Dynamic Permeability Related to Greisenization Reactions in Sn-W Ore Deposits: Quantitative Petrophysical and Experimental Evidence

Figure 2

(a) Drill hole SCB2 showing the vertical mineral zoning of the greisen alteration. (b) Macroscopic textural characteristics of (1) facies of the most altered greisen displaying a well-developed porosity, (2) quartz-muscovite greisen in which it is possible to observe pieces of less altered granite (white dashed lines correspond to the alteration front and white arrows to the expected direction of propagation), (3) propagation of the pervasive greisenization toward the Panasqueira granite, (4) propagation of alteration from the fracture in the deeper part of the drill hole, and (5) the porphyritic two-mica granite of Panasqueira. Mineral abbreviations from Whitney and Evans [45]. Ab: albite; Bt: biotite; Kfs: K-feldspar; Ms: muscovite; Qz: quartz.

(a)

(b)