Late Jurassic Early Research Articles

Mesozoic and Cenozoic exhumation history and magmatic-hydrothermal events of the central Tianshan Mt. Range, NW China: Evidence from (U–Th)/He and 40Ar/39Ar dating

The thermal history of rocks in the Awulale area, central Chinese Tianshan, is significant to understanding the formation and tectonothermal evolution of the Tianshan orogen. K-feldspar 40Ar/39Ar and apatite (U–Th)/He age data reveal at least four Mesozoic–Cenozoic tectonothermal events in the central Tianshan, which occurred during the Middle–Late Triassic (244.4–216.5 Ma), Early Jurassic (ca. 180.3 Ma), Early Cretaceous (99.1–98.1 Ma), and early Miocene (18.6–13.7 Ma). This thermal history is consistent with that throughout the Tianshan orogenic belt and surrounding blocks. Modeling of the thermal history shows that intrusive rocks in the central Tianshan have experienced four stages of cooling in the Mesozoic–Cenozoic. Stage I occurred from ca. 310 to 230 Ma, after magma emplacement, and resulted in cooling to the 40Ar/39Ar closure temperature of K-feldspar (200–180 °C). During this time, tectonism in the central Tianshan was not intense and the rapid cooling was due mainly to thermal exchange, with a maximum cooling rate of ~7.1 °C/Myr. Stage II occurred from ca. 230 to 180 Ma. Collision between the Qiangtang microcontinent and the Eurasia continental margin resulted in active tectonism in the central Tianshan, and cooling was caused mainly by tectonic uplift, with the maximum uplift of intrusive rocks exceeding 9 km. Stage III occurred from ca. 180 to 45 Ma, when regional tectonism was weak and cooling was gradual. During this stage, the apatites in the syenite-porphyry remained in the He partial retention zone for a long time. This indicates that during this stage the central Tianshan was only weakly influenced by the far-field collisions of Lassa and Karakoram–Pamir with the southern margin of Eurasia. Stage IV occurred from 45 Ma to the present-day, and was related to the far-field influence of the middle–late Himalayan Orogeny, during which tectonism in the central Tianshan became more intense. In this final stage, many types of intrusive rock were exhumed to the surface, with the maximum uplift exceeding 2 km. Furthermore, the cooling history and regional structural trends indicate that since the Mesozoic, under the influence of tectonic compression, there has been differential uplift on the northern and southern sides of the east Awulale area. The cooling and exhumation rates of intrusive rocks are much higher on the northern side of the area than the southern side. This was related to reverse movement on the Yuximolegai Fault, as exhumation rate of the hanging wall (northern region) was higher than that of the footwall (southern region) under N–S compression. These findings, combined with the inversion model results, indicate that this differential uplift occurred mainly from the Late Triassic to Early Jurassic.

Late Permian-Early Jurassic vertebrate tracks from patagonia: Biochronological inferences and relationships with southern african realms

In recent years, new studies about vertebrate tracks found in the late Permian-Triassic Los Menucos Complex and Early Jurassic Marifil Volcanic Complex (Río Negro province, Patagonia, Argentina) have been published. In those studies, the chronostratigraphic information of each track-bearing unit has been discussed and the relationships between the record from Patagonia and southern Africa have been highlighted. With the aim of deepening both subjects, the biochronological and palaeobiogeographical information of the main ichnotaxa found in the lower Mesozoic units of Patagonia, Dicynodontipus, Pentasauropus and Anomoepus-like tracks, have been analysed. Moreover, the updated chronological data from the Vera Formation, Los Menucos Complex, in the Tscherig and Yancaqueo farm areas, and from the Marifil Volcanic Complex near Perdomo farm, have been studied. The entire biochronological, chronological and tectonic evidence suggests that within the Los Menucos Complex there are two sequences: a lower one, Wuchiapingian-Olenekian in age, near the Tscherig farm and bearing Dicynodontipus tracks, and an upper sequence of Anisian-Rhaetian (?Norian) age, in the Yancaqueo farm and bearing Pentasauropus tracks. This suggests that the rocks historically defined as Vera Formation have different ages in different areas and span a longer time interval than previously thought. In the case of the Anomoepus-like tracks found in the Marifil Volcanic Complex, the biochronological and geological data are consistent with an Early Jurassic age. According to ichnological information and geological background we propose a correlation between Patagonia and southern Africa constrained in three main phases: 1. Lopingian to Early Triassic, Vera Formation (Tscherig farm) and Balfour Formation, respectively; 2. Middle to Late Triassic, Vera Formation (Yancaqueo farm) and lower Elliot Formation, respectively; and 3. Early Jurassic, Marifil Volcanic Complex and upper Elliot Formation, respectively. In addition, this correlation is supported by a similarity in palaeoclimatic settings that allow inferring a homogeneous distribution of trackmakers in both realms of southern Gondwana. Finally, the palaeobiogeographic information of the studied ichnotaxa and their putative trackmakers is consistent and shows an extensive distribution, during a geotectonic moment with most of the continents assembled forming Pangaea.

