利用多波束回波强度进行中太平洋潜鱼海山底质分类

中、西太平洋海山区是富钴结壳的重要富集区，钙质远洋沉积、碳酸盐岩沉积及重力作用引起的滑塌沉积是海山山顶和斜坡的主要沉积类型，它们的空间分布规律对于富钴结壳的分布至关重要.在国内首次利用EM122多波束回波强度资料对中太平洋潜鱼海山进行了底质类型研究，对回波强度资料进行处理和统计分类，并与浅地层剖面和地质取样结果对比，分析得出了4种底质类型，即富钴结壳、钙质远洋沉积、碳酸盐岩基底及碎屑流沉积.这几种底质类型具有不同的回波强度特征，其中富钴结壳区表现为均一的回波强度高值特征；钙质远洋沉积区表现为均一的回波强度低值特征，二者回波强度值相差约20 dB.结果显示潜鱼海山山顶仅局部发育钙质远洋沉积，大部分为碳酸盐岩基底出露区，山顶边缘及侧翼山脊处为主要的富钴结壳分布区.此外，该海山存在3处较大规模的重力滑塌沉积区，主要为碎屑流沉积. 

Classification of Seafloor Geological Types of Qianyu Seamount from Mid-Pacific Seamounts Using Multibeam Backscatter Intensity Data

Cobalt-rich ferromanganese crusts are mainly distributed around the top brim and on the slope of Mid-Pacific seamounts and West Pacific seamounts. Calcium-pelagic sediment, carbonate rock and debris flow driven by gravity process are main seafloor sediment types of seamounts, which control the distribution of cobalt-rich ferromanganese crusts. In this paper, multibeam backscatter intensity data from EM122 multibeam system are first used in China to recognize seafloor geological types of Qianyu seamount on Mid-Pacific seamounts. Backscatter data are processed and classified statistically with verification of sub-bottom profile and ground-truthing data to identify four seafloor geological types including cobalt-rich crust, calcium-pelagic sediment, carbonate rock and debris flow. Different backscatter intensities are represented by different seafloor geological types, cobalt-rich crust area shows as uniform strong backscatter intensity representing, and calcium-pelagic sediment area shows as uniform weak backscatter, their backscatter difference is about 20 dB. The top of Qianyu seamount is mostly outcropped by carbonate rock, and locally covered by calcium-pelagic sediment, and cobalt-rich crust distribute around the top brim and southern and eastern slope ridges. Furthermore, three gravity slide areas are recognized on the Qianyu seamount, which are of debris flows.