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Dating of igneous rocks from paleo-island arc complexes of orogenic belts makes it possible to determine the precise timing of subduction processes that occurred during the formation of the orogen. Within the central (East Transbaikal) part of the Mongol–Okhotsk orogenic belt, the Kamenka island-arc terrane is an example of such a complex. Its intrusive part is included into the Bereya complex, represented by a gabbro-diorite-tonalite-plagiogranite series of rocks demonstrating subduction geochemical characteristics. The dating of zircons from acidic rocks of this complex by the U–Pb classical method showed that they were formed in a narrow time interval of 203 ± 1–205 ± 1 Ma, which corresponds to the Norian–Rhaetian boundary of the Late Triassic. Taking into account the previously obtained age of the diorites (254 ± 5 Ma), the timing of formation of the entire series of the intrusive rocks is about 50 Ma, thus indicating the probable subduction along the northern (in modern coordinates) margin of the Mongol–Okhotsk Paleocean under the Siberian paleocontinent in the Late Permian – Late Triassic. The diorites of the first phase have positive values of εND(254 Ma) = 3.2–3.6 (TNd(DM) = 879–994 Ma), and the plagiogranites have ɛND(205 Ma) = 2.3–3.5 (TNd(DM) = 859–1028 Ma), which points to the relationship between these rocks and the substance of the depleted mantle source and is consistent with the Sm–Nd isotope characteristics of the juvenile crust of the Central Asian orogenic belt. [ABSTRACT FROM AUTHOR]

High-pressure and ultra-high-pressure metamorphic terrains display an internal architecture consisting of a pile (or stack) of several coherent tectonic thrust sheets or units. Their identification is fundamental for understanding the scale and mechanisms active during subduction and exhumation of these crustal slices. This study investigates the geometry of the northern Dora-Maira Massif and the kinematics of the major tectonic boundaries, combining field and geochronological data. The tectonic stack of the northern Dora-Maira Massif comprises the following units. The lowermost unit (the Pinerolo Unit) is mainly characterized by Upper Carboniferous fluvio-lacustrine (meta-)sediments. The Pinerolo unit is overthrust by a pre-Carboniferous basement. The latter is subdivided in two tectonic units (the Chasteiran and Muret Units) with different Alpine metamorphism (ultra-high-pressure and high-pressure, respectively). The pre-Carboniferous basement of the Muret Unit is thicker than previously thought for two main reasons. Firstly, some paragneisses, traditionally assumed to be Carboniferous and/or Permian in age, display detrital zircon ages indicating a main source at about 600 Ma. Secondly, three samples of the Granero Orthogneiss, previously assumed to be a Permian intrusive body, have provided zircon U–Pb ages of 447 ± 1 Ma, 456 ± 2 Ma and 440 ± 2 Ma, indicating a late Ordovician or early Silurian age for the protoliths. The uppermost unit (the Serre Unit) comprises porphyritic (meta-) volcanic and volcaniclastic rocks dated to the Permian (271 ± 2 Ma), on top of which remnants of the Mesozoic cover is preserved. Detailed mapping of an area about 140 km2 shows that (i) the ultra-high pressure Chasteiran Unit is localized at the boundary between the Pinerolo and Muret Units, (ii) the Granero Orthogneiss may be considered as the mylonitic sole of the Muret Unit, characterized by a top-to-W sense of shear, and (iii) the contact between the Muret and Serre Units displays ductile-to brittle structures (La Fracho Shear Zone), indicating a top-to-the-NW displacement of the hangingwall with respect to the footwall. A final episode of brittle faulting, cutting across the nappe stack (the Trossieri Fault), indicates an extensional stage in the core of the Alpine belt, as previously documented in more external zones. This work provides a necessary and robust basis before an accurate discussion of processes acting during continental subduction of the Dora-Maira Massif may be understood. [ABSTRACT FROM AUTHOR]

The Fang'an gold deposit in the Wuhe area, Anhui Province, is located in the area adjacent to the Bengbu Uplift and Wuhe Platform Depression in the southeastern part of North China. This study aimed to determine the deposit's mineralization age and the source of its metallogenic materials and mineralization processes through investigations into its geological characteristics, Rb–Sr isotopes, and S–Pb isotopes. The orebodies of the Fang'an gold deposit in the Neoarchean Xigudui Formation primarily exhibit a vein-type structure. The ore-forming process can be divided into four stages: (i) the quartz stage (Py1); (ii) the quartz–pyrite stage (Py2); (iii) the polymetallic sulfide stage (Py3); and (iv) the carbonate stage. Of these, the main mineralization stage is also the main period in which gold mineralization occurs. In situ sulfur isotope results of pyrite (Py1 to Py3) in the first three mineralization stages, suggesting a contribution of sulfur from crust–mantle magmatic fluids. The δ34S values for Py2 (average 5.51‰) are higher than Py1 (average 4.45‰) and showed that the magmatic fluids mixed with meteoric waters. The δ34S values for Py3 (average 5.18‰) are lower than Py2 (average 5.51‰), revealing that it related fluid immiscibility. The lead isotopic compositions of sulfides within the ores possessed 206Pb/204Pb ratios ranging from 16.759 to 16.93, 207Pb/204Pb ratios ranging from 15.311 to 15.402, and 208Pb/204Pb ratios ranging from 37.158 to 37.548. These lead data were plotted close to the Xigudui Formation, relatively distant from the Mesozoic granites, indicating that the Xigudui Formation was the source of lead for the Late Mesozoic ores of the deposit. Taken together, due to the degassing of mantle-derived magma in the shallow parts of the crust, it can be determined that the sources of ore-forming sulfur and lead were crust–mantle magmatic activities in the Wuhe area. Rb–Sr dating of pyrite from Fang'an gold deposit reveals that the mineralization occurred at 126.89 ± 0.58 Ma. Considering the previous research into the dating of magmatic rocks in the Wuhe area, we propose that the genesis of the Fang'an gold deposit is closely associated with magmatic activities in the area at around 130 Ma. [ABSTRACT FROM AUTHOR]

In this study, zircon U‐Pb dating of volcanic rocks from the Zhongba ophiolite of the Yarlung Zangbo Suture Zone (YZSZ) in southern Xizang (Tibet) yielded an age of 247 ± 3 Ma. According to whole rock geochemical and Sr‐Nd‐Pb isotopic data, the Early Triassic samples could be divided into two groups: Group 1 with P‐MORB affinity, showing initial 87Sr/86Sr ratios of 0.70253–0.70602, εNd(t) values of 4.2–5.3, (206Pb/204Pb)t ratios of 16.353–18.222, (207Pb/204Pb)t ratios of 15.454–15.564, and (208Pb/204Pb)t ratios of 35.665–38.136; Group 2 with OIB affinity, showing initial 87Sr/86Sr ratios of 0.70249–0.70513, εNd(t) values of 4.4–4.9, (206Pb/204Pb)t ratios of 17.140–18.328, (207Pb/204Pb)t ratios of 15.491–15.575, and (208Pb/204Pb)t ratios of 36.051–38.247. Group 2 rocks formed by partial melting of the mantle source enriched by a former plume, and assimilated continental crustal material during melt ascension. The formation of Group 1 rocks corresponds to the mixing of OIB melts, with the same components as Group 2 and N‐MORBs. The Zhongba Early Triassic rocks belong to the continental margin type ophiolite and formed in the continental–oceanic transition zone during the initial opening of the Neo‐Tethys in southern Xizang (Tibet). [ABSTRACT FROM AUTHOR]

In recent decades, East Borneo has become an increasingly important archaeological "hot-spot" in Island Southeast Asia as a result of early dates for rock art ca. 38,000 BP and the greater number of excavated sites that support a much longer period of human occupation. However, the chronology of settlement and adaptation to environmental changes during the Pleistocene–Holocene transition is still poorly known. Here we report on an excavation at the Liang Abu rock shelter which has contexts dating from the Late Pleistocene (12,660 ± 58 uncal. BP) to the present day, indicating a terminus ante quem (TAQ) for human occupation at 23,790 BP. We present the results of an attempt to systematically integrate and compare data from Liang Abu and Kimanis, a geographically close site with a previously published sequence. Particular attention is paid to post-depositional issues in tropical settings and to data compatibility, reuse, and reproducibility, relying on open-source software for data processing (R scripts) and Bayesian chronological modeling. Two Bayesian models are built and compared using the ChronoModel software, which can handle outliers and uncertainty (e.g., freshwater reservoir effect). This first inter-site comparison for Borneo results in a new chronology of human settlement and mainland–coastal interactions in East Borneo and paves the way for future regional synthesis. [ABSTRACT FROM AUTHOR]

