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A new 'superassemblage' model explaining proximal-to-distal and lateral facies changes in fluvial environments,based on the Proterozoic Sa.j.uli Formation(Lesser Himalaya,India)

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journal of Palaeogeography 2016年第4期5卷 391-408页

作者： Ananya Mukhopadhyay Priyanka Mazumdar a.j. (Tom) van loon Department of Earth Sciences Indian Institute of Engineering Science & Technology Shibpur Howrah West Bengal 711103 India Geocom Consulting Valle del Portet 17 03726 Benitachell Spain

Facies analysis of fluvial deposits of the Proterozoic Sa.j.uli Formation in the Lesser Himalaya was combined with an architectural analysis. On this basis, a model was developed that may be applied to other fluvial systems as well, whether old or recent. The new model, which might be considered as an assemblage of previous models, explains lateral variations in architecture and facies but is not in all respects consistent with the standard fluvial models. The Sa.j.uli fluvial model is unique in that it deals with lateral facies variations due to shifts of the base-level along with fluctuations in accommodation space owing to changes in palaeoclimate.

关键词： Ftuvial model Braided river Sa.j.uli Formation Simta Basin Proterozoic Lesser Himalaya India

The response of stromatolites to seismic shocks： Tomboliths from the Palaeoproterozoic Chaibasa Formation, E India

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journal of Palaeogeography 2016年第4期5卷 381-390页

作者： a.j. (Tom) van loon Rajat Mazumder Shuvabrata De Geocom Consultants Valle del Portet 17 03762 Benitachell Spain Department of Applied Geology Faculty of Science and Engineering Curtin University Sarawak CDT 250 98009 Miri Sarawak Malaysia Indian Institute of Science Education and Research Department of Earth and Environmental Sciences Bhopal By-pass Road Bhopal 462066 Madhya Pradesh India

It is demonstrated here for the first time how Palaeoproterozoic stromatolites survived seismic disturbance of their substrate. The stromatolites under study could have been cyanobacteria or any other photo-autotrophic microbes, which formed mats that covered a substrate of very fine-grained sandstones and mudstones of the Chaibasa Fm. in eastern India. The sediments represent a shelf environment. The local abundance of the stromatotites suggests that the tow-energy environment formed a suitable habitat. The common phases of tectonic quiescence were, however, occasionally interrupted by seismic shocks. These were sufficiently strong to deform the mat layers, the tower parts of which might already have been （semi-） consolidated. The mats became partly folded, partly faulted, and already consolidated parts of the stromatotite layers broke off. This can be deduced from the angular shapes of part of the broken-off fragments. It appears, however, that part of these fragments were stilt sufficiently soft to become rounded and deformed by rotting over the seafloor, probably under the influence of tidal currents. When come to rest, these fragments served as a new substrate for new generations of the microorganisms. These micro-organisms thus survived by continued growth on the reworked fragments and built up new stromatolites that may show an ‘angular disconformity＇ with the stromatotites of their substrate. It thus is shown that stromatotites have an adequate response to a sudden disturbance of their habitat, and that they survive earthquakes by colonization of broken-off fragments. We call the ‘healed＇ fragments ‘tombotiths＇（tumbled stones）.

关键词： Stromatolites Seismic shocks Soft-sediment deformation structures Pataeoproterozoic Singhbhum craton Tombotiths India

Geochemical,mineralogical,and petrological analyses for the interpretation of the sedimentary environment of the Middle-Late Ordovician Majiagou Formation(northern China)as a tool for more effective gas exploration

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Petroleum Science 2022年第6期19卷 2519-2532页

作者： jie Gao Da-Wei Lv a.j.(Tom) van loon Dun Wu Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals Shandong University of Science and TechnologyQingdaoShandong266590China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyShandong266071China College of Earth Science and Engineering Shandong University of Science and TechnologyShandong266590China Exploration Research Institute Anhui Provincial Bureau of Coal GeologyHefeiAnhui230088China

