Improved lithology prediction in channelized reservoirs by integrating stratigraphic forward modelling: towards improved model calibration in a case study of the Holocene Rhine-Meuse fluvio-deltaic system.

Stratigraphic forward modelling (SFM) provide the means to produce geologically coherent and realistic models. In this paper, we demonstrate the possibility of matching lithological variability simulated with a basin-scale advection-diffusion SFM to a data-rich real-world setting, i.e. the Holocene Rhine-Meuse fluvio-deltaic system in the Netherlands. SFM model calibration to real-world data in general has proven non-trivial. This study focuses on a novel inversion process constrained by the top surface and the sand proportion observed at specific pseudo-wells in the study area. Goodness-of-fit expressed by a new fitness function, gives the error calculated as the average of two calibration constraints. Computational efficiency was increased significantly by implementing a new optimization process in two hierarchical steps: a) optimization in terms of sediment load and discharge, which are the most influential parameters having the largest uncertainty and b) optimization with respect to the remaining uncertain parameters, these being sediment transport parameters. The calibration process described allows for the most optimal combination of achieving acceptable levels of goodness-of-fit, feasible runtimes and multiple (non-unique) solutions to obtain synthetic stratigraphic output best matching real-world datasets. By removing model realizations which are geologically unrealistic, calibrated SFM models provide a multiscale stratigraphic framework for reconstructing static models of reservoirs which are consistent with the palaeogeographic layout, basin-fill history and external drivers (e.g. sea level, sediment supply). The static reservoir models that are matched with highest certainty therefore contain the highest geological realism and may be used to improve deep subsurface reservoir or aquifer property prediction. The new methodology was applied to the well-established Holocene Rhine-Meuse dataset which allows a rigorous testing of the optimization and the calibrated SFM allows investigation of controls of the Holocene development on the sedimentary system

Late MIS5a in the southern North Sea: new chronostratigraphic insightsfrom the Brown Bank Formation

The Brown Bank Formation (BB Fm) is a clay‐rich sedimentary unit that is distributed over a large areain the southern North Sea. It is easily recognisable in 2D acoustic reflection profiles, forming sets of subparallel high‐amplitude reflections. Previous studies have provided only fragmentary information on the facies, and a variety ofinterpretations on the depositional environment and age of the BB Fm. In this study we combine high‐resolution 2Dacoustic reflection profiles and multiproxy sedimentological, geochemical and geochronological analyses of threevibrocores, to provide a detailed description and a new age assessment for the BB Fm at its type locality, adjacent tothe Brown Bank ridge. At the study site, the BB Fm shows morphologically well‐preserved submarine sand dunes,deposited in a high‐energy shelf setting, overlain by organic‐rich silty clays that were deposited under lower‐energyconditions in an increasingly compartmentalised marginal marine environment. Elevated terrestrial organic inputshows that the Rhine–Meuse delta was situated relatively close‐by. Luminescence ages indicate that the sediments ofthe BB Fm in our cores were deposited during the Weichselian Odderade interstadial (MIS5a, ca. 80 ka) and earliestparts of the Early Pleniglacial (MIS4, ca. 70 ka), which is later than previously reported in the literature

Targeting the mesolithic: Interdisciplinary approaches to archaeological prospection inthe Brown Bank area, southern North Sea

YesThis paper describes some results of the research undertaken over the Brown Bank area during recent (2018/2019) geoarchaeological surveys in the North Sea which included seismic imaging, shallow (vibro)coring and dredging. It examines the benefits of simultaneous high-resolution (0.5 – 1m) and ultra-high-resolution (10 – 20cm) seismic survey techniques and a staged approach to resolving the submerged Holocene landscape in the highest possible detail for the purpose of targeted prospecting for archaeological material from the Mesolithic landscape of Doggerland. The materials recovered from such surveys offer significantly greater information due to an enhanced understanding of the context in which they were recovered. The importance of this information cannot be understated archaeologically, as few locations on land provide the opportunity to recover archaeological finds in situ within preserved landscapes. Moreover, it allows offshore areas of potential human activity to be prospected with some certainty of success.ER

Japanse excursie- en workshopindrukken XIX INQUA 2015 congres, Nagoya, Japan

Afgelopen juli en augustus waren wij twee weken in Japan als deelnemers van INQUA’s vierjaarlijkse internationale Kwartairgeologische congres. Vóór het eigenlijke congres hebben we deelgenomen aan de PALSEA2 workshop (Paleo constraints on sea-level rise) en gingen we met collega’s van de Japanse geologische dienst op excursie naar de Kanto kustvlakte met haar opgeheven strandwal en laguneafzettingen uit het Laatste Interglaciaal (MIS5e). Na het congres volgde een excursie naar de prefectuur Chiba, het zich dramatisch snel opheffende schiereiland tussen de Baai van Tokyo en de Grote Oceaan. Hier ligt een voorgestelde type-locatie voor de basis van het Midden-Pleistoceen, met daarin de Brunhes-Matuyama magnetische omkering

