scholarly journals The Rosebel gold district (Trans-Amazonian belt, Suriname), a new structural framework

2021 ◽  
Author(s):  
Denis Gapais ◽  
Gilian Alimoenadi ◽  
Nicole Balraadjsing ◽  
Benoît Poupeau
Keyword(s):  
Fault Slip ◽  
Finite Strains ◽  
Continental Lithosphere ◽  
Deformation History ◽  
Complex Deformation ◽  
Crustal Shortening ◽  
Strain Pattern ◽  
Structural Framework

The Rosebel gold district belongs to the Paleoproterozoic Trans-Amazonian belt associated with sub-meridian crustal shortening. Here, we present new structural observations (cleavage, stretching lineations, veins, fault slip data, aeromagnetic maps). Regional cleavages are steeply dipping and bear steeply plunging stretching lineations. Finite strains are of flattening type. Fault slip data reveal a complex deformation history. The overall strain pattern of the reflects vertical motions, a feature consistent with pop-down tectonics involving vertical stretch and burial of supracrustal deposits during horizontal shortening of a hot and weak continental lithosphere.

Structural framework, crustal shortening and Cenozoic exhumation in the eastern Himalaya: A review

2021 ◽  
pp. 103048
Author(s):  
Tapos Kumar Goswami ◽  
Devojit Bezbaruah ◽  
Bashab Nandan Mahanta ◽  
Ranjan Kumar Sarmah
Keyword(s):  
Eastern Himalaya ◽  
Crustal Shortening ◽  
Structural Framework

scholarly journals A multiple-step deformation history of basal ice from the Dye 3 (Greenland) core: new insights from the CO2 and CH4 content

2002 ◽  
Vol 35 ◽  
pp. 231-236 ◽  
Author(s):  
Véronique Verbeke ◽  
Reginald Lorrain ◽  
Sigfús J. Johnsen ◽  
Jean-Louis Tison
Keyword(s):  
Ice Sheet ◽  
Spatial Location ◽  
Deformation History ◽  
Complex Deformation ◽  
High Deformation ◽  
Basal Ice ◽  
History Of ◽  
Straight Lines ◽  
Deformation Layer ◽  
The Relationship

AbstractThe ice depth–age relationship used for the Dye 3 (Greenland) core implies strong deformation of the silty ice present at the bottom. This paper focuses on the study of the relationship between carbon dioxide and methane concentration in the silty ice. In a CO2– CH4 diagram, sample points are well aligned along different straight lines with striking differences in slopes and concentration ranges, depending on their spatial location in the core. These slopes are interpreted as resulting from distinct mixing events between ice-sheet ice flowing from upstream and ice of local origin. Occurrence of these various mixing events suggests a complex deformation history for the basal part of the ice sheet. It involves a progressive build-up of the high-deformation layer along the basal flowline up-glacier from Dye 3, reaching 425 mthickness at the site.

COMPLEX MODIFIED THRUST SYSTEMS ALONG THE SOUTHERN MARGIN OF EAST TIMOR

2005 ◽  
Vol 45 (1) ◽  
pp. 297
Author(s):  
M. Keep ◽  
L. Beck ◽  
P. Bekkers
Keyword(s):  
Regional Scale ◽  
East Timor ◽  
Source Rocks ◽  
Southern Coast ◽  
Deformation History ◽  
Complex Deformation ◽  
Sea Floor ◽  
Oil Seeps ◽  
Structural Levels ◽  
Gas Seeps

Seismic structural interpretation of data across three basins along the southern coast of East Timor (the Suai, Beaco and Aliambata basins) reveals a complex deformation history dominated by intense thrust deformation within the thick (>3 km) Plio-Pleistocene sequence.Our interpreted deformation sequence of the clay-dominated rocks includes a series of south-directed, low-angle thrusts creating extensive thrust piles, and in places, antiformal stacks. These thickened piles exhibit later modification by crestal collapse. Rapid thickening destabilised the growing thrust packages, and caused regional-scale slumping of material into the Timor Trough to the south. The slumping disrupted thrust fronts and caused significant offset at the sea floor. Finally, shale injection and diapirism along the slump faults re-elevated some of the hanging-walls of the slumps.Oil and gas seeps, which occur mainly in southern East Timor, follow structural trends parallel to those offshore. Although sourced from proposed Triassic source rocks, uplift, exposure and subsequent leakage from these seeps probably occurred within the last 2 Ma, and possibly even later, co-eval with Plio-Pleistocene deformation. The proximity of oil seeps to fold and thrust deformation raises the possibility that additional Triassic or other Mesozoic section may occur at various structural levels within the deformed sedimentary wedge.