Core samples from the deeply buried Ordovician Majiagou Formation below the Huainan Coalfield(E China) have been investigated for their carbonate types,major and trace elements(including rare earth elements) and C and O isotopes,The objective was to get a better insight into the possible occurrences of gas(and possibly oil) derived from Carboniferous *** was found that the carbonates are dolomites with strongly varying amounts of CaO and *** low concentrations of SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3)indicate deposition in a normal marine environment with little terrigenous input,The Na_(2)O/K_(2)O,Fe/Mn and Sr/Ba ratios,as well as the Ga values indicate mainly a marine salinity and a hot and humid *** slight depletion of Ce and Eu,the depletion of heavy rare earth elements(HREE) and the enrichment of light rare earth elements(LREE) indicate deposition in a reducing *** thus appears that the Majiagou Formation below the Huainan Coalfield closely resembles that in the eastern part of the Ordos Basin,where several gas reservoirs are present,so that the Majiagou Formation under the Huainan Coalfield represents a promising target for hydrocarbon exploration.

关键词： Majiagou Formation Middle Ordovician Major-element analysis REE analysis Trace-element analysis Hydrocarbon exploration

The hyperpycnite problem: comment

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journal of Palaeogeography 2019年第3期8卷 314-320页

作者： a.j.(Tom) van loon Heiko Hüneke Thierry Mulder Geocom Consulting Valle del Portet 17 03726 Benitachell Spain College of Earth Science and Engineering Shandong University of Science and Technology Qingdao 266590 Shandong China Institute of Geography and Geology Greifswald University Greifswald Germany UMR CNRS EPOC University of Bordeaux Allee Geoffroy St-Hilaire 33615 Pessac Cedex France

A recent review article("The hyperpycnite problem") by Shanmugam(journal of Palaeogeography 7(3):197–238,2018) in this journal has some shortcomings, comes to scientifically incorrect conclusions, and calls for student education in a way that would significantly diminish the students’ changes for a geological career. Having studied--and still studying--hyperpycnites in the field, it seems only appropriate to inform the readers of this journal about our concerns regarding the review article mentioned ***, the article by Shanmugam(journal of Palaeogeography 7(3):197–238, 2018) is not a review paper but rather a comment, criticizing al researchers who have come to the conclusion, on the basis of both field research and theory,that hyperpycnal flows result in sediments(hyperpycnites) with characteristics that make it possible to distinguish them from deposits formed in another way. This is also the essence of Shanmugam’s comment: as he states himself, he is"an ardent critic of al genetic facies models".

关键词： review Shanmugam critic

The control of Pleistocene palaeogeography on the distribution of sandy patches in a silty Holocene lagoon(central Netherlands)

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journal of Palaeogeography 2022年第4期11卷 565-583页

作者： Ai-Ping Fan a.j.(Tom)van loon Ren-Chao Yang College of Earth Science and Engineering Shandong University of Science and TechnologyQingdaoChina Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

The brackish lagoon in the central part of The Netherlands was closed by a dike in 1932 and gradually changed into a *** 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 some1500 km of drainage ditches approx.1.4 m *** 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 *** sandy deposits occur locally,at places that are at first sight distributed in a haphazard *** 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 *** 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 *** 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 *** 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.

关键词： Lagoonal palaeogeography Netherlands Noordoostpolder Wave erosion Abrasion Holocene

Were sauropod dinosaurs responsible for the warm Mesozoic climate?

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journal of Palaeogeography 2012年第2期1卷 138-148页

作者： a.j.(Tom) van loon Geological Institute Adam Mickiewicz UniversityMaków Polnych 1661-606PoznanPoland

It was recently postulated that methane production by the giant Mesozoic sauropod dinosaurs was larger than the present-day release of this greenhouse gas by nature and man-induced activities jointly, thus contributing to the warm Mesozoic climate. This conclusion was reached by correct calculations, but these calculations were based on unrealistic assumptions:the researchers who postulated this dinosaur-induced warm climate did take into account neither the biomass production required for the sauropods’ food, nor the constraints for the habitats in which the dinosaurs lived, thus neglecting the palaeogeographic conditions. This underlines the importance of palaeogeography for a good understanding of the Earth’s geological history.

