Mass-transport deposits and the onset of wedge-top basin development: An example from the Dinaric Foreland Basin, Croatia

2020 ◽  
Vol 90 (11) ◽  
pp. 1527-1548
Author(s):  
Katarina Gobo ◽  
Ervin Mrinjek ◽  
Vlasta Ćosović
Keyword(s):  
Mass Transport ◽  
Sea Level ◽  
Regional Scale ◽  
Foreland Basin ◽  
Combined Effect ◽  
Tectonic Activity ◽  
Relative Sea Level ◽  
Basin Development ◽  
Blind Thrust ◽  
Mass Transport Deposits

ABSTRACT Mass-transport deposits (MTDs) represent resedimentation phenomena triggered by the combined effect of seismic shocks of regional scale, structural tilting, basin-floor gradient, relative sea-level fluctuations, and/or excess pore-water pressure and can be useful in the reconstruction of basin development dynamics. The present study from the Dinaric Foreland Basin in Croatia documents several limestone blocks (olistoliths), carbonate debris, and associated bipartite carbonate megabeds as MTDs of exotic origin encased in deep neritic hyperpycnites, referred to as host deposits. Detailed facies and micropaleontological analyses indicate that host deposits were sourced from a fluvio-deltaic system located in the proximity of the uplifting orogen, while the MTDs originated from gravitational collapses of late Ypresian and early Lutetian limestones that were uplifted on blind-thrust anticline ridges on the opposite side of the basin. Mass wasting-produced carbonate blocks, debris, and gravity flows were probably triggered concurrently during the middle to late Eocene, but the blocks could have travelled faster downslope due to the lubricating effect of the underlying water “cushion,” overpressured mud, and the pull of gravity. Debrisflows and co-genetic turbidity currents that contributed to the formation of bipartite megabeds were likely mobilized deeper and moved slower than the carbonate blocks and could have been partly deflected by the previously emplaced olistoliths, resulting in megabed thinning along the olistoliths' down-dip edges. Those collapses were most likely triggered by the combined effect of relative sea-level changes associated with tectonic activity and seismic shocks of regional scale. The study suggests that progressive uplift of the frontal blind-thrust anticline ridge resulted in episodic emergence and collapses of progressively older limestone units, and marked the onset of development of the wedge-top basin. Conceptual models of olistolith emplacement and onset of basin development are suggested and may be applicable to both ancient and recent settings. The insights obtained from the integration of detailed facies analysis and micropaleontology may be useful in similar areas where such a level of detail cannot be obtained by conventional field methods.

scholarly journals Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin

2018 ◽  
Vol 69 (1) ◽  
pp. 89-113 ◽  
Author(s):  
Slavomír Nehyba
Keyword(s):  
Sea Level ◽  
Foreland Basin ◽  
Sediment Supply ◽  
Coarse Grained ◽  
Basal Surface ◽  
Relative Sea Level ◽  
Sediment Delivery ◽  
Southern Margin ◽  
Stratigraphic Architecture ◽  
Carpathian Foredeep

AbstractTwo coarse-grained Gilbert-type deltas in the Lower Badenian deposits along the southern margin of the Western Carpathian Foredeep (peripheral foreland basin) were newly interpreted. Facies characterizing a range of depositional processes are assigned to four facies associations — topset, foreset, bottomset and offshore marine pelagic deposits. The evidence of Gilbert deltas within open marine deposits reflects the formation of a basin with relatively steep margins connected with a relative sea level fall, erosion and incision. Formation, progradation and aggradation of the thick coarse-grained Gilbert delta piles generally indicate a dramatic increase of sediment supply from the hinterland, followed by both relatively continuous sediment delivery and an increase in accommodation space. Deltaic deposition is terminated by relatively rapid and extended drowning and is explained as a transgressive event. The lower Gilbert delta was significantly larger, more areally extended and reveals a more complicated stratigraphic architecture than the upper one. Its basal surface represents a sequence boundary and occurs around the Karpatian/Badenian stratigraphic limit. Two coeval deltaic branches were recognized in the lower delta with partly different stratigraphic arrangements. This different stratigraphic architecture is mostly explained by variations in the sediment delivery and /or predisposed paleotopography and paleobathymetry of the basin floor. The upper delta was recognized only in a restricted area. Its basal surface represents a sequence boundary probably reflecting a higher order cycle of a relative sea level rise and fall within the Lower Badenian. Evidence of two laterally and stratigraphically separated coarse-grained Gilbert deltas indicates two regional/basin wide transgressive/regressive cycles, but not necessarily of the same order. Provenance analysis reveals similar sources of both deltas. Several partial source areas were identified (Mesozoic carbonates of the Northern Calcareous Alps and the Western Carpathians, crystalline rocks of the eastern margin of the Bohemian Massif, older sedimentary infill of the Carpathian Foredeep and/or the North Alpine Foreland Basin, sedimentary rocks of the Western Carpathian/Alpine Flysch Zone).

