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description Publicationkeyboard_double_arrow_right Article 2018Publisher:The Science Breaker Authors: Daniele Durante;Daniele Durante;add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.25250/thescbr.brk114&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.25250/thescbr.brk114&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2013Publisher:Hindawi Limited Authors: John A. Fornshell; Alessandra Tesei;John A. Fornshell; Alessandra Tesei;doi: 10.1155/2013/678621
The development of acoustic methods for measuring depths and ranges in the ocean environment began in the second decade of the twentieth century. The two world wars and the “Cold War” produced three eras of rapid technological development in the field of acoustic oceanography. By the mid-1920s, researchers had identified echoes from fish, Gadus morhua, in the traces from their echo sounders. The first tank experiments establishing the basics for detection of fish were performed in 1928. Through the 1930s, the use of SONAR as a means of locating schools of fish was developed. The end of World War II was quickly followed by the advent of using SONAR to track and hunt whales in the Southern Ocean and the marketing of commercial fish finding SONARs for use by commercial fisherman. The “deep scattering layer” composed of invertebrates and fish was discovered in the late 1940s on the echo sounder records. SONARs employing high frequencies, broadband, split beam, and multiple frequencies were developed as methods for the detection, quantification and identification of fish and invertebrates. The study of fish behavior has seen some use of passive acoustic techniques. Advancements in computer technology have been important throughout the last four decades of the twentieth century.
International Journa... arrow_drop_down International Journal of OceanographyArticle . 2013 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1155/2013/678621&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 17 citations 17 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert International Journa... arrow_drop_down International Journal of OceanographyArticle . 2013 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1155/2013/678621&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint 2020Publisher:Research Square Platform LLC Authors: Xiaoyan Yang; Juzhi Hou; Feixue San;Xiaoyan Yang; Juzhi Hou; Feixue San;Abstract Continental chemical weathering has been suggested to affect the concentration of atmospheric carbon dioxide that influences global climate change at different time scales. Various indices for chemical weathering have been adopted to investigate past change in chemical weathering intensity and climate change on oceanic and lacustrine sediment archives. The reliability of the chemical weathering indices has been questioned as most sediments likely originate from multiple types of bedrock that may experience various degrees of chemical weathering and can thus be reliably robust indicators of climate and paleoclimate. Here we present Sr-type (e.g. Rb/Sr Sr/Ba) and Na-type (e.g. CIA CIW PIA CPA) chemical weathering indices for top soils across the southern Tibetan Plateau to discuss the chemical weathering characteristic in the Tibetan Plateau and to examine their response to regional climate variation. The results of chemical indices and the A-CN-K ternary plot show that the southern Tibetan Plateau is under the carbonate control of the primary chemical weathering stage with the cold-dry climate. Correlation analyses show shat Sr-type indices co-vary with mean annual temperature and annual precipitation while Na-type indices show little consistence with regional climate. The climate condition is the dominant control of Sr-type indices of top soils in the study area and the bedrock may be the dominant control for the Na-type indices. We also compared the corresponding indices at a Holocene lacustrine sediment profile in the Qaidam Basin in the northeast Tibetan Plateau with regional climatic records which strongly supports our observation in the top soils. The results of the study suggest that for the relative cold and dry climate in Tibetan Plateau the Sr-type indices are more sensitive to climate condition than Na-type indices. This suggests that the Sr-type indices are likely more suitable than Na-type indices to reflect the change of climate on the Tibetan Plateau. Caution should be taken for using the Na-type indices for reconstructing the past change in climate for the study area.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.21203/rs.3.rs-106871/v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.21203/rs.3.rs-106871/v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2019Publisher:State Institution National Antarctic Scientific Center, Ministry of Education and Science of Ukraine Authors: O. V. Charkin; A. V. Zalizovski; Yu. M. Yampolski;O. V. Charkin; A. V. Zalizovski; Yu. M. Yampolski;Objective. Developing a technique for investigation of a dynamic of the equatorial boundary of the night side of the Northern auroral oval using data of registrations of scattered HF signals on superlong radio paths. Methods. Spectral, time, and time-frequency analysis of HF signals from time service stations, recorded at the Ukrainian Antarctic Akademik Vernadsky station (UAS). Selection of the spatial mode of signals scattered on the