Metal Sources and Mechanisms of Enrichment for Cu-Ni-PGE Mineralization in Fe-Ti-Rich Gabbroic Rocks in the Duluth Complex, Minnesota

德卢斯杂岩的巴比特铜-钛-镍-铂族矿床中的浸染型硫化物矿化产于富铁和钛的辉长岩中，这些辉长岩与下伏的弗吉尼亚组的变质沉积岩接触。为了评估可能的金属来源，计划进行Re-Os和铅同位素研究。这两个同位素系统将为地壳或地幔金属来源的相对重要性提供直接证据，将通过追踪伴随分离结晶、地壳同化、岩浆补给和岩浆混合的化学变化来评估金属富集性的机制。德卢斯的地壳硫的加入被认为是富硫化物和贫硫化物氧化物磷灰石岩石之间可能存在连续体差异的主要原因。由于化学成分的相似性，计划与魁北克圣乌尔本和拉布里维尔斜长岩杂岩中的富Fe-Ti-P岩石进行对比研究。这些结果将有助于我们理解层状侵入岩、次火山侵入岩、地块型斜长岩和相关岩石中成矿作用的异同。

Disseminated sulfide mineralization at the Babbitt Cu-Ti-Ni- PGE deposit of the Duluth Complex is found within iron-and titanium-rich gabbroic rocks that occur near the contact with metasedimentary rocks of the underlying Virginia Formation. In order to evaluate possible metal sources Re- Os and Pb isotopic studies are planned. These two isotopic systems will provide direct evidence as to the relative importance of crustal or mantle sources of metals Mechanisms of metal-enrichment will be evaluated by tracing chemical variations that accompany fractional crystallization, crustal assimilation, magma recharge, and magma mixing. The addition of crustal sulfur at Duluth is thought to be a prime reason for the differences in what may be a continuum between sulfide-rich and sulfide-poor, oxide- apatite rocks. Because of the chemical similarities a comparative study with Fe-Ti-P-rich rocks from the St. Urbain and Labrieville anorthosite complexes in Quebec is planned. Results will aid our understanding of similarities and differences between mineralization in layered intrusions, subvolcanic intrusives, and massif-type anorthosites and related rocks.