Thermal signature of the lithosphere below sedimentary basins in extensional, compressive and transform settings

2020 ◽  
Author(s):  
Magdalena Scheck-Wenderoth ◽  
Judith Bott ◽  
Mauro Cacace ◽  
Denis Anikiev ◽  
Maria Laura Gomez Dacal ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Internal Heat ◽  
Sedimentary Basins ◽  
Rift System ◽  
Upper Rhine Graben ◽  
East African Rift System ◽  
Forming Mechanism ◽  
Passive Margins ◽  
The North ◽  
Thermal Signature

<p>The configuration of the lithosphere below sedimentary basins varies in response to the basin-forming mechanism, the lifetime of the causative stress fields and the lithological heterogeneity inherited from pre-basin tectonic events. Accordingly, the deep thermal configuration is a function of the tectonic setting, the time since the thermal disturbance occurred and the internal heat sources within the lithosphere. We compare deep thermal configurations in different settings based on data-constrained 3D lithosphere-scale thermal models that consider both geological and geophysical observations and physical processes of heat transfer. The results presented come from a varied range of tectonic settings including: (1) the extensional settings of the Upper Rhine Graben and the East African Rift System, where we show that rifts can be hot for different reasons; (2) the North and South Atlantic passive margins, demonstrating that magma-rich passive margins can be comparatively hot or cold depending on the thermo-tectonic age; (3) the Alps, where we find that foreland basins are influenced by the conductive properties and heat-producing units of the adjacent orogen; and (4)the Sea of Marmara, along the westernmost sector of the North Anatolian Fault Zone, that suggest strike-slip basins may be thermally segmented.</p>

scholarly journals 3D reconstruction of syn-tectonic strata in a salt-related orogen: learnings from the Llert syncline (South-central Pyrenees)

2020 ◽  
Vol 18 ◽  
pp. 1-19
Author(s):  
Adrià Ramos ◽  
Berta Lopez-Mir ◽  
Elisabeth P. Wilson ◽  
Pablo Granado ◽  
Josep Anton Muñoz
Keyword(s):  
3D Reconstruction ◽  
Field Research ◽  
Rift System ◽  
Passive Margins ◽  
Fold System ◽  
The North ◽  
Structural Framework ◽  
South Central ◽  
Insight Into ◽  
Central Pyrenees

The Llert syncline is located in the South-central Pyrenees, between the eastern termination of the EW-trending Cotiella Basin and the north-western limb of the NS-trending Turbón-Serrado fold system. The Cotiella Basin is an inverted upper Coniacian-lower Santonian salt-floored post-rift extensional basin developed along the northern Iberian rift system. The Turbón-Serrado fold system consists of upper Santonian – Maastrichtian contractional salt-cored anticlines developed along an inverted transfer zone of the Pyrenean rift system. Based on field research, this paper presents a 3D reconstruction of the Llert syncline in order to further constrain the transition between these oblique salt-related structures. Our results suggest that the evolution of the Llert syncline was mainly controlled by tectonic shortening related to the tectonic inversion of the Cotiella Basin synchronously to the growth of the Turbón-Serrado detachment anticline, and by the pre-compressional structural framework of the Pyrenean rift system. Our contribution provides new insight into the geometric and kinematic relationships of structures developed during the inversion of passive margins involving salt.

scholarly journals Geochemistry of the mudrocks and sandstones from the Bredasdorp Basin, offshore South Africa: Implications for tectonic provenance and paleoweathering

2021 ◽  
Vol 13 (1) ◽  
pp. 1187-1225
Author(s):  
Temitope Love Baiyegunhi ◽  
Kuiwu Liu ◽  
Oswald Gwavava ◽  
Christopher Baiyegunhi ◽  
Maropene Rapholo
Keyword(s):  
South Africa ◽  
Chemical Weathering ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Source Area ◽  
Major And Trace Elements ◽  
Rift System ◽  
Moderate Degree ◽  
East African Rift System ◽  
Major Oxide

Abstract An inorganic geochemical investigation of mudrocks and sandstone from the southern Bredasdorp Basin, off the south coast of South Africa was carried out to unravel the provenance, paleoweathering, and tectonic setting of the basin. Seventy-seven representative samples from exploration wells E-AH1, E-AJ1, E-BA1, E-BB1, and E-D3 underwent geochemical analysis involving major and trace elements. The major oxide compositions show that the sandstones could be classified as sub-arkose and sub-lithic arenite. The provenance discrimination diagrams based on major oxide geochemistry revealed that the sandstones are mainly of quartzose sedimentary provenance, while the mudrocks are of quartzose sedimentary and intermediate igneous provenances. The discrimination diagrams indicate that the Bredasdorp sediments were mostly derived from a cratonic interior or recycled orogen. The bivariate plots of TiO2 versus Ni, TiO2 against Zr, and La/Th versus Hf as well as the ternary diagrams of V–Ni–Th∗10 suggest that the mudrocks and sandstones were derived from felsic igneous rocks. The tectonic setting discrimination diagrams support passive-active continental margin setting of the provenance. Also, the closely similar compositions of the analysed samples and recent sedimentary rocks of the East African Rift System perhaps suggest a rifted basin tectonic setting for the Bredasdorp Basin. Chemical index of alteration (CIA) indices observed in the sandstones suggest that their source area underwent low to moderate degree of chemical weathering. However, the mudrocks have high CIA indices suggesting that the source area underwent more intense chemical weathering, possibly due to climatic and/or tectonic variations.