plasma inhomogeneities of the high latitude ionosphere of the northern hemisphere. The developed method is based on the measurement of the Doppler frequency shift and time of the group delay of the radio signal. Results. The possibility of studying the dynamics of the equatorial boundary of the night side of the Northern auroral oval using characteristics of scattered HF signals of time service stations registered at UAS is demonstrated. Conclusions. In the registrations of HF signals of the RWM station (55.75°N, 37.64°E) at UAS (65.25°S, 64.27°W) it is possible to select the mode scattered on the inhomogeneities of the high-latitude ionosphere of the northern hemisphere. The method for diagnosing the equatorial boundary of the auroral oval by observations on UAS of scattered radio signals from stations of the time service is proposed. It is convenient to use such stations as sources of the probe signal for diagnostic of the ionosphere so far as they have a number of advantages, including low relative frequency instability of master oscillators; weakly directed antennas and sufficiently powerful transmitters thanks to which their signals can be recorded in different regions of the globe; continuous work on a previously known schedule and, finally, the fact that they simultaneously emit at several frequencies, which expands the possibilities of their diagnostic use. The technique does not require additional transmitting devices and expensive antenna systems. The regular measurements using the suggested method allow carrying out the monitoring of auroral ionosphere, which will give the possibility for improving the existent models of its behavior.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.33275/1727-7485.1(17).2018.32&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.33275/1727-7485.1(17).2018.32&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Report 1977Publisher:Mitre Corporation, McLean, VA Authors: D. Carstea;D. Carstea;doi: 10.2172/893023
A detailed analysis was conducted to determine the adequacy of the total research efforts regarding the potential environmental impacts related to the exploration, drilling, production, and transmission stages of vapor-dominated, liquid-dominated, geopressured, and hot-dry-rock geothermal resources. The following environmental considerations were selected and analyzed in detail: air emissions (hydrogen sulfide, ammonia, mercury, boron, radon, etc.); liquid emissions (brine, and toxic chemicals); land subsidence; seismic activity; and noise. Following the definition of the problem and the assessment of the past and ongoing research efforts, environmental research needs were then recommended based on: (1) the severity of the environmental problems as perceived by literature and contacts with the research community; (2) probability of occurrence; (3) and the research dependency for a solution to that particular problem. The recommended research needs consisted of: (1) an evaluation of the past and ongoing research efforts to ascertain gaps in knowledge for a particular pollutant, process, or control technology; (2) baseline studies of air, soil, water, and ecology around the existing geothermal facilities and in the locations scheduled for future geothermal development; (3) need for the development of appropriate models for predicting concentration and dispersion of pollutants; (4) development of predictive models for potential health and environmental effects associated with geothermal operations; and (5) development of appropriate control technology to destroy, remove or reduce harmful emissions in order to prevent the occurrence of environmental and health hazards and to comply with existing standards and criteria.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2172/893023&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2172/893023&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1987Publisher:Elsevier BV Funded by:NSF | Presidential Young Invest...NSF| Presidential Young Investigator Award: Inhomogeneous Earth StructureAuthors: Joan L. Welc; Lay Thorne;Joan L. Welc; Lay Thorne;Abstract The Banda Sea earthquake of November 4, 1963 is one of the largest ( M w = 8.3) intraplate events. It involved oblique thrusting at an intermediate depth within the subducted lithosphere near the abrupt bend in the southeastern Banda arc (6.86° S, 129.58° E). To better understand the tectonic significance of this earthquake, the detailed source process of the Banda Sea event was determined by body wave analysis. The rupture history was established by deconvolving source time functions from long-period P wave seismograms, using both individual station and multi-station time-domain deconvolution methods. The seismic moment release occurred within the first 50 s of rupture, initiating at a depth near 120 km and expanding laterally and downdip over a vertical extent of about 50 km. Slip and moment release were concentrated in one main region near the hypocenter, at depths between 110 and 130 km. The along-strike rupture length was only about 100 km, so it is difficult to resolve any horizontal directivity. The compressional stress orientation inferred from the focal mechanism parallels the strike of the slab, and reflects the importance of contortion of the lithosphere in this region. The Banda Sea event may be part of a major detachment at the leading edge of the subducted Australian continental shelf.
