tuffaceous


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Related to tuffaceous: Volcanic Tuff

tuffaceous

[tə′fā·shəs]
(geology)
Pertaining to sediments which contain up to 50% tuff.
References in periodicals archive ?
Andesitic, tuffaceous sedimentary rocks flanking and above massive ore bodies locally contained abundant disseminated pyrite as well as anhydrite, barite and cherty zones (Payne et al.
At such times processes of erosion would have predominated, but localized tuffaceous sediments accumulated in rivers and creeks.
It is hypothesized that densely welded tuffaceous rocks at depth are brittle enough to form openings in which high-grade veins might form.
The permit is underlain by a mixed sequence of sedimentary and tuffaceous rocks with a band of mafic volcanic rocks and breccias underlying the extreme western part of the permit.
In approximate order of abundance the clasts include (1) intermediate to felsic volcanic rocks, generally quartz--and plagioclase-phyric, commonly tuffaceous, and weakly foliated, (2) sandstone and lesser siltstone, (3) mafic volcanic rocks, (4) felsic plutonic rocks, some deformed, and (5) the fault rocks of Force and Barr (2006).
The deposits are commonly associated with relatively small lenses of felsic effusive and tuffaceous rocks within basalt-dominated sequences containing clastic sedimentary rocks and iron formations.
As detailed in our press release of August 11, 2005, which is available on our website, core drilling of the central portion of Anomaly M intersected variably sheared silicified pyritic metasediments of tuffaceous origin and volcanic conglomerates, often with little or no quartz veining.
680 Ma Stirling Group consists primarily of andesitic to basaltic lapilli tuff with interbeds of tuffaceous arenite and laminated siltstone.
Chip Samples CH-011 through CH-013 appear to positively test the area above the postulated supergene enriched zone that appears as visual blebs of copper oxide in the tuffaceous host rock.
The stone quarried from these locations is red and green tuffaceous siltstone and sandstone of the Mistaken Point Formation, the uppermost unit of the Neoproterozoic Conception Group (Williams and King, 1979).
This implies that substantially more diamonds are present in the tuffaceous material of these eruptions.
This proposed stratigraphic relationship supports the interpretation that the tuffaceous and volcaniclastic sedimentary rocks of the Priest Cove Formation represent a distal facies of the mafic flows and fragmental volcanic rocks of the Ross Island Formation.