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<jats:p>Key minerals, including zircon, apatite, titanite, rutile, monazite, xenotime, allanite and garnet, can retain critical information about petrogenetic and geodynamic processes. This Special Publication showcases snapshots of the latest developments using key minerals in igneous, metamorphic and detrital rocks through current-state reviews, contributions focused on case studies and newly developed techniques.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Non-marine gastropod fossils are abundant in the Middle Jurassic Toutunhe Formation in the Ziniquanzi section of the southern Junggar Basin, Xinjiang, NW China, and in the Lower Jurassic Sangonghe Formation in the Tuziakeneigou section of Karamay in the northwestern Junggar Basin. Nine species attributed to the families Viviparidae, Valvatidae and Hydrobiidae and one undetermined species attributed to Truncatelloidea are systematically re-described. Most of these species are widely distributed in China and can be used for biostratigraphic correlation. The palaeoenvironment was reconstructed by using available sedimentological data combined with ecological data for extant gastropod relatives.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> Vertebrate assemblages from the Junggar Basin in Xinjiang, China are the only ones known from palaeoarctic continental strata of Late Triassic and Early Jurassic age. Here we present a preliminary description of these new assemblages, focusing on the underappreciated Arctic palaeolatitude and winter freezing of this coal-bearing sequence. Mostly collected during NIGPAS-led stratigraphic studies in the 2016-2017 field seasons, new assemblages include: 1) small to large, sculptured palaeonisciform cranial elements and scales, small associated palaeonisciforms, a sauropterygian tooth, large-dinosaur bioturbation, and additional as yet unidentified small vertebrate bones from the Haojiagou Formation (?late Norian-Rhaetian); 2) a medium-sized brontozoid dinosaur footprint and a previously described possible <jats:italic>Anomoepus</jats:italic> track from the Badaowan Formation (Hettangian-?Pliensbachian); and 3) a hybodont shark egg case of the form taxon <jats:italic>Palaeoxyris</jats:italic> (only the third reported from the Early Jurassic of China), numerous associated and fragmentary small palaeonisciform remains including one partial skull and several small skeletons, and another possible <jats:italic>Anomoepus</jats:italic> track and associated dinoturbation from the Sangonghe Formation (?Pliensbachian-Toarcian). A possible ash associated with the aforementioned lower Sangonghe fish skull has produced a LA-ICP-MS age of roughly 186 Ma, consistent with a Pliensbachian age. We are optimistic that there will be many additional discoveries in early Mesozoic strata of the Junggar Basin, the importance of which for understanding Earth system processes cannot be overemphasised. </jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6729761">https://doi.org/10.6084/m9.figshare.c.6729761</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p> Hydrocarbon exploration in China has recently expanded to deep tight oil and gas from the Lower Jurassic sandstone reservoirs in the central Junggar Basin. These deeply buried sandstones (&gt;4.5 km) have generally been overpressured due to hydrocarbon saturation, but have not been intensively investigated in terms of diagenesis and reservoir quality. The Lower Jurassic sandstones are feldspathic litharenites (average Q <jats:sub>28</jats:sub> F <jats:sub>29</jats:sub> R <jats:sub>43</jats:sub> ) and were deposited in the lacustrine–deltaic environments of the high-palaeolatitude continental basin under warm, humid climatic conditions. Progressive burial with only slight uplift of the strata led to a relatively stable burial–thermal regime, resulting in minor diagenetic changes consisting of compaction, cementation by carbonates, quartz and clay minerals, and partial dissolution of feldspars and rock fragments. Despite generally similar diagenetic histories, the studied sandstones reveal considerable variations in the development of pore systems, porosity and permeability. The best reservoirs are represented by medium- to coarse-grained depositional facies with higher porosity (average 8.43%) and permeability (average 0.59 mD). All the evidence suggests that integrated consideration of the roles of depositional settings and diagenesis, linked with burial–thermal history and overpressure evolution conditions, provides a helpful means of predicting reservoir quality. </jats:p>

<jats:title>Abstract</jats:title> <jats:p> Large magnitude and rapid negative carbon isotope (δ <jats:sup>13</jats:sup> C) excursions in the Triassic–Jurassic boundary (TJB) interval have been proposed as critical evidence for the hypothesis that the emplacement of the Central Atlantic Magmatic Province (CAMP) triggered global carbon cycle perturbations and the end-Triassic mass extinction (ETE). However, the pattern and timing of δ <jats:sup>13</jats:sup> C variations during the ETE remain poorly constrained. Here I present high-resolution organic carbon isotope (δ <jats:sup>13</jats:sup> C <jats:sub>org</jats:sub> ) records from a terrestrial TJB succession continuously exposed along the Haojiagou valley on the southern margin of the Junggar Basin, northwestern China. The δ <jats:sup>13</jats:sup> C chemostratigraphic correlations, combined with the palynological data, indicate that the position of the TJB should be placed at the base of bed 53. Importantly, the results show that two rapid negative carbon isotope excursions at the end Triassic roughly coincide with two episodes of variations in the palynological records. This observation supports the hypothesis that two pulses of biotic crisis during the ETE may have been triggered by two major episodes of CAMP magmatic activity. In addition, the data in this study support an early start for CAMP magmatic activity in the early Rhaetian, which may have led to a global carbon cycle perturbation and the related biotic crisis or turnover. </jats:p>

