DOCSLIB.ORG

Gogus, O.H. and Russell N. Pysklywec, Mantle Lithosphere Delamination Driving Plateau Uplift and Synconvergent Extension In

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gogus, O.H. and Russell N. Pysklywec, Mantle Lithosphere Delamination Driving Plateau Uplift and Synconvergent Extension In Mantle lithosphere delamination driving plateau uplift and synconvergent extension in eastern Anatolia Og˘uz H. Gög˘üs¸*, Russell N. Pysklywec Department of Geology, University of Toronto, Toronto, Ontario M5S 1V6, Canada ABSTRACT delamination-style separation of the mantle Eastern Anatolia is the site of lithospheric thinning, plateau uplift, heating, and synconver- lithosphere from the crust prior to its detach- gent extension. Using numerical geodynamic experiments, we test the hypothesis that these ment beneath the entire plateau. tectonic anomalies are all related and the consequence of delamination of the mantle litho- Alternatively, Ershov and Nikishin (2004) sphere. Our fi ndings indicate that delamination during plate convergence results in ~2-km- proposed a mantle plume scenario for eastern high plateau uplift. The removal of mantle lithosphere induces distinct regions of contraction Anatolia. However, petrological and geophysi- and thickening, as well as extension and thinning of the crust. The latter occurs even within cal evidence, e.g., the migration of the volcanism a regime of plate shortening, although it is muted with increasing plate convergence. Detach- from north to south within the plateau and its ment of the delaminating slab results in minor surface topographic perturbation, but only change in the chemistry (calc-alkaline to alka- above the delamination hinge. The plateau uplift and pattern of surface contraction and/or line) (Keskin, 2003) and seismic tomographic extension are consistent with a topographic profi le at 42°E and geologically interpreted zone interpretations of the detached slab beneath the of synconvergent extension at eastern Anatolia. plateau (Lei and Zhao, 2007), does not favor the viability of a plume model. Keywords: Eastern Anatolian plateau, delamination, lithospheric thinning, synconvergent extension. Here we propose that all the primary tectonic anomalies for Eastern Anatolia plateau uplift INTRODUCTION Anatolia may be related to lithospheric delami- and heating, but also the notable presence of The Eastern Anatolian plateau has formed nation in the manner defi ned by Bird (1979). synconvergent crustal extension, may be related as part of a Himalayan-type orogenic system That is, mantle lithosphere is removed as a as the coupled response of the crust to active through the collision of the Arabian and Eur- coherent slice by peeling away along the crust- underlying mantle dynamics during plate colli- asian plates (Fig. 1A). Based on receiver func- mantle boundary or at the upper margin of the sion. Using computational geodynamic models, tion studies, the crust beneath the plateau is anomalously dense lower crust (Anderson, we test whether the geological and geophysical only 38–50 km thick (Zor et al., 2003); hence 2007). In the light of the observations given observables are consistent with delamination of it has been suggested that the high topography above, a slab break-off model was proposed the mantle lithosphere. Any mantle lithosphere is not isostatically supported by a thick crustal by Şengör et al. (2003) and Keskin (2003). removal in eastern Anatolia progresses within root (Şengör et al., 2003; Keskin, 2003). Fur- These studies suggest that break-off of the a convergent plate regime, so we conduct a thermore, seismic data for eastern Anatolia are northward-subducting oceanic Arabian plate in series of experiments with variable rates of the interpreted as evidence for the complete absence the past 7–8 m.y. has caused domal uplift and imposed convergence of the delaminated slab of the mantle lithosphere beneath the plateau volcanic activity in eastern Anatolia through and with higher yield strength of the mantle (Gok et al., 2007) (Fig. 1B) and are consistent rising mantle. We note that although Şengör lithosphere. The mantle lithosphere is permitted with high heat fl ow and volcanic activity (e.g., et al. (2003) and Keskin (2003) did not use the to detach and we consider how slab break-off Nemrut, Suphan, and Agri-Ararat volcanoes) term delamination, they implicitly assumed a modifi es the surface tectonic expression. across eastern Anatolia. Large-scale plate deformation in the region is dominated by plate convergence with shorten- A ing and contraction, but normal fault–controlled 32°E 36°E 40°E 44°E extensional basins such as the Kagizman- Y Caucasus Tuzluca , Hinis, Karliova, and Mus basins are Black Sea well documented (Dhont and Chorowicz, 2006) NAF within the plateau. Such extensional features, NEAF as well as the presence of the young volcanics, 40°N Figure 1. A: Topographic are notable because their stress orientations are ANATOLIAN PLATE map of eastern Anatolia cre- inconsistent with E-W extensional deforma- EAF ated