Tectonic evolution of the seismically active western continental margin of the Indian plate: Implications for kinematic history and fluid flow

2020 ◽  
Author(s):  
Mohamedharoon Shaikh ◽  
Deepak Maurya ◽  
Mukherjee Soumyajit ◽  
Naimisha Vanik ◽  
Abhishek Kumar ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Continental Margin ◽  
Deformation Band ◽  
Fault Slip ◽  
Indian Plate ◽  
Fault System ◽  
Tectonic Activity ◽  
Deformation Bands ◽  
Deformation History ◽  
Kachchh Basin

<p>The deformation history along the E-W trending Kachchh rift basin at the western continental margin of the Indian plate located in the state of Gujarat, India, has been controlled by activation of NW-SE, NE-SW and E-W trending, 0.25–50 km long oblique-slip and dip-slip faults.</p><p>The study is an attempt to establish the kinematic framework along sub-parallel, NW-SE striking group of intra-uplift, striated, high-angle reverse faults, consisting of, Vigodi Fault (VF) and its bifurcation – West Vigodi Fault (WVF), Gugriana Fault (GUF) and its bifurcation – Khirasra fault (KHIF) from the western part of the Kachchh basin in the northern part of Gujarat state in western India. They meet the E-W trending master faults – the Kachchh Mainland Fault (KMF) to the north and the Katrol Hill Fault (KHF) to the south at an acute angle.</p><p>Fault-slip data consisting of fault plane and slickenside attitudes along with other kinematic indicators were recorded along the faults at 69 structural stations. A total of 1258 fault-slip data were used to carry out paleostress analysis using Win-Tensor (v.5.8.8) and T-Tecto Studio X5 by executing the Right Dihedral Method.</p><p>The NW-SE trending fault system exposes highly porous and permeable deformed sandstones belonging to the Jhuran and Bhuj Formation. The pure compaction bands, cataclastic deformation band clusters, slipped deformation bands and deformation band faults are documented. These tabular structures are densely populated in the fault damage zones of VF, WVF, GUF and KHIF. The field observations related to fluid flow conduits are discussed. We also present the field characteristics and petrographic evidences of chemical bleaching caused by fluid-rock interaction found in the Bhuj and the Jhuran sandstones. The change in the coloration pattern of deformation bands in comparison with the host rock color, presence of iron concretions, iron rinds and liesegang rings are important records of the diagenetic control over the fluid flow. The study is an attempt to the link the tectonic activity and simultaneous chemical reactions that affect the fluid flow transport.</p><p>We attribute the deformation history in the western continental margin of the Indian plate has been dominantly controlled by intraplate compressional stresses induced by anticlockwise rotation and collision of the Indian plate with the Eurasian plate at ~55 Ma. This correlates well with the Kachchh basin where rifting aborted during the Late Cretaceous, accommodated syn-rifting extensional component in the intra-uplift VF, GUF and KHIF. It has then undergone inversion phase due to onset of compressive stresses during the Post-Deccan Trap time up to the present. The NW-SE trending intra-uplift faults reactivated multiple times and generated deformation bands having high porosity contrast with the host Bhuj sandstone.</p>

Nonlinear Elastic Deformation of MAX Phases

2010 ◽  
Vol 434-435 ◽  
pp. 149-153 ◽  
Author(s):  
Ai Guo Zhou ◽  
M.W. Barsoum
Keyword(s):  
Elastic Deformation ◽  
Mathematic Model ◽  
Layered Crystal ◽  
Deformation History ◽  
Max Phases ◽  
Complex Deformation ◽  
Mechanical Hysteresis ◽  
Layered Crystal Structure ◽  
Nonlinear Elastic ◽  
Ternary Carbides

MAX phases, include Ti3SiC2, Ti2AlC etc, are machinable ternary carbides or nitrides with excellent properties. These materials, however, have obvious nonlinear elastic deformation due to nano- layered crystal structure. The stress-strain curves of cyclically load-unload test have obvious hysteretic loops. Because of this mechanical hysteresis, the strain of MAX phases at one time is not determined only by the stress applied to the sample at this time. Here the influence of grain size, chemical composition and porosity on the nonlinear elastic strain was introduced. Because of two properties of this hysteresis: wiping out and congruency, the classic hysteretic mathematic model (Preisach-Mayergoyz model, P-M model) can be applied to calculate the strain of MAX phases after any complex deformation history.

