In capturing a snapshot of 150 years (1872-2022) of research on deep-water processes, deposits, settings, triggers, and deformation, the following 22 topics are selected: (1) H.M.S. Challenger expedition (1872-1876): The discovering of the “Challenger Deep” by the H.M.S. Challenger in the Mariana Trench has been the single most important achievement in deep-water research. (2) Five pioneers amid 50 notable contributors: R. A. Bagnold, J. E. Sanders, G. D. Klein, F. P. Shepard, and C. D. Hollister. (3) Mass transport: Mass-transport deposits (MTD) are the most important deep-water facies in terms of volume, geohazards, and petroleum reservoirs. (4) Gravity flows: There are six basic types, namely (a) hyperpycnal flows, (b) turbidity currents, (c) debris flows, (d) liquefied/fluidized flows, (e) grain flows, and (f) thermohaline contour currents. Sandy debrites are the most important petroleum reservoir facies. Despite their popularity, turbidites are not an important reservoir facies. (5) Kelvin-Helmholtz (KH) waves: Turbidites, related to KH waves, with internal hiatus are not qualified to function as predictive facies models; nor are they fit for stratigraphic correlations. (6) High-density turbidity currents (HDTC): Misclassification of density-stratified gravity flows with laminar debris flows and turbulent turbidity currents as HDTC is flawed. Experimental generation of density-stratified gravity flows in flume studies has debunked the concept of HDTC. (7) Classification of turbidites: Contrary to the popular groupthink, turbidites are exclusive deposits of turbidity currents. (8) Bottom currents: The four basic types of deep-marine bottom currents are: (a) thermohaline-induced geotropic contour currents, (b) wind-driven bottom currents, (c) tide-driven bottom currents (mostly in submarine canyons), and (d) internal wave/tide-driven baroclinic currents. (9) Classification of contourites: Contrary to the popular groupthink, contourites are the exclusive deposits of thermohaline-induced geotropic contour currents. (10) Tidal currents in submarine canyons: Their velocity measurements have been the single most important achievement in deep-water process sediment logy. (11) Modern and ancient systems: There is a dichotomy between rare observations of turbidity currents in modern settings and overwhelming cases of interpretations of ancient turbidites in outcrops and cores. The reason is that turbidity currents are truly rare in nature, but the omnipotent presence of turbidites in the ancient rock record is the manifestation of groupthink induced by the turbidite facies model (i.e., the Bouma Sequence). (12) Internal waves and tides: Despite their ubiquitous documentation in modern oceans, their ancient counterparts in outcrops are extremely rare. This is another dichotomy. (13) Hybrid flows: They are commonly developed by intersecting of down-slope gravity flows with along-slope contour currents. However, they are often misapplied to down-slope flow transformation of gravity flows. (14) Density (sediment) plumes: Deflected sediment plumes by wind forcing are common. Despite their importance in provenance studies, they are not adequately studied. (15) Hyperpycnal flows: They occur near the shoreline, next to the plunge point; but are of no relevance in deep-water environments. However, their importance in deep-marine settings is overhyped in recent literature. (16) Omission of erosional contact and internal hiatus: In order to promote genetic facies models that must not contain internal hiatuses, some researchers selectively omit internal hiatuses observed by the original authors. (17) Triggers of sediment failures: There are 22 types, but short-term triggers, such as earthquakes and meteorite impacts are more important than the conventional long-term trigger known as Eustace. (18) Tsunami waves: Despite their sedimentologic importance, there are no reliable criteria for recognizing tsunami deposits in the ancient rock record. (19) Soft-Sediment Deformation Structures (SSDS): Although most SSDS are routinely interpreted as seismites, not all SSDS are caused by earthquakes. There are 10 other mechanisms, such as sediment loading, which can trigger liquefaction that can develop SSDS. (20) The Jackfork Group, Pennsylvanian, Ouachita Mountains, USA: Our reinterpretation of this classic North American flysch turbidites as MTD and bottom-current reworked sands has resulted in the longest academic debate with 42 printed pages in the AAPG Bulletin history since its founding in 1917. (21) Basin-floor fan model, Tertiary, North Sea: Our examination of nearly 12, 000 ft. (3658 m) of conventional core from Paleogene and Cretaceous deep-water sandstone reservoirs cored in 50 wells in 10 different areas or fields in the North Sea and Norwegian Sea reveals that these reservoirs are predominantly composed of MTDs, mainly sandy slumps and sandy debris flows, and bottom-current reworked sands. Our core-seismic calibration debunked the conventional wisdom (groupthink) that basin-floor fans are composed of sandy turbidites in a sequence-stratigraphic framework. (22) Turbidite groupthink: A case study illustrating how turbidite groupthink functions on the basis of published information on modern turbity currents in Bute Inlet (fjord and estuary), British Columbia, Canada.
This compendium is hybrid in composition between an atlas (with 108 figures) and a review article (with 364 references). The author admonishes scientists against deep-sea groupthink and provides a roadmap for future researchers by identifying potential topics for research involving density plumes, internal waves, tidal currents, tsunami waves, sediment deformation, and lowstand braid deltas.