with generic mapping tion. Rather, the inferred extension seems to be Bitlis-Zagros tools (GMT) showing the oriented ~N25°E. Global positioning system suture zone major tectonic boundaries. B: Lithospheric structure measure ments slightly to the west of this region ARABIAN PLATE beneath eastern Anatolia also indicate local extension, but directed N-NW Mediterranean 36°N modifi ed from S¸engör et al. (Reilinger et al., 2006). Although there is some Sea 4 2 0 –2 (km) (2003), Dhont and Chorowicz Y′ discrepancy in the precise orientations, the geol- (2006), Gok et al. (2007), and ogy and geodesy both suggest extension in the Strike-slip fault EAF = East Anatolian fault Thrust fault Keskin (2003). NAF = North Anatolian fault NEAF = North East Anatolian fault same general direction and contemporaneous B with the dominant plate convergence. N S crust Bitlis-Poturge massif Anderson (2005) suggested that topographic crust crust 0 uplift with widespread volcanism in eastern PML Sublithospheric mantle AML 100 km YYPML = Pontide mantle lithosphere ′ *E-mail: [email protected]. AML = Arabian mantle lithosphere © 2008 The Geological Society of America. For permission to copy, contact Copyright Permissions, GSA, or [email protected]. GEOLOGY,Geology, September September 2008; 2008 v. 36; no. 9; p. 723–726; doi: 10.1130/G24982A.1; 4 fi gures. 723 MODELING DELAMINATION mantle lithosphere to initiate the delamination SURFACE TOPOGRAPHY AND In our numerical experiments, we used a process (e.g., Morency and Doin, 2004). We CRUSTAL DEFORMATION plane strain viscous-plastic fi nite element code, recognize that anomalously dense (e.g., eclogi- At t = 1.2 m.y., negative surface topography SOPALE (Fullsack, 1995; Pysklywec et al., tized) lower crust may also participate in the (~−2.8 km) develops as the crust is pulled down 2002). The confi guration of the model (Fig. 2A) removal. However, the model setup is simplifi ed by the dense delaminating mantle lithosphere is designed as an idealized representation of the by assuming that such crust is already descend- (Fig. 2B). Flanking uplift features arise as a con- continent-continent plate boundary at eastern ing with the mantle lithosphere. sequence of upward return fl ow and replacement Anatolia. We impose a convergence velocity Figure 2A shows the evolution of our refer- of less dense mantle in the mantle lithosphere VAR to the northern edge of the Arabian litho- ence model that may correspond to the evo- gap (Fig. 2A). Crustal contraction, driven by sphere and pin the southern edge of Eurasian lution of the mantle lithosphere in eastern entrainment toward the downgoing mantle litho- lithosphere at VEU = 0 (Fig. 2A). The top of Anatolia, where VAR = 3.0 cm/yr. At time, sphere and the imposed convergence, is subtly the box is a free surface. A viscous fl ow law of t = 1.2 m.y. the mantle lithosphere is delami- visible within the Lagrangian mesh (Fig. 2A). − n ⎛ Q⎞ nating from the crust, exposing a Moho width Note that the negative surface topography is ε=Aσ exp⎜ ⎟ is used for viscous material ⎝ RT ⎠ of ~300 km to the mantle. Subsequently, hot observed at the surface, even though the crust response, where ε is the strain rate, T is tempera- and buoyant sublithospheric mantle fl ows has thickened by ~5 km. ture, and σ is differential stress. A, n, Q, and R into the region vacated by the peeling mantle At t = 2.9 m.y., positive surface topography are the viscosity parameter, power law expo- lithosphere. The rapid nature of the delamina- dominates with a peak near the delaminating gap nent, activation energy, and ideal gas constant, tion means that the high mantle temperatures where upwelling fl ow is most vigorous. Inspec- respectively. For mantle A = 4.89 × 10−17 Pa–3.5/s, are effi ciently advected upward, heating the tion of the Lagrangian mesh elements also shows n = 3.5, Q = 535 kJ/mol (Hirth and Kohlstedt, lower crust (Gogus and Pysklywec, 2008). that there is localized crustal contraction, with 1996), and a Coulomb yield stress of 120 MPa are The delaminated mantle lithosphere is bent ~12.5 km crustal thickening and as much as 30% used. For continental crust A = 1.1 × 10−28 Pa–4/s, steeply into the mantle but remains intact shortening near the hinge (Figs. 2A and 2B). n = 4, and Q = 223 kJ/mol are used based on as a coherent plate, i.e., as opposed to a vis- At the center of the lithospheric gap, crustal wet quartzite (Gleason and Tullis, 1995). In cous dripping-type removal. Between 2.9 and extension of ~30% and thinning of as much as addition, the upper crust has a brittle Coulomb 7.0 m.y., there is detachment and/or break-off several kilometers are observed (Fig. 2A). This behavior with an internal angle of friction of this mantle lithosphere slab. At the latest extension and thinning are notable as internally φ = 15°. Density, ρ, is a function of composition stage shown (t = 7.0 m.y.), the Eurasian mantle driven tectonic processes within the overall con- and temperature (using α = 2 × 10−5 1/K). lithosphere on the left side undergoes a much vergent plate regime.
