Dolomite Fronts and Associated Zinc-Lead Mineralization, Usa

Abstract

This paper provides previously unpublished drill core and mapping evidence of the spatial relationship between regional dolomitization and Mississippi Valley-type (MVT) mineralization in the midcontinent of the United States. Dolomitization is discussed for several key carbonate units and their contained MVT mineralization. This more complete picture of the relationship between regional dolomitization and mineralization provides constraints on models for MVT mineralization and serves as an exploration guide for new deposits.

Hydrothermal Processes: The Development of Geochemical Concepts in the Latter Half of the Twentieth Century

“…6 .6 and 6 .7) . Except for dolomitisation, replacement textures are not common in these ores, as explained more recently by Harper and Borrok (2007) . These authors have also described a closely related spatial distribution of epithermal dolomite with ore minerals, implying that the same flow produced both sequentially .…”

The ore-forming process of the Maoping Pb–Zn deposit, northeastern Yunnan, China: Constraints from cathodoluminescence (CL) petrography of hydrothermal dolomite

“…Several studies have revealed a common temporal sequence of alteration and mineralization for most MVT deposits and their country rocks: host limestone→partially dolomitized limestone→dolostone consisting of void-filling saddle dolomite→sulfide orebody (consisting of sulfides and saddle dolomite) (e.g., Sass-Gustkiewicz et al, 1982;Ohle, 1985;Sangster, 1988;Davies and Smith, 2006;Smith, 2006;Harper and Borrok, 2007). This sequence has led to the conclusion that dolomite and metal sulfides in MVT deposits resulted from the activity of a single fluid system (Davies and Smith, 2006); however, some uncertainties remain.…”

Self-accelerating dolomite-for-calcite replacement: Self-organized dynamics of burial dolomitization and associated mineralization

“…2) in a general case, adapted here to dolomitization. The predicted forward accumulation of ore appears to be confirmed by the fact that Zn deposits in the U.S. midcontinent (Harper and Borrok, 2007) are largest at the final position of the dolomitization front. Also, ore mineral grains formed in late pulses may replace a little dolomite formed in earlier pulses (as in figs.…”

“…We have loosely adapted their dynamic model to dolomitization in figure 9, which shows that at any given time most or all of the ore formed previously (both in previous pulses of the same slice and in previous slices) accumulates at the current front. In fact Harper and Borrok (2007) have reported that the largest zinc and lead deposits of the midcontinent of the U.S. do occur at the last position of the dolomitization front, against the undolomitized limestone.…”