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The etouchang-type iron deposit is a typical stratabound deposit in the northern part of central Yunnan. The discussion centres on the controlling effect of the generation and development of the structural system in the orefield on the formation of this type of deposit and establish a time-space ore-control model so as to get a better understanding of the mechanism for its formation. During the formation and enrichment of the Etouchang-type iron deposit, the structures performed a dual control function on the generation and distribution and also on the reformation and enrichment of the source bed. The Etouchang-type iron deposit is a typical example for the stratabound deposits of which the formation and distribution are controlled by the generation and development of structural systems. During the embryonic period of the longitudinal structural system shortly after the Dongchuan movement, a N-S rift valley-type trough appeared between the Luzhijiang fault zone and the Luoci-Yimen fault zone. It was along the marginal areas of the trough that the iron-rich clay and sand of dominant terrigenous origin were accumulated, constituting the source bed of iron. During the Jinning movement, the basement had been finally formed and the longitudinal structural system took shape. During the Chengjiang movement, the longitudinal structural system was strengthened and the central Yunnan xi-type structure appeared, which controlled the activities of the Na-rich magma and thermal fluids, and the consequent reformation of the source bed, the migration and enrichment of iron substance and the formation of economic deposits. The Luoci-Yimen fault zone controlled the distribution of the iron orefield while the lateral structures (e.g., the Etouchang compounding shear structure) controlled the occurrence of the deposit. The reformation and enrichment of the Etouchang-type iron deposits were concomitant with the formation of an ore-controlling structure. The scale and grade of the orebodies were strictly controlled by the structural pattern, and the orebodies occurred in the shear structures and were enriched in the tensional portion of a compressive structure.

This paper deals withR-mode cluster analysis for more than 6000 analytical data from the samples of tectonite and mineralized rocks using the method of multivariate statistical analysis on the basis of division of the tectonic fault systems in the Malage Ore Field andR-mode factor analysis for the analytical data from tectonite samples collected along various directions of the faults according to fourteen variables related to the mineralizing elements which are selected in terms ofR-mode cluster analysis from the chemical composition of tectonites. Thus the distribution characteristics of primary halo anomalies have been revealed with respect to the metallogenetic elements Sn, Cu, and Pb, Zn. The tecto-geochemical features are shown by the primary halo anomalies, thus providing the theoretical basis for metallogenetic forecast in the ore field.