High-resolution dating of volcanic rocks is the foundation for understanding the evolution of volcanoes and for estimating possible hazards. However, dating is often difficult for submarine volcanoes, where radiocarbon or other dating is frequently unavailable or imprecise. Here, we report paleointensity results from submarine basalts around Izu-Oshima Island, a typical island-arc volcano, and their bearing on age constraints. Basaltic lava samples were collected from submarine ridges located southeast of Izu-Oshima Island. Rock magnetic data indicate that the samples contain Ti-rich titanomagnetite with blocking temperatures of around 250–400 °C. The magnetic properties of the samples do not change significantly when heated in Ar or vacuum. We apply the Tsunakawa-Shaw method to estimate absolute paleointensity. Samples from different submarine ridges show distinct behavior. One ridge (SE1) shows moderate paleointensity of about 37 μT, while another ridge (SE3) records relatively strong magnetic fields of about 60 μT. Comparing those results with regional paleointensity data, we estimate the age of the SE1 ridge to be younger than 0.5 ka or around 1.4 ka. The other ridge (SE2) exhibits different paleointensity for two samples obtained from different localities, implying that the ridge consists of multiple eruptions. These results demonstrate that paleomagnetism can improve the dating of submarine volcanic rocks. [ABSTRACT FROM AUTHOR]

Direct dating of vertebrate fossils is difficult due to complex postburial diagenetic processes and the often low and heterogeneous concentration of radioisotopes (e.g., U) in fossilized bone material. Here, we demonstrate a novel approach to dating vertebrate fossils via laser ablation–inductively coupled plasma–mass spectrometry U-Pb dating of early diagenetic calcite cements precipitated within bone cavities of a Jurassic sauropod from the Sichuan Basin, South China. Early diagenetic calcite yielded a U-Pb age of 165.3 ± 3.6/5.6 Ma, in agreement with a maximum depositional age of 165.8 ± 1.0 Ma from detrital zircon ages of the surrounding rocks, suggesting that diagenesis occurred shortly after the death of the sauropod. This new age demonstrates that the best-known Jurassic large sauropod faunas in South China are much older than those in North America and Africa, suggesting the geographical isolation of South China. Authigenic apatite U-Pb dating on the fibrolamellar bones from the same sauropod gave a distinctly younger age, indicating more complex U-Pb system behavior, possibly due to U uptake by residual organic matter and recrystallization of apatite after early diagenesis. Our findings demonstrate that U-Pb dating of calcite cements within bone cavities has significant potential for constraining the burial age of vertebrate fossils, which could aid in constructing a more robust temporal framework for the radiation and evolution of vertebrates. [ABSTRACT FROM AUTHOR]

The influence of marine components in the study area is attributed to seafloor spreading and opening in the Indian Ocean during the Aptian, coupled with eustatic sea-level rise throughout the Aptian–Albian period. The present investigation delineates a marine incursion in the Chintalapudi sub-basin of the Godavari Valley Coalfield based on the occurrence of dinocysts, acritarchs and prasinophytes. Noteworthy stratigraphic marker taxa are recognized as key components in the age assignment of the sedimentary rocks. Sum total of four zones have been recognised in the studied part of the sequence. The oldest zone in the deepest set of sedimentation is identified as Cicatricosisporites australiensis Zone. This zone is assigned based on the first occurrence (FO) of Cicatricosisporites australiensis and Biretisporites eneabbaensis. The next zone, further above in the sequence is Foraminisporis wonthaggiensis Zone. The FO of Foraminisporis wonthaggiensis attested to the initiation of this zone. The third zone is Cyclosporites hughesii Zone recognised by the FO of Foraminisporis asymmetricus. The accessory palynotaxa comprised of Retimonocolpites sp., Tricolpites confessus, Tricolpites sp., Tricolporites sp. and Triporites sp. in the recognition of this zone. The youngest zone of this sequence is recognised at the top of the sequence named Crybelosporites striatus zone based on the FO of Crybelosporites striatus. Palynological analysis places the studied part of succession between the Berriasian to early Albian. The primary objective of this investigation is to explicate the characteristics of sedimentation and paleoenvironmental contexts, with a specific emphasis on utilizing palynofacies and Botryococcus morphotypes as distinct benchmarks. Based on the palynofacies investigation three different depositional regimes have been assigned, which are distinguished as follows: (a) continental (384.30–203.75 m) dysoxic–anoxic basin; (b) shallowest nearshore–inner shelf, marginal marine/brackish water settings; and (c) heterolithic proximal shelf deposition with significant sea transgression (94.50–36.50 m). Unpredictable morphotaxonomical responses across diverse habitats with varying pH levels are projected to enhance comprehension of the palaeoecological and palaeoenvironmental significance of fossil Botryococcus colonies. The uppermost marine part of the sequence denotes the least abundance, reduced size, and ill-defined amorphous forms of fossil Botryococcus colonies. The continental part displays the less abundant but well-defined and fully grown sporadic distribution of fossil Botryococcus colonies; the middle part records its presence with a well-diversified, sturdy structural framework and cellular cup-like structures. The investigation of the Cretaceous strata reveals a dynamic geological history influenced by tectonic activities, including plate drifting and rifting. Present investigation enhances our comprehension of palynostratigraphy, and paleoenvironmental history and facilitates the formulation of models elucidating environmental processes during the Early Cretaceous. In addition, the lipid-rich composition of Botryococcus renders it promising for biofuel production, attracting attention in biotechnology and renewable energy research endeavors. [ABSTRACT FROM AUTHOR]

The Klamath Mountains in northern California and southern Oregon are thought to record 200+ m.y. of subduction and terrane accretion, whereas the outboard Franciscan Complex records ocean‐continent subduction along the North American margin. Unraveling the Klamath Mountains' Late Jurassic history could help constrain this transition in subduction style. Key is the Mesozoic Condrey Mountain Schist (CMS), comprising, in part, a subduction complex that occupies a structural window through older, overlying central Klamath thrust sheets but with otherwise uncertain relationships to more outboard Klamath or Franciscan terranes. The CMS consists of two units (upper and lower), which could be correlated with (a) other Klamath terranes, (b) the Franciscan, or (c) neither based on regional structures and limited extant age data. Upper CMS protolith and metamorphic dates overlap with other Klamath terranes, but the lower CMS remains enigmatic. We used multiple geochronometers to constrain the timing of lower CMS deposition and metamorphism. Maximum depositional ages (MDAs) derived from detrital zircon geochronology of metasedimentary rocks are 153–135 Ma. Metamorphic ages from white mica K‐Ar and Rb‐Sr multi‐mineral isochrons from intercalated and coherently deformed metamafic lenses are 133–116 Ma. Lower CMS MDAs (<153 Ma) predominantly postdate other Klamath terrane ages, but subduction metamorphism appears to start before the earliest coherent Franciscan underplating (ca. 123 Ma). The lower CMS thus occupies a spatial and temporal position between the Klamath Mountains and Franciscan and preserves a non‐retrogressed record of the Franciscan Complex's early history (>123 Ma), otherwise only partially preserved in retrogressed Franciscan high grade blocks. Key Points: The Condrey Mountain Schist (CMS) epidote‐blueschist facies rocks were deposited and underplated in the Late Jurassic to Early CretaceousUnderplating postdates Klamath terrane assembly and predates coherent Franciscan underplating, recording the early Franciscan historyCMS pressure‐temperature conditions are consistent with other estimates of early Franciscan subduction zone thermal structure [ABSTRACT FROM AUTHOR]

A geochronological and isotope–geochemical study of alkaline basalts from three areas of young magmatism within the northeastern part of the Arabian Plate (Southeastern Turkey), Batman, Kurtalan and Alemdağ, was carried out. The obtained isotope data have indicated that the volcanism in the studied region developed over a 5-Ma period from the end of Miocene to the middle Pleistocene during four pulses separated by breaks in magmatic activity: 6.1–4.9 Ma (Batman area, hawaiites), ~3.0 Ma (Alemdağ plateau, phase I, basalts), 2.0–1.9 Ma (Alemdağ plateau, phase II, tephrites), and 1.5–1.3 Ma (Alemdağ plateau, phase III, basalts; Kurtalan area, basalts). A comparison of spatial–temporal changes of magmatic activity evolution in the studied part of the Arabian Plate and within the largest basalt plateau of Arabian foreland, Karacadağ Plateau, located to the west, was carried out. The results of Sr–Nd–Pb isotope–geochemical studies show that the development of young basalt volcanism in the Arabian Plate was characterized at different time by the contribution of various mantle sources in magma generation under this region. Initial pulses of magmatic activity are associated with melting of Arabian subcontinental lithospheric mantle (SCLM). The processes of fractional crystallization combined with crustal assimilation (AFC) have played an important role in the petrogenesis of lavas as well. Later, a deep mantle source (PREMA) with a depleted isotopic composition played a leading role in the formation of basaltic magmas of increased alkalinity. The melts generated by this source were mixed with the SCLM material in various proportions at different stages of magmatism with a limited participation of AFC processes in the petrogenesis of the rocks. It was concluded that young basalt volcanism of increased alkalinity in the northeast of the Arabian Plate is not related to the collision of the Eurasian and Arabian plates genetically, but presumably manifested here as a result of the migration of the initial rift geodynamic setting from the Red Sea basin to the north along Levantine and East Anatolian transform faults due to directed convection flows in the lower part of mantle under this part of the Earth. [ABSTRACT FROM AUTHOR]