Load more

Recommended publications
  • Different Causes of the Delamination on the Example of Caucasus and Kyrgyz Tien Shan Collision Zones
    EGU2020-6412 https://doi.org/10.5194/egusphere-egu2020-6412 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Different causes of the delamination on the example of Caucasus and Kyrgyz Tien Shan collision zones. Irina Medved1,2,3, Ivan Koulakov2,3, and Mikhail Buslov1 1IGM SB RAS, Novosibirsk, Russian Federation ([email protected]) 2IPGG SB RAS, Novosibirsk, Russian Federation 3Novosibirsk State University, Novosibirsk, Russian Federation The causes of delamination of the mantle lithosphere in collision zones is actively debated in the scientific community. The main discussions are focused on the initiation of sinking of the continental lithosphere into the asthenosphere to a depth. Most scientists believe that such kind of immersion is impossible. However, there are several articles showing that this process is nonetheless taking place. For example Kay and Kay, (1993), Faccenda, Minelli, Gerya, (2009), Ueda et. al., (2012) and others propose various mechanisms of delamination, for example: eclogitization of the mafic layer of the lower crust, the effect of convection in the upper mantle, or gradual transition of the oceanic subduction into continental collision. Does the mantle part of the lithosphere sink into the mantle or spread laterally, as described in [for example, Deep Geodynamics, 2001; Bird, 1991; Schmeling and Marquart, 1991]? To answer these questions, we study deep structures beneath the Caucasus and Kyrgyz Tien Shan collision zones. The studies were carried out on the basis of multiscale seismic tomography methods: regional and global. This approach made it possible to study heterogeneities both in the crust and in the upper mantle.
    [Show full text]
  • Post-Collisional Mantle Delamination in the Dinarides Implied
    www.nature.com/scientificreports OPEN Post‑collisional mantle delamination in the Dinarides implied from staircases of Oligo‑Miocene uplifted marine terraces Philipp Balling1*, Christoph Grützner1, Bruno Tomljenović2, Wim Spakman3 & Kamil Ustaszewski1 The Dinarides fold‑thrust belt on the Balkan Peninsula resulted from convergence between the Adriatic and Eurasian plates since Mid‑Jurassic times. Under the Dinarides, S‑wave receiver functions, P‑wave tomographic models, and shear‑wave splitting data show anomalously thin lithosphere overlying a short down‑fexed slab geometry. This geometry suggests a delamination of Adriatic lithosphere. Here, we link the evolution of this continental convergence system to hitherto unreported sets of extensively uplifted Oligocene–Miocene (28–17 Ma) marine terraces preserved at elevations of up to 600 m along the Dinaric coastal range. River incision on either side of the Mediterranean‑Black Sea drainage divide is comparable to the amounts of terrace uplift. The preservation of the uplifted terraces implies that the most External Dinarides did not experience substantial deformation other than surface uplift in the Neogene. These observations and the contemporaneous emplacement of igneous rocks (33–22 Ma) in the internal Dinarides suggest that the Oligo‑Miocene orogen‑wide uplift was driven by post‑break‑of delamination of the Adriatic lithospheric mantle, this was followed by isostatic readjustment of the remaining crust. Our study details how lithospheric delamination exerts an important control on crustal deformation and that its crustal signature and geomorphic imprint can be preserved for millions of years. Te infuence of deep-seated processes on deformation patterns and rates in collisional orogens is unequivo- cally accepted, yet challenging to quantify.
