Internal lithospheric rotation at the initiation of intra-oceanic rift-drift: An example of proto-transform tectonics from the Vourinos Ophiolite, Greece

2021 ◽  
Author(s):  
Anne Ewing Rassios ◽  
Dina Ghikas ◽  
Anna Batsi ◽  
Petros Koutsovitis ◽  
Evangelos Tzamos ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Oceanic Lithosphere ◽  
Ductile Deformation ◽  
New Paradigm ◽  
Crustal Rocks ◽  
Mantle Boundary ◽  
Ridge Crest ◽  
Transition Area ◽  
The 1960S

ABSTRACT The “petrological Moho” recognized in the Jurassic Vourinos Ophiolite (northern Greece) was the first “crust-mantle” boundary described within a fossil oceanic lithosphere. Early observations suggested a Cenozoic brittle-field block rotation of the petrological Moho transition area resulting in an oblique clockwise rotation of ∼100°, but a brittle fault system responsible for the mechanism of this rotation was never located. A modern interpretation of research dating from the 1960s to the present documents the occurrence of a diverse set of ductile structures overprinting this primary intra-oceanic feature. The following observations from our original “Moho” studies in the Vourinos complex are still pertinent: the contact between the upper mantle units and the magmatic crustal sequence is in situ and intrusional in nature; high-temperature intragranular ductile deformation (mantle creep at temperatures from around 1200 °C down to ∼900 °C) fabrics terminate at the crust-mantle boundary; the overlying oceanic crustal rocks display geochemical fractionation patterns analogous to crustal rocks in the in situ oceanic lithosphere. Since these original studies, however, understanding the mechanisms of ductile deformation and ridge crest processes have advanced, and hence we can now interpret the older data and recent observations in a new paradigm of oceanic lithosphere formation. Our major interpretational breakthrough includes the following phenomena: lower temperature, intergranular deformation of ∼900 °C to 700 °C extends from the upper mantle tectonites up into the lower crustal cumulate section; the origin of mineral lineations within adcumulate crustal rocks as remnants of ductile deformation during early phases of magmatic crystallization; syn-magmatic folding and rotation of the cumulate section; the tectonic significance of flaser gabbro and late gabbroic intrusions in the crustal sequence; and the relevance and significance of a cumulate troctolite unit within the crustal sequence. These observations collectively point to an important process of a ductile-field, syn-magmatic rotation of the Moho transition area. The most plausible mechanism explaining such a rotation is proto-transform faulting deformation near the ridge crest. By recognizing and distinguishing structures that resulted from such initial rotational deformation in the upper mantle peridotites of ophiolites, future field-based structural, petrographic, and petrological studies can better document the mode of the initiation of oceanic transform faults.

Aqueous Dispersion Polymerization: A New Paradigm for in Situ Block Copolymer Self-Assembly in Concentrated Solution

2011 ◽  
Vol 133 (39) ◽  
pp. 15707-15713 ◽  
Author(s):  
Shinji Sugihara ◽  
Adam Blanazs ◽  
Steven P. Armes ◽  
Anthony J. Ryan ◽  
Andrew L. Lewis
Keyword(s):  
Block Copolymer ◽  
Self Assembly ◽  
Dispersion Polymerization ◽  
Aqueous Dispersion ◽  
New Paradigm ◽  
Concentrated Solution

scholarly journals Distributed Immersive Participation as Crowd-Sensing in Culture Events

2014 ◽  
Vol 7 (2) ◽  
Author(s):  
Theo Kanter ◽  
Rahim Rahmani ◽  
Jamie Walters ◽  
Willmar Sauter
Keyword(s):  
Internet Of Things ◽  
Distributed Computing ◽  
Real Time ◽  
Social Innovation ◽  
The Internet ◽  
New Paradigm ◽  
Content Creation ◽  
Crowd Sensing ◽  
Information Objects

This article investigates new forms for creating and enabling massive and scalable participatory immersive experiences in live cultural events, characterized by processes, involving pervasive objects, places and people. The multi-disciplinary research outlines a new paradigm for collaborative creation and participation towards technological and social innovation, tapping into crowd-sensing. The approach promotes user-driven content-creation and offsets economic models thereby rewarding creators and performers. In response to these challenges, we propose a framework for bringing about massive and real-time presence and awareness on the Internet through an Internet-of-Things infrastructure to connect artifacts, performers, participants and places. Equally importantly, we enable the in-situ creation of collaborative experiences building on relevant existing and stored content, based on decisions leveraging multi-criteria clustering and proximity of pervasive information, objects, people and places. Finally, we investigate some new ways for immersive experiences via distributed computing but pointing forward to the necessity to do more with regard to collaborative creation.

