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Academic literature on the topic 'Crustal anomalies'

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Published: 6 September 2023

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Journal articles on the topic "Crustal anomalies"

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Raymond, Carol A., and Richard J. Blakely. "Crustal magnetic anomalies." Reviews of Geophysics 33 (1995): 177. http://dx.doi.org/10.1029/95rg00444.

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Filho, Nelson Ribeiro, Cristiano Mendel Martins, and Renata de Sena Santos. "A NOVEL REGIONAL-RESIDUAL SEPARATION APPROACH FOR GRAVITY DATA THROUGH CRUSTAL MODELING." Revista Brasileira de Geofísica 36, no. 4 (December 21, 2018): 1. http://dx.doi.org/10.22564/rbgf.v36i4.1980.

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ABSTRACT. Gravity anomalies normally contain information of all sources beneath Earth’s surface. Once residual anomalies exhibit information about the main target, the knowledge of this specific residual signal is extremely important to interpretation. To find this signal, it’s necessary to perform regional-residual separation. We present here a new approach of separation by using gravity crustal modeling. We divide the surface in prisms, with density given by GEMMA. We calculate the regional signal, assuming Earth’s crust can be the source of observed anomaly. This methodology was applied on Barreirinhas basin-Brazil. Its formation is related to geologic events in South America-Africa break. Besides, the complex geology is the main obstacle on finding the residual anomaly. We compare our methodology with robust-polynomial fitting and spectral-analysis. They were not able to identify the residual anomaly. Main trouble relies on absence of crust information. Those kind of environment usually requires forward modeling and/or gravity inversion. On the other hand, our approach considers all crust’s parameters. Then the difficulty on choosing the residual no longer exists. The residual anomaly follows a geologic pattern. The crustal depocenter was mapped between structural faults. Therefore, our results satisfies the main expectation and are extremely linked to Barreirinhas basin’s geological background. We recommend this separation procedure, once Earth’s crustal model and gravity data are available for all planet.Keywords: Gravity modeling; GEMMA model; Barreirinhas basin; residual anomaly. RESUMO. Anomalias gravimétricas contêm informações de todas as fontes na superfície terrestre. Uma vez que anomalias residuais exibem informações sobre alvos principais, o conhecimento desse específico sinal residual é extremamente importante para interpretação. Para encontrá-lo, é necessário realizar separação regional-residual. Apresentamos aqui uma nova abordagem de separação utilizando a modelagem gravimétrica crustal. Discretizamos a superfície em prismas, com densidade fornecida pelo modelo GEMMA. Calculamos o sinal regional, assumindo que a crosta terrestre é a fonte da anomalia observada. Aplicamos esta metodologia na bacia de Barreirinhas - Brasil, que tem sua formação relacionada aos eventos geológicos de separação da América do Sul e África. Além disso, a complexidade geológica é considerada o principal obstáculo para encontrar esta anomalia residual. Comparamos nossa metodologia com Ajuste Polinomial Robusto e Análise Espectral. Essas técnicas não foram capazes de identificar a anomalia residual. O principal problema se dá pela ausência de informações acerca da crosta. Para esse ambiente, geralmente requer modelagem direta e/ou inversão geofísica. Por outro lado, nossa abordagem considera todos os parâmetros crustais e a dificuldade em escolher o residual deixa de existir. A anomalia residual apresenta um padrão geológico. O depocentro crustal foi mapeado entre falhas estruturais. Nossos resultados satisfazem a expectativa principal e estão extremamente ligados ao cenário geológico da bacia. Recomendamos este procedimento de separação, uma vez que os modelos crustais e dados gravimétricos estão disponíveis para todo o planeta.Palavras-chave: Modelagem gravimétrica; modelo GEMMA; bacia de Barreirinhas; anomalia residual
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Phillips, Jeffrey D., Richard L. Reynolds, and Herbert Frey. "CRUSTAL STRUCTURE INTERPRETED FROM MAGNETIC ANOMALIES." Reviews of Geophysics 29, S1 (January 1991): 416–27. http://dx.doi.org/10.1002/rog.1991.29.s1.416.

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Zheng, Shuo, Kai Qin, Lixin Wu, Yanfei An, Qifeng Yin, and Chunkit Lai. "Hydrothermal anomalies of the Earth's surface and crustal seismicity related to Ms8.0 Wenchuan EQ." Natural Hazards 104, no. 3 (August 31, 2020): 2097–114. http://dx.doi.org/10.1007/s11069-020-04263-7.

