| CPC H01J 49/105 (2013.01) [G01N 1/286 (2013.01); G01N 33/389 (2024.05); H01J 49/0463 (2013.01); G01N 2001/2866 (2013.01)] | 6 Claims |

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1. A method for determining a direction and a distance of a metallogenic pluton of a skarn deposit with a garnet, comprising:
(1) collecting a sample:
collecting a representative garnet sample from the skarn;
(2) performing petrographic observation on the sample and designing an experimental area:
grinding a collected sample into a probe piece, and determining and marking a single mineral crystal area of the garnet;
(3) computing a parameter:
obtaining a trace element content of a marked area through laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) in-situ microanalysis, and computing a ratio (L/H) of a light rare earth content to a heavy rare earth content;
(4) building a model:
substituting the obtained ratio (L/H) of the light rare earth content to the heavy rare earth content into exponential models D=a′(L/H) b and D=a′(L/H) b+c and a logarithmic model D=a′(ln(L/H)+4) (b+0.1);
(5) setting a parameter range:
setting a parameter a′∈[−1000,1000] with a step size of 50, and setting a parameter b∈[−10,10] with a step size of 0.5 in the exponential model D=a′(L/H) b;
setting a parameter a′∈[−1000,1000] with a step size of 50, setting a parameter b∈[−10,10] with a step size of 0.5, and setting a parameter c∈[−1000,1000] with a step size of 50 in the exponential model D=a′(L/H) b+c; and
setting a parameter a′∈[−1000,1000] with a step size of 50, and setting a parameter b∈[−10,10] with a step size of 0.5 in the logarithmic model D=a′(ln(L/H)+4) (b+0.1);
(6) optimizing parameters of the model:
optimizing the parameters of the three models through a grid search method, and determining optimized parameters a′, b and c of the three models respectively through repeated circulative iteration and by taking a minimum R as a limit condition;
wherein R represents an optimized buffer radius:
![]() and has a threshold ≤60 m; and
n represents the samples number, i represents a sampling point i, Di represents a linear distance in m between an optimal location of the metallogenic pluton and the sampling point i, ri represents a linear distance in m between a location of the metallogenic pluton obtained from an optimal parameter model for the sampling point i and the sampling point i, and D′ represents an absolute value in m of a difference between Di and ri; and
(7) locating and delineating the metallogenic pluton:
taking a model with a minimum R among the three models as an optimal model, substituting data of all sampling points into the optimal model, computing D of each sampling point, drawing a circle with a corresponding sampling point as a center and D as the radius, determining an intersection point of all circles as coordinates (X, Y) of the metallogenic pluton, and performing delineation with R as a buffer area of the metallogenic pluton.
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