New taxonomic assignment for a dinosaur sauropod bone from Cuba

ABSTRACT The fossil-bearing Jagua Formation of western Cuba was deposited during the early Late Jurassic (middle to late Oxfordian) in the marine corridor developed between western Laurasia and Gondwana, providing a rich assemblage of terrestrial to marine fossils including reptiles, fish and invertebrates. From this formation, De la Torre y Callejas reported in 1949 an isolated dinosaur bone, now missing, originally identified as ‘Diplodocus’ or ‘Brontosaurus’ humerus. Later, this fossil was referred as a camarasauromorph metacarpal. Within Macronaria, metacarpals became long and robust in Titanosauriformes. The strong curvature of the Cuban metacarpus suggests that it probably belongs to the first or second metacarpal of a somphospondylan. The achievement of a eugraviportal forelimb in Sauropoda was a unique event evidenced in metacarpal morphology. The bowed first metacarpal is present only in somphospondylans, particularly in some basal titanosaurs, and reverses in derived forms. Somphospondylans were not recorded yet for the early Late Jurassic neither in North nor in South America.

A new mid-Cretaceous cockroach of stem Nocticolidae and reestimating the age of Corydioidea (Dictyoptera: Blattodea)

Nocticolidae are delicate cockroaches, characterized by simple but unique wing venation. They are included in Corydioidea with Corydiidae. No fossil of this family was reported. Here we describe a stem member of Nocticolidae, Crenocticola burmanica gen. et sp. nov., from mid-Cretaceous Burmese amber. Its morphology appears plesiomorphic for Nocticolidae, and exhibits transitional form between crown Nocticolidae and Latindiinae (in Corydiidae). Placing Crenocticola in stem Nocticolidae is confirmed by a preliminary morphological phylogeny based on 28 non-genital characters. We use Crenocticola and published fossils to calibrate dating analyses of Corydioidea under autocorrelated TK02 relaxed clock model in MrBayes, and the analyses in turn test the power of Crenocticola as a node calibration. The dataset comprises published DNA (12S, 16S, 18S and 28S) of 19 ingroup taxa of Corydioidea, and eight outgroup taxa including termites. As a result, Crenocticola is too young to be an effective calibration. It is suppressed by the oldest fossil of termites, which may also be crucial in previous studies provided that unjustified fossil calibrations (e.g. ‘roachoids’) are excluded. We compare two approaches to applying fossil calibrations: 1) in-analytical calibration, i.e. incorporating the fossil age in prior settings, and 2) post-analytical calibration, i.e. adjusting the fixed prior so that the estimated age does not conflict with the fossil age. In-analytical calibration may underestimate the age, whilst post-analytical calibration yields better estimates. Our dating analyses suggest that crown Corydioidea likely originated in the Late Triassic or Early Jurassic. Questionable genera in Nocticolidae are briefly discussed.

Tectono-stratigraphy of the Dampier Sub-basin, North West Shelf of Australia

Abstract The Dampier Sub-basin, an inboard rift system of the Northern Carnarvon Basin in the North West Shelf, Australia, underwent two major phases of continental rifting in the Late Paleozoic and in the Latest Triassic to Late Jurassic. Six tectono-stratigraphic megasequences separated by regional unconformities have been identified: (1) Pre-Late Carboniferous Pre-rift 1; (2) Late Carboniferous to Late Permian Syn-rift 1; (3) Early to Latest Triassic Post-rift 1; (4) Latest Triassic to Early Late Jurassic Syn-rift 2; (5) Late Jurassic to Early Cretaceous Post-rift 2; and (6) Early Cretaceous to Present-day passive margin megasequences. The Late Paleozoic rifting produced a series of planar extensional faults on the eastern flank, some of which were later rotated by the Latest Triassic to Late Jurassic WNW–ESE extension to low-angles ( c. 30°). This Mesozoic extension was localized above a NE–SW-trending basement structure, resulting in en échelon inboard rift basins and overlapping boundary fault systems. The study outlines an updated basin tectono-stratigraphic model for the Dampier Sub-basin and provides new insights for structural evolution associated with the development of the North West Shelf passive continental margin of Australia.

