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Mts. Kalnik and Požeška gora volcaniclastic sequences hold valuable information concerning the Miocene syn-rift evolution of the North Croatian Basin, and the evolution of the Carpathian–Pannonian Region and the Central Paratethys. We present volcanological, high-precision geochronological, and compositional data of volcanic glass to constrain their tephrochronology, magmatic provenance, and timing of the initial Central Paratethys flooding of the North Croatian Basin. Based on CA-ID-TIMS U–Pb zircon ages (18.060 ± 0.023 Ma for Mt. Kalnik and 15.345 ± 0.020 Ma for Mt. Požeška gora) and coeval 40Ar/39Ar sanidine ages (18.14 ± 0.38 Ma and 18.25 ± 0.38 Ma for Mt. Kalnik and 15.34 ± 0.32 Ma and 15.43 ± 0.32 Ma for Mt. Požeška gora), Mt. Kalnik rhyolitic massive ignimbrites and Mt. Požeška gora rhyolitic primary volcaniclastic turbidites are coeval with Carpathian–Pannonian Region Miocene post-collisional silicic volcanism, which was caused by lithospheric thinning of the Pannonian Basin. Their affiliation to Carpathian–Pannonian Region magmatic activity is supported by their subduction-related geochemical signatures. Although Mts. Kalnik and Požeška gora volcaniclastics are coeval with the Bükkalja Volcanic Field Csv-2 rhyolitic ignimbrites, North Alpine Foreland Basin, Styrian Basin, Vienna Basin, and Dinaride Lake System bentonites and volcaniclastic deposits, reliable tephrochronological interpretations based on comparison of volcanic glass geochemical composition are not possible due to a lack of data and/or methodological discrepancies. Our new high-precision geochronology data prove that the initial Middle Miocene (Badenian) marine flooding of parts of the North Croatian Basin occurred at least ~ 0.35 Ma (during the NN4 Zone) before the generally accepted ~ 15 Ma maximum flooding age at the basin scale, calibrating the timing of the onset of the widespread “mid-Langhian” Central Paratethys flooding.

Acigol volcanic complex is a bimodal volcanic field located at the western margin of the Neogene–Quaternary Cappadocian volcanic province in Central Anatolia (Turkey). Its most voluminous eruptions are preserved as a pair of widespread tuffs known as Lower Acigol Tuff (LAT) and Upper Acigol Tuff (UAT). Both are nearly aphyric high-silica rhyolites that are compositionally identical; they can be distinguished, however, by the presence of obsidian lithics in UAT and the absence thereof in LAT. Here, we report the discovery of medial deposits of these tuffs at ~ 60–65 km distance from their source, and re-estimate the volume for LAT in the range of 21.4–26.7 km3 (similar constraints are lacking for UAT, but a subequal volume is assumed). Development of paleosol between LAT and UAT provides evidence for a hiatus between both events which is further supported by radiometric dating using combined U–Th and (U–Th)/He zircon geochronology. The revised age for LAT based on sequence modeling of U–Th zircon crystallization and (U–Th)/He zircon eruption ages is 190 ± 11 ka, whereas new and published (U–Th)/He zircon ages indicate eruption of UAT at 164 ± 4 ka (uncertainties generally stated at 1σ). The compositional similarity between both eruptions previously known from whole-rock analyses also extends to glass major, minor, and trace element compositions. Moreover, U–Th zircon crystallization ages are also indistinguishable between LAT and UAT in proximal and medial locations. U–Pb zircon ages for crystals in secular equilibrium indicate a provenance from Cretaceous granitic basement and Miocene volcanic overburden typical for Cappadocia, and such xenocrysts appear to be slightly more common in LAT compared to UAT. The compositional similarity between LAT and UAT along with the apparent recycling of zircon from the non-erupted LAT magma during the UAT event indicates sequential tapping of rhyolite melt from a magma system that maintained thermal and compositional uniformity over a protracted time interval. This can be explained by rhyolite melt extraction from a thermally buffered crystal mush that remained viable to produce voluminous high-silica eruptions for few 10s of ka. The subsequent migration of eruptive activity in the Acigol volcanic complex from east to west also led to a change in magma chemistry and triggered a new pulse of zircon crystallization, indicating abandonment of the previous magmatic focus, and a shift of magma input to a new location. The identification of sizable medial deposits of LAT and UAT implies that both tephra units are potentially useful marker horizons for marine isotope stage (MIS) 6 sedimentary sequences in and around Anatolia. The recent discovery of UAT in a Black Sea sediment core supports this view.