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Abstract Hydrothermal anomalies related to the Ms8.0 Wenchuan earthquake (EQ) on May 12, 2009, have been widely reported. However, the reported anomalies have not been associated with multi-geosphere analysis, and space–time analysis with crustal seismicity is lacking. In this paper, the space–time variation of hydrothermal parameters, including soil moisture, soil temperature, near-surface relative humidity (RHsig995) and air temperature (TMPsfc), was first extracted and analyzed with the NCEP-FNL reanalysis dataset. The b-value (a seismic parameter from the Gutenberg–Richter law) was calculated and mapped to unravel the crustal stress and rock rupture. Our results reveal a similar time window for hydrothermal anomalies on April 20 and April 30, 2008, and these anomalies are mainly distributed along the southern and middle parts of the Longmenshan fault zone. The surface temperature anomalies lag behind the humidity anomalies, and the accelerating stress accumulation started since June 2007 and lasted for eight to nine months before the mainshock. The b-value mapping shows a segmented difference along strike of the Longmenshan fault, and that regional stress accumulated mainly in the southern parts of the F2 and F3 faults. We propose the occurrence of a complex coupling process led by crustal stress buildup before the Wenchuan EQ. The anomalies are concentrated in the southern part of the surface rupture zone. The prolonged crustal stress accumulation corresponds to the short intermittent hydrothermal response on the Earth’s surface before the Wenchuan EQ. Our findings reveal new hydrothermal anomalies in the Earth’s surface and atmosphere and explore direct link with seismogenic processes in the crust.
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Tang, Ming, Wei-Qiang Ji, Xu Chu, Anbin Wu, and Chen Chen. "Reconstructing crustal thickness evolution from europium anomalies in detrital zircons." Geology 49, no. 1 (September 4, 2020): 76–80. http://dx.doi.org/10.1130/g47745.1.

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Abstract A new data compilation shows that in intermediate to felsic rocks, zircon Eu/Eu* [chondrite normalized Eu/ ] correlates with whole rock La/Yb, which has been be used to infer crustal thickness. The resultant positive correlation between zircon Eu/Eu* and crustal thickness can be explained by two processes favored during high-pressure differentiation: (1) supression of plagioclase and (2) endogenic oxidation of Eu2+ due to garnet fractionation. Here we calibrate a crustal thickness proxy based on Eu anomalies in zircons. The Eu/Eu*-in-zircon proxy makes it possible to reconstruct crustal thickness evolution in magmatic arcs and orogens using detrital zircons. To evaluate this new proxy, we analyzed detrital zircons separated from modern river sands in the Gangdese belt, southern Tibet. Our results reveal two episodes of crustal thickening (to 60–70 km) since the Cretaceous. The first thickening event occurred at 90–70 Ma, and the second at 50–30 Ma following Eurasia-India collision. These findings are temporally consistent with contractional deformation of sedimentary strata in southern Tibet.
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Oran, Rona, Benjamin P. Weiss, Yuri Shprits, Katarina Miljković, and Gábor Tóth. "Was the moon magnetized by impact plasmas?" Science Advances 6, no. 40 (October 2020): eabb1475. http://dx.doi.org/10.1126/sciadv.abb1475.

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The crusts of the Moon, Mercury, and many meteorite parent bodies are magnetized. Although the magnetizing field is commonly attributed to that of an ancient core dynamo, a longstanding hypothesized alternative is amplification of the interplanetary magnetic field and induced crustal field by plasmas generated by meteoroid impacts. Here, we use magnetohydrodynamic and impact simulations and analytic relationships to demonstrate that although impact plasmas can transiently enhance the field inside the Moon, the resulting fields are at least three orders of magnitude too weak to explain lunar crustal magnetic anomalies. This leaves a core dynamo as the only plausible source of most magnetization on the Moon.
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Zheng, Ying, and Jafar Arkani-Hamed. "Joint inversion of gravity and magnetic anomalies of eastern Canada." Canadian Journal of Earth Sciences 35, no. 7 (July 1, 1998): 832–53. http://dx.doi.org/10.1139/e98-035.

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The power spectra and degree correlation of the surface topography and free-air gravity anomalies of eastern Canada show that the gravity anomalies are subdivided into three parts. The short-wavelength components (30-170 km, shorter than 30 km are not well resolved) largely arise from density perturbations in the crust and to a lesser extent from the surface topography and Moho undulation, whereas the contribution of intracrustal sources to the intermediate-wavelength components (170-385 km) is comparable with that of the topography. The long-wavelength components (385-1536 km) are overcompensated at the Moho. We present a crustal model for the intermediate- and long-wavelength components which takes into account the surface topography, density perturbations in the crust, and Moho undulation with a certain degree of isostatic compensation. The general characteristics of this model resemble the crustal structure revealed from seismic measurements. The reduced-to-pole magnetic anomalies of eastern Canada show no pronounced correlation with the topography and with the vertical gradient of the gravity anomalies, suggesting that the source bodies are within the crust and Poisson's relationship does not hold over the entire area. Assuming that the magnetic anomalies arise from induced magnetization, lateral variations of magnetic susceptibility of the crust are determined while taking into account the effects of the surface topography and the Moho undulation of our crustal model. The intermediate- and long-wavelength components of the susceptibility contrasts delineate major collision zones as low-susceptibility regions. We interpret this in terms of thermal demagnetization of the high-magnetic crustal roots beneath the collision zones.
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Saleh, Salah, Oya Pamukçu, and Ladislav Brimich. "The major tectonic boundaries of the Northern Red Sea rift, Egypt derived from geophysical data analysis." Contributions to Geophysics and Geodesy 47, no. 3 (September 1, 2017): 149–99. http://dx.doi.org/10.1515/congeo-2017-0010.

