scholarly journals PALEOBATHYMETRIC EVOLUTION OF THE EARLY LATE MIOCENE DEPOSITS OF THE PRE-APULIAN ZONE, LEVKAS ISLAND, IONIAN SEA

2018 ◽  
Vol 40 (1) ◽  
pp. 39 ◽  
Author(s):  
H. Drinia ◽  
A. Antonarakou ◽  
G. Kontakiotis ◽  
N. Tsaparas ◽  
M. Segou ◽  
...  

The Manassi section in Levkas Island belongs to the Pre-Apulian (Paxos) zone, the most external domain of the Hellenic realm. Its Early Tortonian sediments contain a rich foraminiferal fauna dominated, in numbers of individuals, by planktic species. Its benthic foraminiferal assemblage is characterized by a high number of taxa, with low numbers of individuals. Their study provides a basis for interpreting the paleobathymetry of the basin.The Manassi section represents deposition in upper to lower bathyal depths, during a period of intense tectonic activity. Downslope transport of fauna by turbidity currents partly overprints the signal of paleobathymetrically-diagnostic foraminifera distribution. The recognition of allochthonous taxa is used, together with %P, to identify turbidite beds intercalated with in-situ marly sediments. The micropaleontological and paleobathymetrical analyses of the studied sediments indicate that these correspond to distal atypical flysch deposited in the foredeep depozone of the most external domain (Pre-Apulian zone) of the Hellenide foreland basin.

2019 ◽  
Vol 13 (12) ◽  
pp. 80
Author(s):  
Yan Rizal ◽  
Aswan Aswan ◽  
Jahdi Zaim ◽  
Mika R. Puspaningrum ◽  
Wahyu D. Santoso ◽  
...  

Java is a volcanic island arc formed by the northwards subduction of the Eurasian and Australian Plates. Due to this active subduction, Java has been frequently shocked by earthquakes, which might induce tsunami events. However, there are hardly any ancient geological records of tsunami events in the area. This study aims to determine the presence and to identify sedimentary characters of tsunami deposit in Tegal Buleud, South Sukabumi, West Java. In the study area, there were 4 tsunami layers which were found as thin intercalation within the claystone layer of the Bentang Formation. Those paleotsunami deposits characterized by the occurrence of irregular/disturbed structure such as siltstone rip up, clay clasts, and flame structure occur in normal graded bedding sandstone layer. The grain-size distributions show bimodal and multimodal patterns, with mixing of marine microfossils from inner and middle neritic. The planktonic foraminiferal assemblage indicates that the age of the sediment comparable to N19 (equivalent to Late Miocene - Early Pliocene, at about 5.33 – 3.6 Ma), suggested that these paleotsunami layers were deposited due to the Mio-Pliocene tectonic activity. All the paleotsunami deposits found in Study area are the first and oldest tsunami deposit recorded in Java even in Indonesia. With the discovery of the previously unexplored Late Miocene to Pliocene tsunami deposits found in the study area, the result of this study can be used as a reference for the identification of the Tertiary tsunami deposits present in other parts of Indonesia.


2011 ◽  
Vol 62 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Wieske Paulissen ◽  
Stefan Luthi ◽  
Patrick Grunert ◽  
Stjepan Ćorić ◽  
Mathias Harzhauser