Physics of The Earth... arrow_drop_down Physics of The Earth and Planetary InteriorsArticle . 1987 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/0031-9201(87)90013-6&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 15 citations 15 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert Physics of The Earth... arrow_drop_down Physics of The Earth and Planetary InteriorsArticle . 1987 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/0031-9201(87)90013-6&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2016Publisher:Oxford University Press (OUP) Authors: Blažej Bucha; Juraj Janák; Juraj Papčo; Aleš Bezděk;Blažej Bucha; Juraj Janák; Juraj Papčo; Aleš Bezděk;doi: 10.1093/gji/ggw311
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1093/gji/ggw311&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 31 citations 31 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1093/gji/ggw311&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1970Publisher:Mining and Materials Processing Institute of Japan Authors: Tadashi Nishida; Ken Goto;Tadashi Nishida; Ken Goto;Journal of the Minin... arrow_drop_down Journal of the Mining and Metallurgical Institute of JapanArticle . 1970 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2473/shigentosozai1953.86.990_571&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Journal of the Minin... arrow_drop_down Journal of the Mining and Metallurgical Institute of JapanArticle . 1970 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2473/shigentosozai1953.86.990_571&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Report 1997Publisher:Natural Resources Canada/CMSS/Information Management Authors: S J Sibbick; R G Balma; C Dunn;S J Sibbick; R G Balma; C Dunn;doi: 10.4095/209006
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.4095/209006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.4095/209006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2018Publisher:Elsevier BV Authors: Vanderlucia dos Anjos Cruz; Simone Cerqueira Pereira Cruz; Lydia Maria Lobato; Francisco Javier Rios; +2 AuthorsVanderlucia dos Anjos Cruz; Simone Cerqueira Pereira Cruz; Lydia Maria Lobato; Francisco Javier Rios; Josafá S. Santos; Geraldo Marcelo Pereira Lima;Abstract The Ibicoara high-grade, hypogene hematite deposits are located in the Sao Francisco Craton, in the Chapada Diamantina Fold Thrust belt. Iron mineralization host rocks are quartz and arkose sandstones from the Tombador Formation, which present planar stratification. Regionally, three deformational phases are identified. The first D1 phase developed kink with subordinate chevron folds, shear zones related to flexural slip with S/C structures, stretch lines (LX1), slickenlines and slickensides. The second phase D2 is represented by dextral and sinistral, reverse high-angle shear zones with NNW-SSE and NW-SE orientation trends, respectively, high-angle tension fractures with an ENE-WSW orientation. During the third deformation phase D3, dextral and sinistral shear zones with ENE-WSW and NE-SW orientations are developed. The richest hematite domains are massive, having Fe2O3total contents to 98%. These irregular-massive domains are distributed along the primary sedimentary foliation (plane-parallel stratification and tangential cross-bedding), of D2 shear zones, or tension fractures generated during D2. The irregular-massive hematite domains grade laterally into platy and stringer domains. In addition, there are vein, stockwork and breccia mineralization styles that crosscut irregular-massive domains or host rock. Chemical analyses of hematite in irregular-massive domains show that Fe2O3 correlates negatively with SiO2, Zr, Th, Sr, Nb, Hf and Ba. On the other hand, it correlates positively with Zn, V, U, Cu, Co, and with the sum of rare earth elements (REE). When normalized to the post-Archean Australian Shale (PAAS), the distribution of REE generally show negative Eu anomalies, and a weak enrichment of light rare earth elements (LREE) compared to the heavy rare earth elements (HREE). The paragenetic succession shows the existence of three groups of hematite. Groups 1 and 2 are mainly related to the irregular-massive domains controlled by rock stratification