Scheenstia bernissartensis (Actinopterygii: Ginglymodi) from the Early Cretaceous of Bernissart, Belgium, with an appraisal of ginglymodian evolutionary history

Lepidotes bernissartensis is a species of holostean ray-finned fish from the Barremian–Aptian of Bernissart, Belgium, described by Traquair in 1911. We provide here a revision of its anatomy, which led us to include this species in the genus Scheenstia, and to consider L. brevifulcratus and L. arcuatus, both from the same site, synonymous with S. bernissartensis. We performed two cladistic analyses in order to assess the phylogenetic position of S. bernissartensis and to do an updated appraisal of the evolutionary history of the ginglymodians. Scheenstia is included in the Lepidotidae, and placed in a pectinated position between the basal genus Lepidotes and the more derived members of the family (other species of Scheenstia, Isanichthys and Camerichthys). The nodes within the lepidotids are weakly supported. Although S. bernissartensis is not directly related to S. mantelli from the Wealden of Europe, the two species have similar palaeoenvironments and stratigraphical ranges. Taken as a whole, the ginglymodians experienced several episodes of diversification that are spatially and temporally restricted. The oldest episode involved basal ginglymodians and occurred in the Middle Triassic, in marine environments along the northern margin of the Tethys. A second episode affected the Semionotidae and occurred in freshwater environments of North America and Europe in the Late Triassic and Early Jurassic. The remaining Semionotiformes, Macrosemiidae and Callipurbeckidae, ranged from the Triassic to the Early Cretaceous and were mostly marine. Among the Lepisosteiformes, two clades, the Lepidotidae and the Lepisosteoidi, show episodes of diversification, first in marine and then in freshwater environments.

Late Jurassic globetrotters compared: A closer look at large and giant theropod tracks of North Africa and Europe

Late Jurassic theropod tracks are very common both in North Africa and Europe. Two recently described ichnotaxa Megalosauripus transjuranicus and Jurabrontes curtedulensis from the Kimmeridgian of Switzerland show the coexistence of two apex predators in the same palaeoenvironment. Similar tracks can be found in tracksites from the Iberian Peninsula and from Morocco. Here, we further explore the similarities among the Swiss ichnotaxa and the other tracks from Germany (Kimmeridgian), Spain (Tithonian-Berriasian), Portugal (Oxfordian-Tithonian) and Morocco (Kimmeridgian) through novel three-dimensional data comparisons. Specimens were grouped in two morphotypes: 1) large and gracile (30 < Foot Length<50 cm) and 2) giant and robust (FL > 50 cm). The analyses show a great morphological overlap among these two morphotypes and the Swiss ichnotaxa (Megalosauripus transjuranicus and Jurabrontes curtedulensis, respectively), even despite the differences in sedimentary environment and age. This suggests a widespread occurrence of similar ichnotaxa along the western margin of Tethys during the Late Jurassic. The new data support the hypothesis of a Gondwana-Laurasia faunal exchange during the Middle or early Late Jurassic, and the presence of migratory routes around the Tethys.