    [Show full text]
  • The Plate Theory for Volcanism
    This article was originally published in Encyclopedia of Geology, second edition published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author’s institution, for non-commercial research and educational use, including without limitation, use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation, commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: https://www.elsevier.com/about/policies/copyright/permissions Foulger Gillian R. (2021) The Plate Theory for Volcanism. In: Alderton, David; Elias, Scott A. (eds.) Encyclopedia of Geology, 2nd edition. vol. 3, pp. 879-890. United Kingdom: Academic Press. dx.doi.org/10.1016/B978-0-08-102908-4.00105-3 © 2021 Elsevier Ltd. All rights reserved. Author's personal copy The Plate Theory for Volcanism Gillian R Foulger, Department of Earth Sciences, Science Laboratories, Durham University, Durham, United Kingdom © 2021 Elsevier Ltd. All rights reserved. Statement of Plate Theory 879 Background, History, Development and Discussion 879 Lithospheric Extension 880 Melt in the Mantle 881 Studying Intraplate Volcanism 882 Examples 883 Iceland 883 Yellowstone 885 The Hawaii and Emperor Volcano Chains 886 Discussion 888 Summary 888 References 888 Further Reading 889 Statement of Plate Theory The Plate Theory for volcanism proposes that all terrestrially driven volcanism on Earth’s surface, including at unusual areas such as Iceland, Yellowstone and Hawaii, is a consequence of plate tectonics.
    [Show full text]
  • Suzanne Y. O'reilly, GEMOC National
    controversy over the physical nature of the lithosphere and asthenosphere and the boundary zone between them. The subcontinental lithospheric mantle is isolated from the convecting mantle and thus tends to resist homogenization over time. At the lithosphere-asthenosphere boundary, the temperatures of the lithosphere and the uppermost asthenosphere coincide, and the greater buoyancy and viscosity of the lithosphere are important in maintaining its mechanical integrity. Suzanne Y. O’Reilly, GEMOC National mantle roots are highly buoyant; they This emphasizes a thermal and Key Centre, Department of Earth cannot be delaminated but require rheological distinction between and Planetary Sciences, Macquarie mechanical disaggregation (lithospheric lithosphere and asthenosphere that also University, Sydney, NSW 2109, Australia thinning and/or rifting) and infiltration coincides well with seismic observations of upwelling fertile material to be and with the geochemical signatures William L. Griffin, GEMOC National Key destroyed or transformed. In contrast, that are used in this paper to help define Centre, Department of Earth and Phanerozoic subcontinental lithospheric the location and character of the Planetary Sciences, Macquarie mantle is denser than the asthenosphere lithosphere-asthenosphere boundary. University, Sydney, NSW 2109, Australia, for observed thicknesses (~100 km) and Four-dimensional lithosphere and CSIRO Exploration and Mining, can “delaminate” under stress. The mapping is a methodology that P.O. Box 136, North Ryde, NSW 1670, contrasting properties of different integrates petrological, geochemical, Australia mantle domains require lateral contrasts geophysical, and tectonic information to in composition, density, thickness, and map the composition of the sub- Yvette H. Poudjom Djomani, GEMOC seismic response in the present-day continental lithospheric mantle (Fig.
    [Show full text]
  • Modelling Delamination As a Process of Lithosphere Thinning Determined by Magnetotelluric Measurements
    28. Schmucker-Weidelt-Kolloquium Haltern am See, 23.–27. September 2019 WWU MÜNSTER Modelling delamination as a process of lithosphere thinning determined by magnetotelluric measurements Fabian Becker, Claudia Stein, Matthew J. Comeau, Michael Becken, Ulrich Hansen Institut für Geophysik, WWU Münster Motivation Results The aim of this work is to develop a The temporal evolution of the model shows the lithosphere thinning as a cause of delamination. The process starts with the geodynamic model of our measured area whole block moving downwards and thickening (Fig. 4 b). If the block becomes gravitationally unstable, the lower part of the in Mongolia [1] using the knowledge from dense material sinks into the mantle (c-d). Finally, the whole block is removed leaving a thinned lithosphere (e). The resistivity our magnetotelluric model and other model and these geodynamic models are comparable: both show the thinned lithosphere and a bulged asthenosphere with an fields, such as geology. In this geodynam- elevated temperature. ically active region, where we observe volcanism and uplift, a thin lithosphere is determined by the magnetotelluric data. One possible process for lithosphere thinning is delamination, which is coupled to convective processes. It has been shown that features in magnetotelluric data can be linked to viscosity structures [2], and these can be investigated with geodynamic models. The combination of magnetotellurics and geodynamics is a new approach which we use to bring further insights into the geological history of Mongolia. Figure 1: The map shows the study area with topography. The circles are magne- totelluric stations between the endpoints of the profile A and A’.