The Longshou Shan, located in western China, plays a crucial role in connecting the Tarim Continent with the North China Craton. It provides valuable insights into the Cenozoic intracontinental deformation, the complex dynamics of Eurasian tectonics, and the relationship between the pre-Cenozoic Tethys and Central Asian orogenic systems. Consequently, comprehending the evolution of the Phanerozoic era in this region holds immense significance. Zircon (U-Th)/He (ZHe) dating was conducted on three granite samples (n = 18) collected from the Longshou Shan. The ZHe dates of these granite rocks range from 7.2 to 517.7 Ma, showing a negative correlation with eU values. Furthermore, a limestone sample from the Longshou Shan yielded ZHe (n = 4) ages of 172.0–277.1 Ma and AHe (n = 4) ages of 17–111.9 Ma. The area has undergone complex tectonic processes involving multiple phases of uplift and burial. Using both forward and inverse modeling methods, we aim to establish plausible thermal histories. Our models reveal: (1) Late Paleozoic unroofing; (2) Early Mesozoic cooling and Late Mesozoic regional stabilization; and (3) Cenozoic reheating and subsequent cooling. By investigating the intricate thermal history of the Longshou Shan through multi-method modeling, we compare different approaches and assess the capabilities of single ZHe dating for understanding a thermal history. This research contributes to unraveling the region's geological complexities and aids in evaluating various modeling methods. [ABSTRACT FROM AUTHOR]

The main structural building blocks that form manganese oxides are MnO6 octahedra; these share corners and edges to construct specific structures, which can either be tunneled or layered. In the layered structures, that is, phyllomanganates, the MnO6 octahedra form sheets, which, in turn, alternate with sheets of metal oxides and H2O. These metal ions can vary (Zn, Co, Ni, Al, Li, ...) and give rise to an entire range of different metal oxides. The characterization of these layered materials is important as they have various economical/industrial applications. Birnessite‐type materials, a specific type of layered manganese oxides, are widely studied for their use as cathode materials in alkali‐ion batteries. Phyllomanganates are also commonly found as constituents in sediments and soils or as coatings on rock surfaces. Their natural occurrence as black colored components have ensured that these minerals were also applied as pigments in archaeological and historical contexts. They are, for example, often found in rock art paintings and on pottery. As the oxides are used in unique archaeological objects, Raman spectroscopy is an evident choice for characterization due to its non‐destructive nature of analysis. In the current study, five mineral samples of (layered) manganese oxides are analyzed with different Raman instrumentations, including mobile systems and a benchtop micro‐Raman setup. The characterization of each selected manganese oxide and their comparison with literature data is discussed for the micro‐Raman instrumentation. In addition, the ability of identifying and characterizing layered manganese oxides and the possible challenges when using mobile instrumentation are discussed as well. [ABSTRACT FROM AUTHOR]

Footprints represent a relevant vestige providing direct information on the biology, locomotion, and behaviour of the individuals who left them. However, the spatiotemporal distribution of hominin footprints is heterogeneous, particularly in North Africa, where no footprint sites were known before the Holocene. This region is important in the evolution of hominins. It notably includes the earliest currently known Homo sapiens (Jebel Irhoud) and the oldest and richest African Middle Stone Age hominin sites. In this fragmented ichnological record, we report the discovery of 85 human footprints on a Late Pleistocene now indurated beach surface of about 2800 m2 at Larache (Northwest coast of Morocco). The wide range of sizes of the footprints suggests that several individuals from different age groups made the tracks while moving landward and seaward across a semi-dissipative bar-trough sandy beach foreshore. A geological investigation and an optically stimulated luminescence dating of a rock sample extracted from the tracksite places this hominin footprint surface at 90.3 ± 7.6 ka (MIS 5, Late Pleistocene). The Larache footprints are, therefore, the oldest attributed to Homo sapiens in Northern Africa and the Southern Mediterranean. [ABSTRACT FROM AUTHOR]

Unveiling the tempo and mode of animal evolution is necessary to understand the links between environmental changes and biological innovation. Although the earliest unambiguous metazoan fossils date to the late Ediacaran period, molecular clock estimates agree that the last common ancestor (LCA) of all extant animals emerged ~850 Ma, in the Tonian period, before the oldest evidence for widespread ocean oxygenation at ~635–560 Ma in the Ediacaran period. Metazoans are aerobic organisms, that is, they are dependent on oxygen to survive. In low‐oxygen conditions, most animals have an evolutionarily conserved pathway for maintaining oxygen homeostasis that triggers physiological changes in gene expression via the hypoxia‐inducible factor (HIFa). However, here we confirm the absence of the characteristic HIFa protein domain responsible for the oxygen sensing of HIFa in sponges and ctenophores, indicating the LCA of metazoans lacked the functional protein domain as well, and so could have maintained their transcription levels unaltered under the very low‐oxygen concentrations of their environments. Using Bayesian relaxed molecular clock dating, we inferred that the ancestral gene lineage responsible for HIFa arose in the Mesoproterozoic Era, ~1273 Ma (Credibility Interval 957–1621 Ma), consistent with the idea that important genetic machinery associated with animals evolved much earlier than the LCA of animals. Our data suggest at least two duplication events in the evolutionary history of HIFa, which generated three vertebrate paralogs, products of the two successive whole‐genome duplications that occurred in the vertebrate LCA. Overall, our results support the hypothesis of a pre‐Tonian emergence of metazoans under low‐oxygen conditions, and an increase in oxygen response elements during animal evolution. [ABSTRACT FROM AUTHOR]

High-aluminous, fluoro-titanites (~ 6.8–11.5 wt% Al2O3, up to ~ 3.8 wt% F) from a suite of calc-silicate granulites in the Chotanagpur Granite Gneiss Complex, East Indian shield, were examined to investigate the controls on Al incorporation in titanite. The studied high aluminous titanites have the third highest Al content (XAl= up to ~ 0.46), reported from low to medium-pressure rocks till date. These titanites develop in three different associations (association 1, 2 and 3) along with the F-bearing hydrous minerals like amphibole or vesuvianite. These three associations occur as veins and patches close to the pegmatitic veins that intruded the granulite facies calc-silicate rocks. The titanite in the host calc-silicate rock (association 4), away from the pegmatite veins, preserves an anhydrous assemblage: garnet-clinopyroxene-plagioclase and low Al titanite (Al2O3 = 3.4–3.8 wt%, F ~ 0.8 wt%). Integrating field features, petrography and textural modeling, it is suggested that infiltration of F-bearing aqueous fluid, presumably derived from the pegmatites, into the host calc-silicate rock was responsible for the partial destabilization of the anhydrous assemblage 4, and formation of the Al-F rich titanite bearing assemblages 1–3. The published information and close proximity of the association 1–4 outcrops suggest that the infiltration-driven growth of Al-F-rich titanite occurred virtually under isothermal-isobaric conditions (5.5–6.5 kbar and 650–750 °C). The titanite in associations 1–3 show a positive correlation between Al2O3/TiO2 and F/OH indicating the substitution Ti+ 4 +O2− = Al+ 3+ (F + OH)−. Based on the findings of the present study, combined with the published information on titanite chemistry, it is argued that the fF2 present in the system plays a dominant role, if not the most important, in regulating the extent of Al substitution in titanites, in addition to pressure, temperature or coexisting mineral assemblage. [ABSTRACT FROM AUTHOR]

Summary: Divergence times based on molecular clock analyses often differ from those derived from total‐evidence dating (TED) approaches. For bryophytes, fossils have been excluded from previous assessments of divergence times, and thus, their utility in dating analyses remains unexplored. Here, we conduct the first TED analyses of the complex thalloid liverworts (Marchantiopsida) that include fossils and evaluate macroevolutionary trends in morphological 'diversity' (disparity) and rates.Phylogenetic analyses were performed on a combined dataset of 130 discrete characters and 11 molecular markers (sampled from nuclear, plastid and mitochondrial genomes). Taxon sampling spanned 56 extant species – representing all the orders within Marchantiophyta and extant genera within Marchantiales – and eight fossil taxa.Total‐evidence dating analyses support the radiation of Marchantiopsida during Late Silurian‐Early Devonian (or Middle Ordovician when the outgroup is excluded) and that of Ricciaceae in the Middle Jurassic. Morphological change rate was high early in the history of the group, but it barely increased after Late Cretaceous. Disparity‐through‐time analyses support a fast increase in diversity until the Middle Triassic (c. 250 Ma), after which phenotypic evolution slows down considerably.Incorporating fossils in analyses challenges previous assumptions on the affinities of extinct taxa and indicates that complex thalloid liverworts radiated c. 125 Ma earlier than previously inferred. [ABSTRACT FROM AUTHOR]

Study on the petrology, LA-ICP-MS zircon U-Pb dating and whole rock geochemistry of the trachyandesite in Wufeng area of Yanbian, Jilin Province in Northeast China, shows that the SiO2 content is 58.33%-61.36%, K2O content 1.61%-3.28% and total alkali content 6.77%-10%, belonging to the medium potassium-high potassium calc-alkaline series. The weighted mean age of magmatic zircon 206Pb/238U is 175.52±2.7 Ma, which is consistent with the subduction time of Early Jurassic paleo-Pacific plate. The trachyandesite is characterized by relative enrichment of LILEs(K, Ba and Rb) and strongly incompatible elements (Th and U), and depletion of HFSEs (Nb, Ta and Ti), with high LREE/HREE ratio, and enriched LREEs and depleted HREEs, indicating that the magma may originate from the partial melting of mantle and its source area is metasomatized by the subducted shell source materials. From the above, it is believed that the trachyandesite was formed in the active continental margin of oceanic subduction system and was the magmatic response to the subduction of Early Jurassic paleo-Pacific plate. [ABSTRACT FROM AUTHOR]

