scholarly journals Contrasting transform and passive margin subsidence history and heat flow evolution: insights from 3D thermo-mechanical modelling

2021 ◽  
pp. SP524-2021-94
Author(s):  
Attila Bálazs ◽  
Taras Gerya ◽  
Dave May ◽  
Gábor Tari
Keyword(s):  
Heat Flow ◽  
Plate Tectonics ◽  
Temporal Dynamics ◽  
Sedimentary Basins ◽  
Passive Margin ◽  
Surface Processes ◽  
Continental Rifting ◽  
Zone Formation ◽  
First Order ◽  
Supplementary Material

AbstractTransform and passive margins developed during the continental rifting and opening of oceanic basins are fundamental elements of plate tectonics. It has been suggested that inherited structures, plate divergence velocities and surface processes exert a first order control on the topographic and bathymetric evolution and thermal history of these margins and related sedimentary basins. Their complex spatial-temporal dynamics have remained controversial. Here, we conducted 3D magmatic-thermo-mechanical numerical experiments coupled with surface processes modelling to simulate the dynamics of continental rifting, continental transform fault zone formation and persistent oceanic transform faulting and zero-offset oceanic fracture zones development. Numerical modelling results allow to explain the first order observations from passive and transform margins, such as diachronous rifting, heat flow rise and cooling in individual depocenters and contrasting basin tectonics of extensional and transtensional origin. In addition, the models reproduce the rise of both marginal ridges and transform marginal plateaus and their interaction with erosion and sedimentation. Comparison of model results with observations from natural examples yield new insights into the tectono-sedimentary and thermal evolution of several key passive and transform continental margins worldwide.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5756555

High heat flow at the SW passive margin of the Gulf of California

Terra Nova ◽  
2021 ◽  
Author(s):  
Rosa Maria Prol‐Ledesma ◽  
Juan Luis Carrillo De La Cruz ◽  
Marco‐Antonio Torres‐Vera ◽  
Alejandro Estradas‐Romero
Keyword(s):  
Heat Flow ◽  
Gulf Of California ◽  
High Heat ◽  
Passive Margin ◽  
High Heat Flow

The Sedimentary Cycle on Early Mars

2019 ◽  
Vol 47 (1) ◽  
pp. 91-118 ◽  
Author(s):  
Scott M. McLennan ◽  
John P. Grotzinger ◽  
Joel A. Hurowitz ◽  
Nicholas J. Tosca
Keyword(s):  
Plate Tectonics ◽  
Sedimentary Rock ◽  
First Order ◽  
Sedimentary Environments ◽  
Source To Sink ◽  
Rock Record ◽  
Mineral Assemblages ◽  
Sedimentary Cycle ◽  
Early Mars ◽  
Over Time

Two decades of intensive research have demonstrated that early Mars ([Formula: see text]2 Gyr) had an active sedimentary cycle, including well-preserved stratigraphic records, understandable within a source-to-sink framework with remarkable fidelity. This early cycle exhibits first-order similarities to (e.g., facies relationships, groundwater diagenesis, recycling) and first-order differences from (e.g., greater aeolian versus subaqueous processes, basaltic versus granitic provenance, absence of plate tectonics) Earth's record. Mars’ sedimentary record preserves evidence for progressive desiccation and oxidation of the surface over time, but simple models for the nature and evolution of paleoenvironments (e.g., acid Mars, early warm and wet versus late cold and dry) have given way to the view that, similar to Earth, different climate regimes on Mars coexisted on regional scales and evolved on variable timescales, and redox chemistry played a pivotal role. A major accomplishment of Mars exploration has been to demonstrate that surface and subsurface sedimentary environments were both habitable and capable of preserving any biological record. ▪ Mars has an ancient sedimentary rock record with many similarities to but also many differences from Earth's sedimentary rock record. ▪ Mars’ ancient sedimentary cycle shows a general evolution toward more desiccated and oxidized surficial conditions. ▪ Climatic regimes of early Mars were relatively clement but with regional variations leading to different sedimentary mineral assemblages. ▪ Surface and subsurface sedimentary environments on early Mars were habitable and capable of preserving any biological record that may have existed.

scholarly journals Transition from continental rifting to oceanic spreading in the northern Red Sea area

2021 ◽  
Author(s):  
Sami El Khrepy ◽  
Ivan Koulakov ◽  
Nassir Al-Arifi ◽  
Mamdouh S. Alajmi ◽  
Ayman N. Qadrouh
Keyword(s):  
Red Sea ◽  
Plate Tectonics ◽  
Continental Rifting ◽  
Low Velocity ◽  
Lower Velocity ◽  
Velocity Anomaly ◽  
Oceanic Spreading ◽  
Lithospheric Extension ◽  
Sea Area ◽  
Northern Red Sea