Timing of the Yanshan Movement: evidence from the Jingxi Basin in the Yanshan fold-and-thrust belt, eastern China

Evidence for the Jurassic–Cretaceous Yanshan Movement (Orogeny) was first identified in the Jingxi Basin, a part of the Yanshan fold-and-thrust belt (YFTB) along the northern margin of the North China Craton. The disconformity or angular unconformity within the Jurassic volcano-sedimentary successions in the basin was interpreted to have resulted from a period of incipient shortening during the Yanshan Movement, commonly known as event A. However, the absolute ages of both event A and associated Jurassic units remain controversial. Here, we present the results of zircon U–Pb geochronology for volcanic and clastic rocks from the Jurassic units in the Jingxi Basin. The results provide better constraints on the depositional ages of formations in the basin: (1) Early-to-early Middle Jurassic (175–167 Ma) for the Nandaling Formation; (2) middle Middle Jurassic for the Yaopo Formation; (3) late Middle Jurassic for the Longmen Formation; (4) early Late Jurassic for the Jiulongshan Formation; and (5) late Late Jurassic (157–149 Ma) for the Tiaojishan Formation. Stratigraphic and geochronological correlations indicate that the Jiulongshan Formation and the Tiaojishan Formation are of different depositional ages in different regions. The Longmen Formation in the Jingxi Basin is equivalent to the Haifanggou Formation in the eastern YFTB. Two sedimentary cycles separated by a sedimentary hiatus, shown as disconformity and local angular unconformity, have been identified in the Jurassic sequences of the YFTB. Depositional ages of the rocks above and below the disconformity, which lies between the Yaopo and Longmen formations in the Jingxi Basin, constrain the timing of event A to 167 ± 2 Ma (late Middle Jurassic). This event is the first phase of shortening deformation in eastern China induced by the paleo-Pacific plate subduction. We propose that the shortening period was relatively transient, in contrast to previous suggestions of long-duration shortening.

The literature on Triassic, Jurassic and earliest Cretaceous dinoflagellate cysts: supplement 4

Since the publication of four compilations issued between 2012 and 2019, 93 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts from Africa, North America, South America, the Arctic, Australasia, East Europe, West Europe, the Middle East and Russia have been discovered in the literature, or were issued in the last 12 months (i.e. between February 2018 and January 2019). Of these, 55 were published during 2018 and 2019, making this period a very productive one. These studies are mostly on the Late Triassic and Early Jurassic of Europe. All the 93 items are listed herein with digital object identifier (doi) numbers where available, as well as a description of each item as a string of keywords. Publications on West Europe comprise 31.2% of the total, and items on Africa, the Arctic, Australasia, East Europe and Russia are also significant (15.1, 6.5, 7.5, 9.7 and 14.0%, respectively). The least well-represented regions are North America, South America and the Middle East (2.2, 1.1 and 1.1%, respectively).

&lt;p&gt;&lt;strong&gt;Late Triassic fossil insects from the Laohugou Formation of northern China (Qinhuangdao, Hebei Province)&lt;/strong&gt;&lt;/p&gt;

Triassic insect fossils from China are very limited. Here we report on numerous insect fossils discovered in the Upper Triassic Laohugou Formation at Heishanyao, Qinhuangdao, Hebei Province. These fossils are represented mainly by forewings of cockroaches and coleopteran elytra. The insect assemblage is most similar to that from the Upper Triassic Momonoki Formation of Japan. Fossils of the Laohugou Formation have been poorly known, so our discovery of new fossil insects bear significance for understanding the biota and sedimentary environment of this formation. The Mesozoic stratigraphic division in the Liujiang Basin has been controversial, and the usage of stratigraphic units has been inconsistent. Here we refine the stratigraphic sequence, from the bottom to the top, of the Upper Triassic Laohugou Formation, the Lower-Middle Jurassic Yaopo Formation, the Upper-Middle Jurassic Longmen Formation, the Upper Jurassic Tiaojishan Formation, and the Lower Cretaceous Zhangjiakou Formation. The Laohugou Formation is scattered in various basins in western Liaoning and northern Hebei, with the lower part mostly characterized by thick layers of complex conglomerates, suggesting a regional tectonic uplift. There is a sedimentary discontinuity between the Laohugou Formation and the Yaopo/Beipiao Formation, reflecting the uplifting activities during the late Late Triassic-early Early Jurassic in eastern China. The Laohugou Formation is overlaying on various ancient strata, representing the first regional unconformity of the northeastern margin of the North China Craton.