and the S0//S2 foliation in shear zones. The distinction between them is given by the finer grain size of the first generation of hematite and the presence of breccia domain in the second group. The third group is related to massive-vein domains. For each group, the hematite grain size increases successively, and there is a relative increase in the HREE in relation to the LREE. Furthermore, similarities between the chemical signatures of the first groups 1 and 2 hematite generation with the signatures of the host rock reveal an important influence of the chemical composition of the original rock. This is not the case for the late hematite of massive domains, as well as vein-style hematite, suggesting high fluid-rock conditions. The hematite hydrothermal alteration at Ibicoara has structural control, with dilational structures associated with D2 shear zones. The host lithotype was also a contributing factor due to its porosity and permeability, and the presence of sedimentary structures that favored flow of the hydrothermal fluid from shear zones. Replacement and direct precipitation took place and are responsible for the transfer of solutions and formation of hematite-rich areas. The hydrothermal fluid probably leached components from the Espinhaco Supergroup metasedimentary units and dikes that are regionally present, and carried these during the deformational phases that inverted the Paramirim Aulacogen. The Espinhaco Supergroup is characterized by a sequence of siliciclastic rocks, predominantly metasandstones, and felsic metavolcanic rocks, sterile in iron, which were deposited between the Statherian and Stenian periods. In the Chapada Diamantina area, the Espinhaco Supergroup is comprised from base to top by the Serra da Gameleira Formation and the Rio dos Remedios, Paraguacu, and Chapada Diamantina groups. The Chapada Diamantina Group contains the Tombador Formation that hosts the high-grade iron deposits investigated in the present study. In light of the tectonic context, and existence of shear-related gold and baryte hydrothermal deposits nucleated during the Paramirim Aulacogen inversion, the Chapada Diamantina Thrust and Fold Belt is considered a potential regional exploration target.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.oregeorev.2018.06.003&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 4 citations 4 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.oregeorev.2018.06.003&type=result"></script>'); --> </script>
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description Publicationkeyboard_double_arrow_right Article 2018Publisher:The Science Breaker Authors: Daniele Durante;Daniele Durante;add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.25250/thescbr.brk114&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2013Publisher:Hindawi Limited Authors: John A. Fornshell; Alessandra Tesei;John A. Fornshell; Alessandra Tesei;doi: 10.1155/2013/678621
The development of acoustic methods for measuring depths and ranges in the ocean environment began in the second decade of the twentieth century. The two world wars and the “Cold War” produced three eras of rapid technological development in the field of acoustic oceanography. By the mid-1920s, researchers had identified echoes from fish, Gadus morhua, in the traces from their echo sounders. The first tank experiments establishing the basics for detection of fish were performed in 1928. Through the 1930s, the use of SONAR as a means of locating schools of fish was developed. The end of World War II was quickly followed by the advent of using SONAR to track and hunt whales in the Southern Ocean and the marketing of commercial fish finding SONARs for use by commercial fisherman. The “deep scattering layer” composed of invertebrates and fish was discovered in the late 1940s on the echo sounder records. SONARs employing high frequencies, broadband, split beam, and multiple frequencies were developed as methods for the detection, quantification and identification of fish and invertebrates. The study of fish behavior has seen some use of passive acoustic techniques. Advancements in computer technology have been important throughout the last four decades of the twentieth century.
