We view the structures and features described in this atlas as sedimentary structures, albeit of a complex organo-physico-chemical origin. Just like their physical sedimentary structure counterparts (e.g., Pettijohn and Potter, 1964), they can be of great assistance in unravelling depositional palaeoenvironments inferred for ancient rock successions. Pettijohn and Potter (1964) included stromat...

27 Supercritical flow phenomena are fairly common in modern sedimentary environments, yet their 28 recognition and analysis remain difficult in the stratigraphic record. This fact is commonly 29 ascribed to the poor preservation potential of deposits from high-energy supercritical flows. 30 However, the number of flume datasets on supercritical flow dynamics and sedimentary 31 structures is ver...

As pointed out in the introduction to this book, shales contain the lion’s share of earth history that is recorded in sedimentary rocks. Understanding their deposition is key to the reconstruction of past oceans, landscapes, climates, and climatic cycles. Yet, whereas students of sandstones and carbonates have been able to learn a great deal about the deposition of these rocks from studying bed...

Upon channel bars or point bars within the lows of the Yellow River, a new sedimentary structure, named 'silt mushroom', has been observed. The process of their formation is interpreted to be via the ice process. The name, the silt mushroom comes from their figurative form. This is because they look somewhat similar to mushroom's in size and shape; being in the range of 1 to 10 cm in diameter, ...

In the arid and semiarid environments of the world, microhabitats serve as models for the structure of vegetation communities. The goal of this study was to identify differences in the structures of the herbaceous communities growing on a crystalline substrate and those growing on a sedimentary substrate in a semiarid region of northeastern Brazil. One hundred 1 × 1 m plots were established in ...

Many sedimentary rocks are formed by migration of sand ripples. Thin layers of coarse and fine sand are present in these rocks, and understanding how layers in sandstone are created has been a longstanding question. Here, we propose a mechanism for the origin of the most common layered sedimentary structures such as inverse graded climbing ripple lamination and cross-stratification patterns. Th...

The Upper Cretaceous facies of Enugu Area are part of the sequence in the Anambra Basin of Southeastern Nigeria. These include the Enugu Shale, Mamu Formation, Ajali Sandstone and Nsukka Formation. The deformation structures within the Upper Cretaceous in Enugu area were dominant to sandstones of the Marnu Formation. The white silty fine sandstone, muddy fine sandstone and heteroliths of this f...

The Tian Shan range offers a natural laboratory to study orogenic processes. Most of the previous studies focused on either the Paleozoic evolution of the range or its Cenozoic intracontinental evolution linked with the India-Asia collision. In this study, detailed field investigations on the relationship between sedimentary cover and basement constrain the Mesozoic evolution of the northern Ti...