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[Objective] A Sinian-Cambrian parallel unconformity has been widely developed in the Aksu area of the northwestern Tarim Basin, and controversy remains over its formation mechanism. [Methods] Based on sedimentological research, the genesis of the above unconformity was studied through detailed field observation and microscopic identification, focusing on the sedimentary facies and karst phenomenon at the top of the Upper Sinian Qigebrak Formation. [Results] The results show that platform margin and slope facies are developed at the top of the Qigebrak Formation in the Aksu area. The platform margin includes grain beach and microbial reef, consisting of thick- to massive bedded dolo-oolite, medium- to thick-bedded intraclast dolopackstone and massive dolostromatolite reef. Lithofacies of the slope include: dolobreccia, turbidite, and thin- bedded dolowackestone. In the Late Sinian, the sedimentary water bodies in the eastern Aksu area were deeper, and the degree of karst development was significantly stronger than that in the western areas, which was dominated by horizontal phreatic zone vertically. In addition, in the Early Cambrian, the Yuertusi Formation maintained the same sedimentary trend as the top of the Qigebrak Formation, and both showed stratigraphic sequences of deepening water bodies from west to east. [Conclusions] This unconformity was formed by tilting movement induced by tectonic activity at the platform margin in the Late Sinian, which resulted in the uplift of the western Aksu area. In addition, this movement led to the atmospheric freshwater hydrological system flowing eastward, resulting in strong karstification in the eastern platform margin zone. This study could provide guidance for oil and gas explorations of the Sinian dolomite reservoirs in the region. [ABSTRACT FROM AUTHOR]

[Objective] The Permian Luhcaoao Formation in the Jimusaer Sag has developed a continental mixed sedimentary system. Insufficient research on the sedimentary microfacies types of mixed fine-grained rocks and the distribution pattern of sweet spots has hindered the development of shale oil in this area. [Methods] Using core, outcrop, logging, and X-ray fluorescence (XRF) element logging data, analytical testing, oil testing, and production are integrated by lithofacies, sedimentary facies coupling analysis, and dynamic static combination. The sedimentary micro-environment, microfacies classification, model, and its controlling factors on deserts were studied. [Results] (1) From the core, eight types of sedimentary structures were identified: wave cross bedding, horizontal bedding, syngenetic deformation structure, pyrite, calcite strip, birds-eye structure and nodule, suture structure, biological fossil, and dolomite dissolution hole. The sub-facies are divided into semi-deep to deep lacustrine, mixed shallow lacustrine, and clastic shallow lacustrine. These are further subdivided into six microfacies: semi deep lacustrine mud, dolomitic flat, mixed beach bar, mixed shallow lacustrine mud, shallow lacustrine sand bar, and clastic shallow lacustrine mud. The sedimentary characteristics and mechanism of different microfacies are different. (2) A sedimentary microfacies model of mixed fine-grained rocks in saline lakes has been established. No.1 member of the Lucaogou Formation evolved from deep to semi-deep to shallow lacustrine from bottom to top. Typical reservoir microfacies are developed in different layers, including shallow lacustrine sand bar, mixed beach bar, and dolomitic flat. Among them, dolomitic flat has a more continuous and large-scale sheet shape, and mixed beach bar has potato shape, with highly developed and different scales. The shallow lacustrine sand bar is intermittent and scale limited; vertically, it is located in the superposition of thin reservoir microfacies and thick mudstone. The Lucaogou Formation No.2 member is dominated by shallow lacustrine facies. The reservoir microfacies are similar to No.1, but the architecture style is different. The development quantity and scale of dolomitic flat and mixed beach bars are greatly reduced, and shallow lacustrine sand bars were developed, showing large-scale scattered potato shapes and thick layer superposition vertically. The profile shows that the stacking style of microfacies changed at different positions of the plane. (3) The deposition of the target layer is a transition environment from dry and hot brackish water to salt water, with a high level of paleo-productivity. The lower desert section was deposited in an oxygen enriched environment, but the upper section was deposited in an anaerobic sub reduction to reduction environment. (4) Sedimentary microfacies control desert distribution and oilfield development strategies. The mixed beach bar microfacies is a type I sweet spot reservoir with high development degree, weak heterogeneity and the best production effect. Large scale deployment of horizontal well platform operation is adopted for development. The dolomitic flat microfacies is a type III sweet spot reservoir, with strong heterogeneity and general development effect. It is a follow-up replacement oil and gas resource. The shallow lacustrine sand bar is a type II sweet spot reservoir being, with overall dispersion, poor continuity, strong heterogeneity, and good production effect. [ Conclusions ] After the detailed study of the spatial distribution of sedimentary microfacies, the horizontal well development is deployed with reference to the parameters of the nuclear magnetic resonance curve. [ABSTRACT FROM AUTHOR]

Liquid biopsy techniques based on deep sequencing of plasma cell‐free DNA (cfDNA) could detect the low‐frequency somatic mutations and provide an accurate diagnosis for many cancers. However, for brain gliomas, reliable performance of these techniques currently requires obtaining cfDNA from patients' cerebral spinal fluid, which is cumbersome and risky. Here we report a liquid biopsy method based on sequencing of plasma cfDNA fragments carrying 5‐hydroxymethylcytosine (5hmC) using selective chemical labeling (hMe‐Seal). We first constructed a dataset including 180 glioma patients and 229 non‐glioma controls. We found marked concordance between cfDNA hydroxymethylome and the aberrant transcriptome of the underlying gliomas. Functional analysis also revealed overrepresentation of the differentially hydroxymethylated genes (DhmGs) in oncogenic and neural pathways. After splitting our dataset into training and test cohort, we showed that a penalized logistic model constructed with training set DhmGs could distinguish glioma patients from healthy controls in both our test set (AUC = 0.962) and an independent dataset (AUC = 0.930) consisting of 111 gliomas and 111 controls. Additionally, the DhmGs between gliomas with mutant and wild‐type isocitrate dehydrogenase (IDH) could be used to train a cfDNA predictor of the IDH mutation status of the underlying tumor (AUC = 0.816), and patients with predicted IDH mutant gliomas had significantly better outcome (P =.01). These results indicate that our plasma cfDNA 5hmC sequencing method could obtain glioma‐specific signals, which may be used to noninvasively detect these patients and predict the aggressiveness of their tumors. [ABSTRACT FROM AUTHOR]