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AbstractIn the present study, we have attempted to map the plate boundary between Arabia and Africa at the Northern Red Sea rift region including the Suez rift, Gulf of Aqaba-Dead Sea transform and southeastern Mediterranean region by using gravity data analysis. In the boundary analysis method which was used; low-pass filtered gravity anomalies of the Northern Red Sea rift region were computed. Different crustal types and thicknesses, sediment thicknesses and different heat flow anomalies were evaluated. According to the results, there are six subzones (crustal blocks) separated from each other by tectonic plate boundaries and/or lineaments. It seems that these tectonic boundaries reveal complex structural lineaments, which are mostly influenced by a predominant set of NNW–SSE to NW–SE trending lineaments bordering the Red Sea and Suez rift regions. On the other side, the E–W and N–S to NNE–SSW trended lineaments bordering the South-eastern Mediterranean, Northern Sinai and Aqaba-Dead Sea transform regions, respectively. The analysis of the low pass filtered Bouguer anomaly maps reveals that the positive regional anomaly over both the Red Sea rift and South-eastern Mediterranean basin subzones are considered to be caused by the high density of the oceanic crust and/or the anomalous upper mantle structures beneath these regions whereas, the broad medium anomalies along the western half of Central Sinai with the Suez rift and the Eastern Desert subzones are attributed to low-density sediments of the Suez rift and/or the thick upper continental crustal thickness below these zones. There are observable negative anomalies over the Northern Arabia subzone, particularly in the areas covered by Cenozoic volcanics. These negative anomalies may be attributed to both the low densities of the surface volcanics and/or to a very thick upper continental crust. On the contrary, the negative anomaly which belongs to the Gulf of Aqaba-Dead Sea transform zone is due to crustal thickening (with limited heat flow values) below this region. Additionally in this study, the crustal thinning was investigated with heat flow, magnetic and free air gravity anomalies in the Northern Red Sea rift region. In fact, the crustal thinning of the study area was also proportional to the regions of observable high heat flow values. Finally, our results were found to be well correlated with the topography, free air, aeromagnetic and heat flow dataset profiles crossing most of the study area.
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Halekas, J. S., D. A. Brain, R. P. Lin, and D. L. Mitchell. "Solar wind interaction with lunar crustal magnetic anomalies." Advances in Space Research 41, no. 8 (January 2008): 1319–24. http://dx.doi.org/10.1016/j.asr.2007.04.003.

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Riad, Samir, and Hassan A. El Etr. "Bouguer anomalies and lithosphere-crustal thickness in Uganda." Journal of Geodynamics 3, no. 1-2 (July 1985): 169–86. http://dx.doi.org/10.1016/0264-3707(85)90027-4.

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Dissertations / Theses on the topic "Crustal anomalies"

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Launay, Nicolas. "Propriétés d'aimantation des sources géologiques des anomalies du champ magnétique terrestre : magnétisme des roches et modélisation numérique." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0212/document.