International Journa... arrow_drop_down International Journal of OceanographyArticle . 2013 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 17 citations 17 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert International Journa... arrow_drop_down International Journal of OceanographyArticle . 2013 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1155/2013/678621&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint 2020Publisher:Research Square Platform LLC Authors: Xiaoyan Yang; Juzhi Hou; Feixue San;Xiaoyan Yang; Juzhi Hou; Feixue San;Abstract Continental chemical weathering has been suggested to affect the concentration of atmospheric carbon dioxide that influences global climate change at different time scales. Various indices for chemical weathering have been adopted to investigate past change in chemical weathering intensity and climate change on oceanic and lacustrine sediment archives. The reliability of the chemical weathering indices has been questioned as most sediments likely originate from multiple types of bedrock that may experience various degrees of chemical weathering and can thus be reliably robust indicators of climate and paleoclimate. Here we present Sr-type (e.g. Rb/Sr Sr/Ba) and Na-type (e.g. CIA CIW PIA CPA) chemical weathering indices for top soils across the southern Tibetan Plateau to discuss the chemical weathering characteristic in the Tibetan Plateau and to examine their response to regional climate variation. The results of chemical indices and the A-CN-K ternary plot show that the southern Tibetan Plateau is under the carbonate control of the primary chemical weathering stage with the cold-dry climate. Correlation analyses show shat Sr-type indices co-vary with mean annual temperature and annual precipitation while Na-type indices show little consistence with regional climate. The climate condition is the dominant control of Sr-type indices of top soils in the study area and the bedrock may be the dominant control for the Na-type indices. We also compared the corresponding indices at a Holocene lacustrine sediment profile in the Qaidam Basin in the northeast Tibetan Plateau with regional climatic records which strongly supports our observation in the top soils. The results of the study suggest that for the relative cold and dry climate in Tibetan Plateau the Sr-type indices are more sensitive to climate condition than Na-type indices. This suggests that the Sr-type indices are likely more suitable than Na-type indices to reflect the change of climate on the Tibetan Plateau. Caution should be taken for using the Na-type indices for reconstructing the past change in climate for the study area.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.21203/rs.3.rs-106871/v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.21203/rs.3.rs-106871/v1&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2019Publisher:State Institution National Antarctic Scientific Center, Ministry of Education and Science of Ukraine Authors: O. V. Charkin; A. V. Zalizovski; Yu. M. Yampolski;O. V. Charkin; A. V. Zalizovski; Yu. M. Yampolski;Objective. Developing a technique for investigation of a dynamic of the equatorial boundary of the night side of the Northern auroral oval using data of registrations of scattered HF signals on superlong radio paths. Methods. Spectral, time, and time-frequency analysis of HF signals from time service stations, recorded at the Ukrainian Antarctic Akademik Vernadsky station (UAS). Selection of the spatial mode of signals scattered on the plasma inhomogeneities of the high latitude ionosphere of the northern hemisphere. The developed method is based on the measurement of the Doppler frequency shift and time of the group delay of the radio signal. Results. The possibility of studying the dynamics of the equatorial boundary of the night side of the Northern auroral oval using characteristics of scattered HF signals of time service stations registered at UAS is demonstrated. Conclusions. In the registrations of HF signals of the RWM station (55.75°N, 37.64°E) at UAS (65.25°S, 64.27°W) it is possible to select the mode scattered on the inhomogeneities of the high-latitude ionosphere of the northern hemisphere. The method for diagnosing the equatorial boundary of the auroral oval by observations on UAS of scattered radio signals from stations of the time service is proposed. It is convenient to use such stations as sources of the probe signal for diagnostic of the ionosphere so far as they have a number of advantages, including low relative frequency instability of master oscillators; weakly directed antennas and sufficiently powerful transmitters thanks to which their signals can be recorded in different regions of the globe; continuous work on a previously known schedule and, finally, the fact that they simultaneously emit at several frequencies, which expands the possibilities of their diagnostic use. The technique does not require additional transmitting devices and expensive antenna systems. The regular measurements using the suggested method allow carrying out the monitoring of auroral ionosphere, which will give the possibility for improving the existent models of its behavior.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.33275/1727-7485.1(17).2018.32&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.33275/1727-7485.1(17).2018.32&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Report 1977Publisher:Mitre Corporation, McLean, VA Authors: D. Carstea;D. Carstea;doi: 10.2172/893023
