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Journal of Palaeogeography 2019年第4期8卷 408-421页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

In this reply,I respond to 18 issues associated with comments made by Zavala(e.g.,inverse-to normally-graded sequence,origin of massive sands,experimental sandy debris flows,tidal rhythmites,facies models,etc.),and 10 issues associated with comments made by Van Loon et al.(e.g.,16 types of hyperpycnal flows,anthropogenic hyperpycnal flow,etc.).

关键词： Hyperpycnal flows Hyperpycnites Sandy debris flows Turbidity currents

A remarkable decade of learning and sharing knowledge through the Journal of Palaeogeography(JoP)(2014-2024):Reminiscences from an Associate Editor-in-Chief

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Journal of Palaeogeography 2024年第4期13卷 1029-1040页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

In this editorial, an Associate Editor-in-Chief of the Journal of Palaeogeography(JoP) reminisces his publication experience in JoP during the period 2014-2024. 1) During a period of nine years, he contributed eight review articles, three discussions, two replies, one book review, one glossary, and one tribute to the first Editor-in-Chief Prof. Zeng-Zhao Feng. His contributions totaled 534 printed pages. 2) His contributions examined 19 different domains, such as landslides, submarine fans, seismites, SSDS, hyperpycnites, rivers,etc. 3) His contributions coincided with the formative years of JoP. 4) The impact of his articles is evident from the Stats published by Researchgate. For example, his review article “The Landslide Problem” has reached11,611 Reads and 186 Citations after nine years of publication in 2015. 5) In 2023, the CNKI(China National Knowledge Infrastructure) recognized his article “Submarine fans: a critical retrospective(1950-2015)” as the Top-1% most-highly cited publications in the Journal of Palaeogeography published during a 10-year survey period: 2012-2022. 6) He was inducted as a Founding Member of the International Society of Palaeogeography(ISP) at Changping District of China University of Petroleum(Beijing), Beijing on July 16, 2022. 7) His JoP editorship during the past 10 years has been the most challenging, inspiring, and rewarding experience of his global scientific journey spanning over six decades(1962-2024).

关键词： Journal of Palaeogeography Associate Editor-in-Chief Editorial Landslides Submarine fans Seismites SSDS Hyperpycnites Zeng-Zhao Feng

The turbidite-contourite-tidalite-baroclinite-hybridite problem: orthodoxy vs. empirical evidence behind the “Bouma Sequence”

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Journal of Palaeogeography 2021年第2期10卷 125-156页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at ArlingtonTX 76019USA

The underpinning problems of deep-water facies still remain unresolved.(1) The Tb, Tc, and Td divisions of the turbidite facies model, with traction structures, are an integral part of the "Bouma Sequence"(Ta, Tb, Tc, Td, Te).However, deposits of thermohaline contour currents, wind-driven bottom currents, deep-marine tidal currents, and baroclinic currents(internal waves and tides) also develop discrete rippled units, mimicking Tc.(2) The application of "cut-out" logic of sequences, which was originally introduced for the "Bouma Sequence", with sharp basal contacts and sandy divisions containing well-developed traction structures, to muddy contorts with gradational basal contacts and an absence of well-developed traction structures is incongruent.(3) The presence of five internal divisions and hiatus in the muddy contoured facies model is in dispute.(4) Intersection of along slope contour currents with down slope sediment-gravity flows, triggering hybrid flows, also develops traction structures.(5) The comparison of genuine hybrid flows with down slope flow transformation of gravity flows is inconsistent with etymology of the term "hybrid".(6) A reexamination of the Annot Sandstone at the Peira Cava type locality in SE France fails to validate either the orthodoxy of five internal divisions of the "Bouma Sequence" or their origin by turbidity currents. For example, the "Ta" division is composed of amalgamated units with inverse grading and floating mudstone clasts, suggesting a mass-transport deposit(MTD). The "Tb" and "Tc" divisions are composed of double mud layers and sigmoidal cross bedding, respectively, which suggest a tidalite origin.(7) Although it was reasonable to introduce a simplistic "Bouma Sequence" in 1962, at a time of limited knowledge on deep-water processes, it is obsolete now in 2021 to apply this model to the rock record amid a wealth of new knowledge.(8)The disconnect between 12 observed, but questionable, modern turbidity currents and over 10,