The brackish lagoon in the central part of The Netherlands was closed by a dike in 1932 and gradually changed into a lake. Parts of this lake were reclaimed and the surficial sediments of one of the polders (Noordoostpolder), reclaimed in 1942, has been investigated in detail by mapping of the walls of some 1500 km of drainage ditches approx. 1.4 m deep. It appeared that the sediments consist of an uncommonly large amount of silt, to different degrees mixed with reworked peat that had developed during the Holocene transgression. Some sandy deposits occur locally, at places that are at first sight distributed in a haphazard way. The various sandy patches have different characteristics (grain-size distribution, rounding of the grains, mineral composition). These sands cannot have been introduced from the sea, nor can they have been supplied by the rivers that discharged into the lagoon, so they must have a local origin. It is found that several types of Pleistocene sandy or diamictic deposits below the Holocene peat and lagoonal sediments had an irregular topography and became eroded during the Holocene by wave activity. This resulted in sandy deposits around these Pleistocene highs, which consisted of glacial tills (boulder clays), river dunes (formed by aeolian activity along rivers under dry permafrost conditions) and coversand ridges, formed by aeolian activity in a belt between the ice margin and the more distal loess belt. This finding implies that palaegeographical interpretations of local grain-size anomalies in a specific deposit should not only consider facies changes due to changes in the sediment supply, but should also consider local erosion leading to the exposure of previously deposited material with a divergent composition.

The ongoing subduction of the Pacific oceanic lithosphere during the Jurassic-Cretaceous time formed large magmatic province as “Basin and Range” at the South China Block. However, timing and mechanisms of such a huge rifting and magmatism belt are still controversial. Here we present new petrological, sedimentological and geochemical analyses for the Cretaceous Lumuwan Formation and coeval intruded mafic dykes under the robust age constrain in Hainan Island. Our results show that the mid-Cretaceous Lumuwan Formation was a typical lacustrine stratigraphic sandwich that accumulated in an intracontinental back-arc extensional basin. The Hainan mafic dykes (~108-93 Ma) were probably sourced from asthenospheric and lithospheric mantle which were metasomatized by subducted oceanic sediments in a back-arc extension of continental lithosphere. The timing of the NW-SE-directed back-arc extension in Hainan basin has been constrained as 108-93 Ma and played a significant role in the formation of Basin and Range-type tectonics and landscape evolution in the South China.

Distributive fluvial systems (DFS) are widespread in drylands in the northwestern China. Analyzing differences in fluvial morphology in drylands is beneficial for studying ancient rock records and the extra-terrestrial surface environment. The remote sensing image, characterized by real-time and possibility of repeated observations, is a vital tool for recording and comparing fluvial systems in drylands. Satellite remote sensing technology is a method of investigating fluvial morphologies. Due to the limited accuracy of satellite imagery, there are few reports on the detailed description of the fluvial system in drylands of NW China. We analyze the pattern of fluvial morphology changes in the Golmud distributive fluvial system (DFS) in the Qaidam Basin, northwestern China, using satellite remote sensing and unmanned aerial vehicles (UAV). Firstly, we use Google Earth real-time image data, historical image data, and radar digital elevation data to extract geomorphological information; then the UAV remote sensing image data were used to interpret fluvial network information; finally, we use the gray-scale differential vector method to describe the fluvial morphologies. Three zones have been identified in the Golmud DFS: the proximal, the medial, and the distal, by comparing the differences in topographic and geomorphic characteristics, fluvial morphologies, and sedimentary characteristics of the Golmud DFS. The proximal slope is higher than the other two zones, and the geomorphic features are mainly gravel gobi. The proximal fluvial morphologies are mainly large braided rivers, and sediments are more gravelly and less sandy. The medial slope is relatively small, and the geomorphic features are mostly oasis plains. The medial fluvial morphologies are mainly meandering rivers associating with braided rivers, and sediments are more sandy and less gravelly. The distal slope is the lowest, and the geomorphic features are mostly oasis plains, lakes, and marsh plains. The distal fluvial morphologies are mainly meandering rivers, and sediments are sandy and muddy. Comparison of the DFS from proximal to medial to distal in Golmud confirmed the potential of remote sensing image technology in identifying the fluvial morphologies and sedimentary facies distribution in dryland.