K–Ar age determinations on the fine fractions of clay mineral ‘Crystallinity Index Standards’ from the Palaeozoic mudrocks of southwest England

AbstractClay mineral ‘Crystallinity Index Standards’ (CIS) composed of Palaeozoic mudrocks from southwest England were investigated systematically in five sub-fractions per sample for the first time. X-ray diffraction was used to determine mineral assemblages, calibrated 001 illite full-width-at-half-maximum (FWHM) values and illite polytype compositions, in addition to K–Ar isotopic analyses of all fine fractions. The FWHM results of the &lt;2 µm fraction are consistent with previous studies and reflect the range of diagenetic to epizonal grades covered by the sample set SW1 to SW7 (~0.61–0.26°2θ). Diagenetic and lower anchizone samples also show significant broadening of 001 illite reflections in the finer fractions and contain mixtures of authigenic 1M+ 1Mdillite and detrital 2M1white mica polytypes suitable for illite age analysis. The estimated end-member ages of the Bude (SW1-1992) and younger Crackington (SW3-2000) mudstones yield detrital ages of Late Cambrian to Middle Ordovician (493–457 Ma) and a broad range of 1M+ 1Mdillite ages between Middle Permian and Early Jurassic (271–190 Ma). The detrital age of the stratigraphically older Crackington Formation mudrock (SW2-1992) is Late Devonian (384–364 Ma) with 1M+ 1Mdillite ages between Late Triassic and Early Jurassic (219–176 Ma). The origin of Mesozoic 1M+ 1Mdillite ages may represent neocrystallized illite associated with Mesozoic hydrothermal events or similar events that thermally reset older authigenic illite with partial loss of radiogenic argon and no renewed crystal growth. In contrast, upper anchizonal and epizonal Devonian slates (SW3-2012, SW4-1992, SW6-1992 and SW7-2012) contain only the 2M1polytype, with K–Ar ages younger than the stratigraphic age. The three finest fractions of SW4-1992 yield consistent Late Carboniferous ages (331–304 ± 7 Ma) that are considered to date the neocrystallized 2M1mica. Most fractions of epizonal slate (SW6-1992, SW7-2012) yield Early Permian ages (293.6–273 Ma) corresponding to published cooling ages of the Tintagel High-Strain Zone and the intrusion of the Bodmin granite (291.4 ± 0.8 Ma). These first K–Ar age constraints for the fine fractions of the CIS should provide useful reference values for testing analytical procedures of illite age analysis.

Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution

The Late Jurassic Tendaguru Formation of Tanzania, southeastern Africa, records a rich sauropod fauna, including the diplodocoids Dicraeosaurus and Tornieria, and the brachiosaurid titanosauriform Giraffatitan. However, the taxonomic affinities of other sympatric sauropod taxa are poorly understood. Here, we critically reassess and redescribe these problematic taxa, and present the largest phylogenetic analysis for sauropods (117 taxa scored for 542 characters) to explore their placement in Eusauropoda. Janenschia robusta has played a prominent role in discussions of titanosaur origins, with various authors referring at least some remains to Titanosauria, a clade otherwise known only from the Cretaceous. Redescription of the holotype of Janenschia, and all referable remains, supports its validity and placement as a non-neosauropod eusauropod. It forms a clade with Haestasaurus from the earliest Cretaceous of the UK, and the Middle/Late Jurassic Chinese sauropod Bellusaurus. Phylogenetic analysis and CT scans of the internal pneumatic tissue structure of Australodocus bohetii tentatively support a non-titanosaurian somphospondylan identification, making it the only known pre-Cretaceous representative of that clade. New information on the internal pneumatic tissue structure of the dorsal vertebrae of the enigmatic Tendaguria tanzaniensis, coupled with a full redescription, results in its novel placement as a turiasaur. Tendaguria is the sister taxon of Moabosaurus, from the Early Cretaceous of North America, and is the first turiasaur recognized from Gondwana. A previously referred caudal sequence cannot be assigned to Janenschia and displays several features that indicate a close relationship with Middle–Late Jurassic East Asian mamenchisaurids. It can be diagnosed by six autapomorphies, so we erect the new taxon Wamweracaudia keranjei gen. et sp. nov. The presence of a mamenchisaurid in the Late Jurassic of southern Gondwana indicates an earlier and more widespread diversification of this clade than previously realized, prior to the geographic isolation of East Asia. Our revised phylogenetic dataset sheds light on the evolutionary history of Eusauropoda, including supporting a basal diplodocoid placement for Haplocanthosaurus, and elucidating the interrelationships of rebbachisaurids. The Tendaguru Formation shares representatives of nearly all sauropod lineages with Middle Jurassic–earliest Cretaceous global faunas, but displays a greater range of diversity than any of those faunas considered individually. Biogeographic analysis indicates that the Tendaguru sauropod fauna was assembled as a result of three main phenomena during the late Early and/or Middle Jurassic: (1) invasions from Euramerica (brachiosaurids, turiasaurs); (2) endemism in west Gondwana (dicraeosaurids, diplodocids); and (3) regional extinctions that restricted the ranges of once widespread groups (mamenchisaurids, the Janenschia lineage). Multiple dispersals across the Central Gondwanan Desert are required to explain the distributions of Jurassic sauropods, suggesting that this geographic feature was at most a filter barrier that became easier to cross during the late Middle Jurassic.