A detailed analysis was conducted to determine the adequacy of the total research efforts regarding the potential environmental impacts related to the exploration, drilling, production, and transmission stages of vapor-dominated, liquid-dominated, geopressured, and hot-dry-rock geothermal resources. The following environmental considerations were selected and analyzed in detail: air emissions (hydrogen sulfide, ammonia, mercury, boron, radon, etc.); liquid emissions (brine, and toxic chemicals); land subsidence; seismic activity; and noise. Following the definition of the problem and the assessment of the past and ongoing research efforts, environmental research needs were then recommended based on: (1) the severity of the environmental problems as perceived by literature and contacts with the research community; (2) probability of occurrence; (3) and the research dependency for a solution to that particular problem. The recommended research needs consisted of: (1) an evaluation of the past and ongoing research efforts to ascertain gaps in knowledge for a particular pollutant, process, or control technology; (2) baseline studies of air, soil, water, and ecology around the existing geothermal facilities and in the locations scheduled for future geothermal development; (3) need for the development of appropriate models for predicting concentration and dispersion of pollutants; (4) development of predictive models for potential health and environmental effects associated with geothermal operations; and (5) development of appropriate control technology to destroy, remove or reduce harmful emissions in order to prevent the occurrence of environmental and health hazards and to comply with existing standards and criteria.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2172/893023&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2172/893023&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1987Publisher:Elsevier BV Funded by:NSF | Presidential Young Invest...NSF| Presidential Young Investigator Award: Inhomogeneous Earth StructureAuthors: Joan L. Welc; Lay Thorne;Joan L. Welc; Lay Thorne;Abstract The Banda Sea earthquake of November 4, 1963 is one of the largest ( M w = 8.3) intraplate events. It involved oblique thrusting at an intermediate depth within the subducted lithosphere near the abrupt bend in the southeastern Banda arc (6.86° S, 129.58° E). To better understand the tectonic significance of this earthquake, the detailed source process of the Banda Sea event was determined by body wave analysis. The rupture history was established by deconvolving source time functions from long-period P wave seismograms, using both individual station and multi-station time-domain deconvolution methods. The seismic moment release occurred within the first 50 s of rupture, initiating at a depth near 120 km and expanding laterally and downdip over a vertical extent of about 50 km. Slip and moment release were concentrated in one main region near the hypocenter, at depths between 110 and 130 km. The along-strike rupture length was only about 100 km, so it is difficult to resolve any horizontal directivity. The compressional stress orientation inferred from the focal mechanism parallels the strike of the slab, and reflects the importance of contortion of the lithosphere in this region. The Banda Sea event may be part of a major detachment at the leading edge of the subducted Australian continental shelf.
Physics of The Earth... arrow_drop_down Physics of The Earth and Planetary InteriorsArticle . 1987 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/0031-9201(87)90013-6&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 15 citations 15 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert Physics of The Earth... arrow_drop_down Physics of The Earth and Planetary InteriorsArticle . 1987 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/0031-9201(87)90013-6&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2016Publisher:Oxford University Press (OUP) Authors: Blažej Bucha; Juraj Janák; Juraj Papčo; Aleš Bezděk;Blažej Bucha; Juraj Janák; Juraj Papčo; Aleš Bezděk;doi: 10.1093/gji/ggw311
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1093/gji/ggw311&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 31 citations 31 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1093/gji/ggw311&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1970Publisher:Mining and Materials Processing Institute of Japan Authors: Tadashi Nishida; Ken Goto;Tadashi Nishida; Ken Goto;Journal of the Minin... arrow_drop_down Journal of the Mining and Metallurgical Institute of JapanArticle . 1970 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2473/shigentosozai1953.86.990_571&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Journal of the Minin... arrow_drop_down Journal of the Mining and Metallurgical Institute of JapanArticle . 1970 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.2473/shigentosozai1953.86.990_571&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Report 1997Publisher:Natural Resources Canada/CMSS/Information Management Authors: S J Sibbick; R G Balma; C Dunn;S J Sibbick; R G Balma; C Dunn;doi: 10.4095/209006
