Research On Metallogenesis And Metallogenic Prediction Of The Songshugou Chromite Deposit In Shaanxi Province

The Songshugou rock body is the largest outcrop ultramafic rock of Q inling orogenic belt, predecessors worked on a large number of exploration, lots of trenches and drills were carried out, the depth of which was 700 meters below the earth’s surface, and controlled chromite ore bodies were mined. Many scholars researched on the genesis of the Songshugou ultramafic rock body, there are ophiolite and Alps type dunite different views. And how about the prospecting potential in the depth of Songshugou rock body? And where are the prospecting targets? The problems haven’t been solved. This paper chooses the Songshugou rock body as the object of study, and on the basic of geological prospecting and research findings of predecessors, by the field investigation, analysis of rocks and minerals, three dimensional modeling of the Songshugou ultramafic rock body and ore body, researched on the genesis and metallogenic model of deposit, metallogenic potential and prospecting methods in the songshugou rock body deep and marginal parts, and the main conclusions are as follows:(1)Songshugou chromite deposit belongs to high-Cr-type chromite, hosting in Songshugou ultramafic rock body. The main composites of ultramafic rock body are dunite and harzburgite, olivine mainly for magnesia olivine with Mg/( Mg+Fe+Mn)=0.89~0.94(average 0.92), Fo=91~94, N iO=0.21%~0.38%(average 0.31%); orthopyroxene for pyroxene with En=91%~94%,Al2O3=0.33%. Through the comprehensive research: Songshugou ultramafic rock body belongs to Alps type ultramafic rock body.(2)The mine three dimensional modeling is established by 3DMine software on the basis of three hundred and forty-three borehole data(A total length of about 108000 meter), which provides a visual maps for the metallogenic prediction of deep and marginal parts and obtains 6.1691 million of poor resources about 700 meters below the earth’s surface(grade is more than 3% and known ore-body included).(3)Systematically collecting and summarizing geologic, geophysical and geochemical prospecting, combined with mine three dimensional model, metallogenic theory of chrome deposit, three metallogenic forecasting areas and a metallogenic prospective areas are put forward for further work: Jielinggou-gangou, Gangou-xiaosongshugou and Yangqigou-donggou metallogenic forecasting areas(lower walls of rock) and N iqiuao metallogenic prospective areas(around Songshugou rock body), and also prospecting and methods in metallogenic forecasting areas.