Seafloor gravity roughness

This data collection is associated with the publication: Whittaker, J. M., Müller, R. D., Roest, W. R., Wessel, P., & Smith, W. H. (2008). How supercontinents and superoceans affect seafloor roughness. Nature, 456(7224), 938-941. doi: 10.1038/nature07573Publication AbstractSeafloor roughness varies considerably across the world's ocean basins and is fundamental to controlling the circulation and mixing of heat in the ocean and dissipating eddy kinetic energy. Models derived from analyses of active mid-ocean ridges suggest that ocean floor roughness depends on seafloor spreading rates, with rougher basement forming below a half-spreading rate threshold of 30-35 mm/yr, as well as on the local interaction of mid-ocean ridges with mantle plumes or cold-spots. Here we present a global analysis of marine gravity-derived roughness, sediment thickness, seafloor isochrons and palaeospreading rates of Cretaceous to Cenozoic ridge flanks. Our analysis reveals that, after eliminating effects related to spreading rate and sediment thickness, residual roughness anomalies of 5-20 mGal remain over large swaths of ocean floor. We found that the roughness as a function of palaeospreading directions and isochron orientations indicates that most of the observed excess roughness is not related to spreading obliquity, as this effect is restricted to relatively rare occurrences of very high obliquity angles (> 45 degrees). Cretaceous Atlantic ocean floor, formed over mantle previously overlain by the Pangaea supercontinent, displays anomalously low roughness away from mantle plumes and independent of spreading rates. We attribute this observation to a sub-Pangaean supercontinental mantle temperature anomaly leading to slightly thicker than normal Late Jurassic and Cretaceous Atlantic crust, reduced brittle fracturing and smoother basement relief. In contrast, ocean crust formed above Pacific superswells, probably reflecting metasomatized lithosphere underlain by mantle at only slightly elevated temperatures, is not associated with basement roughness anomalies. These results highlight a fundamental difference in the nature of large-scale mantle upwellings below supercontinents and superoceans, and their impact on oceanic crustal accretion.Authors and InstitutionsJoanne M. Whittaker - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia. ORCID: 0000-0002-3170-3935R. Dietmar Müller - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia. ORCID: 0000-0002-3334-5764Walter R. Roest - Département des Géosciences Marines, Ifremer, FrancePaul Wessel - Department of Geology and Geophysics (SOEST), University of Hawai'i at Mānoa, USAWalter H. F. Smith - National Oceanic and Atmospheric Administration, USAOverview of Resources ContainedThis collection contains gridded gravity and gravity-derived seafloor roughness data. Predictions of seafloor gravity roughness that consider the influences of sediment thickness and spreading rate, and residual seafloor gravity roughness which are produced by removing the influences of sediment thickness and spreading rate from gravity-derived roughness are also provided.List of ResourcesNote: For details on the files included in this data collection, see “Description_of_Resources.txt”.Note: For information on file formats