The White Pine copper deposit

Abstract

DISCUSSIONS THE WHITE PINE COPPER DEPOSITSir: Reno Sales (3) has offered a remarkably perceptive discussion of the paper by Wright and myself (6) on the White Pine copper deposit. Ira B. Joralemon has added a brief postscript (2) more or less endorsing Sales' views and calling attention to additional data. My reply can hardly be expected to prove the origin of the deposit, but perhaps it will show how many problems one must overlook or oversimplify to be satisfied with the conclusion that the deposit was formed in one episode by hydrothermal solutions of magmatic origin emanating from the White Pine fault.The main thesis of our original paper was that the distribution of shale ore shows virtually complete independence of the structure and is related in almost all its aspects to the lithology and paleogeography of the host beds. From this we concluded (6, p. 713) that "at least three general theories of origin satisfy these conditions: (1) the copper was dropped into or precipitated within the original mud; (2) the copper, diffusing downward into the uppermost few inches of mud, replaced some primary constituent of the mud, perhaps iron sulfide or calcium carbonate; (3) the copper was introduced into the rocks after lithification and presumably deformation, and the loci of deposition were controlled to an extraordinary degree by the physical or chemical character of the host rocks." At least one additional possibility, in some respects more satisfactory than any of the others, should have been added to the list: (4) the copper was introduced into the shales from below after they were buried but before they were deformed or compacted to anything like their present degree; this might be called a "diagenetic" or "cementation" hypothesis. On the basis of some relationships described below that have become apparent since our paper was written, I would favor this fourth hypothesis over the other three if it were essential to choose among them at this time.The version of the third hypothesis that Sales espouses necessarily denies the existence of a significant copper concentration at the site of the present ore body before the deformation and faulting of the area, and in this respect differs fundamentally from the other three hypotheses. The heart of the argument, therefore, lies in this point. Sales takes issue with the arguments for a pretectonic copper concentration as follows: (a) all of our plan maps show "a close relationship areally between the [White Pine] fault fissure and the ore distribution ;" (b) the existence of copper in fissures and the pattern of distribution of copper in sandstone show, as we pointed out in our original article, that at least some of the copper was emplaced after the faulting, and a hypothe- 402

A paleohydrologic model for mineralization of the White Pine copper deposit, northern Michigan

“…1) and of the area in which it occurs has been described in a number of papers (White and Wright, 1954, 1960Ensign and others, 1968). Three formations, of upper Keweenawan age, are involved: the Copper Harbor Conglomerate (100-2,000 m thick), Nonesuch Shale (200 m), and Freda Sandstone (3,000-4,000 m), in order of decreasing age.…”

Constraints on Conceptual and Quantitative Modeling of Early Diagenetic Sediment-Hosted Stratiform Copper Mineralization

“…Replacement textures and sulfide zonings indicated that low-temperature cupriferous brines infiltrated fine-grained basal graybeds from coarse-grained footwall redbeds. Disseminated copper sulfides were deposited by replacement of disseminated syndiagenetic pyrite [1][2][3][4][5]. Early semi-quantitative modeling followed, both at the deposit-scale [6,7] and basin-scale [8].…”

Occurrence of Isoprenoid Alkanes in a Precambrian Sediment

“…as to the precise age of the hydrocarbons; however, the geologic evidence (White, 1960) favours the viewpoint that the organic matter and the associated copper a r e sedimentary in origin, and contra indicates derivatior of the oil from any other iormaiiwrr. alkanes comes from the independent work of Meinschein and his collaborators which was reported (Meinschein e t al, 1964) simultaneously with our own preliminary announcement (Eglinton et al, 1964).…”