U-Pb-Hf isotopes of zircons from the granitic intrusive rocks in the Iwakuni area of Southwest Japan are determined by LA-ICP-MS analysis. The Gamano Granodiorite belonging to the Older Ryoke Granites of the Ryoke Belt yielded U-Pb mean age of 92.3 ± 2.6 Ma (MSWD = 1.8). The Namera Granite belonging to the Younger Ryoke Granites of the Ryoke Belt yielded U-Pb mean age of 106.3 ± 1.6 Ma (MSWD = 2.3). The Shimokuhara Granite belonging to the Hiroshima Granites of the San-yo Belt yielded U-Pb mean age of 103.8 ± 1.5 Ma (MSWD = 0.32). A granite porphyry sample taken from about 15 m thick dike discordantly intruded into pelitic schist of the Ryoke metamorphic rocks yielded U-Pb mean age of 92.5 ± 1.6 Ma (MSWD = 0.63). Hf isotope data, obtained from the same dated zircon grains, show initial 176Hf/177Hf isotopic ratios referred to as “eHf(t)” generally ranging between–4.8 and +1.1 except an anomalously low value (–15.0) from an inherited core. The eHf(t) values, calculated with average crustal 176Lu/177Hf ratio of 0.015, correspond to Hf isotope crustal model ages between 1474 to 1087 Ma (Mesoproterozoic). The Gamano Graodiorite has long been regarded to be a syn-tectonic intrusion, but the zircon ages and eHf(t) values are similar to those of the post-tectonic granite porphyry dike. The results of this study together with available U-Pb zircon ages of granitic rocks in the Iwakuni area reported elsewhere reveal that the order of emplacement indicated by the U-Pb zircon ages are much discrepant with the traditional classification, the Older Ryoke, the Younger Ryoke. It is better to refrain from the use of “Older” and “Younger” for the collective names of the granitic intrusive bodies.

Vehicular wireless networks (VWNs) offer both high-priority safety and low-priority non-safety applications. In VWNs, the high-priority applications are urgent. Transmitting urgent information demands low delay and high bandwidth. When the traffic is heavy, how to reduce the multi-hop wireless delay will be critical for urgent information. In this paper, we propose a blocking strategy to preempt the transmission of low-priority vehicles and to decrease the number of contending vehicles. Thus, the multi-hop wireless delay of high-priority vehicles will be greatly reduced even if the traffic is heavy. Moreover, we also propose a mathematical model to evaluate the performance of the proposed strategy and compare the existing strategy. Performance results show that the proposed strategy can reduce the multi-hop wireless delay significantly.

Complete convergence theorems are obtained for an array of rowwise extended negatively dependent random variables. Special cases of the main results are presented as corollaries. Illustrative examples are also presented.

In recent years, the IEEE 802.11p/1609 wireless access in vehicular environments standards adopt the dedicated short-range communications multi-channel architecture for vehicular wireless networks. To utilize the multi-channel architecture, each vehicle equipped with two sets of transceivers can operate concurrently on three different channels. For example, in cluster-based multi-channel schemes, a cluster head vehicle coordinates and assigns an appropriate channel to its cluster members. However, these schemes are unsuitable for a single channel device performing on only one RF channel at a time which would waste channel resource and increase time to allocate a channel. Another approach, called LEACH-based scheme, selects channels randomly and ensures that each channel is selected once within a round in each vehicle. However, this leads to a situation that different vehicles might select the same channel in short-term duration. In this paper, we propose a multi-channel selection scheme, called minimum duration counter (MDC) scheme, which could apply to a single channel device, while utilizing the multi-channel architecture of an 802.11p/1609 network. In addition, we compare the MDC scheme with pure random (PR) and LEACH-based schemes in terms of fairness index (FI) and utilization to emphasize the fairness and to balance the traffic of multi-channel usage. Furthermore, we analyze the counter overflow probability distribution and propose solutions to the MDC scheme. Numerical results show that our scheme outperforms the PR and LEACH-based schemes in terms of multi-channel usage, traffic balancing, and fairness.