Ultramafic mantle xenoliths in the Late Cenozoic Volcanic rocks of the Antarctic Peninsula and Jones Mountains, West Antarctica

2021 ◽  
pp. M56-2019-44
Author(s):  
Philip T. Leat ◽  
Aidan J. Ross ◽  
Sally A. Gibson
Keyword(s):  
Antarctic Peninsula ◽  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Incompatible Trace Element ◽  
Mantle Xenoliths ◽  
South Shetland Islands ◽  
West Antarctica ◽  
Gondwana Margin

AbstractAbundant mantle-derived ultramafic xenoliths occur in Cenozoic (7.7-1.5 Ma) mafic alkaline volcanic rocks along the former active margin of West Antarctica, that extends from the northern Antarctic Peninsula to Jones Mountains. The xenoliths are restricted to post-subduction volcanic rocks that were emplaced in fore-arc or back-arc positions relative to the Mesozoic-Cenozoic Antarctic Peninsula volcanic arc. The xenoliths are spinel-bearing, include harzburgites, lherzolites, wehrlites and pyroxenites, and provide the only direct evidence of the composition of the lithospheric mantle underlying most of the margin. The harzburgites may be residues of melt extraction from the upper mantle (in a mid-ocean ridge type setting), that accreted to form oceanic lithosphere, which was then subsequently tectonically emplaced along the active Gondwana margin. An exposed highly-depleted dunite-serpentinite upper mantle complex on Gibbs Island, South Shetland Islands, supports this interpretation. In contrast, pyroxenites, wehrlites and lherzolites reflect percolation of mafic alkaline melts through the lithospheric mantle. Volatile and incompatible trace element compositions imply that these interacting melts were related to the post-subduction magmatism which hosts the xenoliths. The scattered distribution of such magmatism and the history of accretion suggest that the dominant composition of sub-Antarctic Peninsula lithospheric mantle is likely to be harzburgitic.

Merengkuh Bumi Merawat Semesta: Mengupayakan Hermeneutik Ekologis dalam Rangka Menanggapi Kerusakan Lingkungan Dewasa Ini

2021 ◽  
Vol 1 (1) ◽  
pp. 71
Author(s):  
Darius Ade Putra
Keyword(s):  
Biblical Text ◽  
New Paradigm ◽  
New Approach ◽  
Ecological Damage ◽  
The Bible ◽  
The Earth ◽  
The 1960S ◽  
The Universe

Abstract Since the 1960s, started by Lynn White, Christianity has begun to get attacks because it is considered to have triggered ecological damage. Christianity through the teachings of the Bible is accused of legitimizing absolute anthropocentric ideas which then give rise to expansive actions to the environment and nature. In the midst of the massive damage to the environment and in order to fi nd a possible solution to this problem, it is felt necessary to resonance the new approach to the Scriptures that further explores the sound of the earth. One approach that can be developed is ecological hermeneutics. Based on several principles it is possible to see and understand the biblical text from the perspective of the earth. In addittion, this approach will be elaborated with local wisdom so that it can help the text contextualization process. In the end, a new paradigm is expected to encourage awareness of the importance to tend the universe.   Abstrak Sejak tahun 1960an, dimulai oleh Lynn White, Kekristenan mulai mendapat serangan karena dinilai telah menjadi pemicu kerusakan ekologi. Kekristenan melalui ajaran Alkitab dituduh melegitimasi gagasan-gagasan antroposentris absolut yang kemudian melahirkan tinndakan- tindakan ekspansif terhadap lingkungan dan alam. Di tengah masifnya kerusakan lingkungan dan dalam rangka mencari kemungkinan jalan keluar dari persoalan ini, dirasa perlu untuk menggemakan pendekatan baru pada Kitab Suci yang lebih mengeksplorasi suara bumi. Salah satu pendekatan yang bisa dikembangkan adalah hermeneutik ekologi. Berdasarkan beberapa prinsip-prinsipnya memungkinkan untuk melihat dan memahami teks Alkitab dari perspektif bumi. Selain itu, pendekatan ini akan dielaborasi dengan local widom agar membantu proses kontekstualisasi teks. Pada akhirnya diharapkan sebuah paradigma baru yang mendorong kesadaran akan pentingnya merawat alam semesta.