Continental-slope instability triggered by seepage: An experimental approach

2020 ◽  
Vol 90 (8) ◽  
pp. 921-937
Author(s):  
Carolina H. Boffo ◽  
Tiago A. de Oliveira ◽  
Daniel Bayer da Silva ◽  
Rafael Manica ◽  
Ana Luiza de O. Borges
Keyword(s):  
Mass Transport ◽  
Sea Level ◽  
Continental Slope ◽  
Physical Simulation ◽  
Slope Instability ◽  
Shear Stresses ◽  
Relative Sea Level ◽  
Hypothetical Scenario ◽  
Experimental Apparatus ◽  
Continental Slopes

ABSTRACT Mass-transport complexes (MTCs), mass-transport deposits (MTDs), and associated facies and features are widely recognized in continental slopes around the world. In most current stratigraphic models of MTCs and MTDs, these submarine sediment failures are related to aquifer outflow (sapping, seepage) along continental slope fronts that originated during relative sea-level fall. We test a hypothetical scenario that is favored during early forced regression using reduced-scale physical simulation. A major underground subaerial hydraulic gradient is assumed to flow towards the basin depocenter as a function of relative sea-level fall. We developed an experimental apparatus with slope angles varying between 15 and 30° to test this concept. Hydraulic gradients, aquifer outflow velocities, and triggered collapses induced by the seepage effect were recorded at various positions of the slope. Analysis shows that steeper slope gradients require lower seepage velocities (and shear stresses) to trigger collapse, but gentler slopes remain unchanged. Experimental data are compatible with a seepage effect that could potentially trigger mass failure and the formation of MTCs during relative sea-level fall. The features produced in the experiment have geometries comparable to natural environments, and the experimental seepage velocities are of an order of magnitude similar to those monitored in submarine aquifers. The experimental results advance understanding of mass transport in continental slopes by introducing and testing new methods, and also provide new insights into potential submarine geohazard risks where tectonic uplift operates along some coastal regions.

scholarly journals Magnetostratigraphic dating of the Paleogene synorogenic sediments of the NE sector of the Ebro Foreland Basin (Spanish Pyrenees)

2021 ◽  
Author(s):  
Charlotte Peigney ◽  
Elisabet Beamud ◽  
Òscar Gratacós ◽  
Eduard Roca ◽  
Alberto Sáez ◽  
...  
Keyword(s):  
Regional Scale ◽  
Foreland Basin ◽  
Late Eocene ◽  
Tectonic Activity ◽  
Orbital Eccentricity ◽  
The South ◽  
Drainage Pattern ◽  
Ebro Basin ◽  
Alluvial Deposits ◽  
Thrust Sheets

<p>In foreland settings at the front of active orogens, the aggradation/progradation of fluvial fans and sedimentary changes in lacustrine systems depends greatly on the tectonic activity and the derived drainage pattern changes in the hinterland. As a result of the emplacement and erosion of the South-Pyrenean thrust sheets, a system of N-S fluvial fans prograded into the Ebro foreland basin from late Eocene to Oligocene times. After the synorogenic deposition of the Priabonian (late Eocene) marine evaporites of the Cardona Fm, the Ebro Basin was characterized by internal drainage, with the fluvial fans grading to lacustrine systems at the center of the basin, which developed and migrated in response to subsidence changes. All these deposits were deformed by variably oriented salt-detached folds, evidencing the basinwards propagation of the deformation. In this work, we study the Solsona-Sanaüja fluvial fan system by means of litostratigraphy and magnetostratigraphy aiming to determine the age of the transition from fluvial fan to lacustrine systems in the NE sector of the Ebro Basin. The precise dating of this succession reveals causal relationships between tectonic and climatic processes affecting the source-to-sink system, including changes in the depositional style linked to the evolution of the Pyrenean fold and thrust belt.</p><p>Our new magnetostratigraphic study consisted in the sampling and analysis of 195 samples along a ca. 1800m thick stratigraphic section of the late Eocene-Oligocene succession in the northern limb of the NW-SE oriented Sanaüja Anticline. Our results show overall Priabonian to Rupelian ages for the succession, considering an age of 36 Ma. (C16n) for the top of the Cardona Fm from previous magnetostratigraphic studies. This allows dating the end of the evaporitic sedimentation (top of the Barbastro Fm) as Priabonian and establishing a late Priabonian to early Rupelian (C13r) age for the transition from the younger lacustrine deposits (Torà Fm) to the continuous and most important fluvial fan episode of progradation in the study area. The final progradation of the fluvial fan system was coeval to a tectonically controlled reorganization of the drainage pattern of the basin responding to the emplacement of the South-Pyrenean thrust sheets. Meanwhile, smaller scale (hectometric-decametric) alternation between lacustrine and alluvial deposits was possibly driven by climatic changes related to orbital eccentricity cycles. The correlation and integration of these results with previous magnetostratigraphic studies in the area can help analyzing sedimentation patterns and architectural changes in the basin margins at a regional scale.</p>

