Browsing by Subject "Midcontinent Rift System"
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Item Midcontinent Rift System Bibliography(University of Minnesota Duluth, 1995-12) Hauck, Steven AThe co-chairs of the IGCP Project 336 field conference on the Midcontinent Rift System felt that a comprehensive bibliography of articles relating to a wide variety of subjects would be beneficial to individuals interested in, or working on, the Midcontinent Rift System. There are 2,543 references (>4.2 MB) included on the diskette at the back of this volume. PAPYRUS Bibliography System software by Research Software Design of Portland, Oregon, USA, was used in compiling the database. A retriever program (v. 7.0.011) for the database was provided by Research Software Design for use with the database. The retriever program allows the user to use the database without altering the contents of the database. However, the database can be used, changed, or augmented with a complete version of the program (ordering information can be found in the readme file). The retriever program allows the user to search the database and print from the database.Item Oxide, Sulphide and Platinum Mineralogy of the South Kawishiwi and Partridge River Intrusions of the Duluth Layered Intrusion Complex Minnesota, U.S.A.(University of Minnesota Duluth, 1998) Komppa, Ulla; Hicks, MalcolmThe Duluth Complex in north-east Minnesota, U.S.A., is one of the largest basic layered intrusion complexes in the world, occupying an area of about 4700 km2 • It is composed of several separate intrusions which discharged via the Midcontinent Rift System about 1100 ± 15 Ma ago. Characteristic of the complex is the occurrence of mineralizations containing Cr-Fe-Ti-V oxides, CuNi sulphides and platinum group elements in the troctolitic South Kawishiwi and Partridge River Intrusions on its western and northern edges. The purpose of this work is to study and compare these two adjacent intrusions in terms of their platinum mineralogy and to provide the basic data necessary for determining the origins of their mineralizations. As the platinum mineralizations are closely connected with oxide and sulphide mineralizations, the latter are also examined in detail. The work is based to a great extent on the available literature and on a set of 221 core samples taken from the two intrusions. A total of 119 whole rock x-ray fluorescence analyses, 253 WDS x-ray microanalyses, 68 EDS analyses and 499 scanning electron microscope analyses ( also employing the EDS method) were performed on these cores for the determination of oxides, sulphides and platinum group minerals. The mineralizations of the Duluth Layered Intrusion Complex resemble other corresponding ones in Cu and Ni-bearing basic igneous rocks in their ore mineralogy and in the rock types present. The mineralizations exhibit properties suggestive of a role for both magmatic and hydrothermal processes in the distribution of platinum group elements. The results obtained here are consistent with earlier findings.