Chalk

Chalk /ˈtʃɔːk/ is a soft, white, porous sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert unique to chalk) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint).

Chalk as seen in Cretaceous deposits of Western Europe is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have very few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones. This presumably indicates very stable conditions over tens of millions of years.

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Annihlate This Week

by: Black Flag

You annihilated this week Now it's Sunday and you weep A future of fun Or a guilt loaded run Your carnal desires fanning the fires You're really burnin' 'em up Partying n' such Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. You never think that hard Til the devil's in your backyard But she can't quite forget that night in my corvette Annihilating the week Sledge hammers to the street But then on Sunday You're looking mighty weak Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. I'm a smokin' and drinkin' thing (you're a regular social machine) I'm a smokin' and drinkin' thing (you're a radical partyin' machine) Annihilating this week Screwing everything that you meet She thinks she's feeling better But her conscience won't let her Your thoughts temporarily deceived But your virginity can't be retreived You never had it before And now you can't close the door Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. All week long. Annihilate. Annihilate. Annihilate. Annihilate. Annihilate. Annihilate. Annihilate.




Latest News for: black chalk

All about D: Final Four teams have been locked in on defense all season

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Tennessee has one of the nation’s best defenses, a bruising crew who leave opponents black and blue ... 1 seeds, joining the 2008 bracket ... It’s going to tough on every team in San Antonio, adding some black and blue to chalk on the Riverwalk. ___ ... ....

Final Four teams have been locked in on defense all season

The Vindicator 01 Apr 2025
(AP Photo/Marcio Jose Sanchez). Tennessee has one of the nation’s best defenses, a bruising crew who leave opponents black and blue ... It’s going to tough on every team in San Antonio, adding some black and blue to chalk on the Riverwalk ... No. .

All about the D: Final Four teams have been locked in on defense all season

York News-Times 01 Apr 2025
Tennessee has one of the nation's best defenses, a bruising crew who leave opponents black and blue ... 1 seeds, joining the 2008 bracket ... It's going to tough on every team in San Antonio, adding some black and blue to chalk on the Riverwalk ... .

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5 ... Getty Images ... First black GOP congresswoman dead at 49 ... Scheduled shows on the chopping block include concerts from Phish, The Black Keys, Alabama Shakes and Leon Bridges. Forest Hills residents, however, are chalking the development up as a win ... 5.
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