Shallow marine carbonate sediments that formed after the end-Permian mass extinction are rich in a thin (maximum ca. 15 m) deposit of microbialites. Microbial communities that constructed the microbialites have geographic variability of composition, broadly divisible into two groups: (1) eastern Tethys sites are calcimicrobe-dominated (appearing as thrombolites in the field), with rare occurrence of sediment-constructed microbialites and uncommon cements either within microbial structure or as inorganic precipitates; (2) other Tethys sites are sediment-dominated structures forming stromatolites and thrombolites, composed of micrites and cements, with some inorganic precipitates. These other Tethys locations include western and central Tethys sites but their palaeogeographic positions depend on the accuracy of continental reconstructions, of which there are several opinions. In contrast to geographic variation of microbialites, the conodont Hindeodus parvus, which appeared after the extinction and defines the base of the Triassic, is widespread, indicating easy lateral migration throughout Tethys. Conodont animals were active nekton, although being small animals were presumably at least partly carried by water currents, implying active Tethyan surface water circulation after the extinction event. Post-extinction ammonoid taxa, presumed active swimmers, show poor evidence of a wide distribution in the Griesbachian beds immediately after the extinction, but are more cosmopolitan higher up, in the Dienerian strata in Tethys. Other shelly fossils also have poorly defined distributions after the extinction, but ostracods show some wider distribution suggesting migration was possible after the extinction. Therefore there is a contrast between the geographic differences of microbialites and some shelly fossils.
Determining the cause of geographic variation of post-extinction microbialites is problematic and may include one or more of the following possibilities: (1) because calcifying microbial organisms that create calcimicrobes were benthic, they may have lacked planktonic stages that would have allowed migration; (2) eastern Tethyan seas were possibly more saturated with respect to calcium carbonates and microbes, so microbes there were possibly more able to calcify; (3) significant reduction of Tethyan ocean circulation, perhaps by large-scale upwelling disrupting ocean surface circulation, may have limited lateral migration of benthic microbial communities but did not prevent migration of other organisms; and (4) microbes may have been subject to local environmental controls, the mechanisms of which have not yet been recognized in the facies. The difficulty of distinguishing between these possibilities (and maybe others not identified) demonstrates that there is a lot still to learn about the post-extinction microbialites and their controls.

Both lithological and palynological analyses were employed to decipher sedimentary stacking patterns and to date the sediments within the interval 50-325 m in Kemar-1 well, Bornu Basin, northeastern Nigeria. Eight different lithofacies units deposited in various environments were recognized. They are: (1) the grayish sandy claystone, rich in organic matter and associated with lignite, deposited in a continental to lacustrine environment; (2) the micaceous claystone, rich in muscovite flakes and organic matter, deposited in a lacustrine environment; (3) the lithified claystone which intercalates the dark gray shale, and deposited in a marine setting; (4) the shale; (5) the micaceous sandstone, which is characterized by presence of muscovite, silty to granular grain sizes, well sorted and deposited in a meandering setting; (6) the poorly-sorted sandstone. It is poorly sorted, poorly-graded, and coarse-grained, with erosive surfaces to underlying facies, and deposited in a fluvial environment; (7) the heterolithic clayey sandstone, poorly graded, grayish, with a degree of organic richness, suggesting an anoxic lacustrine environment; and (8) the grayish claystone which is non-lithic and rarely ferruginized marking the Upper Miocene/Eocene boundary.
One main palynological zone, i.e., the Echitricolporites spinosus assemblage zone, has been established. The base of the studied section at 385 m is characterized by the last up-hole occurrence of Grimsdalea magnaclavata suggestive of Eocene boundary while the overlying sediments are characterized by Late Miocene marker species such as Echitricolporites spinosus, Elaeis guineensis, Anthocerus sp., Nymphaea lotus, and Retistephanocolpites gracilis. The Chad Formation is dated as Late Miocene age unconformably overlying the Eocene Kerri-Kerri Formation which indicated that the Chad Formation was probably deposited during an alternation of lacustrine and continental settings, due to climatic change.

Withoil and gas exploration transferring to deeper and more ancient marine strata, more researches have been conducted about the Meso-Neoproterozoic and Cambrian microbial carbonate rocksby petroleum geologists. The Cambrian deposits experienced the first transgression of the Paleozoic, with shallow marine faciesdepositing in most areas, which are favorable for different kinds of biological reproduction. The Lower Cambrian in Beijing area is lithologically dominated bypurple red shales interbedded with limestones,the Middle Cambrian is mainly composed of thick oolitic limestones, and the Upper Cambrian consists ofthin limestones and flat-pebbleconglomerates. Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing. One is from the Zhangxia Formation of Middle Cambrian, and the other is from the Gushan Formation of Upper Cambrian. The microbialites are characterized by combination of multiple stromatolites forming different bioherms. The bioherms are mostly in oval shape and withdifferent sizes, which are 3-4m long, and 1-3m high. The surrounding strata beneath the bioherms are oolitic limestones. A central core of flat-pebble conglomerates occurred within eachbioherm. Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates, with dentate erosional surfaces. The bioherm carbonate rocks are interpreted as products froma deep ramp sedimentary environment where potential oil and gas reservoirs can be found. The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofaciespalaeogeography has significant implication for petroleum exploration. Research on geological record of microbialites is beneficial to investigating the Earth evolution, biodiversity, palaeoenvironment and palaeoclimate change, as well as biological extinction event during geological transitions. It also gives warning to human beings of modern biological crisis.

