{"title":"Dyke swarms of Onenhste and adjacent coronae in Parga Chasmata, SE of Atla Regio, Venus: Detailed mapping, swarm interactions and geological history","authors":"","doi":"10.1016/j.icarus.2024.116269","DOIUrl":null,"url":null,"abstract":"<div><p>Parga Chasmata is a 10,000 km long rift system on Venus with abundant coronae (enigmatic circular tectonomagmatic features). In order to further investigate the rift-corona relationship, detailed 1:500,000 geological mapping was focused on Onenhste Corona and the surrounding region (16°-24° S, 145°-131° W). More than 46,000 extensional lineaments were mapped and grouped into 50 sets, comprising 17 radiating, 28 circumferential and 5 linear sets (interpreted to overlie mafic dyke swarms). Radiating and circumferential swarms are linked with Onenhste Corona (OC), Momu Coronae (MC), Ulgen-ekhe Coronae (UEC), Rzhanitsa Corona (RzC, centred just outside the study area) and 5 Unnamed Coronae (UC1–5), as well as Malibran Patera (MP) and Fedchenko Patera (FP). Linear swarms are provisionally linked with magmatic centres outside the study area. Crosscutting relationships between the graben sets (dyke swarms) were used to identify the relative ages of magmatic centres. We applied an additional approach to recognize coeval centres, the swinging or deflection of radiating and circumferential dyke swarms to reveal the stress interaction between different coeval centres. The relative ages (oldest to youngest) of the magmatic centres are UC2 > RzC > MC ≥ OC = UC1 = UEC ≥ MP > UC5, and FP > UC3. These new detailed data provide significant information on coronae timing, evolution and relation to rift zones that will serve as a basis for future quantitative studies of lithospheric and mantle evolution and the combined cause and effect of rifting and mantle diapiric upwelling.</p><p>Several centres, RzC, UC2, MC, UC3 and FP, ordered from NW to SE, are aligned along a trend parallel to Parga Chasmata but offset about 900 km to the south from the main zone of rifting. It is inferred that this alignment is related to a zone of weakness associated with the rift extension. Along this trend the centres do not show an age progression.</p><p>Coronae MC, OC, UC1 and UEC are aligned along the NNE trending P13 Linea, orthogonal to the main Parga Chasmata rift. The main centre, Onenhste, is coeval with UC1, which in turn is coeval with UEC. Additional age relationships indicate that the late stage of OC was active at the same time as MP, MC and the UC2–9 centre of UC2. Linea P13 is older than Chondi Chasma. This study, and continuing, detailed geological mapping and analysis are increasing our understanding of the relationships between the formation of the main WNW trending Parga Chasmata rift zone, the orthogonal trends of rifting and the numerous magmatic centres (mainly coronae) distributed along both trends.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0019103524003294/pdfft?md5=91dee2a1412e238618cf7d74a972f653&pid=1-s2.0-S0019103524003294-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Icarus","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0019103524003294","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Parga Chasmata is a 10,000 km long rift system on Venus with abundant coronae (enigmatic circular tectonomagmatic features). In order to further investigate the rift-corona relationship, detailed 1:500,000 geological mapping was focused on Onenhste Corona and the surrounding region (16°-24° S, 145°-131° W). More than 46,000 extensional lineaments were mapped and grouped into 50 sets, comprising 17 radiating, 28 circumferential and 5 linear sets (interpreted to overlie mafic dyke swarms). Radiating and circumferential swarms are linked with Onenhste Corona (OC), Momu Coronae (MC), Ulgen-ekhe Coronae (UEC), Rzhanitsa Corona (RzC, centred just outside the study area) and 5 Unnamed Coronae (UC1–5), as well as Malibran Patera (MP) and Fedchenko Patera (FP). Linear swarms are provisionally linked with magmatic centres outside the study area. Crosscutting relationships between the graben sets (dyke swarms) were used to identify the relative ages of magmatic centres. We applied an additional approach to recognize coeval centres, the swinging or deflection of radiating and circumferential dyke swarms to reveal the stress interaction between different coeval centres. The relative ages (oldest to youngest) of the magmatic centres are UC2 > RzC > MC ≥ OC = UC1 = UEC ≥ MP > UC5, and FP > UC3. These new detailed data provide significant information on coronae timing, evolution and relation to rift zones that will serve as a basis for future quantitative studies of lithospheric and mantle evolution and the combined cause and effect of rifting and mantle diapiric upwelling.
Several centres, RzC, UC2, MC, UC3 and FP, ordered from NW to SE, are aligned along a trend parallel to Parga Chasmata but offset about 900 km to the south from the main zone of rifting. It is inferred that this alignment is related to a zone of weakness associated with the rift extension. Along this trend the centres do not show an age progression.
Coronae MC, OC, UC1 and UEC are aligned along the NNE trending P13 Linea, orthogonal to the main Parga Chasmata rift. The main centre, Onenhste, is coeval with UC1, which in turn is coeval with UEC. Additional age relationships indicate that the late stage of OC was active at the same time as MP, MC and the UC2–9 centre of UC2. Linea P13 is older than Chondi Chasma. This study, and continuing, detailed geological mapping and analysis are increasing our understanding of the relationships between the formation of the main WNW trending Parga Chasmata rift zone, the orthogonal trends of rifting and the numerous magmatic centres (mainly coronae) distributed along both trends.
期刊介绍:
Icarus is devoted to the publication of original contributions in the field of Solar System studies. Manuscripts reporting the results of new research - observational, experimental, or theoretical - concerning the astronomy, geology, meteorology, physics, chemistry, biology, and other scientific aspects of our Solar System or extrasolar systems are welcome. The journal generally does not publish papers devoted exclusively to the Sun, the Earth, celestial mechanics, meteoritics, or astrophysics. Icarus does not publish papers that provide "improved" versions of Bode''s law, or other numerical relations, without a sound physical basis. Icarus does not publish meeting announcements or general notices. Reviews, historical papers, and manuscripts describing spacecraft instrumentation may be considered, but only with prior approval of the editor. An entire issue of the journal is occasionally devoted to a single subject, usually arising from a conference on the same topic. The language of publication is English. American or British usage is accepted, but not a mixture of these.