PLATE BOUNDARY PROCESSES AND SMALL-SCALE MANTLE CONVECTION BENEATH THE REYKJANES RIDGE

2017 ◽  
Author(s):  
Fernando Martinez ◽  
◽  
Richard Hey
Keyword(s):  
Mantle Convection ◽  
Plate Boundary ◽  
Small Scale ◽  
Reykjanes Ridge

Small-scale mantle convection system and stress field under the Pacific plate

1976 ◽  
Vol 13 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Han-Shou Liu ◽  
Edward S. Chang ◽  
George H. Wyatt
Keyword(s):  
Stress Field ◽  
Mantle Convection ◽  
Pacific Plate ◽  
Small Scale ◽  
The Pacific

The consequences of Canadian Cordillera thermal regime in recent tectonics and elevation: a reviewThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.Geological Survey of Canada Contribution 20090195.

2010 ◽  
Vol 47 (5) ◽  
pp. 621-632 ◽  
Author(s):  
R. D. Hyndman
Keyword(s):  
Thermal Regime ◽  
Upper Mantle ◽  
High Surface ◽  
Plate Boundary ◽  
High Elevation ◽  
Mantle Xenoliths ◽  
Tectonic Activity ◽  
Small Scale ◽  
Canadian Cordillera ◽  
Crust And Upper Mantle

The crust and upper mantle thermal regime of the Canadian Cordillera and its tectonic consequences were an important part of the Cordillera Lithoprobe program and related studies. This article provides a review, first of the thermal constraints, and then of consequences in high surface elevation and current tectonics. Cordillera and adjacent craton temperatures are well constrained by geothermal heat flow, mantle tomography velocities, upper mantle xenoliths, and the effective elastic thickness, Te. Cordillera temperatures are very high and laterally uniform, explained by small scale convection beneath a thin lithosphere, 800–900 °C at the Moho, contrasted to 400–500 °C for the craton. The high temperatures provide an explanation for why the Cordillera has high elevation in spite of a generally thin crust, ∼33 km, in contrast to low elevation and thicker crust, 40–45 km, for the craton. The Cordillera is supported ∼1600 m by lithosphere thermal expansion. In the Cordillera only the upper crust has significant strength; Te ∼ 15 km, in contrast to over 60 km for the craton. The Cordillera is tectonically active because the lithosphere is sufficiently weak to be deformed by plate boundary and gravitational forces; the craton is too strong. The Canadian Cordillera results have led to new understandings of processes in backarcs globally. High backarc temperatures and weak lithospheres explain the tectonic activity over long geological times of mobile belts that make up about 20% of continents. They also have led to a new understanding of collision orogenic heat in terms of incorporation of already hot backarcs.

scholarly journals Stratigraphic and tectonic framework of Late Cretaceous and Paleogene strata of southern Aotea Basin, northwest New Zealand

2021 ◽  
Author(s):  
◽  
Callum Skinner
Keyword(s):  
New Zealand ◽  
Late Cretaceous ◽  
System Analysis ◽  
Plate Boundary ◽  
Petroleum Exploration ◽  
Tectonic Activity ◽  
Small Scale ◽  
Southern Boundary ◽  
Seismic Reflection Data ◽  
Reflection Data

<p>Seismic reflection data reveal thick sediment sequences of Late Cretaceous to Paleogene age in the region northwest of Taranaki Basin. A new stratigraphic framework for latest Cretaceous and Paleogene strata is created based on stacking patterns and stratal termination relationships of seismic reflectors. Sequence-bounding reflectors are tied to petroleum exploration wells, including recently-drilled Romney-1, to assign age and paleoenvironment interpretation. I identify the following sequences: (1) a late Haumurian to Teurian (68 – 56 Ma) aggradational shelf sequence, with at least two regressional events linked to eustatic sea-level falls; (2) a diachronous deepening of the basin that progressed from north to south during the late Waipawan to Heretaungan (53 – 46 Ma); (3) small-scale volcanism at the southern boundary with Taranaki Basin is contemporaneous with this deepening; (4) a prograding delta on Challenger Plateau during the Porangan to Runangan (46 – 35 Ma) that is evidence for tectonic uplift of the basin margins; and (5) an onlapping sequence from latest Runangan to present (35 – 0 Ma) that indicates Challenger Plateau subsided 1,300 m. A revised set of paleogeography maps and generalised stratigraphic chart summarise these observations. The Eocene phase (52-46 Ma) of tectonic subsidence and diffuse volcanism is one of the earliest signs of tectonic activity associated with development of the Cenozoic plate boundary through New Zealand. Petroleum system analysis reveals that southern Aotea Basin is prospective for petroleum exploration, with 3 plays identified in the Late Haumurian to Teurian (79 – 56 Ma) strata, in spite of Romney-1 proving unsuccessful.</p>

Effects of strain weakening in self-consistent models of mantle convection with plate-like behavior and continental drift