关键词： sauropod dinosaurs greenhouse conditions methane palaeogeography

“The response of stromatolites to seismic shocks: Tomboliths from the Palaeoproterozoic Chaibasa Formation,E India”: Reply

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journal of Palaeogeography 2017年第3期6卷 235-241页

作者： a.j. (Tom) van loon Rajat Mazumder Shuvabrata De College of Earth Science and Engineering Shandong University of Science and Technology Geocom Consultants Department of Applied Geology Faculty of Science and EngineeringCurtin University Sarawak Geological Studies Division CSIR-National Geophysical Research Institute

Our contribution about a newly recognized sedimentological feature, which we called tombolith,has raised some comments on the etymology of the term, the assumed lack of field data, the usage of a term that has a special meaning in stratigraphy, the origin of the seismic shocks that played a role, so-called basic tenets, the origin of soft-sediment deformation structures, and the role of liquefaction. We argue that most comments result from an insufficiently thorough reading of our text, whereas some other remarks concern aspects that we did not deal with. Finally, several remarks are based on outdated literature and from insufficient knowledge of the regional geology.

关键词： Stromatolites Seismic shocks Palaeoproterozoic Singhbhum Craton Tomboliths India

Lagoonal carbonate deposition preceding rifting-related uplift:evidence from the Bartonian-Priabonian(Eocene)of the northwestern Gulf of Suez(Egypt)

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journal of Palaeogeography 2022年第1期11卷 8-30页

作者： Emad S.Sallam Dmitry A.Ruban a.j.(Tom)van loon Department of Geology Faculty of ScienceBen ha UniversityFarid Nad a Street 15Ben ha 13518Egypt K.G.Razumovsky Moscow State University of Technologies and Management(the First Cossack University) Zemlyanoy Val Street 73Moscow 109004Russia c College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590ShandongChina

Sedimentary successions in the northwestern Gulf of Suez provide important clues to the understanding of the geological evolution of NE Africa during the middle and late *** study focuses on detailed facies analyses in order to characterize the depositional environments and system tracts of the Bartonian-Priabonian succession cropping out in this ***-Priabonian carbonate deposits in five stratigraphic sections constitute,from base to top,the Gebel Hof,Observatory,Sannur,Qurn,and Wadi Hof *** formations contain four local assemblage zones of larger benthic *** of litho-,bio-,and microfacies in the succession resulted in the recognition of 12 lithofacies *** lithofacies are represented by packages of lime-mudstones,wackestones,packstones,pack-to grainstones,grainstones,rudstones,boundstones and *** lithofacies have been grouped into four geneticallyrelated facies associations that represent,respectively,tidal flats/shallow subtidal,restricted-shelf/lagoonal,shoal bar,and outer-shelf lagoon/reefal depositional environments in a downslope shallow-marine inner-ramp *** vertical transitions of these facies associations,representing facies changes through time,imply fluctuations of the regional sea *** two peaks in the Bartonian correspond to well-known global eustatic sea-level rises;the pronounced Priabonian regression must be ascribed to the known global eustatic sea-level fall in combination with regional tectonic *** facies distribution suggests that the study area was located in the direct vicinity of some islands during the Bartonian-Priabonian.

关键词： Lagoonal facies Sea-level fluctuations Middle Eocene Late Eocene Eastern Desert

An Upward Shallowing Succession of Gravity Flow Deposits in the Early Cretaceous Lingshandao Formation,Western Yellow Sea

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1553-1554页

作者： YANG Renchao FAN Aiping HAN Zuozhen a.j.(Tom) van loon College of Earth Science and Engineering Shandong University of Science and Technology Geocom Consultants Valle del Portet

Objective Several well-exposed gravity flow deposits in the Early Cretaceous Lingshandao Formation provide a rare opportunity to study deep-water processes. The main objective of this work is to establish the spatial and temporal relationships between the various gravity flow deposits, and thus to establish their sequence stratigraphic patterns and depositional conditions.

关键词： An Upward Shallowing Succession of Gravity Flow Deposits in the Early Cretaceous Lingshandao Formation,Western Yellow Sea deep cycle