There has been no consensus yet regarding the precise initial timing and duration of the late Mesozoic extensional tectonics in the South‐eastern China Block. This work focusses on the growth strata of the Early Cretaceous red beds in the South‐eastern China Block to determine the late Mesozoic tectonics and the precise timing of the initiation and duration of extensional tectonics in this area. Field observation of several terrigenous basins shows that the dip angles of the Cretaceous red beds have varied from moderate to gentle from basin edges to interiors (or centres). The visible and estimated thickness within a single bed increases slightly downwards from the upper to the lower part. These characteristics indicate that the sedimentary area of these beds has undergone an extensional process with expansion and deepening of the sedimentary basins. Rotation of the border surfaces (limbs) and downward warping of the hanging walls or retreat of the footwalls of listric normal faults causes three types of extensional growth (or syntectonic) strata in the deposits of different basins. Dating of the volcanic rocks related to the growth beds reveals that the sedimentary basins were enlarged and deepened when the Early Cretaceous strata were deposited in the South‐eastern China Block from ca 140 to 137 Ma. Regionally, under the influence of Palaeo‐Pacific plate rollback since ca 140 Ma, the South‐eastern China Block stress field has led to lithospheric uplift and pull‐apart structures near the surface, causing the half‐graben basins to receive sedimentation. Although the extensional event was interrupted by a short compressional event during 120 to 105 Ma, with the oceanward retreat of the trench, the area of extension gradually enlarged and rejuvenated south‐eastwards until the end of the Cretaceous. This Cretaceous extension event of the South‐eastern China Block must belong to a worldwide geological event with global significance. [ABSTRACT FROM AUTHOR]

Metazoans use silicon traces but rarely develop extensive silica skeletons, except for the early-diverging lineage of sponges. The mechanisms underlying metazoan silicification remain incompletely understood, despite significant biotechnological and evolutionary implications. Here, the characterization of two proteins identified from hexactinellid sponge silica, hexaxilin and perisilin, supports that the three classes of siliceous sponges (Hexactinellida, Demospongiae, and Homoscleromorpha) use independent protein machineries to build their skeletons, which become non-homologous structures. Hexaxilin forms the axial filament to intracellularly pattern the main symmetry of the skeletal parts, while perisilin appears to operate in their thickening, guiding extracellular deposition of peripheral silica, as does glassin, a previously characterized hexactinellid silicifying protein. Distant hexaxilin homologs occur in some bilaterians with siliceous parts, suggesting putative conserved silicifying activity along metazoan evolution. The findings also support that ancestral Porifera were non-skeletonized, acquiring silica skeletons only after diverging into major classes, what reconciles molecular-clock dating and the fossil record. Sponges, being early-diverging metazoans and the only animals to develop extensive skeletons of silica, have potential to inform about the evolutionary steps of metazoan traits, including biomineralization. Here, the authors characterize two proteins associated with the hexactinellid sponge silica. [ABSTRACT FROM AUTHOR]

The Huatung Basin (HB), situated on the leading part of the Philippine Sea Plate, is directly involved in oblique subduction and mountain building in the Taiwan region. However, previous studies have reported a wide range of ages for the HB, from 30 to 130 Ma, making it difficult to properly constrain regional tectonics. We analyzed teleseismic waveforms recorded on Taiwan that traveled through the slab associated with the HB. By waveform matching, we have constrained the slab dimensions to approximately 400 km in length and 150 km in width, accompanied by an enhanced P-wave velocity of 6% within the slab core and an apparent dip angle of 55°. We used age-dependent subduction zone thermal models to estimate the thermal ages or the ages since the last thermal event of the HB. The best-fit thermal model indicates thermal ages ranging from 20 to 50 Ma, which is consistent with a suite of geophysical observations and the age inferred from geomagnetic anomaly data. However, our results differ considerably from the ages obtained through radiometric dating of rocks dredged from the seafloor. The discrepancy in age may be attributed to either thermal rejuvenation of the plate or dating of allochthonous samples dredged from the border of the basin. [ABSTRACT FROM AUTHOR]

The Oaxacan Complex Carboniferous-Permian sedimentary cover in southern México records provenance shifts through time, reflecting the collision between Gondwana and Laurentia to amalgamate Pangea. The integration of petrological analysis and LA-ICP-MS U-Pb zircon geochronology from Santiago, Ixtaltepec and Yododeñe formations compared with adjacent terranes suggests that: (1) during the Early Mississippian, the Santiago Formation received sediments mainly from local sources such as the Oaxacan Complex and Tiñu Formation, with minor contributions from adjacent peri-Gondwana sources. The magmatic activity may have started during this time (~359–346 Ma) (2) during the Late Mississippian (Ixtaltepec Formation), detrital zircon grains of Ediacaran-Cambrian age are dominant, derived from sediments either related to the Pan-African/Brasiliano orogeny or the opening of the Iapetus Ocean; (3) during the Late Mississippian-Middle Pennsylvanian, intercalated marine volcaniclastic sandstone (Ixtaltepec Formation) provides the first record of Carboniferous arc-related volcanism reported in southern Mexico, dated between 330 and 308 Ma; (4) the early Permian Yododeñe Formation records the exhumation and erosion of the sedimentary cover during the final stage of Pangea assembly. Rhyodacitic subvolcanic sills and lavas dated at ~282–270 Ma are present throughout the succession. Volcanism and ca. 360–308 Ma detrital zircon grains could be associated with a Carboniferous magmatic arc formed by subduction of the Rheic oceanic plate beneath Gondwana. Slightly younger detrital zircon and subvolcanic rocks dated at ~300–270 Ma are linked to a western Pangea arc developed in response to the subduction of the Paleo-Pacific Ocean following Pangea assembly. Our results suggest that the Carboniferous-Permian units were deposited in a peri-arc basin, sharing sediment provenance with the Maya and Coahuila blocks, the Sierra de Juárez Complex, and northwestern South America. [ABSTRACT FROM AUTHOR]

Burmese amber is a significant source of fossils that documents the mid-Cretaceous biota. This deposit was formed around 99 Ma on the Burma Terrane, which broke away from Gondwana and later collided with Asia, although the timing is disputed. Palpimanoidea is a dispersal-limited group that was a dominant element of the Mesozoic spider fauna, and has an extensive fossil record, particularly from Burmese amber. Using morphological and molecular data, evolutionary relationships of living and fossil Palpimanoidea are examined. Divergence dating with fossils as terminal tips shows timing of diversification is contemporaneous with continental breakup.Ancestral range estimations show widespread ancestral ranges that divide into lineages that inherit different Pangean fragments, consistent with vicariance. Our results suggest that the Burmese amber fauna has ties to Gondwana due to a historical connection in the Early Cretaceous, and that the Burma Terrane facilitated biotic exchange by transporting lineages from Gondwana into the Holarctic in the Cretaceous. [ABSTRACT FROM AUTHOR]

A newly developing method, rock surface luminescence dating, provides a novel means of constraining the burial age of fluvial gravel and unveiling the transport and exposure-burial process of fluvial bed-load. A crucial requirement for successful age determination in luminescence dating of buried rock surfaces is that a sufficiently thick surficial layer was reset to a near-zero level of signal prior to deposition and burial. However, little such effort has been made on modern fluvial gravels from various depositional environments to provide a sound justification for the use of luminescence dating in such settings. In this study, we reported an investigation of daylight bleaching in modern cobbles with different sizes and shapes at a modern river floodplain from the Manas River, Tian Shan, to test the reliability and applicability of fluvial cobble optical dating. Four multi-elevated-temperature post-infrared infrared (MET-pIRIR) stimulated luminescence signals of rock slices were measured using a modified MET-pIRIR protocol to establish residual luminescence-depth profiles. The residual does of pIRIR and MET-pIRIR signals of sub-surface rock slices were also estimated using different modified SAR protocols. The results showed that the high temperature IRSL signal could be reset to ∼2–3 mm depth into cobbles surface and flat cobbles seem easier to bleach than spherical cobbles. The residual doses of sub-surface rock slices of cobbles from modern river floodplain was ∼0.4 Gy and ∼1.1 Gy for the IR 50 and the pIRIR 170 signal respectively, suggesting a residual age of ∼0.1 ka and ∼0.2 ka. The residual ages of MET-pIRIR signals of sub-surface rock slices of cobble MNS2-5 were ∼0.5–1 ka at higher stimulation temperature. Our results show that the fluvial cobble optical dating techniques have great potential for providing reliable chronologies for river floodplain gravel and other fluvial depositional events. [ABSTRACT FROM AUTHOR]

