古地磁学在矿床研究中的应用

黄玺; 郑义; 陈炳辉; 王成明; 虞鹏鹏

doi:10.12090/j.issn.1006-6616.2019.25.S1.002

古地磁学在矿床研究中的应用

doi: 10.12090/j.issn.1006-6616.2019.25.S1.002

黄玺^1,,
郑义^{1, 2, 3, 4, ,},
陈炳辉^{1, 4},
王成明¹,
虞鹏鹏¹

1.
中山大学地球科学与工程学院, 广东广州 510275
2.
广东省地质过程与矿产资源探查重点实验室, 广东广州 510275
3.
广东省地球动力作用与地质灾害重点实验室, 广东广州 510275
4.
南方海洋科学与工程广东省实验室, 广东珠海 519000

基金项目:

广东省自然科学基金杰出青年基金 2018B030306021

详细信息

作者简介:
黄玺(1996-), 男, 在读硕士, 地球化学专业。E-mail:huangx276@mail2.sysu.edu.cn

通讯作者:
郑义(1984-), 男, 博士, 副教授, 矿床学。E-mail:zhengy43@mail.sysu.edu.cn

中图分类号: P318.44
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出版历程
- 刊出日期: 2019-05-01

APPLICATION OF PALEOMAGNETISM IN ORE DEPOSIT STUDY

HUANG Xi^1
,,
ZHENG Yi^{1, 2, 3, 4
, ,},
CHEN Binghui^{1, 4},
WANG Chengming¹,
YU Pengpeng¹

1.
School of Earth Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
2.
Guangdong Provincial Key Lab of Geological Processes and Mineral Resource Survey, Guangzhou 510275, Guangdong, China
3.
Guangdong Provincial Key Lab of Geodynamic and Geohazards, School of Earth Science and Engineering, Guangzhou 510275, Guangdong, China
4.
Southern Laboratory of Ocean Science and Engineering, Zhuhai 519000, Guangdong, China

摘要

摘要: 古地磁学是研究地质历史上地球磁场强度及其变化的一门学科，其核心是岩石中富含若干的磁性矿物。通过测定其保存的剩磁强度和方向等，可计算获得岩石形成时的初始磁性强度和方向，从而为约束岩石形成时的古磁极位置、形成时代和地球动力学背景等研究提供证据。矿石作为地球演化过程中形成的一类特殊的岩石，对其进行古地磁研究可为矿床的"源—运—储—保—变"等过程提供强有力的证据。现有关于矿床古地磁学的研究主要集中在两方面，一是通过矿物的退磁参数限定其形成时的磁化年龄（矿床定年），二是通过磁组构信息获取矿床形成后的构造应力场变化（矿床保存变化）。需要指出的是，矿床古地磁学的研究一定要立足于地质事实。由于地质产状和围岩蚀变对磁性参数的影响极大，在进行矿床地磁数据处理时一定要慎重，并与磁性地层学互相印证，才有可能获得有价值的磁性参数，从而为约束矿床成因提供有效证据。
- 古地磁 /
- 矿床 /
- 磁组构 /
- 磁性地层学
Abstract: Paleomagnetism is a geological methodology focusing on the magnetic parameters and their variation regulation of geomagnetic field during the Earth history. The core is several magnetic minerals in rocks. By measuring preserved remanence and direction, the initial magnetic strength and direction in rock-forming process can be calculated. It constrains paleomagnetic pole position, rock-forming age and geodynamics background. Ore, a special kind of rock in earth evolution, determines source-transport-storage-preserve-change in deposit-forming process by paleomagnetism study. The present study on paleomagnetism of ore deposits mainly focuses on two aspects: (1) Demagnetization parameters of minerals are used to determine the age of magnetization at the time of formation (dating of the ore deposit) (2) Tectonic stress field changes after the formation of the ore deposit are obtained through magnetic fabric data(Ore deposit preservation changes).More importantly, geological facts are the foundation of paleomagnetism of ore deposits. Due to the great influence of geological occurrence and wall-rock alteration on magnetic parameters, caution must be taken in the processing of geomagnetic data of mineral deposits, and the mutual verification with magnetic stratigraphy can make it possible to obtain valuable magnetic parameters, thus providing effective evidence for restricting the genesis of mineral deposits.
- paleomagnetism /
- ore deposit /
- magnetic fabric /
- magnetostratigraphy

HTML全文

图 1 劳伦大陆到欧洲晚古生代部分视极移路径图(APWP)(据文献[7])

Figure 1. Partial apparent polar wander path(APWP) of late Paleozoic from Laurentia to Europe(Figure from [7])

下载: 全尺寸图片幻灯片

图 2 Cloud矿区矿石退磁曲线(据文献[9])

Figure 2. Orthogonal vector plots for the remanence of example specimens on alternating field step demagnetization and thermal step demagnetization (after [9])

下载: 全尺寸图片幻灯片

表 1 区域平均特征剩余磁化强度

Table 1. Group mean characteristic remanent magnetization (ChRM) directions

采样位置	采样点	特征剩磁方向平均值
采样位置	采样点	数量	磁偏角/(°)	磁倾角/(°)	α95	k	Note¹
Black Cloud矿区	8-10	3	173.1	-56.8	16.2	58.7	u, R
Black Cloud矿区	8-10	3	185.2	-57.9	16.2	58.7	c, R
Pando斑岩接触带	11, 12, 26	3	309.4	51.5	13.1	89.5	u, M
Pando斑岩接触带	11, 12, 26	3	326.2	65.6	17.0	53.8	c, M
大陆主要矿区	1, 2, 4, 5	4	340.0	68.9	15.3	37.0	u, N
大陆主要矿区	1, 2, 4, 5	4	335.5	73.6	27.5	12.1	c, N
注：Note¹未校正(u)或校正(c)的顺层倾斜，正常极性(N)，反向极性(R)，极性混乱(M)，数字为采样点

下载: 导出CSV

表 2 各矿区古地磁极位置

Table 2. Pole positions

采样位置	采样点	经度E/(°)	纬度N/(°)	d_p/(°)	d_m/(°)
Black Cloud矿区	1	147.4	84.3	17.1	23.5
大陆主要矿区	5	214.0	71.0	22.0	26.0
第三纪(所有位置)	11	190.6	78.7	10.2	13.1

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