scholarly journals The Tectonic Evolution of Interior Oman

GeoArabia ◽  
1996 ◽  
Vol 1 (1) ◽  
pp. 28-51 ◽  
Author(s):  
Ramon J.H. Loosveld ◽  
Andy Bell ◽  
Jos J.M. Terken
Keyword(s):  
Sedimentary Basins ◽  
Late Eocene ◽  
Indian Plate ◽  
Arabian Plate ◽  
Time Interval ◽  
Passive Margins ◽  
The North ◽  
Hydrocarbon Traps ◽  
Early Oligocene ◽  
Sea Floor Spreading

ABSTRACT The evolution of Oman’s onshore sedimentary basins from the Late Precambrian to the Present is reflected by six tectono-stratigraphic units. Unit I, the Precambrian basement, represents continental accretion. Units II and III, Infracambrian to Ordovician, may reflect two periods of rifting, possibly related to Najd movements in western Saudi Arabia. The northeast-southwest trending salt basins formed during this time interval. A classical “steer’s head” basin geometry is developed in North Oman, whereas a less complete rift-sag sequence is preserved in South Oman. Of the entire time-span from Late Silurian to Mid-Carboniferous, only little Devonian (Emsian) sediment is preserved. Unit IV, Late Carboniferous to Mid-Cretaceous, reflects the break-up of Gondwana and the creation of the northeastern and southeastern passive margins of the Arabian Plate. Unit V documents intra-plate deformation related to Late Cretaceous continent-ocean obduction in the north and transpressional movements of the Indian Plate in the east. Unit VI, spanning the Tertiary, represents a return to quiet conditions followed by continent-continent collision in the north. Following Late Eocene uplift, the Gulf of Aden rift developed in the south in the early Oligocene, with sea-floor spreading from the Late Miocene onwards. Salt flow and dissolution, both playing a major role in the configuration of most intra- and post-salt hydrocarbon traps in Oman, are episodic and can be related to tectonic events.

Imaging active magmatic systems at Oldoinyo Lengai volcano (Tanzania) via earthquake distribution and seismic scattering and absorption mapping

2020 ◽  
Author(s):  
Miriam Christina Reiss ◽  
Luca De Siena ◽  
Georg Rümpker ◽  
Emmanuel Owden Kazimoto
Keyword(s):  
Detection Threshold ◽  
Seismic Network ◽  
Rift System ◽  
Shield Volcano ◽  
East African Rift System ◽  
Oldoinyo Lengai ◽  
Seismic Scattering ◽  
The North ◽  
Cone Field ◽  
Plumbing Systems

<p>Oldoinyo Lengai volcano, located in the Natron Basin (Tanzania), is the only active natrocarbonatite volcano world-wide. As such, it presents an important endmember magmatic system, which occurs in a young rift segment (~3 Ma) of the East African Rift System. At this volcano, effusive episodes of long-duration are interrupted by short-duration explosive eruptions. At the end of February 2019, we installed a dense seismic network and four infrasound stations as part of the SEISVOL - Seismic and Infrasound Networks to Study the Volcano Oldoinyo Lengai - project. The seismic network spans an area of 30 x 30 km and encompasses Oldoinyo Lengai volcano, the extinct 1 Ma-old Gelai shield volcano, the active Naibor Soito monogenetic cone field and surrounding fault population. Here, we present temporal earthquake distributions combined with 2D absorption and scattering imaging.</p><p>On average, we report up to 34 earthquakes per day within and in the vicinity of our network. Given the dense station spacing, we are able to lower the detection threshold to -1.0 M<sub>L</sub> with a M<sub>C</sub> of -0.3. During the first months of data acquisition, the seismicity is clustered in distinct areas as background seismicity and in intermittent seismic swarms:</p><ol><li>Most of the events are located beneath the eastern and southern flank of Gelai shield volcano. These events are shallow and close to the dike intrusion that preceded the last explosive eruption of Oldoinyo Lengai in 2007-2008.</li> <li>In April 2019, a seismic swarm of ~262 earthquakes in three days forms a pipe-like structure beneath the north western flank of Gelai.</li> <li>Deeper events cluster beneath the monogenetic cone field located just NE of Oldoinyo Lengai. A distinct gap in seismicity can be traced down to 10 km depth between the monogenetic cone field and Gelai volcano.</li> <li>While there seems to be little seismicity directly beneath Oldoinyo Lengai in the upper 5 km of the crust, we observe a number of different, recurring seismic and infrasound signals at the crater, which are indicative of magmatic activity.</li> </ol><p>To image the magmatic plumbing system, we map scattering and absorption of the seismic dataset using the MuRAT (Multi-Resolution Attenuation Tomography) code. Our preliminary results show two well-resolved high-absorption and high-scattering anomalies below Oldoinyo Lengai and the Gelai intrusion in 2007 at all frequencies. With decreasing frequency (increasing depth) the anomalies converge, suggesting a link of the plumbing systems at depth.</p>

