scholarly journals A Geophysical-Geochemical Approach to the Study of the Paleogene Julian—Slovenian Basin “Megabeds” (Southern Alps—Northwestern Dinarides, Italy/Slovenia)

Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 155 ◽  
Author(s):  
Kei Ogata ◽  
Željko Pogačnik ◽  
Giorgio Tunis ◽  
Gian Pini ◽  
Andrea Festa ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Open Pit ◽  
Resistivity Tomography ◽  
Fine Grained ◽  
Deformation Structures ◽  
Slide Mass ◽  
Sediment Deformation ◽  
Depositional Units ◽  
Slovenian Basin ◽  
Depositional Setting

The Paleogene “megabeds” of the Julian-Slovenian Basin are regional, basin-wide deposits, produced by catastrophic carbonate platform collapses. They record the emplacement of a bipartite slide mass behaving as a cohesive blocky/debris flow in the lower part, and as a grain to turbulent flow in the upper part. Several types of primary (sedimentary) soft sediment deformation structures testify fluid overpressure conditions during emplacement. Such structures are identified within a brecciated, fine grained matrix that encloses and intrudes slide blocks and clasts, characterized by NE-, NW- and SW-directed paleo-transport directions, indicating a depositional setting close to the basin margins. Here we present an updated review of some representative megabeds, exposed in the open-pit quarry outcrops of Anhovo (SW Slovenia). In particular, we here discuss new interpretations based on X-ray fluorescence spectrometry (XRF), thermo-gravimetry (TG) and electric resistivity tomography (ERT). Our results indicate that basal marly clasts of the megabeds are markedly different from the uppermost draping marls, suggesting two different coeval sources. The relationships with the underlying successions are strongly erosive, with deep localized scouring of the substrate and amalgamations between different megabeds, and the depositional units inside individual megabeds, supporting the geochemical differences.

scholarly journals Soft sediment deformation in dry pyroclastic deposits at Ubehebe Crater, Death Valley, California

Geology ◽  
2020 ◽  
Author(s):  
Greg A. Valentine ◽  
Judy Fierstein ◽  
James D.L. White
Keyword(s):  
Wet Deposition ◽  
Death Valley ◽  
Soft Sediment ◽  
Pyroclastic Deposits ◽  
Fine Grained ◽  
Deformation Structures ◽  
Pyroclastic Surges ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
Steep Slopes

Soft sediment deformation structures are common in fine-grained pyroclastic deposits and are often taken, along with other characteristics, to indicate that deposits were emplaced in a wet and cohesive state. At Ubehebe Crater (Death Valley, California, USA), deposits were emplaced by multiple explosions, both directly from pyroclastic surges and by rapid remobilization of fresh, fine-ash-rich deposits off steep slopes as local granular flows. With the exception of the soft sediment deformation structures themselves, there is no evidence of wet deposition. We conclude that deformation was a result of destabilization of fresh, fine-grained deposits with elevated pore-gas pressure and dry cohesive forces. Soft sediment deformation alone is not sufficient to determine whether parent pyroclastic surges contained liquid water and caused wet deposition of strata.

Pre- and Post-consolidated Sediment Deformations in the Transitional Terrigeneous Series PZt (Zechstein/Lower Buntsandstein)in the Grodziec Syncline, Sudetes: Process Interpretation and Regional Implications

2017 ◽  
pp. 0-0
Author(s):  
Karol Durkowski ◽  
Dominik Sokalski ◽  
Jurand Wojewoda
Keyword(s):  
The Other ◽  
Future Research ◽  
Fine Grained ◽  
Deformation Structures ◽  
The North ◽  
Other Hand ◽  
Important Correlation ◽  
Sediment Deformation

In the Grodziec Syncline (Eastern part of the North-Sudetic Synclinorium) the uppermost Zechstein sediments are represented by mudstones and very fine grained sandstones, which smoothly continue into typical Buntsandstein deposits. These sediments belong to Transitional Terrigeneous Series (PZt), which uppermost part is developed as heterolithic tempestites. A zone abundant in pre- and post-consolidated sediment deformation structures was distinguished within heterolithic sediments. The pre-consolidated sediment deformation structures have numerous features of seismites, on the other hand post-consolidated deformation structures raise more doubts about their origin and require more future research. A zone of pre- and post-consolidated sediment deformation is an important correlation horizon for the Grodziec Syncline. Furthermore, such zone is also observed in the analogous deposits of the Fore-Sudetic Monocline in the Glogow–Rudna area.