Integration of biostratigraphy into a sequence stratigraphic framework for the Surat Basin, eastern Australia

A new sequence stratigraphic framework (SSF) for the Early–Late Jurassic Surat Basin, eastern Australia, is evolving. A second and third order framework based upon an integrated methodology of well-to-well correlations supported by well tied seismic data is being developed. The integration of an additional dataset (palynology) to test for regionally consistent sequence stratigraphic well correlations offers an improvement in defining sequence boundaries related to the geological timescale. The palynological data from 33 wells covering the north-east Surat Basin were extracted from the Queensland Digital Exploration (QDEX) open-file reports, some of which date back to the 1960s. These data were correlated and superposed on the SSF for age comparison. The dataset used in this study represents only a subset of all existing palynology information, as not all data are captured in QDEX. However, the palynology data in this exploratory study generally fits and supports the new SSF with only one exception, the reason for which is not understood at this stage. We recommend expanding this study to include more data because palynology can support stratigraphic interpretation, especially in wells that do not intercept, or have log data across, regional datums.

Late-stage southwards subduction of the Mongol-Okhotsk oceanic slab and implications for porphyry Cu[sbnd]Mo mineralization: Constraints from igneous rocks associated with the Fukeshan deposit, NE China

Multistage igneous rocks identified in the newly discovered Fukeshan porphyry CuMo deposit, NE China give new insights into the late-stage southwards subduction of the Mongol-Okhotsk oceanic slab (MOOS) and CuMo mineralization during the late Mesozoic. The UPb ages of zircons from medium-grained monzogranite, coarse-grained monzogranite, ore-related quartz diorite porphyry, quartz monzonite, ganodiorite porphyry, diorite porphyry and andesitic porphyry associated with the Fukeshan deposit are 192.7 ± 1.9, 192.2 ± 2.7, 148.7 ± 0.8, 148.8 ± 0.9, 144.1 ± 1.1, 144.9 ± 0.9, and 144.8 ± 1.3 Ma, respectively. The Early Jurassic coarse-grained monzogranite, Late Jurassic quartz monzonite and quartz diorite porphyry, and Early Cretaceous granodiorite porphyry are characterized by low Yb and Y contents, and high Sr/Y ratios, indicating adakite affinities. The whole-rock geochemistry, and SrNd and zircon Hf isotopic features of the coarse-grained monzogranite and granodiorite porphyry indicate they were derived from the partial melting of a thickened basaltic lower crust. On the other hand, the quartz monzonite and quartz diorite porphyry probably originated from the melting of oceanic crust together with assimilation of enriched mantle and continental crust. The medium-grained monzogranites were possibly derived from a basaltic lower crust at shallower depths, and the diorite porphyry and andesitic porphyry probably originated from a metasomatized mantle source. Considering the Early Jurassic–Early Cretaceous magmatism and regional tectonic evolution of the Erguna Block, we propose that the MOOS was subducted towards the south during the Early Jurassic (195–170 Ma), slab retreat occurred during the early Late Jurassic (165–155 Ma), oceanic ridge subduction took place during the Late Jurassic (150–147 Ma). The final closure of the Mongol-Okhotsk Ocean occurred during the Early Cretaceous (145–143 Ma). The southwards subduction of a ridge on the MOOS provided a favorable tectonic setting for CuMo mineralization, and this is accordance with the discovery of many Late Jurassic–Early Cretaceous porphyry CuMo deposits in the eastern part of the Erguna Block.

