#Petrify definition how to

Pyritization occurs to a lesser extent in plants in clay environments. Carbonate shell material of the organism is then replaced with pyrite due to a higher concentration of pyrite and a lower concentration of carbonate in the surrounding water. This reaction between iron and sulfides forms pyrite (FeS 2). Organisms release sulfide, which reacts with dissolved iron in the surrounding water, when they decay. In marine environments, pyritization occurs when organisms are buried in sediments containing a high concentration of iron sulfides. Pyritization can result in both solid fossils as well as preserved soft tissues. Pyritization is a process similar to silicification, but instead involves the deposition of iron and sulfur in the pores and cavities of an organism. Under ideal natural conditions, silicification can occur at rates approaching those seen in artificial petrification. For silicification to occur, the geothermic conditions must include a neutral to slightly acidic pH and a temperature and pressure similar to shallow-depth sedimentary environments.

The specimen is transformed to stone (a process called lithification) as water is lost. In wood samples, as the process proceeds, cellulose and lignin, two components of wood, are degraded and replaced with silica. The cell walls of the specimen are progressively dissolved and silica is deposited into the empty spaces. The process begins when a specimen is permeated with an aqueous silica solution. Water must be present for silicification to occur because it reduces the amount of oxygen present and therefore reduces the deterioration of the organism by fungi, maintains organism shape, and allows for the transportation and deposition of silica. Silicification most often occurs in two environments-either the specimen is buried in sediments of deltas and floodplains or organisms are buried in volcanic ash. Studies have shown that in this process, most of the original organic matter is destroyed. A common source of silica is volcanic material. ‘He is the oldest brother, and I went to him many, many times, for advice when I was petrified to go talk to my dad.Silicification is the process in which organic matter becomes saturated with silica.‘She is absolutely petrified and too afraid to leave her own home.’.‘‘We were petrified he was going to use the gun,’ she said.’.‘Obviously we were petrified that a collector would find out where the nest was and raid it.’.‘Her hair was turned into a mass of poisonous snakes and her general appearance became so horrifying that anyone who looked upon her was petrified with terror.’.‘The police have given Mr Bernasconi a panic alarm for his house but he says he is petrified to go out.’.‘However, politicians are still petrified of being accused of being too soft on drugs.’.

#Petrify definition how to

‘As a matter of fact, she was petrified of people informing her of things she had done wrong, even if it came with suggestions on how to improve.’.

‘He enjoyed a long career in engineering, particularly involving locomotives, but as a child was petrified of trains.’.

‘Conventional wisdom would be to go up and talk to her, but I'm petrified of failure.’.‘Spotting a snake in the grass is never simple, but it's easier to do, it seems, if you're petrified of serpents.’.‘Although I was petrified of my father, I'd still sneak it in and my grandfather would smack me on the back of my head as my father gave me the eye!’.‘Now my daughter is absolutely petrified of fireworks and of the noises they make.’.‘My mother is petrified of hospitals and with all the recent bad press I think the look on her face at A&E said it all.’.‘Being young, I was petrified of sitting in the car as it went through the car wash.’.‘Now he is petrified of fireworks and the noise they make and was prompted to write to the Lancashire Evening Telegraph about his fears.’.‘There were so many dogs, I was petrified of getting bitten - I think I've broken the record for a lap around that park.’.‘But I'm also petrified of joblessness, insecurity, and drastic changes happening all at once.’.‘I am petrified of heights and last year did an abseil which I found really scary.’.‘You are petrified of letting people see how vulnerable you can be and have a very bad case of stage fright.’.