologically unique Diporodrilus, but there exists evidence for wide morphological variability within them and the existence of several species-level genetic lineages within Corsica. This work aimed to investigate the genetic diversity and phylogenetic relationships between the genetic lineages of Diporodrilus from Corsica and Sardinia (based on the sequences of 5 mito-nuclear markers), to perform an integrative systematics revision combining species delimitation techniques and morphological data, and to obtain a time-calibrated phylogeny of Diporodrilus and other Corso-Sardinian Lumbricoidea. Within 15 populations of the morphospecies Diporodrilus omodeoi and Diporodrilus pilosus across Corsica and Sardinia, 10 species-level genetic lineages were detected. Phylogenetic independence, high genetic divergence and morphological differences provided the support for the description of five new pseudocryptic species: Diporodrilus rotundus sp. nov., Di. jorgei sp. nov., Di. minor sp. nov., Di. meridionalis sp. nov. and Di. telti sp. nov. Time-calibrated phylogenetic inference estimated the age for genus Diporodrilus at 65.9 Mya; even if other Corso-Sardinian genera were significantly younger, all of them presented deep divergences predating the break-off of the microplate from the continent. The almost threefold increase in the known diversity of Diporodrilus stresses the need for comprehensive earthworm diversity inventories in both Sardinia and Corsica, and for studies on their ecological role and conservation status. The close correspondence between some geological and cladogenetic events suggest that the distribution of Corso-Sardinian earthworms could be used to inform standing geological controversies.

Genetic diversity, spatial connectivity, and population structure of Asian silurid catfish Wallago attu (Bloch and Schneider, 1801) in the Ganga River System: insights from mitochondrial DNA analysis.

The Ganga River System (GRS) is a biodiversity hotspot, its ecological richness is shaped by a complex geological history. In this study, we examined the genetic diversity, spatial connectivity, and population structure of the Asian Silurid catfish, Wallago attu, across seven tributaries of the GRS. We employed three mitochondrial DNA (mtDNA) regions: cytochrome c oxidase subunit I (COXI), cytochrome b (Cyt b), and control region (CR). Our comprehensive dataset encompassed 2420bp of mtDNA, derived from 176 W. attu individuals across 19 sampling sites within the seven rivers of GRS. Our findings revealed high gene diversity (Hd:0.99) within W. attu populations. Analysis of Molecular Variance (AMOVA) highlighted that maximum genetic variations were attributed within the populations, and the observed genetic differentiation among the seven populations of W. attu ranged from low to moderate. Network analysis uncovered the presence of three distinct genetic clades, showing no specific association with seven studied rivers. Bayesian skyline plots provided insights into the demographic history of W. attu, suggesting a recent population expansion estimated to have occurred approximately 0.04million years ago (mya) during the Pleistocene epoch. These results significantly enhance our understanding of the genetic diversity and spatial connectivity of W. attu, serving as a vital foundation for developing informed conservation strategies and the sustainable management of this economically valuable resource within the Ganga River System.

Kinematic reconstruction of the Jurassic intraplate rift deformation in the Northern Carnarvon Basin, Australia

Intraplate rift basins, like the inboard sub-basins of the Northern Carnarvon Basin (NCB), host rich energy resources, but their complex geological histories complicate exploration efforts. The paleo-deformation that formed these intraplate rifts also controlled their resource systems distribution. Hence, understanding their complex kinematic and tectonostratigraphic histories can optimise exploration and targeting. However, without forming oceanic seafloor, these regions lack adjacent magnetic seafloor isochrons to constrain paleo-positions of rift margins, rendering kinematic reconstruction nearly impossible. We present a method that constrains the spatiotemporal paleo-distribution of intraplate rift-related deformation and precisely locates paleo-positions of rift margins using time-dependent backstripped subsidence rasters. This method correlates areas with high subsidence rates with rifted regions within extension settings, and we apply it to reconstruct the kinematic evolution of the NCB sub-basin rift.Reconstruction results indicate that the Late Triassic – Early Jurassic extension initiated rifting in the nearshore parts of the NCB, creating Exmouth and Barrow sub-basin grabens at 8 mm/yr maximum rift widening rates. Rifting shifted northeastwards into the Dampier and Beagle regions from Mid Jurassic to Early Cretaceous. Rifting rates in the nearshore regions slowed at ∼155 Ma, coinciding with the Argoland – Australia separation and seafloor spreading within the outboard Argo region. The rates increased again at ∼145 Ma during the Tithonian extension and then decreased significantly at ∼120 Ma during the seafloor spreading in the Cuvier and Gascoyne regions. The temporal correlation between Gondwana dispersal events and the nearshore sub-basin rift evolution suggests that the sub-basins were part of a broader deformation zone across the margin. However, strain localised and triggered breakup and seafloor spreading within the outboard Argo, Gascoyne, and Cuvier regions. Such breakups released extension forces and caused rift cessation in the nearshore NCB sub-basins.