Geochronology and geochemistry of early Mesozoic magmatism in the northeastern North China Craton: Implications for tectonic evolution

This paper reports geochronological, geochemical, zircon U–Pb and Hf–O isotopic data of the Late Triassic and Early Jurassic intrusive rocks in the northeastern North China Craton (NCC), with the aim of reconstructing the tectonic evolution and constraining the spatial–temporal extent of multiple tectonic regimes during the early Mesozoic. Zircon U–Pb ages indicate that the early Mesozoic magmatism in the northeastern NCC can be subdivided into two stages: Late Triassic (221–219 Ma) and Early Jurassic (180–177 Ma). Late Triassic magmatism produced mainly granodiorite and monzogranite, which occur as a NE–SW-trending belt parallel to the Sulu–Jingji Belt. Geochemically, they are classified as high-K calc-alkaline and metaluminous to weakly peraluminous granitoids, and are enriched in large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depleted in high-field-strength elements (HFSEs; e.g., Nb, Ta, Ti, and P) and heavy rare earth elements (HREEs), indicating an affinity to adakite. Combined with their εHf(t) values (−17.9 to −3.2) and two-stage model ages (2387–1459 Ma), we conclude that the Late Triassic granitoid magma in the northeastern NCC was derived from partial melting of the thickened lower crust of the NCC and was related to deep subduction and collision between the NCC and the Yangtze Craton (YC). The Early Jurassic magmatism is composed mainly of monzogranites, which are classified as metaluminous, high-K calc-alkaline, and I-type granite. Their εHf(t) values and two-stage model ages are −16.7 to −4.2 and 2282–1491 Ma, respectively. Compared with the Late Triassic granitoids, the Early Jurassic granitoids have relatively high HREE contents, similar to calc-alkaline igneous rocks in an active continental margin setting. These Early Jurassic granitoids, together with the coeval calc-alkaline volcanic rocks and gabbro–diorite–granodiorite association in the northeastern (NE) Asian continental margin, comprise a NNE–SSW-trending belt parallel to the NE Asian continental margin, indicative of the onset of Paleo-Pacific Plate subduction beneath Eurasia.

Petrophysical Characteristics of the Intrusive Complexes of Different Age of the Gamow Peninsula (Southwestern Primorye)

The petrophysical data on the granitoids of the Gamow Peninsula are presented and compared with those of the granitoid complexes distributed on the adjacent territory. The physical properties of the Late Permian and Early Jurassic granitoid complexes are considered. Granitoids of different age sharply differ in petrophysical properties. The Late Permian granitoids developed on the Gamow Peninsula have higher density and lower magnetic characteristics relative to the same rocks distributed on the adjacent continental territory. It is established that the petrophysical properties of the Early Jurassic granitoids are similar to those of one phase of the Late Permian granitoids. The simultaneous formation of these complexes is proposed.

Coals of Romania: Geology, petrology and use

This paper is a contribution to the coal geology, coal petrology and end products of coal utilization in Romania. Romanian coals are approached from geological, petrographical and industrial use points of view. This research surveys all Romanian basins yielding terrestrial, coal bearing formations in relation to their stratigraphy, palaeobotany, coal genesis, coal petrography and some industrial utilization, together with historical aspects, most of them Romanian pioneering contributions. Romanian coals range from Late Carboniferous, Early Jurassic, Late Cretaceous, Oligocene, to Miocene and Pliocene in age, from hard coals to lignite with numerous and wide applications in metallurgy and steel industry, chemistry and energy.The paper presents the various aspects of end products of coals utilization by improving coking and semi-coking technology and developing non-conventional technologies, coke-oven gas purification, obtaining of special coal-tar pitches and high grade carbon products, coal combustion, activated carbon precursors, coal wastes and combustion products recovery and recycling, other. This paper is a synthesis of extensive ideas, trends and research experiences carried out in Romania in coal geology and carbochemistry.

Modelling determinants of extinction across two Mesozoic hyperthermal events.

The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the Early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterized by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.