scholarly journals Vulnerability of Venice's coastland to relative sea-level rise

2020 ◽  
Vol 382 ◽  
pp. 689-695
Author(s):  
Luigi Tosi ◽  
Cristina Da Lio ◽  
Sandra Donnici ◽  
Tazio Strozzi ◽  
Pietro Teatini
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Land Subsidence ◽  
Regional Scale ◽  
Sar Interferometry ◽  
Economic Activities ◽  
Relative Sea Level ◽  
Coastal System ◽  
Relative Sea Level Rise ◽  
The Mean

Abstract. Relative sea-level rise (RSLR), i.e. sea-level rise due to climate changes combined with land subsidence, is one of the processes that is most severely threatening the coastal systems around the world. The Venice coastland forms the major low-lying area in Italy and encompasses a variety of environments, such as farmlands, estuaries, deltas, lagoons and urbanized areas. Valuable ecosystems, historical heritages and economic activities are located in this area. Since most of the territory lies at a ground elevation below or slightly above the mean sea-level, also a few mm yr−1 of land subsidence can seriously impacts on the Venice coastal system. In this study, we present an analysis of the vulnerability to RSLR considering an uneven land subsidence distribution, with an application on the Venice coastland. The analysis is delineated at the regional scale by an index-based model and a proper coupling of various thematic layers, such as high spatial resolution land subsidence data retrieved by satellite SAR interferometry, ongoing and projected sea-level rise trends, and morpho-physiographic setting of the coastland.

scholarly journals RECOGNIZING LATE CRETACEOUS TO PALEOGENE CHANGES IN RELATIVE SEA LEVEL IN NORTHERN SANTOS BASIN, BRAZIL

2019 ◽  
Vol 37 (2) ◽  
Author(s):  
A.M. Garcia ◽  
C.A. Pires ◽  
D. Münch ◽  
I. F.P Carvalho ◽  
L.S Freitas ◽  
...  
Keyword(s):  
Sea Level ◽  
Higher Order ◽  
Seismic Facies ◽  
Relative Sea Level ◽  
Seismic Section ◽  
Basin Scale ◽  
System Tracts ◽  
Mass Transport Deposits ◽  
Order Sequence ◽  
Shelf Margin

ABSTRACT. The stratigraphy of the Santos Basin has become of great interest in the last decade because of the large oil accumulations in pre-salt (rift) and post-salt (drift) strata. Nevertheless, the most accepted stratigraphic models for the drift phase are only at a basin scale and can still be improved by more detailed work. In this paper we analyze an inline seismic section in the modern continental slope of the Santos Basin in order to describe the stratigraphy and to reconstruct relative-sea level (RSL) changes from the Campanian to the Eocene/Oligocene boundary. We mapped 40 seismic horizons, in which clinoform rollovers (former shelf margins) and stratal terminations were recognized. These data allowed for the construction of a chronostratigraphic chart and a RSL curve. The proposed stratigraphic chart displays three lower-order sequence sets comprising higher-order sequences including mostly alternating forced-regressive and normal-regressive system tracts, with the exception of three important transgressive episodes. Higher-order sequences above the intra-Maastrichtian unconformity exhibit low-angle ascending to descending shelf-margin trajectories and frequently truncated topsets, while aggradation was more important during Campanian to Maastrichtian. Expressive mass-transport deposits (chaotic seismic facies) at the bottomsets of some mapped horizons all match with forced-regressive episodes.Keywords: seismic interpretation, sequence stratigraphy, shelf-margin clinoforms.RESUMO. A Bacia de Santos tornou-se de grande interesse na última década devido às acumulações de petróleo no pré-sal (rifte) e pós-sal (deriva). No entanto, os modelos estratigráficos mais aceitos para a fase de deriva são em escala de bacia e podem ser incrementados por trabalhos de maior detalhe. Analisamos uma seção sísmica longitudinal no talude continental atual da bacia, a fim de descrever a estratigrafia e reconstruir mudanças do nível relativo do mar (NRM) do Campaniano ao limite Eoceno/Oligoceno. Quarenta horizontes sísmicos foram mapeados, nos quais margens da plataforma (clinoform rollovers) e terminações estratais foram reconhecidas. Esses dados permitiram a construção de um diagrama cronoestratigráfico e uma curva de variação do NRM. Identificou-se três conjuntos de sequências de menor ordem compreendendo sequências de ordem mais elevada, incluindo, na sua maioria, alternância entre regressão forçada e normal, com exceção de três importantes episódios transgressivos. As sequências de maior ordem acima da inconformidade intra-Maastrichtiano exibem trajetórias ascendentes de baixo ângulo a descendentes de margem de plataforma e topsets truncados, enquanto agradação foi mais importante entre o Campaniano e o Maastrichtiano. Depósitos de transporte de massa (fácies sísmicas caóticas) nos bottomsets de alguns horizontes mapeados associam-se com episódios de regressão forçada.Palavras-chave: interpretação sísmica, estratigrafia de sequências, clinoformas de margem de plataforma.

