scholarly journals Constraining mantle density structure using geological evidence of surface uplift rates: The case of the African Superplume

2000 ◽  
Vol 1 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Michael Gurnis ◽  
Jerry X. Mitrovica ◽  
Jeroen Ritsema ◽  
Hendrik-Jan van Heijst
Keyword(s):  
Density Structure ◽  
Geological Evidence ◽  
Surface Uplift ◽  
Uplift Rates ◽  
African Superplume

scholarly journals Dating and morpho-stratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)

2019 ◽  
Vol 7 (1) ◽  
pp. 321-344 ◽  
Author(s):  
Raphaël Normand ◽  
Guy Simpson ◽  
Frédéric Herman ◽  
Rabiul Haque Biswas ◽  
Abbas Bahroudi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Active Surface ◽  
Optically Stimulated Luminescence ◽  
Uplift Rate ◽  
Makran Subduction Zone ◽  
Megathrust Earthquakes ◽  
Surface Uplift ◽  
Marine Terraces ◽  
Uplift Rates ◽  
East West

Abstract. The western part of the Makran subduction zone (Iran) is currently experiencing active surface uplift, as attested by the presence of emerged marine terraces along the coast. To better understand the uplift recorded by these terraces, we investigated seven localities along the Iranian Makran and we performed radiocarbon, 230Th∕U and optically stimulated luminescence (OSL) dating of the layers of marine sediments deposited on top of the terraces. This enabled us to correlate the terraces regionally and to assign them to different Quaternary sea-level highstands. Our results show east–west variations in surface uplift rates mostly between 0.05 and 1.2 mm yr−1. We detected a region of anomalously high uplift rate, where two MIS 3 terraces are emerged, but we are uncertain how to interpret these results in a geologically coherent context. Although it is presently not clear whether the uplift of the terraces is linked to the occurrence of large megathrust earthquakes, our results highlight rapid surface uplift for a subduction zone context and heterogeneous accumulation of deformation in the overriding plate.

scholarly journals Dating and morphostratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)

2018 ◽  
Author(s):  
Raphaël Normand ◽  
Guy Simpson ◽  
Frédéric Herman ◽  
Rabiul Haque Biswas ◽  
Abbas Bahroudi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Surface Deformation ◽  
Late Quaternary ◽  
Makran Subduction Zone ◽  
Megathrust Earthquakes ◽  
Surface Uplift ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Tectonically Active ◽  
East West

Abstract. The western part of the Makran subduction zone (Iran) has not experienced a great megathrust earthquake in recent human history, yet, the presence of emerged marine terraces along the coast indicates that the margin has been tectonically active during at least the late Quaternary. To better understand the surface deformation of this region, we mapped the terraces sequences of seven localities along the Iranian Makran. Additionnaly, we performed radiocarbon, 230Th/U and optically stimulated luminescence (OSL) dating of the layers of marine sediments deposited on top of the terraces. This enabled us to correlate the terraces regionally and to assign them to different Quaternary sea level highstands. Our results show east-west variations in surface uplift rates mostly between 0.05 and 1.2 mm y−1. We detected a region of anomalously high uplift rate, where two MIS 3 terraces are emerged, yet we are uncertain how to insert these results in a geologically coherent context. Although it is presently not clear whether the uplift of the terraces is linked with the occurrence of large megathrust earthquakes, our results highlight heterogeneous accumulation of deformation in the overriding plate.

scholarly journals Long-term river terrace sequences: Evidence for global increases in surface uplift rates in the Late Pliocene and early Middle Pleistocene caused by flow in the lower continental crust induced by surface processes

2002 ◽  
Vol 81 (3-4) ◽  
pp. 305-328 ◽  
Author(s):  
R. Westaway
Keyword(s):  
Continental Crust ◽  
Middle Pleistocene ◽  
River Terrace ◽  
Late Pliocene ◽  
Sea Level Fluctuations ◽  
Surface Uplift ◽  
Uplift Rates ◽  
Global Increase ◽  
Global Sea Level

AbstractLong-term river terrace sequences reveal that many regions have uplifted by several hundred metres since the Middle Pliocene. They indeed provide evidence of a global increase in uplift rates in die Late Pliocene, followed by a calm period then a renewed increase around the Early-Middle Pleistocene boundary. It is suggested that this uplift pattern has resulted from thickening of the continental crust caused by flow in the lower crust which has been induced by cyclic surface loading caused by growth and decay of ice sheets and the associated global sea-level fluctuations. Observed uplift histories are modelled using a technique which incorporates increases in the strength of forcing of this process caused by step changes in the intensity of glaciations starting at~3.1,~2.5,~1.2, and~0.9 Ma.