• Devonian-Carboniferous sedimentation and paleoenvironments along the Iberian Pyrite Belt are analysed. • Several stratigraphic hiatuses are identified and confirmed in the Neves-Corvo region. • Palynostratigraphy is an important tool to define the age of the black shales hosting the mineralization. • IPB bioevents related to the major extinction event and environment changes are documented in the Devonian-Carboniferous Boundary. • Improvement of the stratigraphy of the IPB and geological knowledge. Based on drill hole sampling and sedimentary rock dating by palynology, the present research focuses on the palynostratigraphic events established in the key geological section of Guedelhinha–Lançadoiras–Algaré located in the Portuguese Neves–Corvo mine region, Iberian Pyrite Belt. The age data allow detailing the lithostratigraphic sequence and further understanding the complex structural setting, representing an important contribution to the geological knowledge of this sector located to the immediate WNW of the Neves–Corvo VMS deposit. The combination of the studied events allows the reconstruction of the Devonian-Carboniferous sedimentation and paleoenvironments along the Iberian Pyrite Belt. Several stratigraphic hiatuses identified in the Neves–Corvo region by the palynological record are confirmed, mainly occurring from the mid Frasnian to mid Famennian, from the early and mid Strunian, and from the early to late Tournaisian, which were mainly coincident with the worldwide extinction events, in particular during Frasnian–Famennian and Late Devonian times. Extensional tectonics and related gravitational faults, local uplift mechanisms and intense volcanic activity could also explain the lack of palynological data and sedimentary hiatus. In this research, the importance of the late Strunian times in the Iberian Pyrite Belt (Miospore Biozone LN of the Neves Formation) is highlighted, confirming the contemporaneity of felsic volcanism, hydrothermalism, sulphide mineralization precipitation and black shale anoxic sedimentation. [ABSTRACT FROM AUTHOR]

In a reconnaissance study, we investigated the potential of γ‐ray induced production of 38ArK from 39K for geochronological applications. For this purpose, various age monitors commonly in use for the established 40Ar/39Ar‐method were co‐irradiated for 60 h at 17.6 MeV maximum energy in the ELBE facility, Dresden‐Rossendorf, Germany. Because the available energy was low, total production of 38ArK was depressed, leading to low J38‐values of (2.1–4.1) × 10‐6 and hence resulted in only minor 38Ar excess when compared with atmospheric 38Ar/36Ar ratios. In spite of these restrictions, ages of younger monitors could be reproduced within error, whereas older age reference materials showed discrepancies due to the low production rate. We observed Ca‐derived contributions on 36Ar in analysed CaF2 reference materials, and calculated a limit for Ca‐interference on 38ArCa of (38Ar/36Ar)Ca = 0.07 ± 0.03 (1s). In addition, we investigated a potential recoil redistribution of 38Ar by stepwise heating experiments, but could not quantify this further because of concurring processes. More work at higher photon energies is necessary to resolve other open issues, in particular the potential of utilising 40Ar/37Ar ratios for age determination and the possibility of 42Ar production from 44Ca, which would allow correction for Ca‐interference reactions on other Ar isotopes. This would be a pre‐requisite for dating extra‐terrestrial rocks. [ABSTRACT FROM AUTHOR]

The Qinling Mountain Range (QMR), where more than 500 hominin fossils and Paleolithic sites have been preserved, was a major center of hominin evolution and settlement and an important link for the hominin migration and dispersal between the north and the south during the Pleistocene in China. The rich culture remains and the related data make it possible and meaningful to study the characteristics and mechanisms of hominin occupation and dispersal in the region. This paper has summarized and analyzed the geographical distributions and chronologies of 55 dated hominin fossils and Paleolithic sites in the QMR to date. By combining them with the evidence from the loess–paleosol sequence, a relatively continuous and chronological sequence of hominin occupation and dispersal has been established, in which we have identified five stages, viz. ~before 1.2 Ma, the sporadic occurrence stage of early hominin occupation; ~1.2–0.7 Ma, the initial expansion stage; ~0.7–0.3 Ma, the stability and maintenance stage; ~0.3–0.05 Ma, the large-scale expansion stage; ~0.05–0.01 Ma, the sharp decline stage of the record of hominin occupation. We conclude that the environmental and ecosystem changes associated with the MPT drove early hominins to disperse southwards across the QMR. In addition, the evidence suggests that the hominin occupation and dispersal here was broadly continuous during both glacial and interglacial scales from early to late Pleistocene, and that the southern QMR provided a glacial refuge. [ABSTRACT FROM AUTHOR]

The paper focuses on the Pleistocene deposits in Perspektywiczna Cave, southern Poland, related to cave hyena (Crocuta crocuta). We used direct radiocarbon dating of hyena fossils supported by genetic and stable isotope analyses to infer the paleobiology of this population. Radiocarbon dating of 19 hyena remains suggests long inhabitation of the region during early MIS 3, around 50–34 ky cal BP. The youngest among our dates, 34,355–33,725 cal BP (1σ, combined of two dates for the same specimen) points out the latest appearance of a cave hyena north to Carpathians. Beside this long period of occupation, the Perspektywiczna Cave hyenas stayed ecologically stable, but their genetic structure changed. Two mtDNA haplogroups were present, one typical for other Late Pleistocene European populations and the other one known so far only from recent African populations. [ABSTRACT FROM AUTHOR]

The Easternmost Mediterranean is a transition region from the ocean to the continent where the spreading and collision zones of the lithospheric plates join. The methodology of paleomagnetic mapping of the transition zones is based on combining geological and geophysical techniques for continental and oceanic platforms: magnetic data interpretation, paleomagnetic reconstructions, results of magnetized rock radiometric dating, satellite data analysis, tectonic–structural reconstructions, biogeographical studies, and utilization of different geophysical survey results. The satellite-derived gravity map reflects practically all significant tectonic units in the region, which assists us in the supposed paleomagnetic mapping. The satellite-derived and aeromagnetic maps with the tectonic features and the map of Curie discontinuity of Israel indicate the complexity of this region. Advanced magnetic data analysis supported by paleomagnetic data attraction and other geological–geophysical methods allowed the revealing of the block of oceanic crust with the Kiama paleomagnetic zone relating to the Early Permian age. A narrow reversely magnetized Earth crust block was revealed in the Lower Galilee. Some examples of advanced magnetic anomaly analysis are presented for several areas where the magnetization vector inclination is other than the modern direction: the Sea of Galilee, Carmel, Rosh-Ha-Ayin, Malqishon, and Hebron. In Israeli land, for the combined paleomagnetic mapping, the well-studied using paleomagnetic and radiometric methods (as well as tectonic–structural) areas were selected: (1) Makhtesh Ramon, (2) the Sea of Galilee with the adjoining zones, (3) Carmel, (4) Hula, and (5) Hermon. It is shown that the regional analysis of paleomagnetic data distribution played an essential role in detecting the influence of the recently recognized counterclockwise rotating mantle structure on the near-surface layers. [ABSTRACT FROM AUTHOR]

Gua Sireh, located in western Sarawak (Malaysian Borneo), is known for its rock art. The cave houses hundreds of charcoal drawings depicting people, often with headdresses, knives and other accoutrements. Here, we present direct radiocarbon dates and pigment characterizations from charcoal drawings of two large (>75 cm), unique Gua Sireh human figures (anthropomorphs). To our knowledge, these are the first chronometric ages generated for Malaysian rock art, providing insights into the social contexts of art production, as well as the opportunities and challenges of dating rock art associated with the Malay/Austronesian diasporas in Southeast Asia more generally. Previous archaeological excavations revealed that people occupied Gua Sireh from around 20,000 years ago to as recently as AD 1900. The site is within Bidayuh territory, and these local Indigenous peoples recall the cave's use as a refuge during territorial violence in the early 1800s. The age of the drawings, dated between 280 and 120 cal BP (AD 1670 to 1830), corresponds with a period of increasing conflict when the Malay elites controlling the region exacted heavy tolls on the local hill tribes. We discuss rock art production at Gua Sireh in this context of frontier conflict and Bidayuh resistance. [ABSTRACT FROM AUTHOR]

Thysanoptera, commonly known as thrips, are diverse tiny insects whose earliest fossil record dates back to the Triassic period. Since there are few studies on the divergence time of taxa under Thysanoptera, this study used 13 mitochondrial coding protein genes to reconstruct the phylogenetic tree with divergence time of 26 species of this order and show a reliable phylogenetic relationship of thrips species. The time tree of this study shows that most extant thrips diverged in the early Tertiary period, while the fossil records also support that most extinct thrips appeared in this period. This study expands our understanding of the evolution of thrips and provides a feasible way of using multiple mitochondrial genes to establish robust phylogenetic relationships and explore divergence time between species. [ABSTRACT FROM AUTHOR]

Hymenophyllaceae (filmy ferns), with ca. 430 species, are the most species-rich family of early diverging leptosporangiate ferns but have a poor fossil record dating back to the Late Triassic period. Traditionally, Hymenophyllaceae comprise two species-rich genera or clades: Hymenophyllum (hymenophylloids) and Trichomanes sensu lato (s.l.) (trichomanoids). Unequivocal fossils of Hymenophyllum have been reported from the Early Cretaceous of central Mongolia and the early Eocene of Okanogan Highlands, Washington, USA. However, despite being a highly diversified lineage with an estimated 184 extant species, Trichomanes s.l. lack a definitive fossil record, which severely affects the reliability of the molecular dating of this group. Here, we report the first unequivocal fossil record of Trichomanes s.l. as T. angustum comb. nov. on the basis of fertile material with tubular involucres and long exserted receptacles from the mid-Cretaceous Kachin amber, Myanmar. This species was previously tentatively assigned to Hymenophyllites due to a lack of fertile evidence. Inferred to be an epiphytic fern, T. angustum further enriches the species diversity of the epiphytic palaeocommunities in the mid-Cretaceous Kachin amber, which are mainly composed of Porellalean leafy liverworts and Dicranalean and Hypnodendralean mosses. Fossil records indicate that Hymenophyllaceae probably originated in the tropical Pangea at the latest in the Triassic when all continents were coalesced into a single landmass and had already accumulated some notable diversity in low-middle latitude areas of Laurasia by the mid-Cretaceous period. [ABSTRACT FROM AUTHOR]