Reconstruction of the deformation history of an active fault: implications from the Atera Fault, Central Japan

Atera Fault clay gouges were collected for age dating near Kawaue, Nakatsugawa City, Central Japan, and the results integrated within its complex geological history. The results form an internally consistent data set constrained by extensive geochronological data (AFTA, ZFTA, CHIME) and support the application of gouge dating in constraining timing of brittle deformation in Central Japan. The Atera illite age data complete recently obtained limited illite fault gouge age data from underground exposure in the Toki Granite; the new illite age data are identical within error. The age of the heterogenous welded tuff breccia zone (Atera 1) ranges from 40.6 ± 1.0 Ma to 60.0 ± 1.4 Ma, whereas ages of the fault core gouge sample (Atera 2) range from 41.8 ± 1.0 Ma to 52.7 ± 1.2 Ma. The finest < 0.1 µm fraction of the fault breccia and fault core gouge yield ages around 41 Ma, identical within error. The new illite age data indicate brittle faulting and a following geothermal event occurring in the Paleogene–Eocene, similar to the nearby Toki Granite area and confirm they were both synchronous with a post-intrusive pluton exhumation. The Atera Fault illite age data provide additional insights into an integrated, regional-scale record of the tectonic displacement of Central Japan and might be influenced by large-scale tectonic processes such as the Emperor sea mount kink around 55 to 46 Ma with fault initiation around 50 Ma and brittle fault cessation or reactivation around 40 Ma in the Eocene.Graphical

Highly divergent sympatric lineages of Leptotila verreauxi (Aves: Columbidae) suggest a secondary contact area in the Isthmus of Tehuantepec, Mexico

Due to a complex geological and biotic history, the Isthmus of Tehuantepec (IT), has been long recognized as a driver for the evolutionary divergence of numerous lowland and highland taxa. Widely distributed in the lowlands of the American continent, the White-Tipped Dove (Leptotila verreauxi) is a polytypic species with 13 recognized subspecies. Four of these have been recorded in Mexico, and the distribution of three abuts at the IT, suggesting a contact zone. To estimate phylogenetic patterns, divergence times and genetic differentiation, we examined two mtDNA (ND2 and COI) and one nDNA (β-fibint 7) markers. We also used correlative ecological niche models (ENM) to assess whether ecological differences across the IT may have acted as a biogeographical boundary. We estimated paleodistributions during the Middle Holocene, Last Glacial Maximum and Last Interglacial, to evaluate the influence of climate changes on the distribution and demographic changes. Our results showed genetically distinct lineages that diverged approximately 2.5 million years ago. Climatic and ecological factors may have played a dual role in promoting differentiation, but also in the formation of a secondary contact zone in the southern IT. Our ecological niche comparisons indicated that the ecological niche of sympatric lineages at the IT are not identical, suggesting niches divergence; in addition, environmental niche models across the region indicated no abrupt biogeographic barriers, but the presence of regions with low suitability. These results suggest that genetic differentiation originated by a vicariant event probably related to environmental factors, favored the evolution of different ecological niches. Also, the absence of a biogeographic barrier but the presence of less suitable areas in the contact regions, suggest that secondary contact zones may be also maintained by climatic factors for the eastern group, but also by biotic interactions for the western group.

Biotic assemblages of gelatinous zooplankton in the Gulf of Mexico and adjacent waters: An evolutionary biogeographic approach.