scholarly journals The impact of earthquakes on orogen-scale exhumation

2020 ◽  
Vol 8 (3) ◽  
pp. 579-593
Author(s):  
Oliver R. Francis ◽  
Tristram C. Hales ◽  
Daniel E. J. Hobley ◽  
Xuanmei Fan ◽  
Alexander J. Horton ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Large Earthquake ◽  
Mountain Range ◽  
Cosmogenic Radionuclides ◽  
Surface Uplift ◽  
Bedrock Weathering ◽  
Uplift Rates ◽  
Exhumation Rates ◽  
The Impact ◽  
Large Earthquakes

Abstract. Individual, large thrusting earthquakes can cause hundreds to thousands of years of exhumation in a geologically instantaneous moment through landslide generation. The bedrock landslides generated are important weathering agents through the conversion of bedrock into mobile regolith. Despite this, orogen-scale records of surface uplift and exhumation, whether sedimentary or geochemical, contain little to no evidence of individual large earthquakes. We examine how earthquakes and landslides influence exhumation and surface uplift rates with a zero-dimensional numerical model, supported by observations from the 2008 Mw 7.9 Wenchuan earthquake. We also simulate the concentration of cosmogenic radionuclides within the model domain, so we can examine the timescales over which earthquake-driven changes in exhumation can be measured. Our model uses empirically constrained relationships between seismic energy release, weathering, and landsliding volumes to show that large earthquakes generate the most surface uplift, despite causing lowering of the bedrock surface. Our model suggests that when earthquakes are the dominant rock uplift process in an orogen, rapid surface uplift can occur when regolith, which limits bedrock weathering, is preserved on the mountain range. After a large earthquake, there is a lowering in concentrations of 10Be in regolith leaving the orogen, but the concentrations return to the long-term average within 103 years. The timescale of the seismically induced cosmogenic nuclide concentration signal is shorter than the averaging time of most thermochronometers (>103 years). However, our model suggests that the short-term stochastic feedbacks between weathering and exhumation produce measurable increases in cosmogenically measured exhumation rates which can be linked to earthquakes.

scholarly journals Pliocene–Pleistocene sedimentary–tectonic development of the Mesaoria (Mesarya) Basin in an incipient, diachronous collisional setting: facies evidence from the north of Cyprus

2016 ◽  
Vol 155 (5) ◽  
pp. 997-1022 ◽  
Author(s):  
ROMESH N. PALAMAKUMBURA ◽  
ALASTAIR H. F. ROBERTSON
Keyword(s):  
Late Miocene ◽  
Sediment Accumulation ◽  
Early Pleistocene ◽  
The South ◽  
Geological Evidence ◽  
Northern Margin ◽  
The North ◽  
Surface Uplift ◽  
Basin Development ◽  
Multi Stage

AbstractThe Mesaoria (Mesarya) Basin exemplifies multi-stage basin development within a regional setting of diachronous continental collision. The Plio-Pleistocene represented a period of major sediment accumulation between two topographic highs, the Kyrenia Range in the north and the Troodos Massif in the south. During Pliocene time, open-marine marls and chalks of the Nicosia (Lefkoşa) Formation accumulated in a shelf setting. The Early Pleistocene period was characterized by a relative fall in sea level and a change to shallower-water bioclastic deposition of the Athalassa (Gürpınar) Formation. The northern margin of the basin was approximately delineated by the E–W neotectonic Ovgos (Dar Dere) fault zone. A carbonate ramp system formed directly to the south of this structural feature. During Early Pleistocene time, the basin evolved from an open-marine shelf to semi-enclosed lagoons with deltaic deposits, and finally to a non-marine aeolian setting, flanked by the rising Kyrenia Range to the north. Synthesis of geological evidence from the Mesaoria (Mesarya) Basin as a whole, including outcrop and borehole evidence from the south, adjacent to the Troodos Massif, indicates that the Pliocene – Early Pleistocene represented a relatively quiescent period. This intervened between Late Miocene – earliest Pleistocene southward thrusting–folding of the Kyrenia Range and Pleistocene intense surface uplift of both the Kyrenia Range and the Troodos Massif. The basin development reflects flexurally controlled collapse during Late Miocene – earliest Pliocene time related to southward thrusting, followed by strike-slip during westward tectonic escape of Anatolia, and finally regional uplift controlled by under-thrusting of continental crust from the south, as collision progressed.

scholarly journals Quantification of Erosion and Uplift in a Rising Orogen—A Large-Scale Perspective (Late Tortonian to Present): The Case of the Gibraltar Arc, Betic Cordillera, Southern Spain