2020 ◽  
Author(s):  
Tobias Rolf ◽  
Maëlis Arnould
Keyword(s):  
Mantle Convection ◽  
Previous History ◽  
Plate Boundary ◽  
Continental Drift ◽  
Rheological Parameters ◽  
Plate Boundaries ◽  
The Earth ◽  
Cumulative Strain ◽  
First Results ◽  
Long Time

&lt;p&gt;It is now well-established that the Earth&amp;#8217;s mantle and lithosphere form an integrated, dynamically self-regulating system. Numerical convection models that self-consistently generate plate-like behavior are a powerful tool to investigate this system, but have only recently reached a level at which they can be linked to the geodynamics of the Earth. Strongly temperature-dependent and viscoplastic rheology is known to be a key ingredient for these models to be successful. Such rheologies, however, are typically time-independent and lack a memory on the previous history of deformation. Yet, it is known that the Earth&amp;#8217;s geodynamic evolution is somewhat guided by structures of pre-existing weakness, which was initiated a potentially long time before.&lt;/p&gt;&lt;p&gt;As a step forward we implement a simple form of rheological memory in the mantle convection code &lt;em&gt;StagYY&lt;/em&gt;: strain weakening [&lt;em&gt;Fuchs &amp; Becker, 2019,&lt;/em&gt; &lt;em&gt;Role of strain-dependent weakening memory on the style of mantle convection and plate boundary stability&lt;/em&gt;, &lt;em&gt;Geophys. J. Int., 218, 601-618&lt;/em&gt;]. We present calculations in 2D cases with and without continents, and also selected 3D cases. By varying the governing parameters for plate-like behavior as well as the rates of rheological damage and healing, we examine how strain weakening modifies the generation of plate-like behavior and its time dependence as well as the drift of continents.&lt;/p&gt;&lt;p&gt;First results indicate the importance of the balance of weakening (via the critical strain) and thermal healing. The averaged cumulative strain (effectively the degree of lithospheric weakening) is lower when healing is more effective, so that plastic failure of the lithospheric and the formation of new plate boundaries is complicated, as expected. In initial models with strong, long-living continents, accumulated strain is very small within the continents and seems insufficient to induce substantial weakening, even if the memory on previous deformation is infinite (i.e. no healing with continents). Further models with weaker continents and different rheological parameters will be presented.&lt;/p&gt;

Small-Scale Upper Mantle Convection Beneath the Mongolia-Baikal Rift Zone and Its Geodynamic Significance

2010 ◽  
Vol 53 (4) ◽  
pp. 529-541 ◽  
Author(s):  
Xiong XIONG ◽  
Bin SHAN ◽  
Ji-Ye WANG ◽  
Yong ZHENG
Keyword(s):  
Upper Mantle ◽  
Mantle Convection ◽  
Rift Zone ◽  
Baikal Rift Zone ◽  
Small Scale

scholarly journals Stratigraphic and tectonic framework of Late Cretaceous and Paleogene strata of southern Aotea Basin, northwest New Zealand

2021 ◽  
Author(s):  
◽  
Callum Skinner
Keyword(s):  
New Zealand ◽  
Late Cretaceous ◽  
System Analysis ◽  
Plate Boundary ◽  
Petroleum Exploration ◽  
Tectonic Activity ◽  
Small Scale ◽  
Southern Boundary ◽  
Seismic Reflection Data ◽  
Reflection Data

<p>Seismic reflection data reveal thick sediment sequences of Late Cretaceous to Paleogene age in the region northwest of Taranaki Basin. A new stratigraphic framework for latest Cretaceous and Paleogene strata is created based on stacking patterns and stratal termination relationships of seismic reflectors. Sequence-bounding reflectors are tied to petroleum exploration wells, including recently-drilled Romney-1, to assign age and paleoenvironment interpretation. I identify the following sequences: (1) a late Haumurian to Teurian (68 – 56 Ma) aggradational shelf sequence, with at least two regressional events linked to eustatic sea-level falls; (2) a diachronous deepening of the basin that progressed from north to south during the late Waipawan to Heretaungan (53 – 46 Ma); (3) small-scale volcanism at the southern boundary with Taranaki Basin is contemporaneous with this deepening; (4) a prograding delta on Challenger Plateau during the Porangan to Runangan (46 – 35 Ma) that is evidence for tectonic uplift of the basin margins; and (5) an onlapping sequence from latest Runangan to present (35 – 0 Ma) that indicates Challenger Plateau subsided 1,300 m. A revised set of paleogeography maps and generalised stratigraphic chart summarise these observations. The Eocene phase (52-46 Ma) of tectonic subsidence and diffuse volcanism is one of the earliest signs of tectonic activity associated with development of the Cenozoic plate boundary through New Zealand. Petroleum system analysis reveals that southern Aotea Basin is prospective for petroleum exploration, with 3 plays identified in the Late Haumurian to Teurian (79 – 56 Ma) strata, in spite of Romney-1 proving unsuccessful.</p>

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