Japanse excursie- en workshopindrukken XIX INQUA 2015 congres, Nagoya, Japan

Afgelopen juli en augustus waren wij twee weken in Japan als deelnemers van INQUA’s vierjaarlijkse internationale Kwartairgeologische congres. Vóór het eigenlijke congres hebben we deelgenomen aan de PALSEA2 workshop (Paleo constraints on sea-level rise) en gingen we met collega’s van de Japanse geologische dienst op excursie naar de Kanto kustvlakte met haar opgeheven strandwal en laguneafzettingen uit het Laatste Interglaciaal (MIS5e). Na het congres volgde een excursie naar de prefectuur Chiba, het zich dramatisch snel opheffende schiereiland tussen de Baai van Tokyo en de Grote Oceaan. Hier ligt een voorgestelde type-locatie voor de basis van het Midden-Pleistoceen, met daarin de Brunhes-Matuyama magnetische omkering

Early Holocene inundation of Doggerland and its impact on hunter-gatherers:An inundation model and dates-as-data approach

Sea-level rise was a key factor changing environments during the Early Holocene in Northwest Europe. It affected Mesolithic hunter-gatherer communities by inundating large areas in the current North Sea, commonly referred to as Doggerland. In this paper we present novel inundation models for the southern North Sea providing visualisations of lateral inundation driven by sea-level rise and relate it to frequency analysis of radiocarbon dates from archaeological sites. These improve on previous studies that relied on bathymetric data, which includes post-inundation overprints of Holocene sedimentation and erosion, and thus significantly underestimates the timing of inundation in some areas.We constructed a paleoDEM (a composite elevation grid of the top of the Pleistocene) for the eastern part of the southern North Sea; and sea level surfaces that combine relative sea-level curves from glacio-isostatic adjustment models optimised for Britain and southern Scandinavia respectively. We corrected our paleoDEMs for tectonic background basin subsidence, and in the inundation modelling account for pre-compaction elevation of peat in coastal areas. We evaluated the impact of these model components on our results and describe the possible inundation history of Doggerland. We suggest earlier inundation than predicted by previous models, showing significant area loss around 10.5–10 ka cal BP.Palaeogeographic changes are compared with archaeological radiocarbon data using a dates-as-data approach. Composite Kernel Density Estimate and permutation tested Summed Probability Distributions are used as a proxy for the visibility, nature and intensity of human activity. Results indicate key periods of growth and decline recorded in the dataset, as well as regional differences in growth rate, some correlating with inundation phases. Chiefly, we find elevated growth rates around 10.5–10 ka in northwest Germany and the Netherlands, contemporaneous with the abovementioned phase of extensive area loss, and moreover, with changes in culture and practices on Early Mesolithic sites.However, the spatiotemporal distribution of archaeological data is significantly influenced by accessibility and preservation of sediments of a certain age. We discuss the importance of inundation modelling and sediment data in understanding how landscape taphonomy affects archaeological patterning, especially in dates-as-data approaches

Fluvial evolution of the Rhine during the last interglacial-glacial cycle in the southern North Sea basin : A review and look forward

This paper presents the current state of knowledge on the evolution and depositional history of the River Rhine in the southern part of the North Sea basin during the upper Middle and Late Pleistocene, and its response to climate change, sea-level oscillation and glacio-isostasy. The study focuses on the development of the Eemian interglacial lower-delta in the central Netherlands and its relation to records of climate and sea-level rise, and uses the Saalian and Weichselian pre- and postdating periods to place its development in context. The Rhine fluvial system fills the gradually subsiding North Sea basin, but its development has strongly been affected by the Saalian glaciation and its remaining topography. Ice-pushed ridges originating off the limit of maximum glaciation basically divided the central Netherlands into two sedimentary depocentres: a central depocentre within the former ice-limit, and a southern depocentre south of it. The sedimentary record of the central depocentre, including an incised-valley fill, shows a 20-40m thick stacked sequence consisting of three units. The incised-valley fill consists of a Late Saalian to early Eemian age lower fluvial unit and a Weichselian age upper fluvial unit, both composed of coarse-grained channel deposits. Sandwiched in-between is a 5-15m thick record composed of fine-grained fluvial and estuarine (tidal) floodbasin and shallow-marine deposits. It is of Eemian interglacial and Early Weichselian age, and comprises transgressive and highstand deposits that show the drowning of a fluvial system. Inland parts transformed from fluvial to deltaic and estuarine environments, and the most downstream parts transformed to a shallow-marine embayment. Preservation of these units occurred, despite considerable sea-level fall and climate-controlled erosion taking place in the last-glacial. Preservation potential was increased by the fact that the Rhine system avulsed away to the southern depocentre, halfway the Weichselian Pleniglacial. Consequently, the infill of the southern depocentre is of an entire different nature, and last-interglacial transgressive or highstand units are hardly preserved. Because of glaciation and resulting depocentre configuration, the Netherlands in NW Europe thus offers a very good opportunity to study the transgressive interglacial lower-deltaic records and falling-stage preservation thereof - both key elements for understanding sedimentary development over full 100-ky glacial-interglacial cycles of climate and base-level change