Petrographic analysis and elemental geochemical testing were conducted on the dolostones of Gaoyuzhuang Formation in Beipiao area, Liaoning Province. Through petrographic and sequence stratigraphic analyses, eleven sedimentary cycles were identified within a 24-meter-thick stratigraphic section. It was found that the vertical fluctuations in magnesium isotope compositions of the dolostones broadly correspond to the subdivision of parasequences. This indicates that the thick-bedded dolostones of Gaoyuzhuang Formation in Beipiao area were formed by the cumulative superimposition of dolomitization processes occurring during different episodes (cycles). These results validate previous hypotheses regarding the genesis of thick Cambrian dolostone successions. Furthermore, the findings demonstrate that the genetic hypothesis that thick dolostones form via the progressive superimposition of multiple dolomitization events is also applicable to Precambrian dolostones. 

Based on a large number of cranidial specimens of Jiulongshania acalla Walcott, 1905 from the Cambrian Gushan Formation at the Tangwangzhai section in Jinan City, Shandong Province, the traditional morphometric method and geometric morphometrics were used to measure and quantify the morphological features of the cranidium, revealing the cranidial shape variation during ontogeny. The results show that the growth rate of preglabellar field is the fastest, and the rate for the cranidial width is the slowest. The cranidial shape variation during ontogeny is mainly characterized by elongation of cranidium and gradual increase in the length of preglabellar field. It is proposed that the variation of trilobite exoskeletal morphology, particularly the cephalon, might be related to the feeding mode of trilobite. The results may suggest that the feeding habits of J. acalla might have changed during development.

Thin section observations have revealed a large amount of filamentous cyanobacteria from the dolomite of Cambrian Series 2 Xiaoerblaq Formation in the northwestern Tarim Basin. Specifically, four species belonging to three genera of Oscillatoriaceae fossils have been identified, including Obruchevella meishucunensis, Oscillatoriopsis longa, Oscillatoriopsis sp., and Siphonophycus typicum. These findings represent the first report of such filamentous cyanobacteria in the Xiaoerblaq Formation, and provide an exquisite preservation of their clear threelayer structure, that is, calcified mucilaginous sheath, organic tube wall, and internal black filament, augmenting the knowledge of their internal structure and identification characteristics. The discovery of Oscillatoriaceae fossils greatly increases the diversity of the Xiaoerblaq Biota and provides new materials for further study of fossils and the evolution of life in the early Cambrian.

Microfossils from cherts of the Liuchapo Formation at Bahuang section in eastern Guizhou Province were studied. Through thin section observation, a large number of spherical fossils were revealed, including one type with connected spheroids, and two types with dark outer wall. The former is systematically described, and a new genus Bahuangia gen. nov. is established. The connected bodies of Bahuangia are calabash- or chain-shaped, and resemble the budding unicellular fungi or bacteria in morphology. Spherical fossils similar to these Bahuang specimens are widely distributed in the late Ediacaran deep-water facies of the Yangtze Plate. Through this study, the understanding of deep-water life forms during the ECT is improved, and new materials for both regional stratigraphic correlation and early life evolution are provided.

To investigate the specific processes of deposition and environmental changes in the North China Block during Late Neoproterozoic to Early Cambrian when it received deposition again after a depositional hiatus, chert breccia of the Qingbaikou Series Jingeryu Formation and the Lower Cambrian Fujunshan Formation in the Xiaweidian section of Xishan area of Beijing was analyzed. Based on petrological and geochemical studies, chert layers in Jingeryu Formation and chert breccia in the bottom of the overlying Fujunshan Formation have similar Ge/Si ratios and rare earth element patterns. It indicates that Fujunshan chert breccia might originated from Jingeryu Formation. Breccia-bearing dolomite in the bottom of the Fujunshan Formation is block-shaped, without bedding. The breccia is mixed in component and size, with poor sorting and roundness, and disorderly arranged. Breccia-bearing dolomite in the bottom of Fujunshan Formation may represent glacial deposits.

Macroscopic cone fossils, from the early Cambrian Shuijingtuo Formation of Shennongjia and Zigui areas, Hubei Province, were studied by using stereo light microscopy and scanning electron microscopy. A new species of the genus Sphenothallus was identified by its longitudinal ridges located within the “V” shaped thickenings. The genus Ambrolinevitus of the class Hyolithida was firstly described from Shuijingtuo Formation. The result enriches the biodiversity of the Shuijingshuo Formation and adds new palaeontological data for the research of early life evolution. 

This study scrutinizes the petrological and geochemical signatures by systematically sampling three sections of Yurtus Formation, which deposited during the early Cambrian in the western margin of Tarim Basin. The redox conditions together with the intensity of primary productivity during Yurtus Formation deposition are reconstructed, which provide theoretical basis for the distribution of source rocks and evaluation of reservoir potentials. The extremely high Ba content (>1000 μg/g) and appearance of barite in the lower part of Yurtus Formation implies high primary productivity, which explains the substantive organic matter in the surface ocean and is also consistent with the abundant phytoplankton fossil record and high TOC content. The large positive excursion of δ¹⁵N (>8‰) in the lower parts of Yurtus Formation probably is resulted from denitrification or annamox, both of which occur only when O₂ is depleted. It may indicate that organic matter transporting from the surface ocean to deeper ocean could consume dissolved oxygen by the process of degradation, which would drive the condition of deeper ocean more reduced. Meanwhile, low Ge/Si values of cherts in the lower part of Yurtus Formation indicate normal seawater origin of Si input. Oversaturation state of silica promotes the organic matter preservation due to relatively fast cementation. 

The Neoproterozoic Gaoyuzhuang dolomite from Beipiao area, western Liaoning Province was systematically studied based on outcrop and microscope observations. The whole section is composed of several cyclic shallowing upward units (subsequences), which include subtidal massive dolomite and intertidal thin-bedded dolomite. Three types of microfacies, microspar dolomite, dolomicrite and intraclast dolomite, were identified. Partial recrystallization and silica filling/replacement are associated with each microfacies. The chert bands and
nodules, which are commonly distributed along the stratigraphic layers, was probably formed during the syndepositional stage. Silica filling/replacement may have great contributions to dolomite dissolution and recrystallization and therefore improve the porosity of the dolomite, potentially leading to the formation of the excellent dolomite reservoir. Therefore, silica filling/replacement during the syn-depositional stage is significant for the development and evolution of dolomite reservoirs.