2020 ◽  
Vol 12 (21) ◽  
pp. 3492
Author(s):  
Javier Elez ◽  
Pablo G. Silva ◽  
Antonio M. Martínez-Graña
Keyword(s):  
Large Scale ◽  
Betic Cordillera ◽  
Mountain Range ◽  
Messinian Salinity Crisis ◽  
Surface Uplift ◽  
Temporal Study ◽  
Uplift Rates ◽  
Elevation Data ◽  
The Difference ◽  
Strong Control

The present study deals with the morphometric quantification of erosion and illustrates the uplift component triggered by denudation (isostasy) in the growth and evolution of a rising orogeny by the application of Airy isostasy concepts. The Gibraltar Arc, located in the Western–Central sector of the Betic Cordillera, developed an exceptional geological scenario during the Messinian Salinity Crisis since the thin emerged fringe of the uprising Cordillera disconnected the Atlantic and Mediterranean basins, generating a relevant misbalance and asymmetry in the fluvial erosion between the two slopes of the emergent orogeny. Our analysis was applied to 50 individual drainage basins (spatial isostatic units) in the Western–Central Betic Cordillera, allowing us to obtain individual and bulk estimates for these isostatic parameters. GIS-based numerical estimations were obtained using LiDAR Digital Elevation Models (DEMs) provided by the Spanish Geographical Institute and reconstructed pre-incision surface models obtained from proxy paleo-elevation data, estimated from stratigraphic and geomorphological littoral to shallow marine markers. The obtained values for geophysical relief, denudation plates, erosion/uplift rates and computed accumulated uplift (245–407 ±20 m) are higher for the ancient Mediterranean slope of the orogen. On the contrary, the Atlantic slope presents an accumulated uplift of only 138–236 ±20 m, indicating the strong control of the ancient Messinian Atlantic–Mediterranean water divide. The temporal study of erosion indicates that most of the difference in uplift in the Mediterranean slope was achieved during or soon after the Messinian Salinity Crisis, resulting in mean uplift rates of 0.21 mm/y, but practically null (0.01 mm/y) for the Atlantic slope. The comparison of the geophysical relief models with proxy paleo-elevation data allowed us to assess the current state of the denudation process in the range. The results indicate that, towards the west of the range denudation compensated elevation, and is actively back-feeding isostatic rebound. Therefore, the contribution of external processes to mountain range elevation through isostasy is quantitatively estimated using elevation data. In this case, a relevant part of the surface uplift (50-55%) is undertaken by the orogen. Ultimately, the Messinian Salinity Crisis-related isostatic response to differential denudation may be behind the quaternary westward tilting of Iberia, causing more than 70% of the Peninsula to drain towards the Atlantic.

Evolution of Orogenic Plateaus at Subduction Zones - Sinking and raising the southern margin of the Central Anatolian Plateau

2018 ◽  
Author(s):  
David Fernández-Blanco
Keyword(s):  
Tectonic Evolution ◽  
Subduction Zones ◽  
Inversion Tectonics ◽  
High Discharge ◽  
Anatolian Plateau ◽  
Surface Uplift ◽  
Southern Margin ◽  
Wide Range ◽  
Forearc Basins ◽  
Orogenic Plateaus

Orogenic plateaus have raised abundant attention amongst geoscientists during the last decades, offering unique opportunities to better understand the relationships between tectonics and climate, and their expression on the Earth’s surface.Orogenic plateau margins are key areas for understanding the mechanisms behind plateau (de)formation. Plateau margins are transitional areas between domains with contrasting relief and characteristics; the roughly flat elevated plateau interior, often with internally drained endorheic basins, and the external steep areas, deeply incised by high-discharge rivers. This thesis uses a wide range of structural and tectonic approaches to investigate the evolution of the southern margin of the Central Anatolian Plateau (CAP), studying an area between the plateau interior and the Cyprus arc. Several findings are presented here that constrain the evolution, timing and possible causes behind the development of this area, and thus that of the CAP. After peneplanation of the regional orogeny, abroad regional subsidence took place in Miocene times in the absence of major extensional faults, which led to the formation of a large basin in the northeast Mediterranean. Late Tortonian and younger contractional structures developed in the interior of the plateau, in its margin and offshore, and forced the inversion tectonics that fragmented the early Miocene basin into the different present-day domains. The tectonic evolution of the southern margin of the CAP can be explained based on the initiation of subduction in south Cyprus and subsequent thermo-mechanical behavior of this subduction zone and the evolving rheology of the Anatolian plate. The Cyprus slab retreat and posterior pull drove subsidence first by relatively minor stretching of the crust and then by its flexure. The growth by accretion and thickening of the upper plate, and that of the associated forearc basins system, caused by accreting sediments, led to rheological changes at the base of the crust that allowed thermal weakening, viscous deformation, driving subsequent surface uplift and raising the modern Taurus Mountains. This mechanism could be responsible for the uplifted plateau-like areas seen in other accretionary margins. ISBN: 978-90-9028673-0

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