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Cette étude s’intéresse en premier lieu aux caractéristiques magnétiques d’échantillons de BIFs (Banded Iron Formations) en provenance de Mauritanie, où est observable la plus grande partie de l’Anomalie Magnétique Ouest Africaine (AMOA). On met en évidence des valeurs de susceptibilité magnétique allant jusqu’à 3.4 SI, et d’aimantation rémanente jusqu’à 1350 A/m, dans les BIFs. Des valeurs de rapport de Koenigsberger pour la plupart supérieures à 1 impliquent également que la rémanence devrait être prise en compte pour expliquer l’AMOA. L’effet de la pression sur les propriétés magnétiques de la titanomagnétite a également été étudié, car ce paramètre est peu connu, et la plupart du temps négligé dans les modèles numériques des sources des anomalies magnétiques. On montre ainsi une dépendance à la pression de la température de Curie de l’hématite et de la titanomagnétite, ainsi qu’une augmentation de l’Aimantation Thermo Rémanente (ATR) acquise à des pressions lithosphériques, allant jusqu’à +100% à 675 MPa. Un modèle numérique de la croûte sous l’AMOA est ensuite construit, à l’aide de ces contraintes et de données magnétiques et gravimétriques. On utilise une approche directe pour investiguer la profondeur, l’épaisseur et l’intensité d’aimantation des lithologies crustales. Nos résultats montrent que des couches de BIFs sont les seules sources crustales aimantées nécessaires pour expliquer l’anomalie, et qu’elles pourraient être enfouies à plusieurs kilomètres de profondeur. Les résultats de cette étude fournissent de nouvelles perpectives pour l’étude des sources d’anomalies magnétiques dans d’autres régions cratoniques comportant des affleurements de BIFs
The geological sources of major magnetic field anomalies are still poorly constrained, in terms of nature, geometry and vertical position. A common feature of several anomalies is their spatial correlation with cratonic shields and, for the largest anomalies, with Banded Iron Formations (BIF). This study first unveils the magnetic properties of some BIF samples from Mauritania, where the main part of the West African magnetic anomaly is observed. It shows magnetic susceptibility values up to 3.4 SI and natural remanent magnetization up to 1350 A/m can be reached by BIF rocks. Koenigsberger ratios mostly superior to 1 imply that the remanent magnetization should be taken into account to explain the anomaly. I also investigated the impact of pressure on magnetic properties of titanomagnetite, because it is not well known and most of the time neglected in numerical models of the geological sources of magnetic anomalies. My results show a pressure-dependent Curie temperature increase, as well as an intensity increase for TRM acquired under lithospheric pressure (up to +100% at 675 MPa). A numerical modeling of the crust beneath the West African anomaly is then performed using these constraints and both gravity and magnetic field data. A forward approach is used, investigating the depth, thickness and magnetization intensity of all possible crustal lithologies. Our results show that BIF slices may be the only magnetized lithology needed to explain the anomaly, and that they could be buried several kilometers deep. The results of this study provide a new perspective to address the investigation of magnetic field anomaly sources in other cratonic regions with BIF outcrops
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Telmat, Hamid. "Crustal structure and gravity field anomalies in Eastern Canada." Thèse, Chicoutimi : Montréal : Université du Québec à Chicoutimi ; Université du Québec à Montréal, 1998. http://theses.uqac.ca.

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Hussein, Musa Jad. "Integrated and comparative geophysical studies of crustal structure of pull-apart basins the Salton Trough and Death Valley, California regions /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2007. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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Tozer, Brook. "Crustal structure, gravity anomalies and subsidence history of the Parnaíba cratonic basin, Northeast Brazil." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:90ce8bb0-e55d-4b3c-87e1-aab60084ef42.

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Cratonic basins cover more than 10% of Earth's continental surface area, yet their origin remains enigmatic. In this thesis a suite of new and legacy geophysical and geological data are integrated to constrain the origin of the Parnaíba basin, a cratonic basin in Northeast Brazil. These data include a 1400 km long, deep (20 s two-way travel time) seismic reflection profile, five +/- 110 km offset wide-angle split-spread receiver gathers, gravity anomaly, and well data. In the centre of the basin, the depth to pre-Paleozoic basement is ~ 3.3 km, a zone of midcrustal reflectivity (MCR) can be traced laterally for ~ 250 km at depths between 17-25 km and Moho depth is ~ 42 +/- 2 km. Gravity and P-wave modelling suggests that the MCR represents the upper surface of a high density (2985 kg m3) and Vp (6.7 - 7.0 km s-1) lower crustal body, likely of magmatic origin. Backstripping of well data shows a concave up decreasing tectonic subsidence, similar in form to that commonly observed in rift-type basins. It is shown, however, that the seismic and gravity data are inconsistent with an extensional origin. It is shown that an intrusive body in the lower crust that has loaded and flexed the surface of the crust, combined with sediment loading, provides a satisfactory fit to the observed gravity anomaly, sediment thickness and basin shape. A buried load model is also consistent with seismic data, which suggest that the Moho is as deep or deeper beneath the basin centre than its flanks and accounts for at least part of the tectonic subsidence through a viscoelastic stress relaxation that occurs in the lithosphere following load emplacement. Comparative analysis of the Michigan and Congo basins shows gravity data from these basins is also consistent with a lower crustal mass excess, while subsidence analysis shows viscoelastic stress relaxation may also contribute to their early subsidence histories. However, unlike Parnaíba, both of these basins appear to have been subjected to secondary tectonic processes that obscure the primary 'cratonic basin' subsidence signals. Parnaíba basin, therefore, offers an excellent record for the investigation of cratonic basin formation.
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Hood, L. L., A. Zakharian, J. Halekas, D. L. Mitchell, R. P. Lin, M. H. Acuña, and A. B. Binder. "Initial mapping and interpretation of lunar crustal magnetic anomalies using Lunar Prospector magnetometer data." AMER GEOPHYSICAL UNION, 2001. http://hdl.handle.net/10150/624001.