and what programs to use to interact with various file formats, see “File_Formats_and_Recommended_Programs.txt”.Gravity anomalies (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.89 GB)Gravity roughness 100 km (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.9 GB)Masked gravity roughness 100 km (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.46 GB)Gravity roughness 160 km (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.88 GB)Masked gravity roughness 160 km (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.45 GB)Residual gravity roughness (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.55 GB)Predicted gravity roughness (.txt, .nc, .cpt, .kmz, .jpg, .tif, total 2.52 GB)For more information on this data collection, and links to other datasets from the EarthByte Research Group please visit EarthByteFor more information about using GPlates, including tutorials and a user manual please visit GPlates or EarthByte本数据集关联的发表文献为：Whittaker, J. M.、Müller, R. D.、Roest, W. R.、Wessel, P. 与 Smith, W. H.（2008）。《超大陆与超大洋如何影响海底粗糙度（seafloor roughness）》，《自然》，456(7224), 938-941。DOI: 10.1038/nature07573 ### 文献摘要 海底粗糙度（seafloor roughness）在全球大洋盆地中差异显著，其对于控制海洋热量的循环与混合、消散涡动动能（eddy kinetic energy）至关重要。基于活动洋中脊（mid-ocean ridges）分析构建的模型表明，洋底粗糙度取决于海底扩张速率（seafloor spreading rates）：当半扩张速率（half-spreading rate）低于30~35 mm/yr的阈值时，会形成更为粗糙的洋壳基底；同时洋底粗糙度也与洋中脊和地幔柱（mantle plumes）或冷点（cold-spots）的局部相互作用有关。本研究针对白垩纪（Cretaceous）至新生代（Cenozoic）洋脊侧翼的海洋重力反演海底粗糙度（marine gravity-derived roughness）、沉积物厚度、海底等时线（seafloor isochrons）与古扩张速率（palaeospreading rates）开展了全球尺度分析。分析结果显示，在去除扩张速率与沉积物厚度的影响后，全球大片洋底仍存在5~20毫伽（mGal）的剩余粗糙度异常（residual roughness anomalies）。研究发现，以古扩张方向与等时线走向为变量的粗糙度分布特征表明，绝大多数观测到的过剩粗糙度与扩张斜度无关——该效应仅见于极少数极高斜度角（>45°）的情形。形成于此前被泛大陆（Pangaea）覆盖的地幔之上的白垩纪大西洋洋底，在远离地幔柱且不受扩张速率影响的区域呈现出异常偏低的粗糙度。我们将该现象归因于泛大陆之下的超大陆地幔温度异常：该异常导致晚侏罗世至白垩纪大西洋洋壳厚度略高于正常值，脆性破裂（brittle fracturing）作用减弱，洋壳基底起伏更为平缓。与之相反，形成于太平洋超升区（Pacific superswells）之上的洋壳，其下方为温度仅略微升高的地幔交代岩石圈（lithosphere），并未伴随洋底基底粗糙度异常。上述研究结果揭示了超大陆与超大洋下方大规模地幔上涌的本质差异，以及其对洋壳增生（oceanic crustal accretion）过程的影响。 ### 作者与研究机构 乔安妮·M·惠特克（Joanne M. Whittaker）——澳大利亚悉尼大学地球科学学院EarthByte研究组。ORCID: 0000-0002-3170-3935 R·迪特马尔·米勒（R. Dietmar Müller）——澳大利亚悉尼大学地球科学学院EarthByte研究组。ORCID: 0000-0002-3334-5764 沃尔特·R·罗斯特（Walter R. Roest）——法国法国海洋开发研究院（Ifremer）海洋地质科学系 保罗·韦塞尔（Paul Wessel）——美国夏威夷大学马诺阿分校地质与地球物理系（SOEST） 沃尔特·H·F·史密斯（Walter H. F. Smith）——美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA） ### 数据集资源概览 本数据集包含网格化重力数据与重力反演海底粗糙度（marine gravity-derived roughness）数据。同时还提供了考虑沉积物厚度与扩张速率影响的洋底重力粗糙度预测数据，以及通过从重力反演粗糙度中去除沉积物厚度与扩张速率影响得到的剩余洋底重力粗糙度数据。 ### 资源列表 注意：本数据集包含的文件详情请参阅《Description_of_Resources.txt》。 注意：关于文件格式以及适配各类格式的操作软件信息，请参阅《File_Formats_and_Recommended_Programs.txt》。 重力异常数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.89 GB） 100km分辨率重力粗糙度数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.9 GB） 掩膜100km分辨率重力粗糙度数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.46 GB） 160km分辨率重力粗糙度数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.88 GB） 掩膜160km分辨率重力粗糙度数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.45 GB） 剩余重力粗糙度数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.55 GB） 重力粗糙度预测数据（.txt, .nc, .cpt, .kmz, .jpg, .tif，总大小2.52 GB） 如需了解本数据集的更多信息，以及获取EarthByte研究组发布的其他数据集，请访问EarthByte官网。 如需了解GPlates的使用方法（包括教程与用户手册），请访问GPlates或EarthByte官网。