The strata in the Shita Mountain, Yunkai region, are predominantly composed of clastic rocks with intercalated limestones. However, the precise stratigraphic age remains uncertain due to the scarcity of fossils. Previously, conglomerate layers in this region were considered indicative of the Yunan Orogeny during the Cambrian–Ordovician transition. However, through the identification of 12 lithofacies types and 5 lithofacies combinations in the conglomerate layers of the Shita Mountain section, it has been confirmed that these layers represent a fan delta depositional environment characterized by debris flow, traction flow, torrent, and rock flow. Based on the presence of brachiopod fossils dating to the Early–Middle Ordovician, we propose a novel two-episode model for the Yunan Orogeny. The first episode corresponds to submarine fan deposition, while the second episode involves tectonic uplift and a short-term sedimentary hiatus. Further analysis of the detrital zircon provenance reveals a strong affinity among the Yunkai area, India, Antarctica, the Lhasa, the Himalayas, Southern Qiangtang, and Western Australia during the Early–Middle Ordovician transition under the Gondwana assemblage background. [ABSTRACT FROM AUTHOR]

Recent fossil shell mining for a new rail line in the Orlando area of Orange County, Florida has uncovered two species of the ellobioid genus Carychium O. F. Müller, 1773 in a bed of freshwater marl from the Lower Pleistocene Nashua Formation. To taxonomically interpret these finds, the well-preserved shells were imaged via high-resolution X-ray tomography (micro-CT) to view significant internal diagnostic characters such as the columellar configuration and the degree of lamellar sinuosity and their relationship in context to the entire shell. The image data are compared to that of type material and extant and fossil Carychium species inhabiting the SE USA, Mexico, Central America, and Jamaica. Based on these results, the species Carychium floridanum G. H. Clapp, 1918 and Carychium nashuaense sp. nov. are identified from fossil shells dating from the Early Pleistocene. This work documents the first fossil members of C. floridanum and the first fossil Carychium from the SE USA. [ABSTRACT FROM AUTHOR]

Background: While polyploids are common in plants, the evolutionary history and natural dynamics of most polyploid groups are still unclear. Owing to plentiful earlier systematic studies, Ludwigia sect. Isnardia (comprising 22 wetland taxa) is an ideal allopolyploid complex to investigate polyploid evolution and natural dynamics within and among taxa. With a considerable sampling, we concentrated on revisiting earlier phylogenies of Isnardia, reevaluating the earlier estimated age of the most recent common ancestor (TMRCA), exploring the correlation between infraspecific genetic diversity and ploidy levels, and inspecting interspecific gene flows among taxa. Results: Phylogenetic trees and network concurred with earlier phylogenies and hypothesized genomes by incorporating 192 atpB-rbcL and ITS sequences representing 91% of Isnardia taxa. Moreover, we detected three multi-origin taxa. Our findings on L. repens and L. sphaerocarpa were consistent with earlier studies; L. arcuata was reported as a multi-origin taxon here, and an additional evolutionary scenario of L. sphaerocarpa was uncovered, both for the first time. Furthermore, estimated Isnardia TMRCA ages based on our data (5.9 or 8.9 million years ago) are in accordance with earlier estimates, although younger than fossil dates (Middle Miocene). Surprisingly, infraspecific genetic variations of Isnardia taxa did not increase with ploidy levels as anticipated from many other polyploid groups. In addition, the exuberant, low, and asymmetrical gene flows among Isnardia taxa indicated that the reproductive barriers may be weakened owing to allopolyploidization, which has rarely been reported. Conclusions: The present research gives new perceptions of the reticulate evolution and dynamic nature of Isnardia and points to gaps in current knowledge about allopolyploid evolution. [ABSTRACT FROM AUTHOR]

Spalerosophis Jan, 1865, is a colubrid snake genus distributed in arid and semiarid regions from northwestern Africa to northern India. Six species of Spalerosophis are identified based on traditional morphology; however, there are arguments about their systematic status. We performed the first molecular phylogenetic analyses for this genus using nucleotide sequences of c. 2278 bp from three mitochondrial genes (12S rRNA, 16S rRNA, and cyt b) to investigate the phylogenetic relationships and historical evolution of the poorly known Spalerosophis species and doubtful populations. We used fossil calibrations for dating divergences. Our phylogenetic analyses clearly showed five separate species with high support values, including S. arenarius, S. atriceps, S. microlepis, S. diadema schirasianus, and S. diadema cliffordii. Bayesian calibrated molecular clock suggested that the genus Spalerosophis diverged from the common ancestor in the Paleogene around 35.28 Mya (25.89–44.66). Our analysis indicated that isolated S. atriceps was separated around 21.72 Mya (10.86–33.04) as the basal diverged species of the genus. This suggested that the species of Spalerosophis probably originated from an ancestor somewhere in the Iranian Plateau and then dispersed to its current geographical range. Spalerosophis arenarius and S. atriceps were identified as the two last diverged members of the genus, separated from S. d. schirasianus during the Middle Miocene about 13.31 Mya (5.52–22.33). These results indicate that the separation of Spalerosophis species coincided with the orogenic events of the Zagros Mountains in western Iran and the Sulaiman Mountains in Afghanistan, India, and Pakistan. Their diversification may therefore be the result of vicariance events that promoted their current distribution. This work provides a foundation for future studies on the phylogeny, diversity, and evolution of the genus Spalerosophis and highlights the need for more molecular studies on unknown snakes. [ABSTRACT FROM AUTHOR]

The Pseudoreticulatispora confluens–P. pseudoreticulata spore-pollen zonal datum typically coincides with the end of widespread Permian glacial deposits in Western Australia. Although previously attributed to the mid-Sakmarian, chemical abrasion isotope dilution thermal ionisation mass spectrometry (TIMS) dating of zircons from volcanic tuffs in the Ditji Formation of the Bonaparte Basin and the Grant Group in the Canning Basin point to an Asselian age of about 295.25 Ma for this datum. All dated zircons from the Ditji Formation came from petroleum well cuttings but the accompanying palynology was mostly from sidewall cores; however, all Grant Group samples were from conventional core. TIMS dates from the Ditji Formation range in age from 295.2 to 292.7 Ma whereas the only productive tuff from the Grant Group yielded a 296.26 Ma date. By comparison, there are no zircon dates to constrain the onset of glacial deposition in Australia. The Bonaparte Basin ages overlap with those for the Edie Tuff (296.1–294.5 Ma) in Queensland's Galilee Basin, approximately 2000 km to the southeast, which also lies close to the base of the P. pseudoreticulata Zone. To date the only fossil group within the P. confluens Zone in Western Australia to provide independent age control, albeit loosely, are goniatites from the northern Perth Basin (Uraloceras irwinense and Juresanites jacksoni) that have consistently been attributed to the Sakmarian; these require a reassessment of their affinity with Russian faunas and therefore to global stratotypes. The position of the Carboniferous–Permian boundary is elusive in Australia and will remain so until additional volcanic tuffs containing young datable zircons are found; however, spore-pollen and zircon dates from Namibia place this boundary within the P. confluens Zone. [ABSTRACT FROM AUTHOR]

The Koras Group is a bimodal volcanosedimentary group located in post-tectonic grabens in a foreland thrust complex in the Kaaien Terrane of the Mesoproterozoic Namaqua-Natal Province of southern Africa. It contains two sequences of mafic and felsic volcanic rocks with an unconformity between them, only the lower sequence being slightly folded. The Koras Group was long regarded as having formed at the end of the 1 210 to 1 000 Ma Namaqua Orogeny, because it lacks the severe deformation and metamorphism of the underlying rocks, with igneous minerals preserved in many samples. Following years of unsuccessful attempts to precisely date the volcanic rocks, the first two ion probe U-Pb zircon studies both reported ages of ~1 172 Ma for the Swartkopsleegte Formation felsic lava in the slightly folded lower sequence (based on relatively few dated zircons) and ~1 100 Ma for the Leeuwdraai Formation rhyolite in the undeformed upper sequence. Thus a major 70 m.y. hiatus seemed apparent between the lower and upper sequences despite their similar geochemistry and rift-related setting. This gave rise to models which envisaged the Kaaien Terrane being unaffected by the syn- to late-tectonic deformation, migmatisation and granite intrusions, documented between 1 200 and 1 150 Ma in the adjoining Namaqua-Natal terranes to the west. A high-pressure (10 kbar) metamorphic event, recognised in the Kaaien Terrane basement just south of hardlydeformed Koras Group exposures and dated at 1 150 Ma, is inconsistent with such models. A re-investigation and microbeam dating campaign on the Koras Group confirms the 1 101 ± 2 Ma (n = 6) age for felsic volcanic rocks of the upper sequence, but establishes a new reliable age of 1 114 ± 4 Ma for the lower one (n = 2). The 1 170 ages obtained in the earlier two studies were revisited and are now considered to reflect the age of zircon xenocrysts from the source rocks, which dominate the zircon population of some Swartkopsleegte Formation samples. Several criteria to distinguish autocrystic (magmatic) from antecrystic (age-overlappping xenocrystic) data points were investigated. One sample had high Th levels in only the younger zircons, but histograms of sufficiently precise 207Pb/206Pb ages provided the main criterion. Calculations of zircon crystallisation temperature intervals were not useful in predicting the abundance or proportions of magmatic and antecryst zircons. A multi-episode model of magmatic generation and crystallisation events is probably appropriate. In cases when felsic volcanic samples yield few zircons, care must be taken to avoid the problem exposed in this study. The Koras Group sediments have similar detrital zircon U/Pb age distributions to those of the Rehoboth Basement Inlier. This supports the concept that the Kaaien Terrane originated as the southern part of the Rehoboth Province. [ABSTRACT FROM AUTHOR]

