keyword
MENU ▼
Read by QxMD icon Read
search

Tectonics

keyword
https://www.readbyqxmd.com/read/28522528/global-drainage-patterns-and-the-origins-of-topographic-relief-on-earth-mars-and-titan
#1
Benjamin A Black, J Taylor Perron, Douglas Hemingway, Elizabeth Bailey, Francis Nimmo, Howard Zebker
Rivers have eroded the topography of Mars, Titan, and Earth, creating diverse landscapes. However, the dominant processes that generated topography on Titan (and to some extent on early Mars) are not well known. We analyzed drainage patterns on all three bodies and found that large drainages, which record interactions between deformation and erosional modification, conform much better to long-wavelength topography on Titan and Mars than on Earth. We use a numerical landscape evolution model to demonstrate that short-wavelength deformation causes drainage directions to diverge from long-wavelength topography, as observed on Earth...
May 19, 2017: Science
https://www.readbyqxmd.com/read/28522505/river-systems-reveal-planetary-tectonics
#2
EDITORIAL
Keith T Smith
No abstract text is available yet for this article.
May 19, 2017: Science
https://www.readbyqxmd.com/read/28515078/shifting-quaternary-migration-patterns-in-the-bahamian-archipelago-evidence-from-the-zamia-pumila-complex-at-the-northern-limits-of-the-caribbean-island-biodiversity-hotspot
#3
Dayana E Salas-Leiva, Alan W Meerow, Michael Calonje, Javier Francisco-Ortega, M Patrick Griffith, Kyoko Nakamura, Vanessa Sánchez, Lindy Knowles, David Knowles
PREMISE OF THE STUDY: The Bahamas archipelago is formed by young, tectonically stable carbonate banks that harbor direct geological evidence of global ice-volume changes. We sought to detect signatures of major changes on gene flow patterns and reconstruct the phylogeographic history of the monophyletic Zamia pumila complex across the Bahamas. METHODS: Nuclear molecular markers with both high and low mutation rates were used to capture two different time scale signatures and test several gene flow and demographic hypotheses...
May 17, 2017: American Journal of Botany
https://www.readbyqxmd.com/read/28513689/proton-conduction-in-a-hydrogen-bonded-complex-of-copper-ii-bipyridine-glycoluril-nitrate
#4
Sakharam B Tayade, Vishal M Dhavale, Avinash S Kumbhar, Sreekumar Kurungot, Peter Lönnecke, Evamarie Hey-Hawkins, Bhalchandra Pujari
Bipyridine glycoluril (BPG), a urea-fused bipyridine tecton, forms a square-pyramidal secondary building unit with copper(ii) which further self-assembles to give a porous hydrogen-bonded complex. This complex displays a high proton conductivity of 4.45 × 10(-3) S cm(-1) at 90 °C and 95% relative humidity (RH). Chains consisting of coordinated water, solvent water and nitrate anions embedded in the complex are responsible for high proton conduction. The proton conduction pathway was corroborated by ab initio electronic structure calculations with molecular dynamics (MD) simulations using the Nudged Elastic Band (NEB) method...
May 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28508893/south-american-plate-advance-and-forced-andean-trench-retreat-as-drivers-for-transient-flat-subduction-episodes
#5
Gerben Schepers, Douwe J J van Hinsbergen, Wim Spakman, Martha E Kosters, Lydian M Boschman, Nadine McQuarrie
At two trench segments below the Andes, the Nazca Plate is subducting sub-horizontally over ∼200-300 km, thought to result from a combination of buoyant oceanic-plateau subduction and hydrodynamic mantle-wedge suction. Whether the actual conditions for both processes to work in concert existed is uncertain. Here we infer from a tectonic reconstruction of the Andes constructed in a mantle reference frame that the Nazca slab has retreated at ∼2 cm per year since ∼50 Ma. In the flat slab portions, no rollback has occurred since their formation at ∼12 Ma, generating 'horse-shoe' slab geometries...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28507147/plate-tectonic-regulation-of-global-marine-animal-diversity
#6
Andrew Zaffos, Seth Finnegan, Shanan E Peters
Valentine and Moores [Valentine JW, Moores EM (1970) Nature 228:657-659] hypothesized that plate tectonics regulates global biodiversity by changing the geographic arrangement of continental crust, but the data required to fully test the hypothesis were not available. Here, we use a global database of marine animal fossil occurrences and a paleogeographic reconstruction model to test the hypothesis that temporal patterns of continental fragmentation have impacted global Phanerozoic biodiversity. We find a positive correlation between global marine invertebrate genus richness and an independently derived quantitative index describing the fragmentation of continental crust during supercontinental coalescence-breakup cycles...
