cherts

The energy released created chocolate tablet boudinage in cherts, and their association with distally situated ring thrusts is also thought to be unique.

Vredefort Dome, South Africa 2009

Approximately 98.5% of the pebbles are flints and cherts, the remainder are composed of limestones, vein quartz, porphyry, igneous materials and quartzites.

Dorset and East Devon Coast, United Kingdom 2008

Although shale is common, there is a mixture and interbedding of geologic materials, including cherts, siltstone, sandstone, quartzose limestone, and in Alabama some slate, quartzite, and metasiltstone.

Ecoregions of Alabama and Georgia (EPA) 2008

Among the targets: carbonates, cherts and opals - all characteristic of thermal hot springs.

The Stars Of Mars 2008

These microfossils, found in bedded carbonaceous cherts, are estimated to be between 3.3 billion to 3.5 billion years old.

Teach Both Sides. Really. - The Panda's Thumb 2005

The evidence of the age of the Barberton Mountain Land was found on the cherts of the Fig Tree formation.

Speech at the United Nations University 2001

Radiolarian cherts are covered unconformably by conglomerates (Bennan Hill near Straiton and Kennedy's Pass) which are associated with limestones of

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" Various

Near their northern limit Radiolarian cherts, mudstones and lavas of Arenig age rise from underneath the former along anticlines striking north-east and south-west.

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" Various

Tripoli and rottenstone are light, porous, siliceous rocks which have resulted from the leaching of calcareous materials from various siliceous limestones or calcareous cherts in the process of weathering.

The Economic Aspect of Geology 1915

It consists of cherts that were deposited first under deep-sea pelagic conditions at or near a mid-oceanic ridge, later during transport of the ocean floor towards a subduction zone, and finally the cherts were overlain by clastic infill in the trench.

EurekAlert! - Breaking News 2010