Structural Style and Kinematic History of the Colombian Eastern Cordillera

Fold-and-thrust belts and their associated structures are among the most common geological features of convergent margins. They provide significant information about crustal shortening and mountain-building processes. In subaerial belts, where the erosional rates are high and the growth strata are mostly eroded, methodologies such as that presented here can provide insights into to their formation. Two 2D cross-sections located in the Eastern Cordillera of Colombia are presented in this research. These sections extend from the Bogota Savanna to The Llanos, parallel to the regional deformation direction. Section construction was carried out using commercial surface data, and seismic information provided by Ecopetrol. Published thermochronometric data, gravel-clast petrography analysis, and paleoflora analysis were used to construct a viable tectono-evolutionary history of the study area. This evolutionary model is presented here in two palinpastic restorations from the Early Paleogene to Recent (∼65 Ma to Present-day). Section 1 and Section 10 accumulated 17.3 km and 19.5 km of shortening, respectively. The section reconstruction displays two major tectonic events – post-rift subsidence during the Early-Mid Paleogene, and positive inversion from the Oligocene to Recent (∼33 Ma to Present-day). This investigation focuses on the compressional period, where the structural analysis evidences an acceleration in the shortening rate, as well as a progressive migration of the deformation from northwest to southeast. This research discusses the extent and limitation of this methodology, as well as the principal structural aspects of the reconstruction.

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Contractional salt tectonics and role of pre-existing diapiric structures in the Southern Pyrenean foreland fold–thrust belt (Montsec and Serres Marginals)

Journal of the Geological Society ◽

10.1144/jgs2020-085 ◽

2021 ◽

pp. jgs2020-085 ◽

Cited By ~ 1

Author(s):

Laura Burrel ◽

Antonio Teixell

Keyword(s):

Cross Sections ◽

Foreland Basin ◽

Salt Tectonics ◽

Structural Development ◽

Field Observations ◽

Content Type ◽

Growth Strata ◽

Structural Style ◽

Supplementary Material

Triassic Keuper evaporites have long been recognized as the main detachment level for thrusting in the Pyrenean fold–thrust belts. The deformed Late Cretaceous–Eocene foreland basin of the Southern Pyrenees has structures and stratal geometries that can be interpreted as related to salt tectonics (e.g. unconformities, rapid thickness variations, long-lived growth fans and overturned flaps), although they have been overprinted by shortening and thrusting. Based on field observations and published maps, we build new structural cross-sections reinterpreting two classic transects of the Southern Pyrenees (Noguera Ribagorçana and Noguera Pallaresa river transects). The sequential restoration of the sections explores the variations in structural style, addressing the role of halokinesis in the tectonic and sedimentary development. In the Serres Marginals area, we propose that salt pillows and diapirs started developing locally during the Mesozoic pre-orogenic episode, evolving into a system of salt ridges and intervening synclines filled with early synorogenic sediments. Rapid amplification of folds recorded by widespread latest Cretaceous–Paleocene growth strata is taken as marking the onset of contractional folding in the area. During Pyrenean compression, folding mechanisms transitioned from dominantly halokinetic to a combination of buckling and differential sedimentary loading. Squeezing of salt diapirs and thrust welding occurred as salt ridges were unroofed. We provide new field observations that lead to a reinterpretation of the regional structural development and contribute to the debate about the role of salt tectonics in the Pyrenees.Supplementary material: Table S1, giving the thickness of the main stratigraphic units, is available at https://doi.org/10.6084/m9.figshare.c.5287737

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Recent geological advances in the understanding of the Torres Basin

The APPEA Journal ◽

10.1071/aj12070 ◽

2013 ◽

Vol 53 (2) ◽

pp. 459

Author(s):

Michael Swift

Keyword(s):

Cross Sections ◽

Large Scale ◽

Regional Scale ◽

Coastal Region ◽

Petroleum Potential ◽

Structural Style ◽

Time Space ◽

Australian Plate ◽

History Of ◽

Geological Section

The Torres Basin is a recently discovered Mesozoic basin in the Papuan Plateau, southeast Papua New Guinea. Newly acquired deepwater offshore seismic data and older regional data have been (re)interpreted with the view of defining structural regimes in line with the onshore geological maps and conceptual cross sections. A regional time-space plot has been developed to elucidate the breakup of the northeastern Australian Plate with a focus on the geological history of the Papuan Plateau, which holds the Torres Basin geological section. This in turn has led to a re-evaluation of the structural style and history of the southern coastal region incorporating the East Australian Early Cretaceous Island Arc; it highlights that a significant horizontal structural grain needs to be considered when evaluating the petroleum potential of the region. The southern margin is characterised as a frontal thrust system, similar to the nearby Papuan Basin. A series of regional strike lines in conjunction with the dip lines is used to divide the region into prospective and non-prospective exploration play fairways. The role of transfer faults, basement-detachments faults, regional-scale thrust faults, and recent normal faulting is discussed in the compartmentalisation of the geological section. There is basement-involved anticlinal development on a large scale and a complementary smaller-scale thin-skinned anticlinal trend. These trends are characterised as having significant strike length and breadth. Anticlinal trap fairways have been defined and have similar size and distribution as that of the Papuan Basin.