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Maps of relatively strong crustal magnetic field anomalies detected at low altitudes with the magnetometer instrument on Lunar Prospector are presented. On the lunar nearside, relatively strong anomalies are mapped over the Reiner Gamma Formation on western Oceanus Procellarum and over the Rima Sirsalis rille on the southwestern border of Oceanus Procellarum. The main Rima Sirsalis anomaly does not correlate well with the rille itself but is centered over an Imbrian-aged smooth plains unit interpreted as primary or secondary basin ejecta. The stronger Reiner Gamma anomalies correlate with the locations of both the main Reiner Gamma albedo marking and its northeastward extension. Both the Rima Sirsalis and the Reiner Gamma anomalies are extended in directions approximately radial to the center of the Imbrium basin. This alignment suggests that Imbrium basin ejecta materials (lying in many cases beneath the visible mare surface) are the sources of the nearside anomalies. If so, then the albedo markings associated with the stronger Reiner Gamma anomalies may be consistent with a model involving magnetic shielding of freshly exposed mare materials from the solar wind ion bombardment. Two regions of extensive magnetic anomalies are mapped in regions centered on the Ingenii basin on the south central farside and near the crater Gerasimovic on the southeastern farside. These regions are approximately antipodal to the Imbrium and Crisium basins, respectively. The Imbrium antipode anomaly group is the most areally extensive on the Moon, while the largest anomaly in the Crisium antipode group is the strongest detected by the Lunar Prospector magnetometer. A consideration of the expected antipodal effects of basin-forming impacts as well as a combination of sample data and orbital measurements on the nearside leads to the conclusion that the most probable sources of magnetic anomalies in these two regions are ejecta materials from the respective impacts. In both regions the strongest individual anomalies correlate with swirl-like albedo markings of the Reiner Gamma class visible on available orbital photography.
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Halekas, J. S., D. L. Mitchell, R. P. Lin, S. Frey, L. L. Hood, M. H. Acuña, and A. B. Binder. "Mapping of crustal magnetic anomalies on the lunar near side by the Lunar Prospector electron reflectometer." American Geophysical Union, 2001. http://hdl.handle.net/10150/624000.

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Lunar Prospector (LP) electron reflectometer measurements show that surface fields are generally weak in the large mare basalt filled impact basins on the near side but are stronger over highland terranes, especially those lying antipodal to young large impact basins. Between the Imbrium and Nectaris basins, many anomalies correlate with the Cayley and Descartes Formations. Statistical analyses show that the most strongly magnetic nearside terranes are Cayley-type light plains, terra materials, and pre-Imbrian craters. Light plains and terrae include basin impact ejecta as a major component, suggesting that magnetization effects from basin-forming impacts were involved in their formation. The magnetization of pre-Imbrian craters, however, may be evidence of early thermal remanence. Relatively strong, small-scale magnetic anomalies are present over the Reiner Gamma feature on western Oceanus Procellarum and over the Rima Sirsalis rille on the southwestern border of Procellarum. Both Apollo subsatellite and LP data show that the latter anomaly is nearly aligned with the rille, though LP magnetometer and reflectometer data show that the anomaly peak is actually centered over a light plains unit. This anomaly and the Reiner Gamma anomaly are approximately radially aligned with the center of Imbrium, suggesting an association with ejecta from this basin.
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Leinweber, Volker Thor. "Geophysical study of the conjugate East African and East Antarctic margins." Brest, 2011. http://www.theses.fr/2011BRES2017.

