基于地形的海底热液区沉积物分布趋势预测方法研究——以西南印度洋中脊龙角区为例

Study on prediction method of sediment distribution trend in seafloor hydrothermal field based on topography:A case study of Dragon Horn area on the Southwest Indian Ridge

热液区沉积物接受了大量热液物质的输入,其矿物组成及地球化学空间分布特征是多金属硫化物勘探的有效指标。由于重力作用,洋中脊区域沉积物主要分布于低洼和平坦地形区。为了探索地形因素对热液区沉积物分布的影响规律,本文通过ArcGIS提出了一种基于地形数据的海底热液区沉积物分布趋势预测方法,并对西南印度洋中脊龙角区地形数据进行了分析,包括沉积物重力搬运方向提取、沉积物汇集量估算、海底沟谷提取和沉积物源区划分。通过与研究区底质解译结果进行对比验证发现,预测结果与研究区内沉积物的实际分布范围较为吻合,表明本方法在一定程度上可以有效地指示地形影响下海底热液区沉积物的分布情况。本方法对海底硫化物矿产勘探工作具有一定指导意义,可为海底沉积物取样站位设置与海底硫化物成矿远景区圈定提供参考依据。

The sediments in the hydrothermal field received a large amount of hydrothermal input,and their mineral compositions and geochemical spatial distribution characteristics are effective indicators for polymetallic sulfide exploration.Due to gravity,sediments in the mid-ocean ridge area are mainly distributed in low-lying and flat terrain areas.In order to explore the influence of topographical factors on the distribution of sediments in the hydrothermal field,this paper proposes a prediction method of sediment distribution trend in seafloor hydrothermal field based on topography data through ArcGIS,and analyzes the topographic data of Dragon Horn area on the Southwest Indian Ridge,including the extraction gravity transport direction of sediment,the estimation of sediment accumulation amount,the extraction of submarine ditch valley and the division of sediment source area.By comparison and verification with the interpretation results of the seafloor camera data of the study area,we found that the prediction results are in good agreement with the actual distribution range of the sediments in the study area,indicating that this method can effectively indicate the distribution of sediments in the submarine hydrothermal field under the influence of terrain to a certain extent.This method has certain guiding significance for the exploration of submarine sulfide minerals,and could provides a reference basis for the setting of sampling stations for seafloor sediments and the delineation of polymetallic sulfide mineralization prospects.