This volcanic succession hosts Au-rich mineralized sub-volcanic felsic bodies yielding slightly younger ages and is covered by Paleocene intermediate lavas with hypabyssal
intrusions with ages around 48 Ma.
The [(La/Yb).sub.N] ratios of quartz show a negative correlation with formation depth of deposit (Zhao, 1997), indicating that the Gaosongshan gold deposit is a hypabyssal
one, of which the [(La/Yb).sub.N] is much higher than 1.
Previous studies have shown three potential fluid formation mechanisms: (1) formation at magmatic temperatures, in which intermediate-felsic magma in a chamber becomes saturated to oversaturated in terms of volatile content through crystallization and separation to a certain extent, forming high- and low-salinity fluids [37, 38]; (2) formation from hydrothermal fluids with low to moderate salinities through liquid immiscibility or decompression boiling resulting from the fracturing of caprocks; or (3) volatile exsolution from late residual magma associated with crystallization during hypabyssal
magmatic emplacement .
The West Scotch Settlement porphyry is a small, hypabyssal
felsic intrusion that is less than 1 kilometre in diameter.
Geophysical results infer the Groundhog Project lies along the Northeast margin of the large Cretaceous granodiorite Kaskanak batholith and is intersected by a north-northeast-trending corridor of distinctive co-magmatic hypabyssal
Following Dickinson (2006), the term "microphanerite" here covers plutonic and hypabyssal
Extrusive rocks (e.g., basalt and dacite) have much higher [rho] than those of intrusive rocks; among them, [rho] of plutonic rock is generally higher than that of hypabyssal
rock (Table 2).
These rocks have textures and compositions similar to those of their volcanic equivalents and might be the hypabyssal
parts of the komanitic volcanic suites (Arndt et al.
The basement of the graben and the fabric of the hills that surround it consist essentially of plutonic and hypabyssal
(1987) Petrology of the alkalic hypabyssal
and volcanic rocks at Cripple Creek, Colorado.
Francois Mountains Complex regardless of inferred mode or depth of crystallization (volcanic phenocryst versus volcanic matrix versus hypabyssal
ring pluton versus subvolcanic massif) or crystallization age (1.47 Ga versus 1.36-1.38 Ga) to be evidence for a single, pervasive alteration event subsequent to (or coincident with) the last major igneous event in the area.