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The study deals with the relative movements between Africa and Antarctica in Middle Jurassic to Lower Cretaceous times using new data from four campaigns (2006-2010). Aeromagnetic measurements in the 5W Enderby Basin clearly image the continent-ocean-transition east of the Gunnerus Ridge. Spreading anomalies are absent, pointing to a formation of the oceanic crust during Cretaceous Normal superchron times. Velocity and density modelling of two wide-angle seismic profiles across the Central Mozambique continental margin reveal continental crust, thinning seawards by 50% over a distance of ~130 km. Farther south, oceanic crust is overlain by sediments with high P-wave velocities around 4. 8 km/s. An extensive lower crustal high-velocity-body has been found in both profiles. Identifications of magnetic spreading anomalies reveal that the COT is located closer to the coast than supposed so far. M41 n is interpreted as oldest existing spreading anomaly. New magnetic and gravity data across the Mozambique Ridge and the Northern Natal Valley and their similarity to potential field data on the Mozambique Coastal Plains point to a mainly oceanic nature from the plains south and two southward jumps of the spreading centre. The Astrid Ridge is subdivided by the Astrid Fracture Zone into a northern and a southern part with different magnetic signatures and is interpreted to consist of oceanic crust. The regional results were implemented into a new kinematic model between Africa and Antarctica, postulating a tight continental Gondwana fit, a two-stage breakup and a southward movement of the Grunehogna Craton east of the Mozambique Ridge during the second stage of breakup
L’étude traite des mouvements relatifs de l’Afrique et de l'Antarctique, du Jurassique moyen jusqu’à la fin du Crétacé inférieur, en utilisant les données de quatre campagnes (2006-2010). Des mesures aéromagnétiques dans le bassin Enderby Sud-Ouest montrent la COT à l’est de la dorsale de Gunnerus. Il n’y a pas d’anomalie évidente dans les données, ce qui indique une formation de croûte océanique durant le superchron normal du Crétacé. La modélisation de deux profils sismiques grand-angles à travers la marge continentale du Mozambique central révèle une croûte continentale qui s’amincit ~50% sur une distance de ~130 km vers le large. Plus au sud, de la croûte océanique se trouve sous des sédiments à hautes vitesses d’ondes P autour de 4,8 km/s. Dans la croûte inférieure se retrouve un vaste corps de grande vitesse d’ondes. Des identifications des anomalies (M41n étant interprétée comme la plus vieille) révèlent que la COT est plus proche de la côte qu’on ne le croyait. De nouvelles données magnétiques et gravimétriques à la ride du Mozambique et au bassin nord du Natal et leur similitude avec les données des plaines de la côte du Mozambique indiquent une nature de croûte océanique majoritaire des plaines vers le sud ainsi que deux sauts du centre d’écartement vers le Sud. La ride d’Astrid est scindée en deux parties magnétiquement différentes, interprétées en croûte océanique. Les résultats régionaux ont été implémentés dans un nouveau modèle cinématique, qui postule un ajustement étroit des continents du Gondwana, une fracturation diphasée et un mouvement du Craton Grunehogna vers le sud à l’est de la ride du Mozambique pendant la deuxième phase de la fracturation
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Takayama, Hiromi. "Statistical Model Analysis of the Geoelectric Field to Detect Anomalous Changes due to Crustal Activities." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/148604.

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Sato, Kazutoshi. "Development of a monitoring technique of anomalous crustal deformations with temporally high resolution by the application of kinematic GPS." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/145091.

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Rey, Denis. "Structure crustale des Alpes occidentales le long du profil ECORS-CROP d'après la sismique réflexion et le champ de pesanteur." Montpellier 2, 1989. http://www.theses.fr/1989MON20157.

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Ce travail, realise dans le cadre du programme ecors-crop alpes 1986-1987, a pour but l'etude de la structure profonde sous la chaine des alpes occidentales a l'aide de donnees gravimetriques acquises et incorporees aux leves anterieurs. Deux profils gravimetriques ont ainsi ete modelises a l'aide des contraintes apportees par les donnees sismiques. Ils ont permis la confirmation du caractere cylindrique de la chaine ainsi que le mode probable de raccourcissement qui d'opererait grace a de grands chevauchements intracrustaux. Une carte d'anomalie de bouguer sur l'ensemble de la chaine des alpes occidentales a ete etalie avec une precision superieure a 410##5 m. S##2 grace aux soins apportes a la realisation des corrections de relief. Les donnees topographiques acquises dans ce but ont egalement permis la realisation d'une carte d'anomalie isostatique qui a servi de controle indirect pour etudier le comportement mecanique de la lithosphere europeenne en flexion. Plusieurs modeles sont presentes, utilisant des approches elastiques pour tenter de rendre compte de la geometrie de la lithosphere europeenne. L'un d'entre eux, adoptant une approche en rigidite variable, explique en partie la pente et la rupture du gradient du moho observe, et permet de mieux comprendre le comportement mecanique de la lithosphere lors de collisions continentales. D'autres approches, faisant appel a des modeles mecaniques plus sophistiques, sont envisagees et donnent une idee sur le type d'etudes a realiser dans l'avenir
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Books on the topic "Crustal anomalies"

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1926-, Kleinkopf M. Dean, and Geological Survey (U.S.), eds. Crustal structure of Kuwait: Constraints from gravity anomalies. [Reston, Va.]: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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E, John Barbara, and Geological Survey (U.S.), eds. Crustal extension and the peak Colorado River gravity high, southern Sacramento Mountains, California: A preliminary correlation. [Reston, Va.]: Dept. of the Interior, U.S. Geological Survey, 1994.

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E, John Barbara, and Geological Survey (U.S.), eds. Crustal extension and the peak Colorado River gravity high, southern Sacramento Mountains, California: A preliminary correlation. [Reston, Va.]: Dept. of the Interior, U.S. Geological Survey, 1994.

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Sobczyk, Stanley Michael. Crustal thickness and structure of the Columbia Plateau using geophysical methods. 1994.

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Khurshid, Akbar. Crustal structure of the Sulaiman Range, Pakistan, from gravity data. 1991.

