Flint - Wikipedia
Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. [3] [4] Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance. A thin, oxidised layer on the outside of the nodules is usually different in colour, typically white and rough in ...
How were flints in chalk formed? - Geomusings
Short answer: Flint was formed in chalk, after it was deposited on the seabed as a chalky ooze, but before it was compressed into chalk rock. Silica, which was dissolved in sea water, precipitated within permeable pathways in this sediment.
How flint is formed - South Downs National Park
The formation of flint is a complex process which began in the chalk seas millions of years ago and is, summarised below: Organisms such as sponges (on the macro scale) and radiolaria/diatoms (on...
Chalk Flints and the Age of the Earth | Scientific American
These are the well- known flints of the Upper Chalk. We notice how they occur here in more or less parallel lines, following the stratification of the chalk.
Flint : Properties, Formation, Uses » Geology Science
Sep 15, 2023 · Occurrence: Flint is commonly found in sedimentary rock formations, particularly in chalk and limestone. It often forms nodules within these rocks and can be abundant in certain geological regions.
Flint has not often been used as a building stone as it occurs in nodules of awkward shape but this has usually been overcome by ‘knapping’ flint to produce a flat face. Several fine flint buildings can be seen in Essex, usually in areas where chalk (and flint) occurs at the surface such as at Saffron Walden.
Rhythmic chalks and flints - Earth History
In the chalk, flint bands formed at regular intervals, one may infer, because the radiolaria blooms were seasonal. The intervals were generally annual. During burial and dissolution silica-rich fluids most easily passed along bedding planes.
Identification - flint, fossil sponge - Saffron Walden Museum
May 1, 2020 · In Essex and south east England, almost every pebble on the beach and in gardens is flint. It’s a hard rock found in the Chalk, a soft, white, limestone layer that is up to 200m (600 ft) thick in north Essex and Cambridgeshire.
Origin and growth of flint nodules | SpringerLink
Oct 20, 2005 · Cryptocrystalline quartz concretions (flint) of different density, size, morphology and abundance, occur isolated and concentrated in layers in the Late Cretaceous (Tuffaceous) Chalk of NW Europe.
DISCOVERING FOSSILS | Flint formation, uses and fossils
Over time the chalk hills have been eroded, exposing and depositing flint nodules as they retreat. These flints then accumulate to form the flints seen in fields and the characteristic flint pebble beaches along the coast.