Mass-transport deposits in a Variscan wedge-top foreland basin (Pisuerga area, Cantabrian Zone, NW Spain)

2014 ◽  
Vol 356 ◽  
pp. 71-87 ◽  
Author(s):  
G. Martín-Merino ◽  
L.P. Fernández ◽  
J.R. Colmenero ◽  
J.R. Bahamonde
Keyword(s):  
Mass Transport ◽  
Foreland Basin ◽  
Nw Spain ◽  
Cantabrian Zone ◽  
Mass Transport Deposits

Spatial variability of Holocene relative sea level on the China coast

2021 ◽  
Author(s):  
Nicole Khan ◽  
Howard Kwok Yin Yu ◽  
Circle Yuanyuan Hong ◽  
Erica Ashe ◽  
Tanghua Li ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Sea Level ◽  
Regional Scale ◽  
Tidal Range ◽  
Fujian Province ◽  
Relative Sea Level ◽  
Xisha Islands ◽  
The Holocene ◽  
Model Predictions ◽  
China Coast

<p>The coast of China is located in the far-field of past large ice sheets, and therefore relative sea-level (RSL) data from this region have been used to infer sea-level equivalent changes during the Holocene using geophysical models of the glacial-isostatic adjustment (GIA) process. However, there are known misfits between GIA models and Holocene RSL data along the coast of China. For example, GIA model predictions compared to RSL data from China and the Malay-Thailand peninsula show misfits in the amplitude and timing of maximum RSL (highstand) and temporal variations of RSL from the highstand to the present. Furthermore, two different preferred viscosity profiles were recognized between China and the Malay-Thai Peninsula, suggesting the presence of lateral (3D) variations in mantle viscosity across this region. These previous findings lead to several questions: 1) Are the interpretations of RSL proxies and ages robust? 2) Do 3D GIA models improve the fit compared to 1D models? and 3) Are other local- to regional-scale processes significantly influencing RSL on the China coast?</p><p>We aim to answer these questions by completing an updated, quality-controlled database of Holocene RSL data and integrating it into a spatio-temporal empirical hierarchical model (STEHM) and comparing the results to GIA models. Here, we use standardized protocols to present a preliminary compilation of Holocene RSL data (105 index points and 134 limiting points) from the southern China coast, which extends geographically from 119.19°N (Fuzhou city of Fujian Province) to 111.82°N (Xisha Islands) and 21.82 °E (Qinzhou city of Guanxi Province) to 25.22 °E (Putian city of Fujian Province). Sedimentary (salt marsh, mangrove, tidal flat, lagoon), geomorphic (Chenier ridge, beach rock), fixed biological (oyster), and coral indicators comprise the majority of RSL data in the compilation for the last 12 ka. The database is divided into sub-regions to investigate the influence of tectonics and GIA on RSL.</p><p>We apply the STEHM to the preliminary dataset to estimate the magnitudes and rates of RSL, and compare them to the radially symmetric (1D) ICE-6G_C (VM5a) GIA model pairing and an analysis of the sensitivity of the region to 3D viscosity structure. We find that sub-regional variability (i.e., spatial variability over a shorter spatial scale than the long-wavelength GIA signal) is observed throughout the Holocene. This spatial pattern suggests there is strong influence of local- to regional-scale processes causing RSL to vary from GIA model predictions because no data from sub-regions most sensitive to 3D viscosity structure (e.g., Bohai Bay) were included in these model runs. This preliminary analysis lays the groundwork to assess the potential influence of local-scale processes, such as sediment compaction and tidal range change, as well as regional impacts from tectonic vertical motion.</p>

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