Penecontemporaneous sandstone dykes, Nonacho Basin (early Proterozoic, Northwest Territories): horizontal injection in vertical, tabular fissures

1986 ◽  
Vol 23 (6) ◽  
pp. 827-838 ◽  
Author(s):  
Lawrence B. Aspler ◽  
J. A. Donaldson
Keyword(s):  
Sedimentary Rocks ◽  
Fluid Injection ◽  
Soft Sediment ◽  
Sand Liquefaction ◽  
Fine Grained ◽  
Lacustrine Deposits ◽  
Deformation Structures ◽  
Tectonic Disturbances ◽  
Sediment Deformation ◽  
Host Rocks

Sandstone dykes in Proterozoic sedimentary rocks of Nonacho Basin cut only the fine-grained portions of cyclic fluvial, pond, and lacustrine deposits but occur repetitively through hundreds of metres of section. Such restriction to specific beds, in conjunction with erosional truncations of the dykes and association with sand volcanoes, indicates that the dykes are penecontemporaneous. Minimal compaction-related deformation, sharp dyke walls, and mud chips within dykes suggest that the fine-grained host rocks were cohesive before dyke emplacement. In sections parallel to bedding, the dykes are polygonal; normal to bedding, dyke configurations range from tabular to branching to fully developed reticulate networks. The dykes are generally massive, but grain size locally increases towards dyke centers. In contrast to most dykes described in the literature, internal stratification is generally at high angles to dyke walls and at low angles to sill walls.Of the hypotheses considered for dyke emplacement (sedimentary infill, hydroplastic squeezing, fluid injection, and foundering of the flanks of sand volcanoes), fluid injection is favoured as the most likely mechanism. Concurrent mudstone Assuring, sand liquefaction, and injection are attributed to earthquake shocks. Vertical fissures were filled with sand that was injected horizontally, a phenomenon not commonly reported. Widespread stratigraphic distribution of the dykes and an abundance of other soft-sediment deformation structures attest to numerous tectonic disturbances during sedimentation in Nonacho Basin.

3D soft-sediment deformation structures: evidence for Quaternary seismicity in the Madrid basin, Spain

Terra Nova ◽  
1997 ◽  
Vol 9 (5) ◽  
pp. 208-212 ◽  
Author(s):  
P.G. Silva ◽  
J.C. Canaveras ◽  
S. Sanchez-Moral ◽  
J. Lario ◽  
E. Sanz
Keyword(s):  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Dead Sea shoreline facies with seismically-induced soft-sediment deformation structures, Israel

2000 ◽  
Vol 49 (4) ◽  
pp. 197-214 ◽  
Author(s):  
Dan Bowman ◽  
Dorit Banet-Davidovich ◽  
Hendrik J. Bruins ◽  
Johannes Van der Plicht
Keyword(s):  
Dead Sea ◽  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

scholarly journals Lacustrine Slope-Related Soft-Sediment Deformation Structures in the Cretaceous Gyeokpori Formation, Buan Area, SW Korea, and Volcanism-Induced Seismic Shocks as Their Possible Trigger

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 721
Author(s):  
Ukhwan Byun ◽  
A.J. (Tom) van Loon ◽  
Kyoungtae Ko
Keyword(s):  
Facies Analysis ◽  
Deformation Mechanisms ◽  
Volcanic Area ◽  
Cohesive Sediments ◽  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
Siliciclastic Rocks ◽  
Sediment Layers

The Gyeokpori Formation in the Buan volcanic area primarily contains siliciclastic rocks interbedded with volcanoclastics. These sediments are characterized by a variety of soft-sediment deformation structures (SSDS). The SSDS in the Gyeokpori Formation are embedded in poorly sorted conglomerates; slump folds are also present in the formation. The deformation mechanisms and triggers causing the deformation are not yet clear. In the present study, the trigger of the SSDS in the Gyeokpori Formation was investigated using facies analysis. This included evaluation of the reworking process of both cohesive and non-cohesive sediments. The analysis indicates that the SSDS are directly or indirectly associated with the alternation of conglomerates and mud layers with clasts. These layers underwent non-cohesive and cohesive deformation, respectively, which promoted SSDS formation. The slump folds were controlled by the extent of cohesive and non-cohesive deformation experienced by the sediment layers in the slope environment. The SSDS deformation style and morphology differ, particularly in the case of reworking by slump activity. This study contributes to the understanding of lacustrine slope-related soft-sediment deformation structures.

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