Radial Anisotropy and it's Relation to Fast and Slow Moving Tectonic Plates

2021 ◽  
Author(s):  
Tak Ho ◽  
Keith Priestley ◽  
Eric Debayle
Keyword(s):  
Upper Mantle ◽  
Large Scale ◽  
Oceanic Lithosphere ◽  
Azimuthal Anisotropy ◽  
Plate Motion ◽  
Moho Depth ◽  
Dispersion Characteristics ◽  
Anisotropic Models ◽  
Ocean Ridges ◽  
Average Dispersion

<p>We present a new radially anisotropic (<strong>ξ)</strong> tomographic model for the upper mantle to transition zone depths derived from a large Rayleigh (~4.5 x 10<sup>6 </sup>paths) and Love (~0.7 x 10<sup>6</sup> paths) wave path average dispersion curves with periods of 50-250 s and up to the fifth overtone. We first extract the path average dispersion characteristics from the waveforms. Dispersion characteristics for common paths (~0.3 x 10<sup>6</sup> paths) are taken from the Love and Rayleigh datasets and jointly inverted for isotropic V<sub>s </sub>and <strong>ξ</strong>. CRUST1.0 is used for crustal corrections and a model similar to PREM is used as a starting model. V<sub>s</sub> and <strong>ξ</strong> are regionalised for a 3D model. The effects of azimuthal anisotropy are accounted for during the regionalisation. Our model confirms large-scale upper mantle features seen in previously published models, but a number of these features are better resolved because of the increased data density of the fundamental and higher modes coverage from which our <strong>ξ</strong>(z) was derived. Synthetic tests show structures with radii of 400 km can be distinguished easily. Crustal perturbations of +/-10% to V<sub>p</sub>, V<sub>s</sub> and density, or perturbations to Moho depth of +/-10 km over regions of 400 km do not significantly change the model. The global average decreases from <strong>ξ~</strong>1.06 below the Moho to <strong>ξ</strong>~1 at ~275 km depth. At shallow depths beneath the oceans <strong>ξ</strong>>1 as is seen in previously published global mantle radially anisotropic models. The thickness of this layer increases slightly with the increasing age of the oceanic lithosphere. At ~200 km and deeper depths below the fast-spreading East Pacific Rise and starting at somewhat greater depths beneath the slower spreading ridges, <strong>ξ</strong><1. At depths ≥200 km and deeper depths below most of the backarc basins of the western Pacific <strong>ξ</strong><1. The signature of mid-ocean ridges vanishes at about 150 km depth in V<sub>s</sub> while it extends much deeper in the <strong>ξ</strong> model suggesting that upwelling beneath mid-ocean ridges could be more deeply rooted than previously believed. The pattern of radially anisotropy we observe, when compared with the pattern of azimuthal anisotropy determined from Rayleigh waves, suggests that the shearing at the bottom of the plates is only sufficiently strong to cause large-scale preferential alignment of the crystals when the plate motion exceeds some critical value which Debayle and Ricard (2013) suggest is about 4 cm/yr.</p>

The Elusive Harmony between Government and Market Roles

2020 ◽  
pp. 179-200
Author(s):  
Vito Tanzi
Keyword(s):  
Great Depression ◽  
The State ◽  
Market Failures ◽  
New Paradigm ◽  
The Great Recession ◽  
The Great Depression ◽  
Role Of The State ◽  
New Harmony ◽  
The 1960S

At any moment in time there ought to be some harmony between the intervention of the state that the market requires (to correct its market failures), and that citizens demand (to promote equity and a desirable income distribution) and the actual government intervention. This chapter argues that such harmony may have existed in the years when laissez faire was in place and was broadly accepted by those who had political power. The harmony became less and less evident in the later decades of the nineteenth century and during the Great Depression. There seemed to have been greater harmony in the 1960s. That harmony went down in the late 1970s and in the 1980s. It might have been partly restored in the 1990s, with a different conception of the role of the state, with less state and more market, at least in some countries. The harmony broke down again with the Great Recession in 2008–10, There is now, once again, a search for a new paradigm that would indicate the existence of a new harmony.