    [Show full text]
  • Piecewise Delamination of Moroccan Lithosphere from Beneath the Atlas
    PUBLICATIONS Geochemistry, Geophysics, Geosystems RESEARCH ARTICLE Piecewise delamination of Moroccan lithosphere 10.1002/2013GC005059 from beneath the Atlas Mountains Key Points: M. J. Bezada1, E. D. Humphreys1, J.M. Davila2, R. Carbonell3, M. Harnafi4, We image lithospheric cavities I. Palomeras5, and A. Levander5 beneath the Middle Atlas and central HighAtlas 1Department of Geological Sciences, University of Oregon, Eugene, Oregon, USA, 2Real Instituto y Observatorio de la We image the delaminated 3 4 lithosphere of the Middle Atlas at Armada, San Fernando, Spain, CSIC––Institute of Earth Sciences ‘‘Jaume Almera,’’, Barcelona, Spain, Institut Scientifique, 5 400 km depth Universite Mohammed V Agdal, Rabat, Morocco, Department of Earth Science, Rice University, Houston, Texas, USA We propose piecewise delamination of Atlas lithosphere Abstract The elevation of the intracontinental Atlas Mountains of Morocco and surrounding regions Supporting Information: requires a mantle component of buoyancy, and there is consensus that this buoyancy results from an Supplementary Information Text abnormally thin lithosphere. Lithospheric delamination under the Atlas Mountains and thermal erosion caused by upwelling mantle have each been suggested as thinning mechanisms. We use seismic tomogra- Correspondence to: phy to image the upper mantle of Morocco. Our imaging resolves the location and shape of lithospheric M. J. Bezada, [email protected] cavities and of delaminated lithosphere 400 km beneath the Middle Atlas. We propose discontinuous delamination of an intrinsically unstable Atlas lithosphere, enabled by the presence of anomalously hot Citation: mantle, as a mechanism for producing the imaged structures. The Atlas lithosphere was made unstable by a Bezada, M. J., E. D. Humphreys, J.M. combination of tectonic shortening and eclogite loading during Mesozoic rifting and Cenozoic magmatism.
    [Show full text]
  • Evolution of Cratonic Lithosphere After a Rapid Keel Delamination Event
    Journal of Geophysical Research: Solid Earth RESEARCH ARTICLE Craton Destruction 2: Evolution of Cratonic Lithosphere After a 10.1029/2017JB015374 Rapid Keel Delamination Event Special Section: Liang Liu1,2,3 , Jason P. Morgan2,4, Yigang Xu1 , and Martin Menzies1,2 Magnetism in the Geosciences - Advances and Perspectives 1Department of Earth Sciences, Royal Holloway University of London, Egham, UK, 2State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China, 3College of Earth 4 This article is a companion to Liu et al. Sciences, University of Chinese Academy of Sciences, Beijing, China, Department of Earth and Planetary Sciences, Harvard (2018), https://doi.org/10.1029/ University, Cambridge, MA, USA 2017JB015372. Abstract Cratonic lithosphere beneath the eastern North China Craton has undergone extensive Key Points: • Keel delamination followed by destruction since early Jurassic times (approximately 190 Ma). This is recorded in its episodic tectonic and convective erosion and lithospheric magmatic history. In this time, its lithosphere changed thickness from approximately 200 km to <60 km. This extension can explain the change was associated with a peak time (approximately 120 Ma) of lithospheric thinning and magmatism destruction of the eastern North fl China Craton that was linked with high surface heat ow recorded in rift basins. We believe that these records are best • Reactivation of an enriched mantle explained by a two-stage evolutionary process. First, approximately
    [Show full text]
  • The Controversy Over Plumes: Who Is Actually Right? V
    ISSN 0016-8521, Geotectonics, 2009, Vol. 43, No. 1, pp. 1–17. © Pleiades Publishing, Inc., 2009. Original Russian Text © V.N. Puchkov, 2009, published in Geotektonika, 2009, No. 1, pp. 3–22. The Controversy over Plumes: Who Is Actually Right? V. N. Puchkov Institute of Geology, Ufa Scientific Center, Russian Academy of Sciences, ul. K. Marksa 16/2, Ufa, 450000, Russia e-mail: [email protected] Received February 5, 2008 Abstract—The current state of the theory of mantle plumes and its relation to classic plate tectonics show that the “plume” line of geodynamic research is in a period of serious crisis. The number of publications criticizing this concept is steadily increasing. The initial suggestions of plumes' advocates are disputed, and not without grounds. Questions have been raised as