Method for delineating exploration reserved areas of deep-sea polymetallic sulfide resources

A method for delineating exploration reserved areas of deep-sea polymetallic sulfide resources, comprising the following steps:

• Step 1, a stage of extracting and grading prospecting indicators, including extracting prospecting indicators of deep-sea sulfide resources, specifying the characteristics of the indicators and determining the grades of the indicators;
• wherein the specific steps are as follows:
• Step 1.1:
• during carrying out exploration operations for the deep-sea polymetallic sulfide resources in a target sea area, through measured data obtained by geological investigation, sampling tests, and geophysical and geochemical measurements, extracting the prospecting indicators of deep-sea polymetallic sulfide resources, including (1) plume information, (2) geophysical information, (3) geochemical information, (4) biological information, (5) wall rock alteration information and (6) mineralized outcrop information;
• Step 1.2:
• specifying the characteristics of the prospecting indicators;
• (1) characteristics of the plume information:
• high temperature-salinity, high turbidity, low redox potential, high methane, high dissolved Mn2+ and Fe2+, high He isotope and 3He/4He ratio, with the seawater elements within 100 m around as background values;
• (2) the characteristics of the geophysical information:
• weak magnetism, high polarization, low resistance and high density relative to the background values within 200 m from the seabed;
• (3) the characteristics of the geochemical information:
• Cu—Zn—Fe—Mn combination element anomaly, metalliferous sediment index (MSI, calculated as Al/(Al+Fe+Mn)) anomaly, Cu/Fe anomaly;
• (4) the characteristics of the biological information:
• typical hydrothermal organisms, including anemones, armored shrimp, mioga and mussels;
• (5) the characteristics of the wall rock alteration information:
• silicification, chloritization, epidotization, zeolitization, iddingsitization, serpentinization and carbonatization;
• (6) the characteristics of the mineralized outcrop information:
• polymetallic sulfide chimneys and polymetallic sediments;
• Step 1.3:
• specifying the grades of the prospecting indicators according to the credibility of the prospecting indicators, wherein the grades of the prospecting indicators are from low to high as follows:
• (1) plume information, (2) geophysical information, (3) geochemical information, (4) biological information, (5) wall rock alteration information and (6) mineralized outcrop information;
• Step 2:
• a stage of evaluating metallogenic prospect areas, including delineation of control ranges indicated by various prospecting indicators, and delineation of the prospect areas based on the prospecting indicators;
• wherein the specific steps are as follows:
• Step 2.1:
• delineating the scopes of abnormal areas based on the prospecting indicators, which is specifically as follows:
• (1) the plume information:
• firstly, excluding terrain areas higher than a water body anomaly near where the water body anomaly is discovered according to topographic data, and then tracing the plume information according to local flow field distribution characteristics so as to delineate the scopes of water abnormal areas;
• (2) geophysical information:
• delineating magnetic abnormal areas according to magnetic detection result;
• (3) the geochemical information:
• delineating geochemical information abnormal areas in different grades according to the number of sulfide particles found in sediments, and the intensity of heavy mineral anomalies and the anomalies of Cu, Zn, Fe and Pb elements;
• (4) the biological information:
• areas that are 100 m away from the borders of enrichment areas of anemones, armored shrimps, mioga and mussels or remains thereof are taken as biological abnormal areas;
• (5) the wall rock alteration information:
• areas that are 2000 m away from rocks or sediments with grayish brown, brown, yellow and red color changes are taken as wall rock alteration abnormal areas;
• (6) the mineralized outcrop information:
• areas that are 800 m away from brown and reddish-brown sulfides with mound, chimney, layer and breccia shapes that are direct evidences of sulfide areas are taken as sulfide abnormal areas;
• for distribution areas with hydrothermal opals, chimneys, areas that are 500 m away from mounds and chimneys are taken as mounds and chimneys abnormal areas, and areas 2000 m away from layered and other occurrences are taken as layered occurrences abnormal areas;
• Step 2.2:
• delineating the prospect areas with closed curves based on the prospecting indicators in the previous step and the delineation scopes of the abnormal areas, wherein a single prospecting indicator can be delineated as a prospect area;
• when the prospect area contains all prospecting indicators, and the positions of various types of prospecting indicators overlap, but the positions do not completely overlap, all kinds of abnormal scopes are delineated within the prospect area;
• Step 3:
• a stage of delineation of the exploration reserved areas, including evaluation and classification of the prospecting indicators, delineating grades of the prospect areas, and taking prospect areas with higher grades as the exploration reserved areas in turn;
• wherein the specific steps are as follows:
• Step 3.1:
• dividing the grades of the prospect areas into grade I, grade II and grade III sequentially in terms of resource potentials from high to low according to the types of the prospecting indicators and the grades of the prospecting indicators in the prospect areas, wherein low-grade prospect areas can contain high-grade prospect areas, and high-grade prospect areas cannot contain low-grade prospect areas;
• Step 3.2:
• delineating the exploration reserved areas according to the grades of the prospect areas, and obtaining exploration reservation area delineation results for guiding subsequent exploration and resource evaluation of deep-sea polymetallic sulfide resources.