Archaeologists keep a limited arsenal of methods for dating stone features at alpine sites. Radiocarbon (14C) dating is rarely possible, and it is common that dates do not accurately represent the activity of interest (stone feature construction). In this paper I review a legacy set of 89 14C dates for stone driveline sites built by hunter-gatherers in Colorado's Southern Rocky Mountains. I amend the sample of dates using chronometric hygiene and focus on dates with direct association to hunting features. I then present a newly calibrated set of 29 lichenometric dates for rock features at these sites and use hygiene protocols to remove inaccurate dates. Size-frequency lichenometry, though poorly known in archaeology, provides a way to date stone features indirectly by measuring the growth of long-lived lichens that colonize rock surfaces after construction events. Bayesian modeling of the combined set of dates suggests that the tradition of alpine game driving spans over 6000 years BP, with abundant use over the last 2000 years. Archaeologists must use multiple methods for dating stone features in alpine environments. This Bayesian analysis is a formal effort to combine lichenometry and 14C dating for archaeological interpretation. [ABSTRACT FROM AUTHOR]

Detachment faulting is one of the main styles of seafloor spreading at slow to intermediate mid-ocean ridges. However, we have limited insight into its role in back-arc basin formation. We surveyed a remnant back-arc spreading center in the Philippine Sea and determined the detailed features and formation processes of the Mado Megamullion (Mado MM) oceanic core complex (OCC). This was undertaken in the context of back-arc evolution, based on the shipborne bathymetry, magnetics, and gravity with radiometric age dating of the rock samples collected. The Mado MM OCC has a typical OCC morphology with prominent corrugations on the domed surface and positive gravity anomalies, suggesting that there has been an exposure of the lower crust and mantle materials by a detachment fault. The downdip side of the detachment continues to the relict axial rift valley, which has indicated that the Mado MM OCC was formed at the end of the back-arc basin opening. The spreading rate of the basin decreased once when the spreading direction changed after six million years of stable trench perpendicular spreading. The rate then further decreased immediately prior to the end of the spreading when the Mado MM OCC was formed. The existence of other OCC-like structures in the neighboring segment and the previously reported OCCs along the Parece Vela Rift have indicated that the melt-poor, tectonic-dominant spreading is a widespread phenomenon at the terminal phase of back-arc spreading. The decrease in spreading rate in the later stage is consistent with the previous numerical modeling because of the decrease in trench retreat. In the Izu–Bonin–Mariana arc trench system, the rotation of the spreading axis and the resultant axis segmentation have enhanced the lithosphere cooling and constrained mantle upwelling, which caused the tectonic-dominant spreading at the final phase of the basin evolution. [ABSTRACT FROM AUTHOR]

Eumelanin, a macromolecule widespread in all the living world and long appreciated for its protective action against harmful UV radiation, is considered the beneficial component of the melanin family (ευ means good in ancient Greek). This initially limited picture has been rather recently extended and now includes a variety of key functions performed by eumelanin in order to support life also under extreme conditions. A lot of still unexplained aspects characterize this molecule that, in an evolutionary context, survived natural selection. This paper aims to emphasize the unique characteristics and the consequent unusual behaviors of a molecule that still holds the main chemical/physical features detected in fossils dating to the late Carboniferous. In this context, attention is drawn to the duality of roles played by eumelanin, which occasionally reverses its functional processes, switching from an anti-oxidant to a pro-oxidant behavior and implementing therefore harmful effects. [ABSTRACT FROM AUTHOR]

This archaeometric study aims at characterizing the archaeological finds belonging to the lithic industry from La Calvera rock shelter (Camaleño, Cantabria) and at hypothesizing the possible provenance of each material. The site, located in the mountainous area of Picos de Europa National Park (more than 1000 m a.s.l.) close to the megalithic complex of Peña Oviedo, is characterized by the presence of hearths and charcoal remains, ancient pottery, and a rich lithic assemblage composed of siliceous rocks dating back to >8000 BP and linked to the first Holocene occupations of the Cantabrian Mountains. For the study of the rock shelter's lithic assemblage, a multi-analytical approach was used: SEM-EDS and XRD analyses were performed to define the microtextural characteristics of samples and to identify the amorphous/crystalline phases; physical and mechanical tests were conducted to define the petrophysical properties (density, porosity, imbibition and saturation indexes, mechanical strength) of the samples. Preliminary data of chemical compositions, obtained by portable XRF, are also presented. The results show that the different siliceous materials (quartzite, cherts, hyaline quartz) can be distinguished through the basic analytical techniques used here. In addition, most of the archaeological samples have mineralogical and petrographic features similar to the natural samples coming from nearby outcrops, corroborating the hypothesis of a local material supply. The presence of local sources of useful raw materials could have favoured the site's occupation. Finally, the diverse compositional and textural feature of the analysed materials result in different mechanical properties (porosity, density, hardness, workability), so they likely had different uses and technical functions. [ABSTRACT FROM AUTHOR]

We successfully measured four radiocarbon dates on two specimens of a black geometric rock painting with a fragment in jeopardy of naturally spalling off in the wall of a rock shelter in the Ẓufār region, in the south of the Sultanate of Oman. Extraction of carbon dioxide (CO2) for radiocarbon dating of the binder in the black pigment of the rock painting specimen was conducted in the plasma oxidation laboratory at the Office of Archeological Studies in Santa Fe, NM. The radiocarbon content was measured on the Swiss ETH-Zürich accelerator mass spectrometer MICADAS. The dates obtained agreed with one another within the statistical uncertainty and the average date of the four samples was 1500 ± 35 radiocarbon years BP. The calendric equivalents of the average date results in calendric calibration date ranges that span the mid-fifth through mid-seventh centuries (440–453 CE, 478–496 CE, and 534–646 CE). This research demonstrates that it is possible to date the black paintings of the Jebel al-Qara' area of Oman; this is the first pictogram that was dated using radiocarbon dating in the region. [ABSTRACT FROM AUTHOR]

Granitoids, an important part of the continental crust, are the direct and indelible evidence of the accretion and reworking process of the continental crust in different tectonic settings. Therefore, these early geodynamic mechanisms can be roughly reconstructed by analysing the geochemical characteristics of granitoids. In this study, the Permian–Triassic Granitoids widely distributed in the East Kunlun Orogenic Belt (EKOB) are studied to determine their chronology and petrogenesis to restrict their source regions and establish the significance of their geodynamic and crustal growth. Zircon inductively coupled plasma mass spectrometry (ICP–MS) dating results show that the crystallization ages of these granitoids are between 252–240 Ma, during the early and middle Triassic. These granitoids have high SiO2 and medium Na2O + K2O contents, plotting into the granite region, and calc-alkaline to high-K calc-alkaline series on the SiO2–Na2O + K2O and SiO2–K2O diagrams, respectively. All the samples have aluminium saturation index (A/CNK) values from 1.00 to 1.25 showing peraluminous characteristics. In terms of trace and rare earth elements, the samples are depleted in high field strength elements (HFSEs) such as Nb, Ta, P, and Ti and are enriched in large ion lithophile elements (LILEs) such as Rb, K, Ba, and U. Moreover, all granitoids show right-inclined rare earth element (REE) distribution patterns with weak to moderate Eu anomalies (δEu = 0.50–0.93). In addition, the samples have low P2O5 contents, 10,000*Ga/Al ratios (1.65–2.39), and Zr + Nb + Ce + Y (212–262 ppm) displaying affinities to I-type granite. Combined with their εHf (t) values of −2.31 to 4.44, with 1.0–1.4 Ga two stage model ages (TDM2), they are considered to be the products of the reworking of the Mesoproterozoic lower crust; therefore, they are not related to the continental net growth in the EKOB. On the tectonic discrimination diagrams of granitoids, all the samples fall into the area of volcanic arc granite (VAG) and continental margin arc; this suggests that the Paleo-Tethys Ocean slab was still in the subduction stage during 252–240 Ma, and the continental collision had not yet started. Based on the plenty of magmatic rock dating results published previously, it appears there are two magmatic peak periods (260–240 Ma and 230–210 Ma) and one magmatic intermittence period (240–230 Ma) during the late Permian to Triassic of the EKOB, corresponding to three geodynamic evolution stages of subduction, post-collision extension, and syn-collision, respectively. [ABSTRACT FROM AUTHOR]