May 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28504256/explosive-eruption-flank-collapse-and-megatsunami-at-tenerife-ca-170-ka
#7
Raphaël Paris, Juan J Coello Bravo, María E Martín González, Karim Kelfoun, François Nauret
Giant mass failures of oceanic shield volcanoes that generate tsunamis potentially represent a high-magnitude but low-frequency hazard, and it is actually difficult to infer the mechanisms and dynamics controlling them. Here we document tsunami deposits at high elevation (up to 132 m) on the north-western slopes of Tenerife, Canary Islands, as a new evidence of megatsunami generated by volcano flank failure. Analyses of the tsunami deposits demonstrate that two main tsunamis impacted the coasts of Tenerife 170 kyr ago...
May 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28500352/whole-mantle-convection-with-tectonic-plates-preserves-long-term-global-patterns-of-upper-mantle-geochemistry
#8
T L Barry, J H Davies, M Wolstencroft, I L Millar, Z Zhao, P Jian, I Safonova, M Price
The evolution of the planetary interior during plate tectonics is controlled by slow convection within the mantle. Global-scale geochemical differences across the upper mantle are known, but how they are preserved during convection has not been adequately explained. We demonstrate that the geographic patterns of chemical variations around the Earth's mantle endure as a direct result of whole-mantle convection within largely isolated cells defined by subducting plates. New 3D spherical numerical models embedded with the latest geological paleo-tectonic reconstructions and ground-truthed with new Hf-Nd isotope data, suggest that uppermost mantle at one location (e...
May 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28496117/the-guanacaste-volcanic-arc-sliver-of-northwestern-costa-rica
#9
Walter Montero, Jonathan C Lewis, Maria Cristina Araya
Recent studies have shown that the Nicoya Peninsula of northwestern Costa Rica is moving northwestward ~11 mm a(-1) as part of a tectonic sliver. Toward the northwest in El Salvador the northern sliver boundary is marked by a dextral strike-slip fault system active since Late Pleistocene time. To the southeast there is no consensus on what constitutes the northern boundary of the sliver, although a system of active crustal faults has been described in central Costa Rica. Here we propose that the Haciendas-Chiripa fault system serves as the northeastern boundary for the sliver and that the sliver includes most of the Guanacaste volcanic arc, herein the Guanacaste Volcanic Arc Sliver...
May 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28495906/emergency-corneal-grafting-in-the-uk-a-6-year-analysis-of-the-uk-transplant-registry
#10
Parwez Hossain, Abdo Karim Tourkmani, Dimitri Kazakos, Mark Jones, David Anderson
BACKGROUND: Corneal graft (CG) surgery is the most common and successful tissue transplant worldwide. A small and important group of patients are operated in emergency situations, typically to save a perforated eye. Our knowledge of the indications and outcomes of emergency corneal graft (eCG) is limited. METHODS: Retrospective, multifactorial analysis of all CGs registered by the UK Transplant Service from April 1999 to March 2005. RESULTS: A total of 12 976 CGs were performed...
May 11, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28492730/paleoenvironmental-evolution-of-continental-carbonates-in-west-central-brazil
#11
Emiliano C Oliveira, Dilce F Rossetti, Giselle Utida
This paper presents a sedimentological and stratigraphical study of Quaternary (Middle to Late Pleistocene/Holocene) continental carbonates outcrops inside Pantanal Basin and its surroundings, especially in Serra da Bodoquena, Pantanal do Miranda and Corumbá/Ladário plateau, in the state of Mato Grosso do Sul, as well as in Serra das Araras, in the state of Mato Grosso. The aim is to understand the depositional paleoenvironments and analyse climate and tectonic influences in their genesis and evolution. The results show that the deposition of these continental carbonates started in the Middle to Late Pleistocene and have continued, with some interruptions, until the present days...
May 4, 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28492631/molecular-tectonics-gas-adsorption-and-chiral-uptake-of-l-and-d-tryptophan-by-homochiral-porous-coordination-polymers
#12
Donata Asnaghi, Romain Corso, Patrick Larpent, Irene Bassanetti, Abdelaziz Jouaiti, Nathalie Kyritsakas, Angiolina Comotti, Piero Sozzani, Mir Wais Hosseini
Combinations of two enantiomerically pure organic tectons 1 and 3 with either Zn(ii) or Cu(ii) cations lead to the formation of four homochiral 3D networks among which two, 1-Cu and 3-Cu, are robust porous crystals displaying homochiral cavities and permanent microporosity. 3-Cu porous crystals capture 66% and 20% of l- and d-tryptophan, respectively, after 30 min of adsorption.
May 11, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28489866/magmatic-evolution-of-panama-canal-volcanic-rocks-a-record-of-arc-processes-and-tectonic-change
#13
David W Farris, Agustin Cardona, Camilo Montes, David Foster, Carlos Jaramillo
Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm...
2017: PloS One
https://www.readbyqxmd.com/read/28486928/patterns-of-divergence-in-fish-species-separated-by-the-isthmus-of-panama
#14
Christine E Thacker
BACKGROUND: The Pleistocene closure of Isthmus of Panama, separating the basins of the Eastern Pacific and the Caribbean Sea, created a unique natural experiment that reveals how marine faunas respond to environmental change. To explore how fishes have been affected by this tectonic event, I compare transisthmian patterns in phylogeny and morphology for geminate lineages in two families, Eleotridae (sleepers) and Apogonidae (cardinalfishes). RESULTS: Time-calibrated phylogenies for these families show different diversification patterns...
