> Pinnatiramosus qianensis Geng, 1986, is a plant with a complex, extensive pinnate branching system and pitted tracheids, collected from marine Lower Silurian (Llandovery; c . 430 Ma) rocks in Guizhou Province, China. It challenges long-held theories on the origin and early evolution of vascular plants in the Silurian and Devonian. However, there is a hypothesis that the fossils were not syngenetic with the entombing rock, but were the rooting systems of much younger plants, probably of Permian age. New sections and collections of P. qianensis have been subjected to detailed analyses, which indicate that P. qianensis belongs to an early Permian ( c . 285 Ma) rooting system growing down into lower Silurian rocks.

中国遗迹化石研究经历了零星(1929-1978)、系统(1978-2004)和创新(2004～)研究3阶段.在前寒武纪一寒武纪之交遗迹化石研究;海相遗迹化石及其古环境和古生态意义研究;陆相遗迹化石及其与能源形成环境关系研究;前寒武纪遗迹化石与后生动物的起源与演化研究;拓扑遗迹分析;遗迹化石在浊流、风暴事件和层序地层研究中的应用;复杂遗迹化石的地球生物学研究和遗迹化石模拟与可视化研究8个方面取得了显著的进展和成就.研究队伍偏少且不稳定;原创、系统、有深度、有影响的研究成果不多;缺少有力度的学科交叉和国际合作是存在的主要问题.加强遗迹学人才和团队培育,稳定支持几个有特色的遗迹学研究方向;基于遗迹学资料的系统积累,拓展和深化遗迹化石的地球生物学研究;加强遗迹化石在海、陆相油气资源评价和储层研究中的应用;创新遗迹化石的研究方法手段,重视和加强现代生物遗迹研究是值得今后进一步关注的问题.

Influenced by the sedimentary models of turbidity currents and the turbidite mind set, the concepts of turbidity currents and turbidites have been expanded gradually since 1970s. Specially, Some deposition of debris flows and bottom flows are considered as turbidites by the introduction of the term “highdensity turbidity currents” and the incorrect comparison of subaerial rive currents and subaqueous turbidity currents. Turbidity currents and debris flows, especially sandy debris flows, have been rerecognized with application of modern observation facilities and detailed description of conventional cores. Turbidity currents are sedimentgravity flows with Newtonian rheology and turbulent state in which sediment is supported by fluid turbulence. Debris flows are sedimentgravity flows with plastic rheology and laminar state in which sediment is mainly  supported by matrix strength and frictional strength (caused by interlocking of grains and clasts). The normal grading is the main sedimentary rhythm of turbidites. The basal contacts of turbidites are invariably sharp or erosive, and the top contacts are gradational. Generally, the sedimentary rhythm of debris flows consist of the rigid raft with massive bedding in the upper part and the laminar flow zone with planar clast fabrics in the lower part.  When debris flows undergo only partial transformation by assimilation of ambient fluids (i.e., the diluteion effect), strongly coherent debris flows can transform into moderately coherent and weakly coherent debris flows, and its depositions from the bottom to the top are characterized by inverse to normal grading with complications (such as floating quartzose granules, mudstone clasts and so on), which distinguish from the turbidites with simple normal grading. Both basal and top contacts of debris flows are sharp. Depositional models of turbidity currents are simple baseofslope models with smooth basin floors, whereas the debris flows are complex slope models.

受浊流沉积模式（即鲍马序列和浊积扇模式）的驱动和浊积岩思维定势的影响，自1970s浊流与浊积岩的概念逐渐扩大，特别是通过“高密度浊流”术语的引入，以及将水下浊流与陆上河流的错误类比，使得一部分碎屑流与底流的沉积被认为是浊积岩。随着现代观测设备的应用以及详细的岩芯观察，碎屑流（特别是砂质碎屑流）和浊流被重新认识。浊流是一种具牛顿流变性质和紊乱状态的沉积物重力流，其沉积物支撑机制是湍流。碎屑流是一种具塑性流变性质和层流状态的沉积物重力流，其沉积物支撑机制主要是基质强度和颗粒间的摩擦强度。浊流沉积具特征的正粒序韵律结构，底部为突变接触而顶部为渐变接触；碎屑流沉积一般具上、下两层韵律结构，即下部发育具平行碎屑结构的层流段，上部发育具块状层理的“刚性”筏流段。但当碎屑流被周围流体整体稀释改造且改造不彻底时，强碎屑流可变为中—弱碎屑流，相应自下而上可形成逆—正粒序的沉积韵律结构，其中发育有呈漂浮状的石英颗粒和泥质撕裂屑等碎屑颗粒，明显区别于浊流沉积单一的正粒序韵律结构特征。碎屑流沉积顶、底部均为突变接触。浊流的沉积模式为简单的具平坦盆底的坡底模式，而碎屑流则为复杂的斜坡模式。

The destruction and preservation of primary porosity during burial diagenesis is an important part of the sandstone reservoir quality research, and their significance to the research of oil and gas geology is self-evident. Compared with the formation and preservation of secondary porosity, the factors affecting the destruction and preservation of primary porosity are with unique complexity and diversity. Based on the recent progresses from extensive documents, the paper tries to further understand the significance and effect of different diagenetic mechanisms on  the destruction and preservation of primary porosity in the sandstone reservoirs, such as the mechanical compaction, cementation, formation overpressure, grain coats, allochthonous salt and hydrocarbon emplacement. Currently, the new generation of reservoir quality models has  successfully predicted porosity and permeability in diverse sandstone reservoirs under many different burial conditions, which largely benefited from some important update of the destruction and preservation of primary porosity in modern diagenetic models of sandstone. However, this is just a milestone building accurate pre-drill reservoir quality prediction models, and there are still many problems in those models. The indefinite kinetics and processes of primary porosity evolution are  difficult problems to achieve more accurate  pre-drill predictions. The closer integration of the diagenesis, fluids, depositional processes and basin evolution may be one of most promising development directions of solving the destruction and preservation of primary porosity in the sandstone reservoirs in  future.

埋藏条件下原生孔隙的破坏与保存机制是含油气盆地砂岩储层质量研究的一个核心领域，其在油气地质学研究中的意义不言而喻。与次生孔隙的形成与保存机制相比，影响原生孔隙破坏与保存的因素有着其特殊的复杂性和多样性。在总结国内外研究进展的基础上，试图深入理解不同成岩机制在砂岩储层原生孔隙破坏与保存中的意义和作用，包括破坏机制（如机械压实、胶结作用等）和保存机制（如地层超压、颗粒包膜、盐体侵位和烃类占位等）。目前难以实现砂岩储层质量钻前准确预测的一个困难在于无法明确原生孔隙演化的动力和过程，将来成岩作用、流体作用、沉积过程和盆地演化的更紧密结合可能是解决砂岩储层原生孔隙破坏与保存机制研究中最有希望的发展方向之一。