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Kinematics of Cenozoic shortening across the foothills of the Western Kunlun Range (Xinjiang, China): the case of the Hotan anticline

10.5194/egusphere-egu21-7443 ◽

2021 ◽

Author(s):

Guillaume Baby ◽

Martine Simoes ◽

Laurie Barrier ◽

Christelle Guilbaud ◽

Jérôme Van der Woerd ◽

...

Keyword(s):

Cross Sections ◽

Large Scale ◽

The Tibetan Plateau ◽

Seismic Profiles ◽

Growth Strata ◽

Subsequent Decrease ◽

Western Kunlun ◽

Mountain Front ◽

Shortening Rate ◽

Seismic Reflectors

Quantitative constraints on the Cenozoic deformation of the northwestern edge of the Tibetan Plateau remain limited, in particular in terms of shortening rates and of their possible evolution over time. This is indeed the case for the Western Kunlun Range, along the southwestern rim of the Tarim Basin, even though surface geological data and an extensive database of seismic profiles allow to explore the sedimentary record of Cenozoic deformation. Here, we take advantage of these data to document the structural geometry and Cenozoic kinematics of the large scale east-west striking Hotan anticline along the mountain front. Four balanced cross-sections are constructed, and the temporal evolution of deformation is deciphered from the exceptionally seismically well imaged growth strata on the forelimb of the anticline.The fold results from a broad unfaulted basement ramp anticline, subsequently deformed by a duplex structure that developed in the footwall units. The total shortening of the Hotan thrust system is relatively constant along strike, from ~40 to ~32 km. The shortening accommodated by the duplex varies laterally from west to east, from ~50-40 % to 0 % of the total shortening.&#160;Two distinct successive patterns of growth strata are recognised in the forelimb, and are interpreted to be representative of deformation on the basement ramp, followed by deformation related to the growth of the underlying duplex. Deformation on the basement ramp initiated by ~17 Ma, when calibrating growth seismic reflectors on surface magnetostratigraphic sections. Deformation of the underlying duplex began at ~12 Ma to the west and subsequently propagated eastward.From these results on shortening and timing of deformation, we determine a shortening rate of 4-3 mm/yr from ~17 to ~7 Ma across the Hotan anticline. We find a significant subsequent decrease in shortening rates, possibly down to <0.5 mm/yr since the uppermost Miocene. These rates are compared to existing values and their regional significance is discussed.

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Streptococcus pluranimalium meningoencephalitis in a horse

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211023465 ◽

2021 ◽

pp. 104063872110234

Author(s):

Dah-Jiun Fu ◽

Akhilesh Ramachandran ◽

Craig Miller

Keyword(s):

Ribosomal Rna ◽

Cross Sections ◽

Nucleotide Sequencing ◽

Formalin Fixed Paraffin ◽

Quarter Horse ◽

Formalin Fixed Paraffin Embedded ◽

History Of ◽

The Brain ◽

Gram Positive Cocci ◽

Formalin Fixed

A 3-y-old, female Quarter Horse with a history of acute neurologic signs was found dead and was submitted for postmortem examination. Areas of petechial and ecchymotic hemorrhage were present on cross-sections of the cerebrum, cerebellum, and brainstem. Histologic examination of the brain revealed severe, purulent meningoencephalitis and vasculitis with a myriad of intralesional gram-positive cocci. Streptococcus pluranimalium was identified from formalin-fixed, paraffin-embedded tissue obtained from sites with active lesions by PCR and nucleotide sequencing of bacterial 16S ribosomal RNA. S. pluranimalium should be considered as a cause of meningoencephalitis in a horse.

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CHARMONIUM PRODUCTION IN Pb–Pb COLLISIONS AT ALICE: FROM SUPPRESSION TO REGENERATION?

