Cycles of fine-grained sedimentation and their influences on organic matter distribution in the second member of Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay Basin,East China

According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G108-8 in the Cangdong Sag,Bohai Bay Basin,was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins.A logging vectorgraph in red pattern was plotted,and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member.The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales.It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals,a low paleosalinity,a relatively humid paleoclimate and a high density of laminae,while the fifth-order R cycles display a high content of carbonate minerals,a high paleosalinity,a dry paleoclimate and a low density of laminae.The changes in high-frequency cycles controlled the abundance and type of organic matter.The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters,implying a high primary productivity of lake for the generation and enrichment of shale oil.

Breeding and Simple-rapid Regeneration Protocol for Jisheng 1 with Glandless Trait and High-frequency Somatic Embryo Production Ability

Most of model cotton varieties used in tissue culture have glands on both the reproductive and vegetative parts of the plant.These glands contain compounds that are toxic to human and non-ruminant animals.The presence of these compounds limits their usage as food and feed.To obtain a glandless cotton variety with high-frequency somatic embryo production ability,27 glandless varieties

Sequence Stratigraphy of the Permian--Triassia Boundary Section of Changxing, Zhejiang, Southern China

Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhejiang Province, southern China, the candidate stratotype sec-tion of the global Permo-Triassic boundary, based on a detailed study of the biological,ecological and high-resolution allochthonous cyclic events, microfacies and depositional systems.Furthermore, the stacking pattern of the depositional systems across various Changxingian andGriesbachian sedimentary facies of the Lower Yangtze and the sequence stratigraphic frameworkare outlined with the Meishan section as the principal section. In this paper the habitat types offossil biota are applied to semiquantitative palaeobathymetry and the study of relative sea levelchanges.

Carbonate Diagenesis Controlled by Glacioeustatic Sea-Level Changes: A Case Study from the Carboniferous-Permian Boundary Section at Xikou, China

The platform-facies carbonate rocks of the Carboniferous-Permian boundary strata are well developed and outcropped in Xikou （西口）, Zhen＇an （镇安） County, Shaanxi （ 陕西 ） Province, China. The carbonate diagencsis in the Carboniferous-Permian boundary section at Xikou contains many processes with conspicuous effects, including micritization, cementation, mechanical and chemical compaction, neomorphism, and dissolution. Based on mineralogical composition and microfabrics, the diagenetic environments are distinguished into marine, near surface meteoric and burial environments. Detailed petrographical observation of abundant thin sections integrated with previous studies on sequence stratigraphy reveals that the carbonate diagenesis in the Carboniferous-Permian boundary section is related to the relative stratigraphic position of the rocks in the high-frequency cycles and controlled by the glacioeustatic sea-level changes. There are distinctive differences in diagenetic patterns between the lower transgressive sequence and the upper regressive sequence in a cyclothem. The diagenesis in the lower transgressive sequence is mainly characterized by pressure dissolution and recrystallization of mudstone and wackstone in a burial environment, and the diagenesis in the upper regressive sequence by cementation and leaching of freshwater in a meteoric environment.

Late Permian- Early Triassic Conodont Biofacies and Bioprovinces in South China and Himalaya

On the basis of existing conodont data, the authors have studied the Late Permian-Early Triassic conodonts of different forms and biofacies in detail. Five conodont biofacies are recognized, from shallow to deep waters 1. Hindeodus conodont biofacies, 2. Pachycladina-Parachi rognathus conodont biofacies, 3. Gondolella -Hindeodus conodont biofacies, 4. Gondolella-Neospathodus conodont biofacies, and 5. Xaniognathus conodont biofacies. Considering the temporal and spatial changes of these conodont biofacies, 3 conodont bloprovinces have been divided. In light of the biofacies changes of each bioprovince, the authors also discuss, in this paper, the regularity of transgression-regression cycles of eastern Tethys and their possible relation to the mass biotic alternation.