<jats:title>Abstract</jats:title> <jats:p> We show that the Late Triassic-Early Jurassic continental Arctic experienced wintertime freezing conditions, despite the exceptionally high atmospheric CO <jats:sub>2</jats:sub> ( <jats:italic>p</jats:italic> CO <jats:sub>2</jats:sub> ), by quantitative identification of common lake ice-rafted debris (L-IRD) in the Junggar Basin of Xinjian, northwest China. This L-IRD consists of outsized (0.1-12 mm) lithic clasts ‘floating’ in otherwise fine-grained, profundal lake sediment matrix. Laser diffraction grain size analysis demonstrates that the grain size distribution for lacustrine strata of Junggar Basin is very similar to modern sediments from the seasonally ice-covered Sea of Okhotsk, reflecting the same depositional mechanism. 3-D computed tomography and 2-D thin sections demonstrate that the outsized clasts are dispersed, rather than in sand lenses or layers. These results are inconsistent with alternative methods of bi-modal sediment deposition such as mud flows, algae rafting or root rafting. The discovery of Triassic-Jurassic continental freezing provides new context for understanding global climate during times of high <jats:italic>p</jats:italic> CO <jats:sub>2</jats:sub> conditions and provides new context for climate and biotic changes in the Mesozoic Era. </jats:p> <jats:p content-type="supplementary-material"> Supplementary material at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" specific-use="dataset is-supplemented-by" xlink:href="https://doi.org/10.6084/m9.figshare.c.6723341">https://doi.org/10.6084/m9.figshare.c.6723341</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p> Orthoptera constitutes an important ecological component of the global fauna, but the order's Early Jurassic record is limited in China and its evolution is poorly understood after the end-Triassic mass extinction. Several orthopterans are described herein from the Lower Jurassic Badaowan and Sangonghe formations of the southern Junggar Basin, Xinjiang, NW China. From the Badaowan Formation, a new species, <jats:italic>Parahagla cheni</jats:italic> sp. nov., is established and assigned to Chifengiinae (Hagloidea: Prophalangopsidae), which represents the oldest record of this subfamily. From the Sangonghe Formation, a forewing fragment is attributed to <jats:italic>Sinagryllus xinjiangensis</jats:italic> <jats:xref ref-type="bibr"> Wang <jats:italic>et al.</jats:italic> , 2019 </jats:xref> (Grylloidea: Baissogryllidae); another forewing fragment and a metathoracic leg without attribution are also described. The discovery of these fossils increases the biodiversity of Orthoptera in the Early Jurassic, and further indicates that orthopterans probably flourished in the Junggar area during the Early Jurassic. An analysis of orthopteran biodiversity at generic and species levels reveals an extinction in Orthoptera in the Late Triassic, especially for the superfamilies Hagloidea and Oedischioidea, which suffered a substantial extinction. This extinction occurred in the Late Triassic, earlier than the mass extinction of marine animals at the end of the Triassic. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Core analysts principally study the storage, flow, and saturation properties of porous rocks and sediments. Some parameters are specific to hydrocarbon production, but many have commonality with other subsurface disciplines such as hydrology and soil science. Traditional core analysis involves direct physical experimentation on core plugs to derive a range of parameters used as calibration for conventional well logs, and to predict hydrocarbon reserves and recovery. The mechanisms and processes for obtaining such data have evolved significantly during the last century, from the manual instruments of the mid-twentieth century to the accredited digital data collection and recording of the 1990s onwards.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Mesozoic continental basins of northern China, including the Junggar Basin, provide some of the most spectacular and important fossil assemblages in the world, but their climatic and environmental contexts have been shrouded in uncertainty. Here we examine the main factors that determine those contexts: palaeolatitude; the effects of changing atmospheric gases on the radiative balance; and orbitally paced variations in insolation. Empirical evidence of these factors is accumulating rapidly and promises to upend many long-standing paradigms. We focus primarily on the Junggar Basin in Xinjiang, NW China, with the renowned Shishugou Biota, and the basins in Liaoning, Hebei and Inner Mongolia with their famous Jehol and Yanliao biotas. Accurate geochronology is necessary to disentangle these various factors, and we review the Late Triassic to Early Cretaceous U–Pb ages for these areas and supply a new laser ablation inductively coupled plasma mass spectrometry age for the otherwise un-dated Sangonghe Formation of Early Jurassic age. We review climate-sensitive facies patterns in North China and show that the climatic context changed synchronously in northwestern and northeastern China consistent with a previously proposed huge Late Jurassic–earliest Cretaceous true polar wander event, with all the major plates of East Asia docked with Siberia and moving together since at least the Triassic when the North China basins were at Arctic latitudes. We conclude that this true polar wander shift was responsible for the coal beds and ice-rafted debris being produced at high latitudes and the red beds and aeolian strata being deposited at low latitudes within the same basin. The climatic and taphonomic context in which the famous Shishugou, Yanliao and Jehol biotas were preserved was thus a function of true polar wander, as opposed to local tectonics or climate change.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>Nothocarapacestheria</jats:italic> <jats:xref ref-type="bibr"> Rohn <jats:italic>et al.</jats:italic> , 2014 </jats:xref> was erected based on material from the Upper Triassic–Lower Jurassic of the Paraná Basin, Brazil. Here we describe a <jats:italic>Nothocarapacestheria</jats:italic> species that has been discovered in the Lower Jurassic Badaowan Formation in Xinjiang, northwestern China. The described species is characterized by: (1) almost the whole carapace being ornamented with medium reticulations, 3–6 polygons per growth band, 20–60 µm mesh diameter; (2) the gradual transition to radially elongated reticulations in the distal region of the carapace, sometimes ending as radial lirae; and (3) fine puncta in the mesh of reticulations. Through this study, we are able to infer that the distribution of <jats:italic>Nothocarapacestheria</jats:italic> was more widespread than previously thought, and that <jats:italic>Euestheria</jats:italic> sp. previously reported from the Lower Jurassic Badaowan Formation are probably poorly preserved or juvenile individuals of <jats:italic>Nothocarapacestheria</jats:italic> . </jats:p>