Integrated high-resolution stratigraphy of a Middle to Late Miocene sedimentary sequence in the central part of the Vienna BasinIn order to determine the relative contributions of tectonics and eustasy to the sedimentary infill of the Vienna Basin a high-resolution stratigraphic record of a Middle to Late Miocene sedimentary sequence was established for a well (Spannberg-21) in the central part of the Vienna Basin. The well is located on an intrabasinal high, the Spannberg Ridge, a location that is relatively protected from local depocentre shifts. Downhole magnetostratigraphic measurements and biostratigraphical analysis form the basis for the chronostratigraphic framework. Temporal gaps in the sedimentary sequence were quantified from seismic data, well correlations and high-resolution electrical borehole images. Stratigraphic control with this integrated approach was good in the Sarmatian and Pannonian, but difficult in the Badenian. The resulting sedimentation rates show an increase towards the Upper Sarmatian from 0.43 m/kyr to > 1.2 m/kyr, followed by a decrease to relatively constant values around 0.3 m/kyr in the Pannonian. The sequence reflects the creation of accommodation space during the pull-apart phase of the basin and the subsequent slowing of the tectonic activity. The retreat of the Paratethys from the North Alpine Foreland Basin during the Early Sarmatian temporarily increased the influx of coarsergrained sediment, but eventually the basin acted mostly as a by-pass zone of sediment towards the Pannonian Basin. At a finer scale, the sequence exhibits correlations with global eustasy indicators, notably during the Sarmatian, the time of greatest basin subsidence and full connectivity with the Paratethyan system. In the Pannonian the eustatic signals become weaker due to an increased isolation of the Vienna Basin from Lake Pannon.


2019 ◽  
Author(s):  
Samuel Mock ◽  
Christoph von Hagke ◽  
Fritz Schlunegger ◽  
István Dunkl ◽  
Marco Herwegh

Abstract. Additional to classical nappe tectonics, the Oligocene to mid-Miocene post-collisional evolution of the Central European Alps was characterized by vertically directed tectonics, with backthrusting along the Insubric Line and the subsequent uplift of the External Crystalline Massifs (ECMs). Thereafter, the orogen experienced axis-perpendicular growth when deformation propagated into its external parts. For the North Alpine foreland between Lake Geneva and Lake Constance, in the past, this has been kinematically and spatially linked to the uplift and exhumation of the ECMs. Based on apatite (U-Th-Sm)/He thermochronometry, we constrain thrusting in the Subalpine Molasse between 12–4 Ma, thus occurring coeval to main deformation in the Jura fold-and-thrust belt (FTB) and late stage exhumation of the ECMs. However, this pattern of tectonic activity is not restricted to areas which are bordered by ECMs, but is consistent along the northern front of the Alps between Geneva and Salzburg. Therefore, late Miocene foreland deformation is not necessarily a consequence of uplift and exhumation of the ECMs. While the local geometry of the Subalpine Molasse results from lateral variations of the mechanical stratigraphy of the foreland basin sediments, we suggest that the large-wavelength tectonic signal is the response to a shift in tectonic forces possibly caused by deep-seated geodynamic processes. This resulted in a change from dominantly vertical to horizontal tectonics and orogen-perpendicular growth of crustal thickening. We constrain the onset of this major tectonic change to ca. 12 Ma in the North Alpine foreland, resulting in thrusting and folding in the Subalpine Molasse west of Salzburg and in the Jura FTB until at least 4 Ma.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Francesco Brozzetti ◽  
Daniele Cirillo ◽  
Lucina Luchetti

A large dataset of lithostratigraphic and biostratigraphic data, concerning the Early-Late Miocene turbidite succession of the Umbria pre-Apennines, is presented and analyzed. The data come from the study of 24 sections that are representative of all the main tectonic units cropping out between the front of the Tuscan allochthon and the Umbria-Marche calcareous chain. The sections have been dated using quantitative calcareous nannofossil biostratigraphy and, wherever possible, they were correlated through key-beds recognition. Such a multidisciplinary approach allowed us to reconstruct the evolution of the Umbria foredeep over time and to unveil the chronology of compressive deformations by defining: (i) the onset of the foredeep stage in each structural unit, (ii) the age of depocenter-shifting from a unit to the adjacent one, (iii) the progressive deactivation of the western sector of the foredeep due to the emplacement of allochthon units, and (iv) the internal subdivisions of the basin due to the presence of foreland ramp faults or thrust-related structures. A further original outcome of our study is having brought to light the Late Burdigalian “out-of-sequence” reactivation of the Tuscan allochthon which bounded westward the foredeep, and the subsequent protracted period of tectonic stasis that preceded the deformations of the Umbrian parautochthon.