Modern Physics Letters A ◽

10.1142/s0217732313300188 ◽

2013 ◽

Vol 28 (21) ◽

pp. 1330018 ◽

Cited By ~ 1

Author(s):

ENRICO SCOMPARIN

Keyword(s):

Phase Transition ◽

Cross Sections ◽

Short Review ◽

Heavy Ion ◽

Gluon Plasma ◽

Alice Experiment ◽

Model Calculations ◽

Ion Collisions ◽

Quark Production ◽

History Of

Heavy quarkonium states are considered as one of the key observables for the study of the phase transition from a system made of hadrons towards a Quark–Gluon Plasma (QGP). In the last 25 years, experiments at CERN and Brookhaven have studied collisions of heavy ions looking for a suppression of charmonia/bottomonia, considered as a signature of the phase transition. After an introduction to the main concepts behind these studies and a short review of the SPS and RHIC results, I will describe the results obtained in Pb – Pb collisions by the ALICE experiment at the LHC. The ALICE findings will be critically compared to those of lower energy experiments, to CMS results, and to model calculations. The large cross-sections for heavy-quark production at LHC energies are expected to induce a novel production mechanism for charmonia in heavy-ion collisions, related to a recombination of [Formula: see text] pairs along the history of the collision and/or at hadronization. The occurrence of such a process at the LHC will be discussed. Finally, prospects for future measurements will be shortly addressed.

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The influence of backstop geometry in the structural style of the Eastern Cordillera of Colombia: A sandbox modeling approach

10.5194/egusphere-egu21-13914 ◽

2021 ◽

Author(s):

Camilo Andrés Conde Carvajal ◽

Cristhian Bolívar Riascos Rodríguez ◽

Michael Andres Avila Paez ◽

Andreas Kammer

Keyword(s):

Kink Band ◽

Ductile Deformation ◽

High Plains ◽

Angle Of Internal Friction ◽

Eastern Cordillera ◽

Surface Uplift ◽

Structural Style ◽

Mountain System ◽

Mountain Front ◽

Structural Relief

Among the foreland belts of the Andean mountain system, the Eastern Cordillera of Colombia (EC) represents a unique example of an isolated, bi-vergent mountain belt. In contrast, to block tectonics of broken foreland basins, it displays a ductile deformation style which involves two mountain fronts with a structural relief of the order of 10 km. Internal parts of the EC have been shortened by buckling at high and a homogeneously strained basement at deeper structural levels. These deformation patterns likely attest to conditions of a thermally weakened backarc setting. Two opposed scenarios have been postulated for its surface uplift and consequent exhumation: 1) an E-migrating deformation front and the formation of progressively forward breaking faults; and 2) the pop-up of a weak crustal welt enclosed by strong foreland blocks. In this latter setting, a synchronous early formation of marginal mountain fronts and a late-stage surface uplift of a central domain may be anticipated. These two constellations compare, in terms of a contrasting model setup, to a foreland migrating orogenic wedge or a relatively stable, doubly vergent wedge formed above a structural discontinuity or rheologic boundaries that acted as sites for the nucleation of the marginal faults.In this contribution, we opt to examine the &#8220;boundary&#8221; conditions for the development of a doubly vergent wedge formed at the tip line of a rigid tapering backstop, that simulates a rigid foreland block. With respect to the shape of this backstop, we examine the effects of tip angles less than the angle of internal friction (<30&#176;) and find, that at a low tip angle of 10&#176; the pop-up evolves above a forward-breaking principal kink-band with the synchronous formation of a sequence of conjugate back-kinks that cut into the sand pack, as it is pushed toward the backstop. At a moderate tip angle of 20o the forward-breaking kink-band is slightly steeper than the backstop and gives rise to a frontal fold with an overturned limb. This latter geometrical configuration loosely compares to the structural relations of a structural section through the high plains of Bogot&#225;, where the eastern mountain front defines a strongly deformed antiform, that is juxtaposed against an undeformed margin of the adjacent Guyana shield.

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ON THE FORMATION OF LEGAL AND SCIENTIFIC BASES OF ENSURING THE SAFETY OF CRITICAL INFORMATION INFRASTRUCTURE OF THE RUSSIAN FEDERATION

Bulletin of Udmurt University. Series Economics and Law ◽

10.35634/2412-9593-2019-29-5-644-654 ◽

2019 ◽

Vol 29 (5) ◽

pp. 644-654

Author(s):

N.M. Kurbatov

Keyword(s):

Information Security ◽

Russian Federation ◽

Critical Infrastructure ◽

Information Infrastructure ◽

Significant Information ◽

Critical Information ◽

Foreign Countries ◽

History Of ◽

The Russian Federation ◽

Definition Of

The concept of critical information infrastructure is analyzed. The history of its formation and consolidation in the legal space of Russian legislation is considered. The article studies the experience of foreign countries in the field of ensuring information security in general and protecting critical infrastructure in particular. The relevance of the chosen topic is due to the course taken by the Russian Federation for the development of the information society in the country, as well as the need to protect significant information systems and resources of state authorities. The author of the article reveals the terms included in the definition of critical information infrastructure, enshrined in the legislation of the Russian Federation. In conclusion, the main problems of the considered regulatory legal acts are highlighted, recommendations are given on the further development of the information security system of critical infrastructure.