to whether all plumes are derived from the mantle–core interface; whether they all have a wide head and a narrow tail; whether they are always accompanied by uplifting of the Earth’s surface; and whether they can be reliably identified by geochemical signatures, e.g., by the helium-iso- tope ratio. Rather convincing evidence indicates that plumes cannot be regarded as a strictly fixed reference frame for moving lithospheric plates. More generally, the very existence of plumes has become the subject of debate. Alternative ideas contend that all plumes, or hot spots, are directly related to plate-tectonic mechanisms and appear as a result of shallow tectonic stress, subsequent decompression, and melting of the mantle enriched in basaltic material. Attempts have been made to explain the regular variation in age of volcanoes in ocean ridges by the crack propagation mechanism or by drift of melted segregations of enriched mantle in a nearly horizontal asthenospheric flow.
    [Show full text]
  • Melt-Induced Buoyancy May Explain the Elevated Rift-Rapid Sag Paradox
    www.nature.com/scientificreports OPEN Melt-induced buoyancy may explain the elevated rift-rapid sag paradox during breakup of Received: 26 January 2018 Accepted: 12 June 2018 continental plates Published: xx xx xxxx David G. Quirk 1 & Lars H. Rüpke 2 The division of the earth’s surface into continents and oceans is a consequence of plate tectonics but a geological paradox exists at continent-ocean boundaries. Continental plate is thicker and lighter than oceanic plate, foating higher on the mantle asthenosphere, but it can rift apart by thinning and heating to form new oceans. In theory, continental plate subsides in proportion to the amount it is thinned and subsequently by the rate it cools down. However, seismic and borehole data from continental margins like the Atlantic show that the upper surface of many plates remains close to sea-level during rifting, inconsistent with its thickness, and subsides after breakup more rapidly than cooling predicts. Here we use numerical models to investigate the origin and nature of this puzzling behaviour with data from the Kwanza Basin, ofshore Angola. We explore an idea where the continental plate is made increasingly buoyant during rifting by melt produced and trapped in the asthenosphere. Using fnite element simulation, we demonstrate that partially molten asthenosphere combined with other mantle processes can counteract the subsidence efect of thinning plate, keeping it elevated by 2-3 km until breakup. Rapid subsidence occurs after breakup when melt is lost to the embryonic ocean ridge. Te aim of this paper is to test the geological causes of problematic subsidence patterns at the margins of ocean basins.
    [Show full text]
  • Change Moho in Stabilization and Preservation of the Southern Uralide Orogen, Russia Camelia C
    University of South Carolina Scholar Commons Faculty Publications Earth, Ocean and Environment, School of the 2002 Role of a Phase: Change Moho in Stabilization and Preservation of the Southern Uralide Orogen, Russia Camelia C. Diaconescu University of South Carolina - Columbia, [email protected] James H. Knapp University of South Carolina - Columbia, [email protected] Follow this and additional works at: https://scholarcommons.sc.edu/geol_facpub Part of the Earth Sciences Commons Publication Info Published in AGU Monograph Series, ed. D. Brown, C. Juhlin, & V. Puchkov, Volume 132, 2002, pages 67-82. Diaconescu, C. C. & Knapp, J. H. (2002). Role of a phase: Change Moho in stabilization and preservation of the southern Uralide Orogen, Russia. AGU Monograph Series, 132, 67-82. ©AGU Monograph Series 2002, American Geophysical Union This Article is brought to you by the Earth, Ocean and Environment, School of the at Scholar Commons. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Role of a Phase: Change Moho in Stabilization and Preservation of the Southern Uralide Orogen, Russia 1 Camelia C. Diaconescu ,2,3 and James H. Knappl,2 1University of South Carolina, South Carolina, USA 2Cornell University, Ithaca, New York, USA 3Nationallnstitute for Earth Physics, Bucharest-Magurele, Romania Geophysical (URSEIS experiment) and geological data from the South­ ern Uralides of central Russia provide the basis for a geodynamic model involving eclogitization of the Uralian crustal root in Late Triassic to Early Jurassic time as a mechanism for stabilization and preservation of this Paleozoic orogen.