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Investigation of lunar crustal structure and isostasy: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1987.

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Soofi, Muhammad Asif. Crustal structure of the northwestern continental margin of the Indian subcontinent from gravity and magnetic data. 1991.

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Roberts, Timothy H. Gravity investigation of crustal structure in the eastern Olympic Peninsula - Puget Lowland Area, Washington. 1991.

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Zamora, Osvaldo Sánchez. Crustal structure and thermal gradients of the northern Gulf of California determined using spectral analysis of magnetic anomalies. 1988.

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Braga, Luiz F. S. Isostatic evolution and crustal structures of the Amazon continental margin determined by admittance analyses and inversion of gravity data. 1991.

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Book chapters on the topic "Crustal anomalies"

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Ostenso, Ned A. "Magnetic Anomalies and Crustal Structure." In The Earth's Crust and Upper Mantle, 457–63. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0457.

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Ogata, Yosihiko. "Anomalies of Seismic Activity and Transient Crustal Deformations Preceding the 2005 M 7.0 Earthquake West of Fukuoka." In Seismogenesis and Earthquake Forecasting: The Frank Evison Volume II, 261–73. Basel: Springer Basel, 2010. http://dx.doi.org/10.1007/978-3-0346-0500-7_17.

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Ma, Zongjin, Zhengxiang Fu, Yingzhen Zhang, Chengmin Wang, Guomin Zhang, and Defu Liu. "Crustal Deformation and Anomalous Variations of Stress." In Earthquake Prediction, 112–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-61269-5_6.

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Malahoff, Alexander. "Gravity Anomalies Over Volcanic Regions." In The Earth's Crust and Upper Mantle, 364–79. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0364.

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Kim, Hyung Rae, Luis R. Gaya-Piqué, Ralph R. B. von Frese, Patrick T. Taylor, and Jeong Woo Kim. "CHAMP Magnetic Anomalies of the Antarctic Crust." In Earth Observation with CHAMP, 261–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/3-540-26800-6_41.

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Nagata, Takesi. "Reduction of Geomagnetic Data and Interpretation of Anomalies." In The Earth's Crust and Upper Mantle, 391–98. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0391.

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Pandey, Om Prakash. "Vindhyan Basin: Anomalous Crust-Mantle Structure." In Society of Earth Scientists Series, 143–66. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-40597-7_5.

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Simonenko, Tatiana. "Relation of Magnetic Anomalies to Topography and Geology in the USSR." In The Earth's Crust and Upper Mantle, 415–21. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0415.

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Khan, M. A. "Figure of the Earth and Mass Anomalies Defined by Satellite Orbital Perturbations." In The Earth's Crust and Upper Mantle, 293–304. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0293.

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Coron, S. "Gravity Anomalies as a Function of Elevation: Some Results in Western Europe." In The Earth's Crust and Upper Mantle, 304–12. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm013p0304.

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Conference papers on the topic "Crustal anomalies"

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Arkani-Hamed, J., and D. W. Strangway. "Inversion of scalar magnetic anomalies of regional scale to crustal magnetization anomalies." In 1985 SEG Technical Program Expanded Abstracts. SEG, 1985. http://dx.doi.org/10.1190/1.1892713.

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Chen, C. H., Y. Hobara, and R. Miyake. "Potential relationship between seismo-crustal displacement and EM anomalies." In 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS). IEEE, 2014. http://dx.doi.org/10.1109/ursigass.2014.6929864.

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Tang, Ming, Weiqiang Ji, Xu Chu, Anbin Wu, and Chen Chen. "Reconstructing Crustal Thickness Evolution from Eu Anomalies in Detrital Zircons." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2553.

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Zeng, Hualin, Qinghe Zhang, Yishi Li, and Jun Liu. "Fault distribution and upper crustal thickness from gravity anomalies in South China." In SEG Technical Program Expanded Abstracts 1997. Society of Exploration Geophysicists, 1997. http://dx.doi.org/10.1190/1.1885958.

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Peleli, Sophia, Maria Kouli, and Filippos Vallianatos. "Thermal anomalies and crustal deformation related to the November 26, 2019, Albania (Durrës) earthquake." In 2023 Joint Urban Remote Sensing Event (JURSE). IEEE, 2023. http://dx.doi.org/10.1109/jurse57346.2023.10144203.

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Nair, Manoj, Arnaud Chulliat, Adam Woods, Patrick Alken, Brian Meyer, Benny Poedjono, Nicholas Zachman, and John Hernandez. "Next Generation High-Definition Geomagnetic Model for Wellbore Positioning, Incorporating New Crustal Magnetic Data." In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31044-ms.