scholarly journals Structure and deformation history of Astypalea island, Aegean Sea

2001 ◽  
Vol 34 (1) ◽  
pp. 329 ◽  
Author(s):  
U. RING
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
Aegean Sea ◽  
Structural Data ◽  
Crustal Extension ◽  
High Angle ◽  
Deformation History ◽  
Crustal Shortening ◽  
Tectonic Position ◽  
History Of

Astypalea Island lies south of the Late Cretaceous to Eocene high-pressure belt of the Cyclades and north of the Miocene high-pressure belt of the External Hellenides. The rocks of the island belong to the Tripolitza unit. The latter unit occupies a critical tectonic position in Astypalea between the unmetamorphosed Tripolitza rocks in Crete and the high-pressure Basal unit, which is correlated to the Tripolitza unit, in the Cyclades. We have subdivided the deformation history of Astypalea Island into four events, D; through D4. The problem with interpreting the structural data is that the Di and D2 events cannot unequivocally be ascribed to horizontal crustal contraction or crustal shortening. In our interpretation, Dt caused top-S internal imbrication within the Tripolitza unit as a result of crustal shortening. We envision that this event occurred when the Phyllite-Quartzite and Plattenkalk units were underthrust beneath the Tripolitza unit in the Oligocene. D was probably associated with top-N extension and may be related to large-scale crustal extension across the Cretan detachment in the Early Miocene. D3 caused high-angle faulting due to E-W contraction and D4 was due to N-S extension.

scholarly journals Lattice Preferred Orientation as an Indicator of a Complex Deformation History of Rocks

1999 ◽  
Vol 33 (1-4) ◽  
pp. 45-60 ◽  
Author(s):  
K. Ullemeyer ◽  
K. Weber
Keyword(s):  
Reference Frame ◽  
Preferred Orientation ◽  
Horizontal Shear ◽  
Deformation History ◽  
Deformation Path ◽  
Complex Deformation ◽  
Lattice Preferred Orientation ◽  
Principal Axes ◽  
Shear Component ◽  
History Of

The deconvolution of the deformation history of rocks is one of the main goals of texture analysis in geology. The frequent observation that the macroscopic structures are obliquely oriented with respect to the margins of the deformation zone gave rise to the hypotheses that the deformation path might be complex, and that the lattice preferred orientation of the rock-forming minerals should reflect such complicated deformation conditions as well. Hence, texture determinations of polyphase rock samples were carried out and the relationship of the mineral textures to the commonly used sample reference frame foliation–lineation, which is assumed to represent the principal axes of the bulk finite strain tensor, was investigated. It was confirmed that particular mineral textures are typical for different stages of the deformation path. Especially the quartz textures exhibit an uncommon but consistent deviation from the sample reference frame, which is consistent with respect to the geographical coordinates, too. Such a characteristic may be used to evaluate the direction of a large-scale horizontal shear component, which is known as the transpressive shear vector in the geological literature.

Strain pattern and late Precambrian deformation history in southern Madagascar

2000 ◽  
Vol 102 (1-2) ◽  
pp. 1-20 ◽  
Author(s):  
Jean-Emmanuel Martelat ◽  
Jean-Marc Lardeaux ◽  
Christian Nicollet ◽  
Raymond Rakotondrazafy
Keyword(s):  
Deformation History ◽  
Late Precambrian ◽  
Strain Pattern

Plastic Response of Polycrystalline Metals Subjected to Complex Deformation History

1984 ◽  
Vol 106 (4) ◽  
pp. 299-303 ◽  
Author(s):  
Jan Kratochvil ◽  
Masataka Tokuda
Keyword(s):  
Constitutive Equations ◽  
Bauschinger Effect ◽  
Plastic Response ◽  
Deformation History ◽  
Microscopic Mechanism ◽  
Complex Deformation ◽  
Polycrystalline Metals ◽  
Polycrystal Plasticity ◽  
Basic Features ◽  
Good Agreement

We attempt to formulate the elasto-plastic constitutive equations which reflect the basic features of the microscopic mechanism of plastic deformation and at the same time remains sufficiently simple to be applicable in FEM solution of the practical problems. The constitutive equations are based on a simplified verison of polycrystal plasticity. In modeling of the properties of single crystal grains of the polycrystal attention is paid to active and latent hardenings, and especially to the Bauschinger effect. The stress response along three sets of typical examples of complex deformation histories are predicted and compared with precise data of tension-torsion tests. The predictions are in good agreement with the observed behavior.

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