Sedimentological and foraminiferal paleoecological studies were carried out for the Oligocene-Miocene Ogwashi-Asaba Formation of the Anambra Basin at the Issele-Uku area in southern Nigeria, to reconstruct paleoenvironments. The pattern of rock successions and textural characteristics suggest the prevalence of fluvio-deltaic setting during the formation of lignites and clastic rocks of Ogwashi-Asaba Formation. Agglutinated benthic foraminiferal species such as Ammotium sp., Textularia sp., Gavelinella sp., Milliamina sp., Reophax sp., Bolivina sp., Eponides sp., Pseudobolivina sp. and Lenticulina sp. dominate the shale units whereas the planktonic forms are absent. All these species have very low population and diversity in the shales, which could be due to the presence of harsh conditions such as low oxygen level and scarcity of food, leading to poor survival. The assessments of benthic foraminifera’s habitat suggest middle-to-inner neritic marine environment for the shales. Granulometric results suggest fluvial environment for the sandstone and deltaic for the lignite. The Ogwashi-Asaba Formation in Issele-Uku area of Anambra Basin, southern Nigeria, therefore, have records of shallow marine, and fluvio-deltaic paleoenvironments.

Here we describe two newly discovered dinosaur eggs from the Upper Cretaceous Chishan For-mation in the Qianshan Basin, Anhui Province, East China. These dinosaur eggs can be assigned to a new oospecies of Stalicoolithidae, Shixingoolithus qianshanensis, based on the following combined features: the larger size of eggs, the uniform eggshell microstructure in the radial section, the smaller height and the larger density of radial microstructures at the inner surface of the eggshell. Radial sections of S. qianshanensis show closely arranged columnar eggshell units forming relatively uniform and dense microstructure; some secondary eggshell units and numerous sub-circular radial microstructures appear separately in the middle and inner parts of the tangential sections, respectively. The discovery of S. qianshanensis provides new fossil types of Stalicoolithidae and represents the first dinosaur relative record in the Qianshan Basin, which offer accurate paleontological evidence of Late CretaceouseEarly Paleocene stratigraphic classification in the Qianshan Basin, Anhui Province.

Most modern birds have scales covering feet, but our knowledge of early avian scales is limited, mainly due to their scarcity in the fossil record. Here we describe the morphological details of scutellate and interstitial scales preserved in IVPP V15077, a specimen of the Early Cretaceous bird Gansus from the Changma Basin in northwestern Gansu Province, Northwest China. These results, combined with previous reports of scutate and reticulate scales, show that all four types of scales present in modern birds already appeared in the Early Cretaceous. The phylogenetic distribution of skin appendages of feet, including feathers and scales, shows that non-avian dinosaurs already evolved scales resembling those in modern birds, and that scales can coexist with feathers on feet, suggesting that avian scales may be homologue with scales of non-avian dinosaurs. However, to further test this hypothesis, more research combined with a strengthened focus on detecting specimens with soft tissue preservation is necessary.

The Hongshuizhuang Formation is a Meso-Neoproterozoic high-quality source rock in the North China Craton (NCC), comprising abundant organic matter. The present study focuses on the analysis of the Hongshuizhuang Formation in the Zhoukoudian area of the Jingxi sag, discussing its genesis and mechanisms of organic matter enrichment through geological and geochemical methods. The Hongshuizhuang Formation is divided into three members from bottom to top respectively as the lower, middle and upper member. Trace elements analysis indicate that the Hongshuizhuang Formation developed restricted neritic facies in an extensional environment within a continental island arc under a post-orogenic background.The lower and upper members were deposited in a relatively shallow, strongly retained water mass within a suboxic and saline environment influenced by subhumid climate, while the middle member was deposited in an anoxic deep-water environment with relatively low salinity and weak restrictions. The PAAS-normalized rare earth element distributions of the middle and upper members show an enrichment of LREEs and a depletion of HREEs, and a low mean Y/Ho ratio with a positive Eu anomaly, indicating that the regional deposition has been affected by hydrothermal fluids. The negative δ¹³C and δ¹⁸O values and the positive⁸⁷Sr/⁸⁶Sr values confirm that the deposition of the middle and upper members was accompanied by crustal hydrothermal activities. Accumulation of organic matter and enrichment of Ba_xs and P indicate that productivity is the basis of organic matter enrichment in the Hongshuizhuang Formation, where high-quality source rocks are concentrated in the middle member. In addition, reduced water mass controls the preservation of organic matter. Hydrothermal activity, humid climate, and salinity support a higher primary productivity and the formation of reduced water masses. However, due to limitationsin depth, the high-quality source rocks in the Jingxi sag are thinner than the Jibei sag.