An exploration method for the radiation of ion adsorption-type rare earth element deposits based on multi-channel gamma-ray spectrometry: A case study of the Dechang area in the Panzhihua-Xichang region
LI Huai-Yuan1,2(), NIE Fei1(), JIANG Shou-Jin1, HU Jun-Feng1, ZOU Jia-Zuo1, GUO Jin-Chen1
1. Civil-Military Integration Center of Geological Survey, China Geological Survey, Chengdu 610000,China 2. School of Geophysics, Chengdu University of Technology, Chengdu 610000, China
The Mianning-Dechang rare earth element (REE) metallogenic belt exhibits considerable resource potential. Previous prospecting was oriented to hard-rock REE deposits associated with Himalayan alkaline complexes, with ion adsorption-type REE deposits under-studied. To explore the mineralization prospect of granite weathering crusts widespread in the metallogenic belt, this study investigated the Shizishan area through multi-channel gamma-ray spectrometry, soil profile survey, and shallow drilling. One ion adsorption-type REE ore occurrence was identified in the granite weathering crust at Mosuoying. This study analyzed the radioactive response of the geological, geophysical, and geochemical profiles and ore contents, finding that the elemental contents of thorium (Th) and potassium (K) were highly indicative of REE and rare metal mineralization. Highly mineralized, industrial-scale ion adsorption-type REE deposits will likely occur when 6.25<w(Th)/w(K)<10, w(eTh)>37×10-6, and w(eK)>4.2%. As revealed by the analysis of the response of radioactive anomalies to supergene weathering, thorium anomaly halos can effectively indicate granitic plutons while potassium anomaly halos can well delineate the extent of granite weathering crusts.
Huai-Yuan LI,Fei NIE,Shou-Jin JIANG, et al. An exploration method for the radiation of ion adsorption-type rare earth element deposits based on multi-channel gamma-ray spectrometry: A case study of the Dechang area in the Panzhihua-Xichang region[J]. Geophysical and Geochemical Exploration,
2024, 48(5): 1275-1283.
Tectonic map (a) and geological map (b) of the study area 1—fine-grained dolomitic diorite of Maoping unit; 2—coarse-medium-grained black dolomitic diorite of Kelang unit; 3—fine-grained porphyritic dolomitic diorite of Ranfangou unit; 4—Quaternary system; 5—measured faults; 6—extent of gamma-energetic spectral profiles; 7—extent of soil profiles; 8-Physical and chemical composite profiles; 9—phyllic dyke veins, granitic porphyritic veins; 10—drill holes
代号
铀含量/10-6
钍含量/10-6
钾含量/10-6
异常上限/10-6
频数
S
CV
S
CV
S
CV
U
Th
K
Q
4.98
1.88
0.38
18.85
9.02
0.48
2.12
1.04
0.49
7.35
26.39
3.63
41
Pt2R
7.90
2.47
0.31
28.64
10.87
0.38
3.81
1.31
0.34
7.90
64.47
6.64
243
Pt2K
7.45
2.31
0.31
30.64
10.44
0.34
3.71
1.24
0.33
16.91
68.33
7.37
1159
Pt2M
11.07
2.49
0.23
34.01
11.69
0.34
5.98
1.37
0.23
11.07
60.06
5.98
15
Q
7.09
2.12
0.29
24.7
7.98
0.32
3.29
0.98
0.29
16.58
65.98
6.25
755
平均值
7.28
2.33
0.32
28.01
10.47
0.37
3.56
1.25
0.35
Gamma-ray spectrum parameters of major geologic bodies in the study area
Plane contour map of the results of ground-based gamma spectrometry measurements at Shizishan a—plane contour of uranium channel content;b—plane contour of thorium channel content;c—plane contour of potassium channel content;d—plane of total tract content
参数
土壤地球化学元素
元素
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Y
Sc
Nb
Ta
最小值/10-6
15
35.8
3.99
15.7
4.67
0.24
4.41
0.88
5.9
1.23
3.49
0.54
3.29
0.51
32.6
5
6.88
0.73
最大值/10-6
310
522
114
402
95.3
4.05
84.8
17.6
117
24.7
70.4
9.55
55.6
7.23
723
52.3
50.7
6.52
平均值/10-6
81.7
185.4
23.3
83
20.2
1.2
17.3
3.5
23.3
4.9
14.1
2.2
13.6
2
139.6
16.8
28
3.1
藏北地台 丰度/10-6
16.4
30.8
3.69
17.8
2.85
0.68
2.7
0.44
2.4
0.46
1.4
0.21
1.4
0.21
11.3
9.8
18
2.3
丰度系数
5
6
6.3
4.7
7.1
1.7
6.4
7.9
9.7
10.7
10.1
10.4
9.7
9.4
12.4
1.7
1.6
1.4
Characterization of measured content of soil profiles in the study area
Shallow drill sampling grade map of Shizishan (red line is boundary grade)
L240 comprehensive physico-chemical profile
Scatter plot of the correlation between rare earth oxides and the content of each single element a—Th,K element scatter plot;b—U,K element scatter plot;c—Th,U element scatter plot
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