    [Show full text]
  • The Role of Lithospheric Delamination and Ice-Driven Rockfall
    THE ROLE OF LITHOSPHERIC DELAMINATION AND ICE-DRIVEN ROCKFALL EROSION IN THE EVOLUTION OF MOUNTAINOUS LANDSCAPES by TRISTRAM CHARLES HALES A DISSERTATION Presented to the Department of Geological Sciences and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2006 ii “The Role of Lithospheric Delamination and Ice-Driven Rockfall Erosion in the Evolution of Mountainous Landscapes,” a dissertation prepared by Tristram Charles Hales in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Geological Sciences. This dissertation has been approved and accepted by: ____________________________________________________________ Joshua J. Roering, Chair of the Examining Committee ________________________________________ Date Committee in Charge: Joshua J. Roering, Chair Eugene D. Humpherys Ray J. Weldon II W. Andrew Marcus Accepted by: ____________________________________________________________ Dean of the Graduate School iii © 2006 Tristram Charles Hales iv An Abstract of the Dissertation of Tristram Charles Hales for the degree of Doctor of Philosophy in the Department of Geological Sciences to be taken December 2006 Title: THE ROLE OF LITHOSPHERIC DELAMINATION AND ICE-DRIVEN ROCKFALL EROSION IN THE EVOLUTION OF MOUNTAINOUS LANDSCAPES Approved: _______________________________________________ Joshua J. Roering This dissertation discusses the evolution of mountains, particularly the interaction between uplift, which is controlled by horizontally-directed plate tectonic and vertically- directed isostatic forces, and erosion, which encompasses glacial, periglacial, fluvial and hillslope processes. Eruption of the Columbia River Basalts (CRB) in northeastern Oregon is coincident with rapid uplift of the Wallowa Mountains. I mapped the modern distribution of CRB flows to quantify the amount of post-eruptive uplift in northeastern Oregon, which creates a broad “bull’s eye” pattern centered on a large granitic pluton.
    [Show full text]
  • The Origin of Intraplate Volcanism on the New Zealand Micro- Continent Zealandia
    The Origin of Intraplate Volcanism on the New Zealand micro- continent Zealandia Dissertation zur Erlangung des Doktorgrades an der Mathematischen-Naturwissenschaftlichen Fakultät der Christian-Albrechts-Universität zu Kiel vorgelegt von Christian Timm Kiel 2008 Hiermit erkläre ich, dass ich die vorliegende Doktorarbeit selbständig und ohne unerlaubte Hilfen erstellt habe. Ferner habe ich weder diese noch eine ähnliche Arbeit an einer anderen Abteilung oder Hochschule im Rahmen eines Prüfungsverfahrens vorgelegt, veröffentlicht oder zur Veröffentlichung vorgelegt. …………………………….. Christian Timm Referent/in…………………………………………………Prof. Dr. Kaj Hoernle, Ph.D. Koreferent/in………………………………………………Prof. Dr. Colin Devey Tag der mündlichen Prüfung………………………………04.07.2008 Zum Druck genehmigt: Kiel, ………………………………………………………… Prof. Dr. J. Grotemeyer (Dekan) Kurzfassung Der Ursprung von Intraplatten-Vulkanismus wird hauptsächlich mittels einer stationären thermalen Anomalie unterhalb der Lithosphäre (Mantel Plume), oder durch kontinentales „Rifting“ erklärt. Diese beiden Prozesse sind oftmals mit voluminösem Vulkanismus assoziiert. Der langlebige und diffus auftretende Vulkanismus auf dem Neuseeländischen Mikro-Kontinent, Zealandia, hingegen kann nicht durch diese Theorien erklärt werden und wird in dieser Dissertation genauer untersucht. Bis in die mittlere Kreidezeit (~ 100 Mio. Jahre) stellte Zealandia einen Teil im NW des ehemaligen Superkontinents Gondwana dar und lag über einer aktiven Subduktionszone. Subduktionbezogener Vulkanismus endete allerdings zwischen
    [Show full text]