Two new types of sandbar are found in distributary channels of the modern Ganjiang Delta, Poyang Lake, China, respectively named as branching-point bar (BPB) and merging-point bar (MPB). BPB is defined as sandbar formed at the branching point of a channel where one channel branches into two. MPB is defined as sandbars formed at the merging point of two channels.
BPB results from current velocity decrease at the branching point. BPB, arrowhead-shaped and growing towards upstream through upstream accretion, can be divided into bar head, middle and tail. Bar head refers to the lower part of the bar below average low water level, submerges under water whether in rainy seasons or dry seasons, and no plants grow on it. Bar middle refers to the middle part of the bar between average low and average high water levels, and sparse plants grow on it. Bar tail refers to the upper part of the bar above average high water level, and plants grow densely on it. From bar head to bar tail, sediment becomes finer and sorting degree becomes poorer; plant fossils increase in number, and silting-mud layers increase both in number and thickness. Vertically BPB shows a fining-upward sequence. BPB can be classified into 3 types: baby BPB with only bar head, child BPB with bar head and middle, and adult BPB with bar head, middle and tail. Generally from the lower delta plain to upper delta plain, BPB becomes more and more mature. If a channel is suddenly abandoned, BPB at different stages may be preserved. MPB is very similar to BPB in depositional characteristics, and main differences lie in its origin and growth direction.
Discovery of BPB and MPB has important implications in finding remaining oil in oilfields. Previously, geologists considered point bars on convex bank of meandering channels or longitudinal bars and transverse bars in the middle of braided channels as favorable locations for finding remaining oil. Our study shows such locations as branching-points and merging-points of channels are also significant because BPB and MPB develop at these locations. Remaining oil has been found at branching points of channels in Pubei Oilfield, Songliao Basin, Northeast China.

The lower Permian (Wolfcampian) Sangre de Cristo Formation of northern New Mexico consists of silty mudstones and laterally discontinuous sandstones deposited on an aggrading alluvial plain. Locally, mudstones display a variety of pedogenic features. Common mudstone fabrics vary from platy to prismatic; some beds display prominent pedogenic slickensides. Drab-colored root traces are common throughout the section, as are calcareous nodules, which vary from small bodies with diffuse boundaries to vertically stacked, discrete, cm-scale nodules (rhizocretions), and less commonly form coalescing horizons. Vertisols occur only in the lower portion of the ca. 90-m measured section. Most of the mudstone beds contain calcretes that are immature (calcic Protosols to calcic Argillisols), but the lower to middle portion of the section also contains mature calcrete horizons (argillic Calcisols and Calcisols).
Intercalated micritic limestone beds with sharp contacts containing root traces, are of laterally variable thickness and grade to nodular calcretes. These are interpreted as floodplain pond carbonates that have undergone pedogenic alteration (palustrine limestones), indicating long periods of exposure under strongly seasonal climatic conditions. The isotopic composition of the pedogenic carbonate displays a substantial range of values, but most of the range of variation in isotopic composition is accounted for by isotopically heavier carbonate (both carbon and oxygen) precipitated in shallow ponds subject to intense pedogenic reworking (palustrine carbonate).
During the early Permian, northern New Mexico was situated in a near equatorial position (ca. 4° N). The overall character of the paleosols suggests a persistent warm, semi-humid, seasonal climate throughout most of the interval of deposition during the Wolfcampian, but with episodically increased aridity during formation of the more mature calcretes. No long-term trend of climate change is evident in the stratigraphic section examined for this study.

The study on soft-sediment deformation structures (SSDS) of Lingshan Island has been one of the hot topics of sedimentology researches in China in recent years, and SSDS developed in turbidite system in the Laiyang Group are widely known by domestic researchers. However, few studies were conducted on the SSDS in fan delta system in the Qingshan Group, Lingshan Island.
This study analyzes the classification and characteristics of SSDS especially their lithofacies association and lithologic characteristics through field outcrops investigation and thin section analysis as well. A conclusion was acquired that the paleoenvironment was a fan delta system with occurrence of several volcanic eruptions, where the water became gradually shallower.
The SSDS types in the Qingshan Group includes load and flame structure, ball and pillow structure, water-escape structure, hydroplastic deformation structure, plastic sandstone breccia structure, volcanic drop stone and V-shaped ground fissure mainly caused by volcanic earthquakes of three types: (1) seismic waves, (2) gravity and inertia effect of pyroclastic flows, (3) instant differential air pressure; which is different from slumping and tectonic earthquakes occurred in the Laiyang Group. In addition, with the lithofacies association analysis between pyroclastic flow and SSDS beds, a distribution model of SSDS related to volcanic earthquakes can be established: SSDS types changed gradually with their distance further away from the volcanic activity core. Brittle deformation which was common in the proximal zone disappeared gradually; liquefied and plastic SSDS continued to dominate in the medial zone; and slightly liquefied SSDS were developed in the distal zone. Meanwhile, the scale and size of SSDS is negatively correlated with the distance of SSDS depositional locations from the volcanic vent.