{"title":"Bottom Relief and Magnetic Anomaly of the Ninetyeast Ridge Near 5°","authors":"","doi":"10.1134/s0001437023060073","DOIUrl":null,"url":null,"abstract":"<span> <h3>Abstract</h3> <p>The geophysical survey on cruise 42 of the R/V <em>Akademik Boris Petrov</em> (2017) in the survey area near site 758 ODP significantly refined knowscarp about the bottom topography of the northern segment of the Ninetyeast Ridge. It is crossed by E–W transversal linear troughs, which are apparently young tectonic fractures. The morphology of the narrow elevated block in the central part of the deep depression between neighboring large volcanic edifices has been characterized in detail. In addition to linear tectonic structures, the main features of this block are two volcanic seamounts. A detailed magnetic survey in this area identified for the first time the nature of sources of magnetic anomalies on the Ninetyeast Ridge. Intense local magnetic anomalies have been observed here, both confined to local structures of the bottom and basement relief, and clearly unrelated to them. These anomalies have a complex interfering nature caused by the superposition of fields from sources separated by magnetization, spatial position, and age. According to the results of paleomagnetic analysis of the anomalies, the age of the structures here is very wide: the youngest features formed about 20 Ma ago, and the oldest, over 80 Ma ago.</p> </span>","PeriodicalId":54692,"journal":{"name":"Oceanology","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Oceanology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1134/s0001437023060073","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"OCEANOGRAPHY","Score":null,"Total":0}
引用次数: 0
Abstract
The geophysical survey on cruise 42 of the R/V Akademik Boris Petrov (2017) in the survey area near site 758 ODP significantly refined knowscarp about the bottom topography of the northern segment of the Ninetyeast Ridge. It is crossed by E–W transversal linear troughs, which are apparently young tectonic fractures. The morphology of the narrow elevated block in the central part of the deep depression between neighboring large volcanic edifices has been characterized in detail. In addition to linear tectonic structures, the main features of this block are two volcanic seamounts. A detailed magnetic survey in this area identified for the first time the nature of sources of magnetic anomalies on the Ninetyeast Ridge. Intense local magnetic anomalies have been observed here, both confined to local structures of the bottom and basement relief, and clearly unrelated to them. These anomalies have a complex interfering nature caused by the superposition of fields from sources separated by magnetization, spatial position, and age. According to the results of paleomagnetic analysis of the anomalies, the age of the structures here is very wide: the youngest features formed about 20 Ma ago, and the oldest, over 80 Ma ago.
摘要 Akademik Boris Petrov 号考察船第 42 航次（2017 年）在 758 ODP 号站点附近的勘测区进行的地球物理勘测极大地完善了对九曲东海脊北段底部地形的认识。它被东西向的横向线槽穿过，这些线槽显然是年轻的构造断裂。在相邻大型火山建筑物之间的深凹陷中央部分的狭窄隆起地块的形态特征已得到详细描述。除线性构造结构外，该区块的主要特征是两个火山海山。在这一地区进行的详细磁力勘测首次确定了九曲海脊磁异常源的性质。在这里观察到了强烈的局部磁异常现象，既有局限于海底和基底地形的局部结构，也有明显与之无关的异常现象。这些异常现象具有复杂的干扰性质，是由磁化、空间位置和年代不同的磁场源叠加造成的。根据对异常现象的古地磁分析结果，这里的结构年代非常宽泛：最年轻的特征形成于大约 20 Ma 之前，而最古老的则形成于 80 Ma 之前。
期刊介绍：
Oceanology, founded in 1961, is the leading journal in all areas of the marine sciences. It publishes original papers in all fields of theoretical and experimental research in physical, chemical, biological, geological, and technical oceanology. The journal also offers reviews and information about conferences, symposia, cruises, and other events of interest to the oceanographic community.
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