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.4095/209006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.4095/209006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2018Publisher:Elsevier BV Authors: Vanderlucia dos Anjos Cruz; Simone Cerqueira Pereira Cruz; Lydia Maria Lobato; Francisco Javier Rios; +2 AuthorsVanderlucia dos Anjos Cruz; Simone Cerqueira Pereira Cruz; Lydia Maria Lobato; Francisco Javier Rios; Josafá S. Santos; Geraldo Marcelo Pereira Lima;Abstract The Ibicoara high-grade, hypogene hematite deposits are located in the Sao Francisco Craton, in the Chapada Diamantina Fold Thrust belt. Iron mineralization host rocks are quartz and arkose sandstones from the Tombador Formation, which present planar stratification. Regionally, three deformational phases are identified. The first D1 phase developed kink with subordinate chevron folds, shear zones related to flexural slip with S/C structures, stretch lines (LX1), slickenlines and slickensides. The second phase D2 is represented by dextral and sinistral, reverse high-angle shear zones with NNW-SSE and NW-SE orientation trends, respectively, high-angle tension fractures with an ENE-WSW orientation. During the third deformation phase D3, dextral and sinistral shear zones with ENE-WSW and NE-SW orientations are developed. The richest hematite domains are massive, having Fe2O3total contents to 98%. These irregular-massive domains are distributed along the primary sedimentary foliation (plane-parallel stratification and tangential cross-bedding), of D2 shear zones, or tension fractures generated during D2. The irregular-massive hematite domains grade laterally into platy and stringer domains. In addition, there are vein, stockwork and breccia mineralization styles that crosscut irregular-massive domains or host rock. Chemical analyses of hematite in irregular-massive domains show that Fe2O3 correlates negatively with SiO2, Zr, Th, Sr, Nb, Hf and Ba. On the other hand, it correlates positively with Zn, V, U, Cu, Co, and with the sum of rare earth elements (REE). When normalized to the post-Archean Australian Shale (PAAS), the distribution of REE generally show negative Eu anomalies, and a weak enrichment of light rare earth elements (LREE) compared to the heavy rare earth elements (HREE). The paragenetic succession shows the existence of three groups of hematite. Groups 1 and 2 are mainly related to the irregular-massive domains controlled by rock stratification and the S0//S2 foliation in shear zones. The distinction between them is given by the finer grain size of the first generation of hematite and the presence of breccia domain in the second group. The third group is related to massive-vein domains. For each group, the hematite grain size increases successively, and there is a relative increase in the HREE in relation to the LREE. Furthermore, similarities between the chemical signatures of the first groups 1 and 2 hematite generation with the signatures of the host rock reveal an important influence of the chemical composition of the original rock. This is not the case for the late hematite of massive domains, as well as vein-style hematite, suggesting high fluid-rock conditions. The hematite hydrothermal alteration at Ibicoara has structural control, with dilational structures associated with D2 shear zones. The host lithotype was also a contributing factor due to its porosity and permeability, and the presence of sedimentary structures that favored flow of the hydrothermal fluid from shear zones. Replacement and direct precipitation took place and are responsible for the transfer of solutions and formation of hematite-rich areas. The hydrothermal fluid probably leached components from the Espinhaco Supergroup metasedimentary units and dikes that are regionally present, and carried these during the deformational phases that inverted the Paramirim Aulacogen. The Espinhaco Supergroup is characterized by a sequence of siliciclastic rocks, predominantly metasandstones, and felsic metavolcanic rocks, sterile in iron, which were deposited between the Statherian and Stenian periods. In the Chapada Diamantina area, the Espinhaco Supergroup is comprised from base to top by the Serra da Gameleira Formation and the Rio dos Remedios, Paraguacu, and Chapada Diamantina groups. The Chapada Diamantina Group contains the Tombador Formation that hosts the high-grade iron deposits investigated in the present study. In light of the tectonic context, and existence of shear-related gold and baryte hydrothermal deposits nucleated during the Paramirim Aulacogen inversion, the Chapada Diamantina Thrust and Fold Belt is considered a potential regional exploration target.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routeshybrid 4 citations 4 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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