The distribution and abundance of halogens in eclogites: An in situ SIMS perspective of the Raspas Complex (Ecuador)

2020 ◽  
Vol 105 (3) ◽  
pp. 307-318 ◽  
Author(s):  
Benjamin M. Urann ◽  
Véronique Le Roux ◽  
Timm John ◽  
Grace M. Beaudoin ◽  
Jaime D. Barnes
Keyword(s):  
Upper Mantle ◽  
Subduction Zones ◽  
Secondary Ion Mass Spectrometry ◽  
Bulk Rock ◽  
Ocean Island Basalts ◽  
High Pressure Metamorphism ◽  
Southern Ecuador ◽  
And Behavior ◽  
Secondary Ion

Abstract We present in situ secondary ion mass spectrometry (SIMS) and electron microprobe analyses of coexisting garnet, omphacite, phengite, amphibole, and apatite, combined with pyrohydrolysis bulk-rock analyses to constrain the distribution, abundance, and behavior of halogens (F and Cl) in six MORB-like eclogites from the Raspas Complex (Southern Ecuador). In all cases concerning lattice-hosted halogens, F compatibility decreases from apatite (1.47–3.25 wt%), to amphibole (563–4727 μg/g), phengite (610–1822 μg/g), omphacite (6.5–54.1 μg/g), and garnet (1.7–8.9 μg/g). The relative compatibility of Cl in the assemblage is greatest for apatite (192–515 μg/g), followed by amphibole (0.64–82.7 μg/g), phengite (1.2–2.1 μg/g), omphacite (<0.05–1.0 μg/g), and garnet (<0.05 μg/g). Congruence between SIMS-reconstructed F bulk abundances and yield-corrected bulk pyrohydrolysis analyses indicates that F is primarily hosted within the crystal lattice of eclogitic minerals. However, SIMS-reconstructed Cl abundances are a factor of five lower, on average, than pyrohydrolysis-derived bulk concentrations. This discrepancy results from the contribution of fluid inclusions, which may host at least 80% of the bulk rock Cl. The combination of SIMS and pyrohydrolysis is highly complementary. Whereas SIMS is well suited to determine bulk F abundances, pyrohydrolysis better quantifies bulk Cl concentrations, which include the contribution of fluid inclusion-hosted Cl. Raspas eclogites contain 145–258 μg/g F and at least 7–11 μg/g Cl. We estimate that ~95% of F is retained in the slab through eclogitization and returned to the upper mantle during subduction, whereas at least 95% of subducted Cl is removed from the rock by the time the slab equilibrates at eclogite facies conditions. Our calculations provide further evidence for the fractionation of F from Cl during high-pressure metamorphism in subduction zones. Although the HIMU (high U/Pb) mantle source (dehydrated oceanic crust) is often associated with enrichments in Cl/K and F/Nd, Raspas eclogites show relatively low halogen ratios identical within uncertainty to depleted MORB mantle (DMM). Thus, the observed halogen enrichments in HIMU ocean island basalts require either further fractionation during mantle processing or recycling of a halogen-enriched carrier lithology such as serpentinite into the mantle.

scholarly journals Paving the Way towards an Armenian Data Cube

Data ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 117 ◽  
Author(s):  
Shushanik Asmaryan ◽  
Vahagn Muradyan ◽  
Garegin Tepanosyan ◽  
Azatuhi Hovsepyan ◽  
Armen Saghatelyan ◽  
...  
Keyword(s):  
Environmental Issues ◽  
Data Cube ◽  
New Paradigm ◽  
Band Ratio ◽  
Earth Observations ◽  
In Situ Data ◽  
Global Concern ◽  
Sentinel 2 ◽  
The Way