In-situ U-Pb geochronology and Hf isotopic studies of zircons from the Pre-Tertiary basement complex and Eocene rocks of the Central Range of Taiwan were carried out to elucidate the history of detrital zircons older than 2.3 Ga. Zircons from the eastern Backbone Range and Eastern Central Range show Paleoproterozoic to late Neoarchean ages (2.3−≥2.5 Ga), whereas those from the Hsuehshan Range yield Neoarchean to Mesoarchean ages (2.6–3.2Ga). The ɛHf(T) for the Paleoproterozoic to late Neoarchean zircons varies from −7.4 to +5.1, implying both juvenile crustal growth and reworking of old crusts. This dual origin could extend back to Mesoarchean-Paleoarchean (3.0–3.4 Ga) based on Hf isotopic model ages. Consistent but narrower ɛHf(T) values and Hf crustal model ages for zircons from Taiwan compared to Cathaysia suggest a possible common origin for these zircons, although Taiwan has a generally younger crustal evolution history than SE China.

With the development of the geographic information system (GIS), the analysis of regional slope stability under seismic loading has evolved rapidly in recent years. In many studies, the Newmark’s method is used for the computation of displacements triggered by an earthquake on a single slope, while for regional analysis, the infinite slope theory is frequently used due to its simplicity when large amount of computations are required. In this research, the infinite slope theory was examined considering various seismic conditions, material properties, and slope geometry to verify the suitability of the method when applied to regional analysis and development of potential shallow landslide maps. The landslide cases induced by Chi-Chi earthquake in central Taiwan were used in this study for verification. It was found that the infinite slope theory is valid for regional analysis when used with discretion. Based on the calculated Newmark’s displacement and combining the GIS technique, procedures for the potential map development are established in this study.

The uplift of the Tibetan plateau is generally regarded as a response to the convective removal of the lower portion of the thickened Asian lithosphere1. This removal is also thought to be responsible for the east–west extension2 that took place during the India–Asia collision. The timing of these events has been a subject of great interest for understanding mountain-building processes, collisional tectonics and the influence of these processes on climate change3,4. In western Tibet, potassic lavas related to east–west extension were found to have been extruded over the past 20?Myr (refs 5, 6). Here we report the widespread occurrence of magmas in eastern Tibet which show similar geochemical signatures to the potassic lavas to the west but formed 40–30?Myr ago. These magmatic activities suggest a diachronous uplift history for the Tibetan plateau, with the convective removal of the lower lithosphere inducing rapid uplift in the east beginning some 40?Myr ago and in the west about 20?Myr later. This observation is consistent with sedimentation records from the Ganges–Brahmaputra delta to the Bengal fan7,8 and can better account for the tectonically driven models for strontium isotope evolution in the ocean9 and global cooling10 over the past 40?Myr.

This study reports age and geochemical analyses of basaltic rocks dredged from volcanic seamounts offshore SW Taiwan. 40Ar/39Ar dating results of these rocks show them to be of the early Miocene age of ~22 - 21 Ma. They are evolved alkali basalts that show OIB-type geochemical features similar to post-spreading seamount basalts (14 - 3.5 Ma) in the South China Sea (SCS) and Miocene intraplate basalts on the Penghu Islands (16 - 8 Ma) and NW Taiwan (23 - 9 Ma). Their Sr-Nd-Pb isotope data plot within the range of the SCS seamount basalts that show an EM2-like component in the mantle source. The age and overall geochemical characteristics of the dredged basalts are comparable to those of the Kungkuan basalts, NW Taiwan and Baolai basalts, SW Taiwan, suggesting an extensive alkali basaltic volcanism along the southeastern Eurasian continental margin during the early Miocene that resulted from regional lithospheric extension in association with seafloor spreading in the South China Sea.