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Abstract Magnetic wellbore positioning depends on an accurate representation of the Earth's magnetic field,where the borehole azimuth is inferred by comparing the magnetic field measured-whiledrilling (MWD) with a geomagnetic reference model. Therefore, model accuracy improvements reduce the position uncertainties. An improved high-resolution model describing the core, crustal and external components of the magnetic field is presented, and it is validated with anindependent set of measurements. Additionally, we benchmark it against other high-resolution geomagnetic models. The crustal part of the improved high-definition model is based on NOAA/NCEI's latest magnetic survey compilation "EMAG2v3" which includes over 50 millionnew observations in several parts of the world, including the Gulf of Mexico and Antarctica, and does not rely on any prior information from sea-floor geology, unlike earlier versions. The core field part of the model covers years 1900 through 2020 andis inferred from polar-orbiting satellite data as well as ground magnetic observatory data. The external field part is modelled to degree and order 1 for years 2000 through 2020. The new model has internal coefficients to spherical harmonic degree and order 790, resolving magnetic anomalies to approximately 51 km wavelength at the equator. In order to quantitatively assess its accuracy, the model was compared with independent shipborne, airborne and ground magnetic measurements. We find that the newmodel has comparable or smaller errors than the other models benchmarkedagainst it over the regions of comparisons. Additionally, we compare theimproved model against magnetic datacollected from MWD; the residual error lies well within the accepted industry error model, which may lead tofuture error model improvements.
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Clark, Chris, Steven M. Reddy, Martin Hand, Denis Fougerouse, David W. Saxey, William D. A. Rickard, and Rich Taylor. "MICRO- TO NANOSCALE CONSTRAINTS ON THE TIMING AND CONDITIONS ASSOCIATED WITH THE FORMATION LITHOSPHERIC-SCALE CONDUCTIVITY ANOMALIES IN ANHYDROUS CRUSTAL ROCKS." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-324416.

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Lepland, A., A. Cremiere, S. Chand, D. Sahy, S. R. Noble, D. J. Condon, H. Brunstad, and T. Thorsnes. "CH4-derived Carbonate Crusts of the Barents Sea - Formation Controls and Chronology." In EAGE Shallow Anomalies Workshop. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20147422.

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Milsom, John, Phil Roach, Chris Toland, Don Riaroh, Chris Budden, and Naoildine Houmadi. "Comoros – New Evidence and Arguments for Continental Crust." In SPE/AAPG Africa Energy and Technology Conference. SPE, 2016. http://dx.doi.org/10.2118/afrc-2572434-ms.

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ABSTRACT As part of an ongoing exploration effort, approximately 4000 line-km of seismic data have recently been acquired and interpreted within the Comoros Exclusive Economic Zone (EEZ). Magnetic and gravity values were recorded along the seismic lines and have been integrated with pre-existing regional data. The combined data sets provide new constraints on the nature of the crust beneath the West Somali Basin (WSB), which was created when Africa broke away from Gondwanaland and began to move north. Despite the absence of clear sea-floor spreading magnetic anomalies or gravity anomalies defining a fracture zone pattern, the crust beneath the WSB has been generally assumed to be oceanic, based largely on regional reconstructions. However, inappropriate use of regional magnetic data has led to conclusions being drawn that are not supported by evidence. The identification of the exact location of the continent-ocean boundary (COB) is less simple than would at first sight appear and, in particular, recent studies have cast doubt on a direct correlation between the COB and the Davie Fracture Zone (DFZ). The new high-quality reflection seismic data have imaged fault patterns east of the DFZ more consistent with extended continental crust, and the accompanying gravity and magnetic surveys have shown that the crust in this area is considerably thicker than normal oceanic and that linear magnetic anomalies typical of sea-floor spreading are absent. Rifting in the basin was probably initiated in Karoo times but the generation of new oceanic crust may have been delayed until about 154 Ma, when there was a switch in extension direction from NW-SE to N-S. From then until about 120 Ma relative movement between Africa and Madagascar was accommodated by extension in the West Somali and Mozambique basins and transform motion along the DFZ that linked them. A new understanding of the WSB can be achieved by taking note of newly-emerging concepts and new data from adjacent areas. The better-studied Mozambique Basin, where comprehensive recent surveys have revealed an unexpectedly complex spreading history, may provide important analogues for some stages in WSB evolution. At the same time the importance of wide continent-ocean transition zones marked by the presence of hyper-extended continental crust has become widely recognised. We make use of these new insights in explaining the anomalous results from the southern WSB and in assessing the prospectivity of the Comoros EEZ.
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Stapel, G., J. Verhoef, H. Kooi, and S. Cloetingh. "Iberian Crust Analyzed by, Residual Gravity Anomalies - Moho Prediction and Isostasy." In 59th EAGE Conference & Exhibition. European Association of Geoscientists & Engineers, 1997. http://dx.doi.org/10.3997/2214-4609-pdb.131.gen1997_p108.

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