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Oblique convergence causes both thrust and strike-slip ruptures during the 2021 M 7.2 Haiti earthquake

10.31223/x5gg8m ◽

2021 ◽

Author(s):

Ryo Okuwaki ◽

Wenyuan Fan

Keyword(s):

Strike Slip ◽

Fault Rupture ◽

Plate Convergence ◽

Regional Deformation ◽

Blind Thrust ◽

Oblique Convergence ◽

Block Movement ◽

History Of ◽

Tectonic Boundary ◽

Blind Thrust Fault

A devastating magnitude 7.2 earthquake struck Southern Haiti on 14 August 2021. The earthquake caused severe damages and over 2000 casualties. Resolving the earthquake rupture process can provide critical insights into hazard mitigation. Here we use integrated seismological analyses to obtain the rupture history of the 2021 earthquake. We find the earthquake first broke a blind thrust fault and then jumped to a disconnected strike-slip fault. Neither of the fault configurations aligns with the left-lateral tectonic boundary between the Caribbean and North American plates. The complex multi-fault rupture may result from the oblique plate convergence in the region that the initial thrust rupture is due to the boundary-normal compression and the following strike-slip faulting originates from the Gonâve microplate block movement, orienting towards the SW-NE direction. The complex rupture development of the earthquake suggests that the regional deformation is accommodated by a network of segmented faults with diverse faulting conditions.

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The naked ape as an evolutionary model, 50 years later

Animal Biology ◽

10.1163/15707563-17000167 ◽

2018 ◽

Vol 68 (3) ◽

pp. 227-246

Author(s):

Nico M. van Straalen

Keyword(s):

Natural Selection ◽

Evolutionary Biology ◽

Evolutionary Model ◽

Developmental Constraints ◽

Body Hair ◽

Product Evolution ◽

Adaptive Explanation ◽

History Of ◽

Popular Texts ◽

The Brain

AbstractEvolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.

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Interplay between tectonic inheritance and salt tectonics in the tectono-sedimentary evolution of the Sahel basin (eastern Tunisia): implications for hydrocarbon prospectivity

10.5194/egusphere-egu21-13593 ◽

2021 ◽

Author(s):

Wajdi Belkhiria ◽

Haifa Boussiga ◽

Imen Hamdi Nasr ◽

Adnen Amiri ◽

Mohamed Hédi Inoubli

Keyword(s):

Early Cretaceous ◽

Late Cretaceous ◽

Gravity Data ◽

Hydrocarbon Exploration ◽

Passive Margin ◽

Growth Strata ◽

Tectonic Inheritance ◽

Sedimentary Evolution ◽

Structural Style ◽

Half Graben

The Sahel basin in eastern Tunisia has been subject for hydrocarbon exploration since the early fifties. Despite the presence of a working petroleum system in the area, most of the drilled wells were dry or encountered oil shows that failed to give commercial flow rates. A better understanding of the tectono-sedimentary evolution of the Sahel basin is of great importance for future hydrocarbon prospectivity. In this contribution, we present integration of 2D seismic reflection profiles, exploration wells and new acquired gravity data. These subsurface data reveal that the Sahel basin developed as a passive margin during Jurassic-Early Cretaceous times and was later inverted during the Cenozoic Alpine orogeny. The occurrence of Triassic age evaporites and shales deposited during the Pangea breakup played a fundamental role in the structural style and tectono-sedimentary evolution of the study area. Seismic and gravity data revealed jointly important deep-seated extensional faults, almost along E-W and few along NNE&#8211;SSW and NW-SE directions, delimiting horsts and grabens structures. These syn-rift extensional faults controlled deposition, facies distribution and thicknesses of the Jurassic and Early cretaceous series. Most of these inherited deep-seated normal and transform faults are ornamented by different types of salt-related structures. The first phase of salt rising was initiated mainly along these syn-extensional faults in the Late Jurassic forming salt domes and continued into the Early and Late Cretaceous leading to salt-related diapir structures. During this period, the salt diapirism was accompanied by the development of salt withdrawal minibasins, characterized important growth strata due the differential subsidence. These areas represent important immediate kitchen areas to the salt-related structures. The later Late Cretaceous - Cenozoic shortening phases induced preferential rejuvenation of the diapiric structures and led to the inversion of former graben/half-graben structures and ultimately to vertical salt welds along salt ridges. These salt structures represent key elements that remains largely undrilled in the Sahel basin. Our results improve the understanding of salt growth in eastern Tunisia and consequently greatly impact the hydrocarbon prospectivity in the area.

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