May 10, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28482358/continental-crust-formation-on-early-earth-controlled-by-intrusive-magmatism
#15
A B Rozel, G J Golabek, C Jain, P J Tackley, T Gerya
The global geodynamic regime of early Earth, which operated before the onset of plate tectonics, remains contentious. As geological and geochemical data suggest hotter Archean mantle temperature and more intense juvenile magmatism than in the present-day Earth, two crust-mantle interaction modes differing in melt eruption efficiency have been proposed: the Io-like heat-pipe tectonics regime dominated by volcanism and the "Plutonic squishy lid" tectonics regime governed by intrusive magmatism, which is thought to apply to the dynamics of Venus...
May 8, 2017: Nature
https://www.readbyqxmd.com/read/28481441/one-dimensionally-disordered-chiral-sorting-via-racemic-tiling-in-surface-confined-supramolecular-assembly-of-achiral-tectons
#16
Yi-Qi Zhang, Tao Lin, Borja Cirera, Raphael Hellwig, Carlos Andres Palma, Zhi Chen, Mario Ruben, Johannes V Barth, Florian Klappenberger
The aggregation of (pro)chiral/achiral molecules into crystalline structures at interfaces forms conglomerates, racemates and solid solutions, comparable to known bulk phases. Here, we employ scanning tunneling microscopy and Monte Carlo simulations to unveil a distinct racemic phase, expressing one-dimensionally (1D)-disordered chiral sorting through random tiling, in surface-confined supramolecular assembly of achiral 4,4"-diethynyl-1,1':4',1"-terphenyl molecules. Through analytical modeling, we verify that the configurational entropy of the 1D-disordered racemic tiling phase lies between that of a perfectly-ordered 2D racemate and a racemic solid-solution...
May 8, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28480934/hierarchical-chirality-transfer-in-the-formation-of-chiral-silica-fibres-with-dna-porphyrin-co-templates
#17
Yuanyuan Cao, Yingying Duan, Lu Han, Shunai Che
Screw-like hierarchical chiral fibres were constructed by co-templating two building tectons, DNA and porphyrin, under the bridging effect of cationic organosilane. The chirality transfer from the DNA molecule to meso-tetra(4-sulfonatophenyl)porphyrin assemblies in turn affected the subsequent arrangement of DNA assemblies, thus indicating a multi-dimensional hierarchical chiral amplification process from the molecular scale to the macroscopic scale.
May 8, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28480020/the-distribution-diversity-and-conservation-status-of-cycas-in-china
#18
REVIEW
Ying Zheng, Jian Liu, Xiuyan Feng, Xun Gong
As ancient gymnosperm and woody plants, cycads have survived through dramatic tectonic activities, climate fluctuation, and environmental variations making them of great significance in studying the origin and evolution of flora biodiversity. However, they are among the most threatened plant groups in the world. The principal aim of this review is to outline the distribution, diversity, and conservation status of Cycas in China and provide suggestions for conservation practices. In this review, we describe the taxonomy, distribution, and conservation status of Cycas in China...
May 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28471343/influence-of-static-magnetic-fields-in-phototaxis-and-osmotic-stress-in-gymnodinium-catenatum-dinophyceae
#19
Paulo Vale
Phototaxis response of the toxic microalgae Gymnodinium catenatum was studied in vitro. The percentage of cells remaining at mid-depth 20 min after stirring increased with solar radio, X-ray and solar flares output. It also increased with geomagnetic activity and temperature, and was dependent on culture time. Increase in the local static magnetic field with a permanent magnet did not influence the positive phototaxis response. However, survival and growth to a provoked hypo-osmotic shock in an altered static magnetic field was dependent on culture time and geomagnetic activity at a threshold below 22 nT...
May 4, 2017: General Physiology and Biophysics
https://www.readbyqxmd.com/read/28467819/the-concurrent-emergence-and-causes-of-double-volcanic-hotspot-tracks-on-the-pacific-plate
#20
T D Jones, D R Davies, I H Campbell, G Iaffaldano, G Yaxley, S C Kramer, C R Wilson
Mantle plumes are buoyant upwellings of hot rock that transport heat from Earth's core to its surface, generating anomalous regions of volcanism that are not directly associated with plate tectonic processes. The best-studied example is the Hawaiian-Emperor chain, but the emergence of two sub-parallel volcanic tracks along this chain, Loa and Kea, and the systematic geochemical differences between them have remained unexplained. Here we argue that the emergence of these tracks coincides with the appearance of other double volcanic tracks on the Pacific plate and a recent azimuthal change in the motion of the plate...
May 3, 2017: Nature
keyword
keyword
101750
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"