<p><strong>Lithosphere extension, which plays an essential role in plate tectonics, occurs both in continents (as rift systems) and oceans (spreading along mid-oceanic ridges). The northern Red Sea area is a unique natural geodynamic laboratory, where the ongoing transition from continental rifting to oceanic spreading can be observed. Here, we analyze travel time data from a merged catalogue provided by the Egyptian and Saudi Arabian seismic networks to build a three-dimensional model of seismic velocities in the crust and uppermost mantle beneath the northern Red Sea and surroundings. The derived structures clearly reveal a high-velocity anomaly coinciding with the Red Sea basin and a narrow low-velocity anomaly centered along the rift axis. We interpret these structures as a transition of lithospheric extension from continental rifting to oceanic spreading. The transitional lithosphere is manifested by a dominantly positive seismic anomaly indicating the presence of a 50–70-km-thick and 200–300-km-wide cold lithosphere. Along the forming oceanic ridge axis, an elongated low-velocity anomaly marks a narrow localized nascent spreading zone that disrupts the transitional lithosphere. Along the eastern margins of the Red Sea, the lithosphere is disturbed by the lower-velocity anomalies coinciding with areas of basaltic magmatism.</strong></p>

scholarly journals Geothermal field and geology of the Caspian Sea region

2019 ◽  
pp. 104-118 ◽  
Author(s):  
Vladimir I. Zui ◽  
Siamak Mansouri Far Far
Keyword(s):  
Heat Flow ◽  
Flow Pattern ◽  
Caspian Sea ◽  
Sedimentary Basins ◽  
Geothermal Field ◽  
Flow Density ◽  
General Tendency ◽  
The Caspian Sea ◽  
Northern Iran ◽  
The North

The Caspian Sea and adjacent areas form the vast oil and gas-bearing megabasin. It consists of North Caspian, Middle Caspian, and South Caspian sedimentary basins. The granite-metamorphic basement of the basins becomes from north to south younger in the direction from Early Precambrian to Early Cimmerian age. It represents a transitional zone from the southern edge of the East European Craton to Alpine folding. Geothermal investigations have been carried out both in hundreds of deep boreholes and within the Caspian Sea and a few preliminary heat flow maps were published for the Caspian Sea region. All they excluded from consideration the southern part of the region within Iranian national borders. We prepared a new heat flow map including the northern Iran. The purpose of the article is to consider heat flow pattern within the whole Caspian Sea region including its southern part. Two vast high heat flow anomalies above 100 mW/m2 distinguished in the map: within the southwestern Iran and in waters of the Caspian Sea to the North of the Apsheron Ridge, separated by elongated strip of heat flow below 50 –55 mW/m 2 . A general tendency of heat flow from growing was distinguished from the Precambrian crustal blocks of the North Caspian Depression to the Alpine folding within the territory of Iran. Analysis of the heat flow pattern is discussed and two heat flow density profiles were compiled.

scholarly journals International Heat Flow Commission: History and Accomplishments over the last fifty-five years

2018 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Vladimir Cermak ◽  
Alan Beck ◽  
Valiya Hamza
Keyword(s):  
Heat Flow ◽  
Heat Loss ◽  
Plate Tectonics ◽  
Internal Heat ◽  
Volcanic Eruptions ◽  
Sources And Sinks ◽  
Geologic Materials ◽  
Present Rate ◽  
Internal Constitution ◽  
Global Data

The study of the earth's internal heat plays an important role in understanding the Earth's origin, internal constitution, and plate tectonics. The outflow of heat from the Earth's interior is, energy-wise, the most impressive terrestrial phenomenon. The present rate of heat loss is estimated to be about 1021 joules per year, which is orders of magnitude greater than the energy dissipation of earthquakes or heat loss from volcanic eruptions. Knowledge of terrestrial heat flow is essential in investigating the internal thermal field of the Earth. Initially focus has been on measurements of underground temperatures and thermal properties of geologic materials, assessment of sources and sinks of heat, institution of global data base, development of thermal models of crust and qualification of geothermal energy resources. During later stages, other implications of heat flow studies has also been recognized in fields such as paleoclimatology, global warming, exploration geophysics and hydrogeology. The International Heat Flow Commission – IHFC plays a guiding role in development of such investigations.

scholarly journals Meiofauna in stream habitats: temporal dynamics of abundance, biomass and secondary production in different substrate microhabitats in a first-order stream

2020 ◽  
Vol 54 (4) ◽  
pp. 1079-1095
Author(s):  
Henrike Brüchner-Hüttemann ◽  
Christoph Ptatscheck ◽  
Walter Traunspurger
Keyword(s):  
Density Distribution ◽  
Leaf Litter ◽  
Secondary Production ◽  
Dead Wood ◽  
Temporal Dynamics ◽  
Seasonal Patterns ◽  
Order Stream ◽  
First Order ◽  
Relative Contribution ◽  
Meiofaunal Abundance

Abstract Meiofaunal abundance, biomass and secondary production were investigated over 13 months in an unpolluted first-order stream. Four microhabitats were considered: sediment and the biofilms on dead wood, macrophytes and leaf litter. The relative contribution of the microhabitats to secondary production and the influence of environmental factors on meiofaunal density distribution were estimated. We expected (1) meiofaunal abundance and biomass to exhibit seasonal patterns, with more pronounced seasonal fluctuations on macrophytes and leaf litter than in the other microhabitats, (2) annual secondary production to be highest in sediment; however, the relative contribution of the microhabitats to monthly secondary production would change during the year, and (3) a bottom-up driven influence on meiofaunal density distribution in the microhabitats. Meiofaunal annual mean abundance, biomass and secondary production were 7–14 times higher in sediment and on dead wood than on macrophytes and leaf litter. Significant seasonal patterns described the meiofaunal abundance in sediment and on leaf litter as well as the biomass in sediment, on macrophytes and leaf litter. Organisms in sediment and on dead wood contributed 48 and 43%, respectively, to secondary production m−2, but in regard to the stream area covered by the microhabitats, sediment had the highest share (80%). Significant determinants of the density distribution were AFDM, protozoans, bacteria and Chl-a, which influenced all meiofaunal groups. Our study clearly indicates that meiofaunal organisms in sediment and on dead wood have a remarkable share on total secondary production of lotic systems which is especially relevant for forested low-order streams.

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