Skip to Main Content
Book Chapter

Gravity and Magnetic Methods

January 01, 1989


Over thirty years ago geophysical prospecting for iron ore deposits in China began and has resulted in significant progress in all aspects. This paper presents a summary of the experiences gained in China. Field procedure has changed from prospecting along irregular grids to conducting systematic geophysical surveys over a large iron mining district. To improve the measurement of magnetic parameters, a static magnetic laboratory was established. The anisotropy of magnetic susceptibility of iron ore has been studied and model studies of orebodies carried out using both isotropic and anisotropic magnetic susceptibility. In China, the study of magnetic anomalies has gone through three stages; strong anomalies in the 1950s, weak and smooth anomalies in the 1960s, and complicated magnetic anomalies at the end of the 1970s. New iron ore deposits were discovered in every stage.

Strong lightning-induced remanence (Q-5) was found for the near-surface parts of banded iron formation in the Qianan mining district. The Q decreases to about one tenth this value in the deeper parts of the iron formation.

The magnetic, gravity, and induced polarization methods were tried in the search for hematite ores but no universally acceptable approach was found. Each area must be analyzed individually.

An example from the Chengchao iron deposit in Hubei province shows the need for initial interpretation to be followed by drilling and reinterpretation in several successive steps. At each step the residual anomaly defines a target for further drilling. Much additional tonnage was added using this process.

Scale model studies using anisotropic magnetic susceptibilities were particularly useful in studying synformal banded iron formations. Guides to interpretation were developed from these studies.

The Zhaocun deposit in Shanxi province, occurring in mountainous terrain, is of a complex synformal type. The interpretation of the ground magnetic anomaly over it was greatly aided by model studies and by removal of the topographic effect.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables


Society of Exploration Geophysicists Geophysical References Series

An Overview of Exploration Geophysics in China — 1988

Zhao Jingxiang
Zhao Jingxiang
Search for other works by this author on:
Wang Yanjun
Wang Yanjun
Search for other works by this author on:
Fu Xuexin
Fu Xuexin
Search for other works by this author on:
Stanley H. Ward
Stanley H. Ward
Search for other works by this author on:
Society of Exploration Geophysicists
ISBN electronic:
Publication date:
January 01, 1989




A comprehensive resource of eBooks for researchers in the Earth Sciences

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now