2017 ◽  
Vol 43 (2) ◽  
pp. 568
Author(s):  
A. Antonarakou

Planktonic foraminiferal biostratigraphy is carried out in an Early Tortonian tectonically active setting, located in the Pre-Apulian Foreland Basin in Levkas Island. The studied section (Manassi section) is composed of hemipelagic silty clays and turbidite sandstones, reflecting sedimentation as a result of thrust activity. The distributional pattern of biostratigraphical significant species suggests that the Manassi section has been deposited during the time interval that Globigerinoides obliquus occurs regularly, the neogloboquadriniids are present in low percentages and Paragloborotalia siakensis is continuously present. The correlation with astronomical tuned sections allowed dating the studied section as ranging between 11.54Ma to 11.2Ma, having a lower Tortonian age, above the Serravallian/Tortonian boundary (Paragloborotalia siakensis planktonic foraminiferal zone). On the basis of the obtained palaeoclimatic curve, a series of palaeoclimatic events are recognized. The faunal composition suggests a cooling trend in the lower part which has been correlated with the Mi5 event. This cooling is followed by a warm-temperate phase, punctuated by several negative peaks in the palaeoclimatic curve. The palaeoclimatic evolution of the study area generally corresponds to the global palaeoclimatic trend with some subtle differences, supporting that the regional climate of this area was not merely controlled by global changes in climate.


2019 ◽  
Author(s):  
Samuel Mock ◽  
Christoph von Hagke ◽  
Fritz Schlunegger ◽  
István Dunkl ◽  
Marco Herwegh

Abstract. Besides classical emplacement and accretion related nappe tectonics, the Oligocene to middle Miocene post-collisional evolution of the central European Alps was also characterized by pronounced vertically directed tectonics. These are expressed by backthrusting along the Insubric Line and the subsequent uplift of the External Crystalline Massifs (ECMs). During late Miocene times, the Central Alps experienced lateral growth when deformation propagated into the external parts of both the pro- and retro-side of the orogen. For the North Alpine foreland, pro-wedge propagation of deformation has been kinematically and spatially linked to the uplift and exhumation of the ECMs. In this paper, we investigate the young exhumation history of the North Alpine foreland. Based on low-temperature apatite (U-Th-Sm)/He thermochronometry, we constrain thrusting in the Subalpine Molasse between 12 Ma and 5 Ma, thus occurring coeval to the main deformation phase in the adjacent Jura fold-and-thrust belt (FTB) and late stage exhumation of the ECMs. However, this pattern of tectonic activity is not restricted to areas which are bordered by the ECMs, but is consistent along the entire front of the Central Alps, regardless of its hinterland architecture. The local-scale pattern of strain partitioning and style of deformation is governed by lateral variations in the sedimentary foreland basin architecture. We suggest that the large-scale constant tectonic signal is the response to a shift in tectonic forces caused by a deep-seated geodynamic process. This resulted in a change from dominantly vertical to orogen-scale horizontal tectonics and an associated orogen-perpendicular growth of crustal thickening. We constrain the onset of this major tectonic change to ca. 15 Ma in the Southern Alps and ca. 12 Ma in the North Alpine foreland, where it results in (re-)activation of thrusts in the Subalpine Molasse and folding in the Jura FTB.


2021 ◽  
Vol 9 (6) ◽  
pp. 639
Author(s):  
Hong Zhang ◽  
Xiaolei Liu ◽  
Anduo Chen ◽  
Weijia Li ◽  
Yang Lu ◽  
...  

Liquefied submarine sediments can easily lead to submarine landslides and turbidity currents, and cause serious damage to offshore engineering facilities. Understanding the rheological characteristics of liquefied sediments is critical for improving our knowledge of the prevention of submarine geo-hazards and the evolution of submarine topography. In this study, an in situ test device was developed to measure the rheological properties of liquefied sediments. The test principle is the shear column theory. The device was tested in the subaqueous Yellow River delta, and the test results indicated that liquefied sediments can be regarded as “non-Newtonian fluids with shear thinning characteristics”. Furthermore, a laboratory rheological test was conducted as a contrast experiment to qualitatively verify the accuracy of the in situ test data. Through the comparison of experiments, it was proved that the use of the in situ device in this paper is suitable and reliable for the measurement of the rheological characteristics of liquefied submarine sediments. Considering the fact that liquefaction may occur in deeper water (>5 m), a work pattern for the device in the offshore area is given. This novel device provides a new way to test the undrained shear strength of liquefied sediments in submarine engineering.