关键词： Turbidity currents Contour currents Tidal currents Internal waves and tides Hybrid flows The Bouma Sequence BCRS(i.e. bottom-current reworked sands)

150 Years(1872-2022)of research on deep-water processes,deposits,settings,triggers,and deformation:A difficult domain of progress,dichotomy,diversion,omission,and groupthink

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Journal of Palaeogeography 2022年第4期11卷 469-564页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at ArlingtonArlingtonTX 76019USA

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)*** expedition(1872-1876):The discovering of the“Challenger Deep”by the *** in the Mariana Trench has been the single most important achievement in deep-water research.(2)Five pioneers amid 50 notable contributors:***,***,***,***,and ***.(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 *** debrites are the most important petroleum reservoir *** 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 *** 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:Th

关键词： Mass transport gravity flows Bottom currents High-density turbidity currents Contour currents Tidal currents Internal waves and tides Kelvin-helmholtz waves Hybrid flows The Bouma Sequence Tsunami waves Deflected sediment plumes Basin-floor fans Tutbidite groupthink Bute Inlet(BC Canada) Soft-Sediment Deformation structures(SSDS)

glossary:A supplement to “Submarine fans:A critical retrospective(1950-2015)” in the Journal of Palaeogeography (2016,5[2])

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Journal of Palaeogeography 2016年第3期5卷 258-277页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

In this gtossary, setected terms and concepts associated with submarine fans are defined.

关键词： Submarine fans Submarine canyons Submarine channeLs Submarine Lobes Abyssal plains

The fallacy of interpreting SSDS with different types of breccias as seismites amid the multifarious origins of earthquakes:Implications

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Journal of Palaeogeography 2017年第1期6卷 12-44页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at ArlingtonArlingtonTX 76019USA

At present, there are no criteria to distinguish soft-sediment deformation structures （SSDS） formed by earthquakes from SSDS formed by the other 20 triggering mechanisms （see a companion paper in Vol 5, No. 4 of this journal by shanmugam, 2016）. Even if one betieves that earthquakes are the true triggering mechanism of SSDS in a given case, the story is stiff incomptete. This is because earthquakes （seismic shocks） are induced by a variety of causes： 1） glbaltectonics and associated faults （i.e., midocean ridges, trenches, and transform fautts）; 2） meteorite-impact events; 3） volcanic eruptions; 4） post-gtacialuplift; 5） tsunami impact; 6 cyclonic impact; 7） landslides （mass-transport deposits）; 8） tidal activity; 9） sea-tevet rise; 10） erosion; and 11） fluid pumping. These different causes are important for devetoping SSDS. Breccias are an important group of SSDS. Although there are many types of breccias classified on the basis of their origin, five types are discussed here （fault, volcanic, meteorite impact, sedimentary-depositionaL, sedimentary-collapse）. Atthough different breccia types may resemble each other, distinguishing one type （e.g., meteorite breccias） from the other types （e.g., fault, volcanic, and sedimentary breccias） has important imptications. 1） Meteorite breccias are characterized by shock features （e.g., planar deformation features in mineral grains, planar fractures, high-pressure polymorphs, shock melts, etc.）, whereas sedimentary- depositional breccias （e.g., debrites） do not. 2） Meteorite breccias imply a confined sediment distribution in the vicinity of craters, whereas sedimentary-depositional breccias imply an unconfined sediment distribution, variable sediment transport, and variable sediment provenance. 3） Meteorite, volcanic, and fault breccias are invariabty subjected to diagenesis and hydrothermat mineratization with attered reservoir quality, whereas sedimentary-depositional breccias exhibit primary （unaltered） reservoir quality.