Seismic wave attenuation in the lithosphere of the North Tanzanian divergence zone (East African rift system)

2017 ◽  
Vol 58 (2) ◽  
pp. 253-265 ◽  
Author(s):  
A.A. Dobrynina ◽  
J. Albaric ◽  
A. Deschamps ◽  
J. Perrot ◽  
R.W. Ferdinand ◽  
...  
Keyword(s):  
Seismic Wave ◽  
Wave Attenuation ◽  
East African Rift ◽  
Rift System ◽  
East African Rift System ◽  
East African ◽  
Seismic Wave Attenuation ◽  
The North ◽  
African Rift

The North Tanganyika hydrothermal fields, East African Rift system: Their tectonic control and relationship to volcanism and rift segmentation

1994 ◽  
Vol 237 (3-4) ◽  
pp. 155-173 ◽  
Author(s):  
C. Coussement ◽  
P. Gente ◽  
J. Rolet ◽  
J.-J. Tiercelin ◽  
M. Wafula ◽  
...  
Keyword(s):  
East African Rift ◽  
Rift System ◽  
East African Rift System ◽  
East African ◽  
Tectonic Control ◽  
The North ◽  
African Rift ◽  
Hydrothermal Fields

scholarly journals The Crustal Stress Field of Germany - A Refined Prediction

2021 ◽  
Author(s):  
Steffen Ahlers ◽  
Luisa Röckel ◽  
Tobias Hergert ◽  
Karsten Reiter ◽  
Oliver Heidbach ◽  
...  
Keyword(s):  
Stress Field ◽  
Sedimentary Basins ◽  
Horizontal Stress ◽  
Rock Properties ◽  
Upper Rhine Graben ◽  
Calibration Data ◽  
Directional Drilling ◽  
In Situ Data ◽  
The North ◽  
The Absolute

Abstract Information about the absolute stress state in the upper crust plays a crucial role in the planning and execution of e.g., directional drilling, stimulation and exploitation of geothermal and hydrocarbon reservoirs. Since many of these applications are related to sediments, we present a refined geomechanical-numerical model for Germany with focus on sedimentary basins, able to predict the complete 3D stress tensor. The lateral resolution of the model is 2.5 km, the vertical resolution about 250 m. Our model contains 22 units with focus on the sedimentary layers parameterized with individual rock properties. The model results show an overall good fit with magnitude data of the minimum (Shmin) and maximum horizontal stress (SHmax) that are used for the model calibration. The mean of the absolute stress differences between these calibration data and the model results is 4.6 MPa for Shmin and 6.4 MPa for SHmax. In addition, our predicted stress field shows good agreement to several supplementary in situ data from the North German Basin, the Upper Rhine Graben and the Molasse Basin.

Revisiting Hotspots and Continental Breakup – Updating the Classical Three-arm Model

2021 ◽  
Author(s):  
Carol Stein ◽  
Seth Stein ◽  
Molly Gallahue ◽  
Reece Elling
Keyword(s):  
North Atlantic Ocean ◽  
Ocean Basin ◽  
Rift System ◽  
Plate Boundaries ◽  
East African Rift System ◽  
Continental Rifting ◽  
East African ◽  
Continental Breakup ◽  
The North ◽  
Junction Points

<p>In two classic papers, Burke and Dewey (1973) and Dewey and Burke (1974) proposed that continental rifting begins at hotspots - domal uplifts with associated magmatism - from which three rift arms extend. Rift arms from different hotspots link up to form new plate boundaries along which the continent breaks up, generating a new ocean basin and leaving failed arms termed aulacogens within the continent.  In subsequent studies, hotspots became increasingly viewed as manifestations of deeper upwellings or plumes, which were the primary cause of continental rifting. We revisit this conceptual model and find that it remains useful, though some aspects require updates based on subsequent results.  Many three-arm systems identified by Burke and Dewey (1973) are now recognized to be or have been boundaries of transient microplates accommodating motion between diverging major plates. Present-day examples include the East African Rift system and the Sinai microplate.  Older examples include rifts associated with the opening of the South Atlantic in the Mesozoic and the North Atlantic Ocean over the last 200 Ma,  rifts in the southern U.S associated with the breakup of Rodinia, and intracontinental rifts formed within India during the breakup of Gondwanaland. The microplates form as continents break up, and are kinematically distinct from the neighboring plates, in that they move separately. Ultimately, the microplates are incorporated into one of the major plates, leaving identifiable fossil features on land and/or offshore. In many cases the boundaries of microplates during continental breakup are located on preexisting zones of weakness and influenced by pre-existing fabric, including older collisional zones. Hotspots play at most a secondary role in continental breakup, in that most of the associated volcanism reflects plate divergence, so three-arm junction points may not reflect localized upwelling of a deep  mantle plume.</p>

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