Aim: Were postglacial recolonizations facilitated by persistence close to the colonized areas rather than by dispersal ability allowing for colonization from distant sources? This question is particularly relevant for organisms with low active dispersal abilities and lacking specialized propagules. Here we identified glacial refugia of four Central European land snail species, including one for which a northern glacial refugium in the region was indicated by indirectly dated fossils. Location: Central Europe and the Balkans. Taxon: Pulmonate land snails: Monachoides incarnatus (Hygromiidae) and Helix pomatia, Helix thessalica and Caucasotachea vindobonensis (Helicidae). Methods: We used continuous phylogeographic analysis of mitochondrial sequence data to trace the origin of postglacially expanding lineages. We assessed the credibility of results from our focal species, M. incarnatus, by comparison to three other broadly sympatric land snail species. In addition, we performed direct radiocarbon dating of fossil shells to verify the presumed glacial presence of M. incarnatus on the territories of Czechia and Slovakia and to test the reliability of the available fossil data. Results: In three of the four species, the molecular data supported refugia located south of the Pannonian Basin, from the south‐eastern Alps to the south‐western Carpathians, but not more northerly. The direct radiocarbon dating resulted in younger dates than previously assumed. However, the molecular data also revealed unexpected, yet substantial postglacial southward expansions of M. incarnatus and C. vindobonensis into the Balkans. Main Conclusions: Neither the phylogeographic analyses nor the direct radiocarbon dating provided evidence for the glacial survival of studied land snail species in Central Europe. The refugia located adjacent to the Pannonian Basin were the most important source of postglacial expansions to Central Europe, but were also the source of the expansion southwards. Both climatic factors and biological interactions might explain why such southward expansions seem rather rare in Europe. [ABSTRACT FROM AUTHOR]

Rock art paintings are notoriously difficult to date numerically. Recently, luminescence dating has been shown to provide reliable rock surface burial ages in various archaeological settings. Here we use the cross‐cutting relationship between a fallen rock and two paintings of the Iberian Levantine (older) and Schematic (younger) styles to constrain the age of the paintings by dating the rockfall event using rock surface luminescence dating. Infrared‐stimulated luminescence (IRSL) signals as a function of depth into the buried face of the talus border indicate that the IRSL signal measured at 50°C (IR50) was sufficiently reset to a depth of about 1.6 mm prior to burial. An uncorrected IR50 age of 1.6 ± 0.2 ka was calculated for the rockfall event by dividing the surface equivalent dose (De) by the total dose rate. This age was corrected using both conventional and field‐to‐laboratory saturation approaches to yield indistinguishable ages of 2.7 ± 0.5 and 2.9 ± 0.3 ka, respectively. Since the panel with Schematic art was first available to the artist after the rockfall, we conclude the Schematic rock art at Villar del Humo is younger than ~2.9 ka. The Levantine rock art was painted on a panel constrained by the talus boulder before detachment, and so it is likely to be older than ~2.9 ka. [ABSTRACT FROM AUTHOR]

The process of slab tearing profoundly affects interchanges of material and energy between the lithosphere and asthenosphere and has been invoked as a trigger of magmatism in modern and ancient subduction‐collision systems. Horizontal slab tears may occur after continental collision and subsequent slab break‐off, whereas vertical slab tears may occur in response to along‐strike variations in rollback velocity, thereby ripping the subducting lithosphere. Previous studies have documented tearing of subducting slabs in modern convergent settings using geophysical methods, but in ancient collisional belts, where these methods cannot be applied, detection of slab tearing is more difficult, particularly if the oceanic plate was fully subducted and the geological evidence for subduction is limited. Here, we employ multiproxy element‐isotope imaging, as well as zircon petrochronology and whole‐rock geochemistry, to assess evidence of vertical tearing of the Mianlue slab in the Triassic Qinling Orogen in central China. Our results show evidence of anomalous, inferred tear‐related magmatism east of 107°E, at 225–210 Ma. Vertical tearing of the northward subducting Mianlue slab is recorded by geochemically anomalous igneous rocks, and the recognition of N–S to NE–SW trending boundaries defined by Sr‐Nd‐Hf isotopes, elemental ratios (Nb/Ta, and Ca/Al), Mg#, and reduced crustal thickness between 107° and 108°E. The inferred vertical tear may have been driven by slab rollback of the Mianlue slab at 225–210 Ma. The results show that multiproxy element‐isotope imaging (e.g., of εNd(t), εHf(t), (87Sr/86Sr)i, Nb/Ta, Mg#, and Ca/Al) can be used to reconstruct the evolution of fossil subduction systems. Plain Language Summary: Subduction zones are natural factories for the circulation of material in the Earth as they allow tectonic plates to descend into the mantle. Pieces of subducting plates, normally referred to as slabs, can be torn and segmented, but reconstructing the geometry of such tears in ancient convergent plate boundary settings is difficult. Based on the observation that slab tearing can trigger anomalous magmatism in convergent plate margins, we present a multiproxy geochemical and isotopic imaging method that enables us to understand the process of slab tearing in the Qinling Orogen (China) during the Triassic. We found that igneous rocks from the Qinling Orogen, east of 107°E, are geochemically anomalous (relative to typical arc rocks). These rocks are dated 225–210 Ma. By imaging various geochemical characteristics, our results demonstrate that the subducting Mianlue slab was likely torn at longitude 107°–108°E, thereby producing geochemically and isotopically anomalous mafic and felsic magmatism. Key Points: The geometry of slab tearing in an ancient orogen is constrained by a multiproxy geochemical approachAnomalous arc magmatism dated at 225–210 Ma is identified in the Qinling Orogen east of 107°EThe Mianlue slab underwent southward vertical slab tearing at 107°−108°E in the Late Triassic [ABSTRACT FROM AUTHOR]

Giant gravel bars are important archives of megafloods; however, determining their depositional ages requires reliable geochronometric methods. Five gravel bars, reaching heights of 150-170 m, formed in the bedrock-lined Alberton Gorge along the Clark Fork River, Montana (USA), during draining of Glacial Lake Missoula (GLM). We report the first numerical ages for megaflood deposits in the GLM basin by successfully applying the novel optically stimulated luminescence (OSL) rock surface dating technique to date cobbles collected from three locations along one bar's transport direction. Depth-dependent infrared stimulated luminescence and post-infrared pulsed OSL signals showed that exteriors of only 3 out of the 38 collected cobble samples were well bleached by exposure to daylight before burial, and hence suitable for dating. The cobbles provided ages of 16.5 ± 0.9, 18.5 ± 1.4, and 21.7 ± 1.1 ka, all of which are indistinguishable from the average cosmogenic nuclide age of 18.2 ± 1.5 ka (n = 4) for a large megaflood in the Channeled Scabland, eastern Washington State. The average of the two younger ages, 17.5 ± 1.0 ka, is our best estimate of the deposit age. We interpret the older age to be from a cobble that was reworked by the flood. Our results show that these techniques have great potential for providing reliable chronologies for paleofloods and other high-energy depositional events. [ABSTRACT FROM AUTHOR]

The Mount Meager volcanic complex (MMVC) is one of the eight major calc-alkaline volcanic centres within the Garibaldi Volcanic Belt, Canada. MMVC volcanism spans ∼2 Ma and has been mainly intermediate to felsic in composition. However, small-volume mafic centres are located around the periphery of the Mount Meager massif and have been collectively referred to as the Mosaic Assemblage or Mount Meager basalts. Here, we present new 40Ar/39Ar ages and expanded chemical datasets for the MMVC mafic rocks. We show that mafic eruptive ages are both older and longer-lived than previously interpreted, spanning the last ∼450 ka, and occurring in four episodes at ∼440, 200, 106, and 17 ka. We also found that chemical signatures for the MMVC mafic rocks have evolved across the four periods, fluctuating from "OIB"-like melt characteristics to more typical slab-influenced, calc-alkaline, before returning to "OIB"-like in the youngest phase. These findings provide the first evidence of a temporal-chemical evolution of melt sourcing for the Garibaldi belt volcanism. Lastly, field mapping has identified edifices and deposits that are glaciovolcanic in origin (vs. nonglaciovolcanic), which were used in conjunction with our new 40Ar/39Ar age estimates to document the presence or absence of Coast Mountain sectors of earlier Cordilleran ice sheets in southwest British Columbia over the last 500 ka. [ABSTRACT FROM AUTHOR]

Complete Neanderthal skeletons are almost unique findings. A very well-preserved specimen of this kind was discovered in 1993 in the deepest recesses of a karstic system near the town of Altamura in Southern Italy. We present here a detailed description of the cranium, after we virtually extracted it from the surrounding stalagmites and stalactites. The morphology of the Altamura cranium fits within the Neanderthal variability, though it retains features occurring in more archaic European samples. Some of these features were never observed in Homo neanderthalensis, i.e. in fossil specimens dated between 300 and 40 ka. Considering the U-Th age we previously obtained (>130 ka), the morphology of Altamura suggests that the archaic traits it retains may have been originated by geographic isolation of the early Neanderthal populations from Southern Italy. 3D reconstruction of a human cranium held within a deep cave in Italy is achieved with advanced virtual anthropology techniques; its features indicate that geographic isolation contributed to variation and evolution along the Neanderthal lineage. [ABSTRACT FROM AUTHOR]