Jurassic integrative stratigraphy and timescale of China

The Jurassic stratigraphy in China is dominated by continental sediments. Marine facies and marine-terrigenous facies sediment have developed locally in the Qinghai-Tibet area, southern South China, and northeast China. The division of terrestrial Jurassic strata has been argued, and the conclusions of biostratigraphy and isotope chronology have been inconsistent. During the Jurassic period, the North China Plate, South China Plate, and Tarim Plate were spliced and formed the prototype of ancient China. The Yanshan Movement has had a profound influence on the eastern and northern regions of China and has formed an important regional unconformity. The Triassic-Jurassic boundary (201.3 Ma) is located roughly between the Haojiagou Formation and the Badaowan Formation in the Junggar Basin, and between the Xujiahe Formation and the Ziliujing Formation in the Sichuan Basin. The early Early Jurassic sediments generally were lacking in the eastern and central regions north of the ancient Dabie Mountains, suggesting that a clear uplift occurred in the eastern part of China during the Late Triassic period when it formed vast mountains and plateaus. A series of molasse-volcanic rock-coal strata developed in the northern margin of North China Craton in the Early Jurassic and are found in the Xingshikou Formation, Nandailing Formation, and Yaopo Formation in the West Beijing Basin. The geological age and markers of the boundary between the Yongfeng Stage and Liuhuanggou Stage are unclear. About 170 Ma ago, the Yanshan Movement began to affect China. The structural system of China changed from the near east-west Tethys or the Ancient Asia Ocean tectonic domain to the north-north-east Pacific tectonic domain since 170–135 Ma. A set of syngenetic conglomerate at the bottom of the Haifanggou or Longmen Fms. represented another set of molasse-volcanic rock-coal strata formed in the Yanliao region during the Middle Jurassic Yanshan Movement (Curtain A1). The bottom of the conglomerate is approximately equivalent to the boundary of the Shihezi Stage and Liuhuanggou Stage. The bottom of the Manas Stage creates a regional unconformity in northern China (about 161 Ma, Volcanic Curtain of the Yanshan Movement, Curtain A2). The Jurassic Yanshan Movement is likely related to the southward subduction of the Siberian Plate to the closure of the Mongolia-Okhotsk Ocean. A large-scale volcanic activity occurred in the Tiaojishan period around 161–153 Ma. Note that 153 Ma is the age of the bottom Tuchengzi Formation, and the bottom boundary of the Fifth Stage of the Jurassic terrestrial stage in China should have occurred earlier than this. This activity was marked by a warming event at the top of the Toutunhe Formation, and the change in the biological assembly is estimated to be 155 Ma. The terrestrial Jurassic-Cretaceous boundary (ca. 145.0 Ma) in the Yanliao region should be located in the upper part of Member 1 of the Tuchengzi Formation, the Ordos Basin in the upper part of the Anding Formation, the Junggar Basin in the upper part of the Qigu Formation, and the Sichuan Basin in the upper part of the Suining Formation The general characteristics of terrestrial Jurassic of China changed from the warm and humid coal-forming environment of the Early-Middle Jurassic to the hot, dry, red layers in the Late Jurassic. With the origin and development of the Coniopteris - Phoenicopsis flora, the Yanliao biota was developed and spread widely in the area north of the ancient Kunlun Mountains, ancient Qinling Mountains, and ancient Dabie Mountain ranges in the Middle Jurassic, and reached its great prosperity in the Early Late Jurassic and gradually declined and disappeared and moved southward with the arrival of a dry and hot climate.

Paleoecological Response of Corals to the End-Triassic Mass Extinction: An Integrational Analysis

The end-Triassic (also Triassic-Jurassic) mass extinction severely affected life on planet Earth 200 million years ago. Paleoclimate change triggered by the volcanic eruptions of the Central Atlantic Magmatic Province (CAMP) caused a great loss of marine biodiversity, among which 96% coral genera were get lost. However, there is precious little detail on the paleoecology and growth forms lost between the latest Triassic extinction and the Early Jurassic recovery. Here a new pilot study was conducted by analyzing corallite integration levels among corals from the latest Triassic and Early Jurassic times. Integration levels in corals from the Late Triassic and Early Jurassic were determined through both the Paleobiology Database as well as from a comprehensive museum collection of fossil corals. Results suggest that in addition to a major loss of diversity following the end-Triassic mass extinction, there also was a significant loss of highly integrated corals as clearly evidenced by the coral data from the Early Jurassic. This confirms our hypothesis of paleoecological selectivity for corals following the end-Triassic mass extinction. This study highlights the importance of assigning simple to advanced paleoecological characters with integration levels, which opens a useful approach to understanding of mass extinction and the dynamics of the recovery.