Environmental issues become an increasing global concern because of the continuous pressure on natural resources. Earth observations (EO), which include both satellite/UAV and in-situ data, can provide robust monitoring for various environmental concerns. The realization of the full information potential of EO data requires innovative tools to minimize the time and scientific knowledge needed to access, prepare and analyze a large volume of data. EO Data Cube (DC) is a new paradigm aiming to realize it. The article presents the Swiss-Armenian joint initiative on the deployment of an Armenian DC, which is anchored on the best practices of the Swiss model. The Armenian DC is a complete and up-to-date archive of EO data (e.g., Landsat 5, 7, 8, Sentinel-2) by benefiting from Switzerland’s expertise in implementing the Swiss DC. The use-case of confirm delineation of Lake Sevan using McFeeters band ratio algorithm is discussed. The validation shows that the results are sufficiently reliable. The transfer of the necessary knowledge from Switzerland to Armenia for developing and implementing the first version of an Armenian DC should be considered as a first step of a permanent collaboration for paving the way towards continuous remote environmental monitoring in Armenia.

scholarly journals A multicomponent Isabella anomaly: Resolving the physical state of the Sierra Nevada upper mantle from Vp/Vs anisotropy tomography

Geosphere ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 2018-2042 ◽  
Author(s):  
Melissa V. Bernardino ◽  
Craig H. Jones ◽  
William Levandowski ◽  
Ian Bastow ◽  
Thomas J. Owens ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Upper Mantle ◽  
Oceanic Lithosphere ◽  
P Wave ◽  
Wave Speeds ◽  
High Wave ◽  
The Core ◽  
High Speeds ◽  
Great Valley ◽  
Isabella Anomaly

Abstract The Isabella anomaly, a prominent upper-mantle high-speed P-wave anomaly located within the southern Great Valley and southwestern foothills of the Sierra Nevada, has been interpreted either as foundering sub-Sierran lithosphere or as remnant oceanic lithosphere. We used Vp/Vs anisotropy tomography to distinguish among the probable origins of the Isabella anomaly. S waveforms were rotated into the Sierran SKSFast and SKSSlow directions determined from SKS-splitting studies. Teleseismic P-, SFast-, SSlow-, SKSFast-, and SKSSlow-wave arrival times were then inverted to obtain three-dimensional (3-D) perturbations in Vp, Vp/VsMean, and percent azimuthal anisotropy using three surface wave 3-D starting models and one one-dimensional (1-D) model. We observed the highest Vp/Vs anomalies associated with slower velocities in regions marked by young volcanism, with the largest of these anomalies being the Mono anomaly under the Long Valley region, which extends to depths of at least 75 km. Peak Vp/Vs perturbations of +4% were found at 40 km depth. The low velocities and high Vp/Vs values of this anomaly could be related to partial melt. The high wave speeds of the Isabella anomaly coincide with low Vp/Vs values with peak perturbations of −2%, yet they do not covary spatially. The P-wave inversion imaged the Isabella anomaly as a unimodal eastward-plunging body. However, the volume of that Isabella anomaly contains three separate bodies as defined by varying Vp/Vs values. High speeds, regionally average Vp/Vs values (higher than the other two anomalies), and lower anisotropy characterize the core of the Isabella anomaly. The western and shallowest part has high wave speeds and lower Vp/Vs values than the surrounding mantle. The eastern and deepest part of the anomaly also contains high speeds and lower Vp/Vs values but exhibits higher anisotropy. We considered combinations of varying temperature, Mg content (melt depletion), or modal garnet to reproduce our observations. Our results suggest that the displaced garnet-rich mafic root of the Mesozoic Sierra Nevada batholith is found in the core of the Isabella anomaly. If remnant oceanic lithosphere exists within the Isabella anomaly, it most likely resides in the shallow, westernmost feature. Within the Sierra Nevada, the highest upper-mantle anisotropy is largely contained within the central portion of the range and the adjacent Great Valley. Anisotropy along the Sierra crest is shallow and confined to the lithosphere between 20 and 40 km depth. Directly below, there is a zone of low anisotropy (from 170 to 220 km depth), low velocities, and high Vp/Vs values. These features suggest the presence of vertically upwelling asthenosphere and consequent horizontal flow at shallower depths. High anisotropy beneath the adjacent western foothills and Great Valley is found at ∼120 km depth and could represent localized mantle deformation produced as asthenosphere filled in a slab gap.

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