关键词： Breccias Earthquakes Faults global tectonics Meteorite impacts Seismites Soft-sedimentdeformation structures (SSDS)

global case studies of soft-sediment deformation structures(SSDS): Definitions,classifications, advances, origins, and problems

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Journal of Palaeogeography 2017年第4期6卷 251-320页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

Soft-sediment deformation structures（SSDS）have been the focus of attention for over 150 *** unconstrained definitions allow one to classify a wide range of features under the umbrella phrase＂SSDS＂.As a consequence,a plethora of at least 120 different types of SSDS（e.g.,convolute bedding,slump folds,load casts,dish-and-pillar structures,pockmarks,raindrop imprints,explosive sandegravel craters,clastic injections,crushed and deformed stromatolites,etc.）have been recognized in strata ranging in age from Paleoproterozoic to the present *** two factors that control the origin of SSDS are prelithification deformation and liquidization.A sedimentological compendium of 140 case studies of SSDS worldwide,which include 30 case studies of scientific drilling at sea（DSDP/ODP/IODP）,published during a period between 1863and 2017,has yielded at least 31 different *** have remained the single most dominant cause of SSDS because of the prevailing＂seismite＂*** advances on SSDS research are：（1）an experimental study that revealed a quantitative similarity between raindrop-impact cratering and asteroid-impact cratering;（2）IODP Expedition 308 in the gulf of Mexico that documented extensive lateral extent（〉12 km）of mass-transport deposits（MTD）with SSDS that are unrelated to earthquakes;（3）contributions on documentation of pockmarks,on recognition of new structures,and on large-scale sediment deformation on *** that hinder our understanding of SSDS still *** are：（1）vague definitions of the phrase＂soft-sediment deformation＂;（2）complex factors that govern the origin of SSDS;（3）omission of vital empirical data in documenting vertical changes in facies using measured sedimentological logs;（4）difficulties in distinguishing depositional processes from tectonic events;（5）a model-driven interpretation of SSDS（i.e.,earthquake being the singular cause）;（6）routine application of the genetic term＂seismites＂to the＂SSDS＂,thus undermining the

关键词： Soft-sediment deformation structures(SSDS) Prelithification deformation Liquidization Pockmarks Impact cratering Scientific drilling

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The seismite problem

Journal of Palaeogeography 2016年第4期5卷 318-362页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

During a period of 82 years （1931-2013）, 39 genetic terms were introduced for various deposits. Of the 39 terms, only ten are meaningful in understandin8 the true depositional origin （e.9., turbidites）, the remaining 29 are just jargons （e.g., seismites, tsunamites, etc.）. The genetic term ＂seismites＂, introduced by Seitacher （1969） for recognizing pa[aeoearthquakes in the sedimentary record, is a misnomer. The term was introduced in haste, based on an examination of a single exposure of the Miocene Monterey Formation （10 m） in California, without a rigorous scientific analysis. The fundamental problem is that earthquake is a triggering mechanism, not a depositional process. Type of triggers cannot be recognized in the ancient sedimentary record because evidence for triggers is not preserved by nature. Soft-sediment deformation structures （SSDS）, commonly used as the criteria for interpreting seismites, are a product of liquefaction. However, liquefaction can be induced by any one of 21 triggers, which include earthquakes, meteorite impacts, tsunamis, sediment loading, among others. Brecciated ciasts, typically associated with earthquake-induced deposits in the Dead Sea Basin, are also common depositional products of debris flows （i.e., synsedimentary product unrelated to earthquakes）. Also, various types of SSDS, such as duplex-like structures and ctastic injections, can be explained by synsedimentary processes unrelated to earthquakes. Case studies of sandstone petroleum res- ervoirs worldwide, which include gulf of Mexico, North Sea, Norwegian Sea, Nigeria, Equatorial guinea, gabon, and Bay of Bengal, reveal that there is compelling empirical evidence for sediment loading being the primary cause of SSDS. The Krishna-godavari Basin, located on the eastern continental margin of India, is ideal for sediment failures by multiple triggering mechanisms where overpressure and liquefaction have ted to multi-origin SSDS. Because tsunamis and meteorite impacts are importan