Gelatinous zooplankton constitutes a polyphyletic group with a convergent evolutionary history and poorly known biogeographical patterns. In the Gulf of Mexico, a region with complex geological, hydrological, and biotic histories, the study of this group has been limited to taxonomical and ecological aspects. In this study, we implemented a track analysis to identify distributional patterns of gelatinous zooplankton in the Gulf of Mexico and adjacent waters based on a dataset of 6067 occurrence records corresponding to Hydrozoa, Scyphozoa, Cubozoa, Ctenophora, Chaetognatha, Thaliacea, and Appendicularia. Information was compiled from the Global Biodiversity Facility Information (GBIF) and Ocean Biodiversity Information System (OBIS) databases and peer-reviewed literature. Individual tracks were constructed by joining the minimum distance between the occurrence localities of each taxon using a minimum spanning tree algorithm. We identified generalized tracks using parsimony analysis of endemicity with progressive character elimination (PAE-PCE). The areas where different generalized tracks overlapped were considered to represent panbiogeographical nodes. Seven generalized tracks (two with nested patterns) and six panbiogeographical nodes were recognized, mainly in neritic zones. The distributional patterns of gelatinous zooplankton allowed us to identify four biogeographic areas, supporting previously proposed biogeographic schemes. Gelatinous zooplankton in the Gulf of Mexico showed a convergent spatial distribution that can be explained by vicariant and dispersal events. The historical biogeography of the gelatinous biotas of the Gulf of Mexico has been little studied compared to ecological approaches, and the lack of integrative studies considering historical patterns is evident. This type of research is fundamental to understanding the evolutionary history of natural resources from a spatial perspective, identifying sites of biodiversity and endemism, and establishing a biogeographic baseline of the region for further studies.

Geochemical exploration and baseline from marine sediments in the fjords, channels and straits of Magellan, Chilean Patagonia

AbstractChilean Patagonia has a complex geological history dominated recently by Quaternary glaciers and rivers that have carried sediments from the mountains to depositional environments within marine fjords and channels. Although much is known about onshore placer deposits, little is known about these deposits and depositional systems in the offshore realm. This study analyzes the chemistry and mineralogy of marine sediments collected in the Strait of Magellan and around the region. This study aims to comprehend the distribution, concentration and provenance of critical/strategic elements and precious metals. In collaboration with the Cabo de Hornos research vessel of the Chilean Navy, 63 sediment samples were collected using a box core sampler, complemented with coastal beach samples. These samples underwent petrographic and geochemical analysis. The predominant opaque minerals identified in these samples are mainly iron oxides (magnetite–hematite‐ilmenite) and sulfides (pyrite, exceptional greigite). A comparison of the average element concentration for all samples for different baseline values revealed the following findings. As, Bi, Li, Re, Sb, Se, Te, and Pd exhibit positive anomalies for the Upper Continental Crust (UCC); Re, Se, and Sr. exhibit positive anomalies for Marine Sediments (MS), and Bi, Cs, Li, Re, Se, Sn, and Te show positive anomalies relative to the Folded Belt (FB). The main contrast anomalies occur in the following locations. Almirantazgo Sound (Sn, Ba, Sb, and Tm); Concepción Channel (Re, Sr., and Te); Smyth Channel (Mn, Re, Sb, Sr., Te, and Se); Almirante Montt Gulf (Mn, Re, and Sb); Nelson Strait (Re, Sr., and Te); Ancho Pass (Ti and Sr); Europa Fjord (Bi and Sn); Del Hambre Pass (Sr); Magdalena Channel and Sound (Sr); Froward Pass (Se), and Whiteside Channel (Mn). Regarding precious metals, silver exhibits contrasting anomalies relative to the UCC in seafloor sediments in the Almirante Montt Gulf (0.161 ppm) and Concepción Channel (0.101 ppm). Palladium contrast anomaly is observed in the Peel Estuary (8 ppb) and Platinum contrast anomalies occur in the Concepción (3 and 5 ppb) and Smyth Channels (4 ppb). Finally, gold, in comparison to the South Patagonian Batholith, reveals contrasting anomalies that occur in the Concepción Channel (8 ppb), Peel Estuary (6.7 and 8 ppb), Nelson Strait (7 ppb), Almirante Montt Gulf (6 ppb), Forward Pass (8 ppb), and Ancho Pass (7 ppb). In summary, the presented results provide valuable insights into the geological and geochemical baseline of the region, offering a better understanding of the relationship with depositional basins and source zones onshore during the late‐Quaternary.