2016 ◽  
Vol 45 (24) ◽  
pp. 9770-9773 ◽  
Author(s):  
Michael R. Talley ◽  
Ryjul W. Stokes ◽  
Whitney K. Walker ◽  
David J. Michaelis

In situ assembly of a heterobimetallic Pt–Ti catalyst from a titanium-containing phosphinoamide ligand enables fast room temperature catalysis in enyne cycloisomerization reactions.


2021 ◽  
Author(s):  
Erik Wolfgring ◽  
Michael A. Kaminski ◽  
Anna Waśkowska ◽  
Maria Rose Petrizzo ◽  
Eun Young Lee ◽  
...  

<p>Site U1512 was drilled during Expedition 369 of the International Ocean Discovery Program (IODP), which is located in the Great Australian Bight, southern Indian Ocean. It provides exceptional insights into the benthic foraminiferal biostratigraphy and paleoecology of a high southern latitude restricted marginal marine basin during the Late Cretaceous hot greenhouse climate and the rifting between Australia and Antarctica. The sedimentary sequence recovered at Site U1512 presents a rare record of a deep water agglutinated foraminifera (DWAF) community from the Southern High Latitudes. The Cretaceous record at Site U1512 covers the lower Turonian through Santonian (nannofossil zones UC8b to UC12/CC10b to CC16, <em>H. helvetica</em> to <em>Marginotruncana</em> spp. - <em>Planoheterohelix papula</em> - <em>Globotruncana linneana</em> planktonic foraminifera zones). Diverse benthic foraminiferal assemblages yield many new taxa that are yet to be described.</p><p>Agglutinated forms dominate the assemblage in most intervals. In lower to mid Turonian and Santonian strata, calcareous benthic as well as planktonic foraminifera are frequent. Abundant radiolaria are recovered from the mid Turonian, and they increase up-section and exceed 50% of the microfossil assemblage. We documented a diverse benthic foraminiferal assemblage consisting of 162 taxa (110 agglutinated and 52 calcareous). The most common taxa of the DWAF assemblage are tubular (i.e., <em>Kalamopsis grzybowskii,</em> <em>Bathysiphon</em> spp.) and planispiral forms (i.e., <em>Ammodiscus</em> spp., <em>Haplophragmoides</em> spp., <em>Buzasina</em> sp., <em>Labrospira</em> spp.).</p><p>The Turonian strata yield highly abundant <em>Bulbobaculites problematicus</em> and <em>Spiroplectammina navarroana</em>. The presence of the agglutinated foraminiferal marker taxa <em>Uvigerinammina jankoi</em> and <em>Bulbobaculites problematicus</em> provides a tie-point to the Tethyan DWAF biozonation of Geroch and Nowak (1984). The composition of foraminiferal assemblages and the increase in radiolaria abundance suggest unstable environmental conditions at Site U1512 during the early Turonian through Santonian. These characteristics refer to changes in bathymetry associated with changing ocean chemistry. Results of quantitative analyses of the benthic foraminiferal assemblages indicate a restricted paleoenvironmental regime, dictated by changes in paleobathymetry, unstable patterns in ocean circulation, and the discharge of a nearby river delta system.</p><p>References: Geroch, S., Nowak, K., 1984. Proposal of zonation for the Late Tithonian – late Eocene. based upon arenaceous Foraminifera from the Outer Carpathians, Poland, 225-239, In: Oertli, H.J. (Ed.), Benthos ´83; 2nd international 915 Symposium on Benthic Foraminifera, Pau (France) April 11-15, 1983, Elf Aquitaine, ESO REP and TOTAL CFP, Pau and Bordeaux.</p><p> </p>


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