关键词： Soft-sediment deformation structures (SSDS) Seismites Earthquakes Meteorite impacts Liquefaction Clastic injections

The hyperpycnite problem

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Journal of Palaeogeography 2018年第3期7卷 197-238页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

Sedimentologic, oceanographic, and hydraulic engineering publications on hyperpycnal flows claim that （1） river flows transform into turbidity currents at plunge points near the shoreline, （2） hyperpycnal flows have the power to erode the seafloor and cause submarine canyons, and, （3） hyperpycnal flows are efficient in transporting sand across the shelf and can deliver sediments into the deep sea for developing submarine fans. Importantly, these claims do have economic implications for the petroleum industry for predicting sandy reservoirs in deep-water petroleum exploration. However, these claims are based strictly on experimental or theoretical basis, without the supporting empirical data from modern depositional systems. Therefore, the primary purpose of this article is to rigorously evaluate the merits of these claims. A global evaluation of density plumes, based on 26 case studies （e.g., Yellow River, Yangtze River, Copper River, Hugli River （ganges）, guadalquivir River, Rio de ]a Plata Estuary, Zambezi River, among others）, suggests a complex variability in nature. Real-world examples show that density plumes （1） occur in six different environments （i.e., marine, lacustrine, estuarine, lagoon, bay, and reef）; （2） are composed of six different compositional materials （e.g., siliciclastic, calciclastic, planktonic, etc.）; （3） derive material from 11 different sources （e.g., river flood, tidal estuary, subglacial, etc.）; （4） are subjected to 15 different external controls （e.g., tidal shear fronts, ocean currents, cyclones, tsunamis, etc.）; and, （5） exhibit 24 configurations （e.g., lobate, coalescing, linear, swirly, U-Turn, anastomosing, etc.）. Major problem areas are：（1） There are at least 16 types of hyperpycnal flows （e.g., density flow, underflow, high-density hyperpycnal plume, high-turbid mass flow, tide-modulated hyperpycnal flow, cyclone-induced hyperpycnal turbidity current, multi-layer hyperpycnal flows, etc.）, without an underpinning principle of flu

关键词： Density plumes Facies model Hyperpycnites Submarine fans Tidal shear fronts Ocean currents Turbiditycurrents Yellow River Yangtze River

The landslide problem

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Journal of Palaeogeography 2015年第2期4卷 109-166页

作者： g.shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

The synonymous use of the general term ＂landslide＂, with a built-in reference to a sliding motion, for all varieties of mass-transport deposits （MTD）, which include slides, slumps, debrites, topples, creeps, debris avalanches etc. in subaerial, sublacustrine, sub- marine, and extraterrestrial environments has created a multitude of conceptual and nomen- clatural problems. In addition, concepts of triggers and Iong-runout mechanisms of mass movements are loosely applied without rigor. These problems have enormous implications for studies in process sedimentology, sequence stratigraphy, palaeogeography, petroleum geol- ogy, and engineering geology. Therefore, the objective of this critical review is to identify key problems and to provide conceptual clarity and possible solutions. Specific issues are the fol- lowing：（1） According to ＂limit equilibrium analyses＂ in soil mechanics, sediment failure with a sliding motion is initiated over a shear surface when the factor of safety for slope stability （F） is less than 1. However, the term landslide is not meaningful for debris flows with a flowing mo- tion. （2） Sliding motion can be measured in oriented core and outcrop, but such measurement is not practical on seismic profiles or radar images. （3） Although 79 MTD types exist in the geological and engineering literature, only slides, slumps, and debrites are viable depositional facies for interpreting ancient stratigraphic records. （4） The use of the term landslide for high- velocity debris avalanches is inappropriate because velocities of mass-transport processes cannot be determined in the rock record. （5） Of the 21 potential triggering mechanisms of sediment failures, frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more relevant in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years （e.g.,

关键词： debris flows landslides mass-transport deposits (MTD) slides slumps soilstrength triggering mechanisms reservoir characterization