Geology of the Mutis Complex, Miomaffo, West Timor

Mesozoic forearc assemblages are widespread across Indonesia, and these are also exposed in the overthrust terranes on Timor. The oldest rocks in the allochthonous Mutis Complex, West Timor are Mesozoic basaltic volcaniclastic rocks and melange containing blocks of normal mid-ocean ridge basalt (N-MORB) basalt (194 ± 5 Ma), amphibolite (metamorphism at 184 ± 6 Ma), garnet and actinolite-bearing schists, arkosic sandstone and volcanogenic sedimentary rocks. Based on the large component of Jurassic material, these rocks were probably derived from the Woyla terrane. The eastern part of the Miomaffo massif is complexly deformed with a dominant foliation overprinted by several fold and fault events including late normal cataclastic zones. This sequence is intruded by calc-alkaline andesitic dykes (possibly in the Eocene). The Central Sector of the massif is a block of high-strain greenschist facies rocks where the primary texture can no longer be recognised, but the bulk composition is the same as the volcaniclastic rocks in the east. Further west is an amphibolite facies metamorphic province. Amphibolite from the Western Sector have the same N-MORB composition as the basalt in the east, but the gneissic rocks have a higher proportion of arc-sourced protoliths. The peak metamorphic conditions were 650 °C and 0.9 GPa. This metamorphic event occurred at 37 Ma, reflecting subduction on the southeast margin of Sundaland, whereas the low-grade Mesozoic metamorphism of the Eastern Sector of the massif occurred in the accretionary prism along the Woyla Arc. The Mutis Complex at Miomaffo demonstrates the complex geological history of Mesozoic rocks in eastern Indonesia.

Species Delimitation in a Polyploid Group of Iberian Jasione (Campanulaceae) Unveils Coherence between Cryptic Speciation and Biogeographical Regionalization.

Groups with morphological stasis are an interesting framework to address putative cryptic species that may be hidden behind traditional taxonomic treatments, particularly when distribution ranges suggest disjunct and environmentally heterogeneous biogeographic patterns. New hypotheses of delimitation of evolutionary independent units can lead to the identification of different biogeographic processes, laying the foundation to investigate their historical and ecological significance. Jasione is a plant genus with a distribution centered in the Mediterranean basin, characterized by significant morphological stasis. Within the western Mediterranean J. gr. crispa species complex, J. sessiliflora s.l. and allied taxa form a distinct group, occupying environmentally diverse regions. At least two ploidy levels, diploid and tetraploid, are known to occur in the group. The internal variability is assessed with phylogenetic tools, viz. GMYC and ASAP, for species delimitation. The results are compared with other lines of evidence, including morphology and cytology. The fitting of distribution patterns of the inferred entities to chorological subprovinces is also used as a biogeographical and environmental framework to test the species hypothesis. Despite the scarcity of diagnostic morphological characters in the group, phylogenetic delimitation supports the description of at least one cryptic species, a narrow endemic in the NE Iberian Peninsula. Moreover, the results support the segregation of a thermophilic group of populations in eastern Iberia from J. sessiliflora. Ploidy variation from a wide geographical survey supports the systematic rearrangement suggested by species delimitation. Taxonomic reorganization in J. sessiliflora s.l. would allow ecological interpretations of distribution patterns in great accordance with biogeographical regionalization at the subprovince level, supporting geobotanical boundaries as a framework to interpret species ecological coherence of cryptic lineages. These results suggest that species differentiation, together with geographic isolation and polyploidization, is associated with adaptation to different environments, shifting from more to less thermophilic conditions. Thus, the recognition of concealed evolutionary entities is essential to correctly interpret biogeographical patterns in regions with a complex geologic and evolutionary history, such as the Mediterranean basin, and biogeographical units emerge as biologically sound frameworks to test the species hypothesis.