Carbonate Deposits Through Ages
description
Transcript of Carbonate Deposits Through Ages
![Page 1: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/1.jpg)
CARBONATE DEPOSITS CARBONATE DEPOSITS THROUGH AGESTHROUGH AGES
SOUMYABRATA BISWASSOUMYABRATA BISWASUG-IIIUG-III
GEOLOGICAL SCIENCESGEOLOGICAL SCIENCESJADAVPUR UNIVERSITYJADAVPUR UNIVERSITY
![Page 2: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/2.jpg)
•“Present is the key to the past”.
•Does not true always.
•“Present is the key to the Pleistocene”.
![Page 3: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/3.jpg)
Why law of UNIFORMITARIANISM is not applicable?The major controls on carbonate facies are geotectonics and climate.
Some evidencesCARBONATE SANDREEF COMPLEXESTEMPORAL FLUCTUATION IN MARINE CARBONATEDEPOSITIONDOLOMITE PROBLEM
•Why PLEISTOCENE?
Holocene carbonate sediment reflects recent changes in sea level that can be used to interpret PLEISTOCENE carbonate formations.
![Page 4: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/4.jpg)
CARBONATE SAND Deposited high energy environment
Relative abundance of marine carbonate rocks during the Phanerozoic
Pattern of global sea-level change during Phanerozoic
![Page 5: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/5.jpg)
OOLITE IS NON SKELETAL CARBONATE GRAINSTONES.IT’S ABUNDANCE ALSO DEPENDS ON GLOBAL SEA-LEVEL.
Abundance of Oolite in Phanerozoic limestone sequences.
![Page 6: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/6.jpg)
SKELETAL GRAINSTONES
PALEOZOIC dominated by brachiopod,crinoidal,bryozoans and corals.
MESOZOIC dominated by bivalves
CAINOZOIC dominated by mollusc,brachiopod and echinoderm
Diversity,abundance and composition of calcareous marine organisms
![Page 7: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/7.jpg)
REEF COMPLEXES
Occurrences of major reef complexes
![Page 8: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/8.jpg)
TEMPORAL VARIATION IN PHANEROZOIC MARINE PRESIPITATES
TWO MAJOR CONTROLS ON MARINE PRESIPITATESPCO2 Mg/Ca ratio
MARINE PRECIPITATES- High Mg Calcite and Aragonite Calcite-Mg content generally low
Mineralogy of marine carbonate precipitates through Phanerozoic
![Page 9: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/9.jpg)
![Page 10: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/10.jpg)
DOLOMITE PROBLEM
Why dolomites are much more common than limestones in Precambrian compared with the Phanerozoic?
The relative abundance of limestones and dolomites through time.
![Page 11: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/11.jpg)
ABUNDANCE OF DOLOMITES MOSTLY DEPENDS ON CA/MG RATIOS.
Ca/Mg ratio in carbonate rocks.
![Page 12: Carbonate Deposits Through Ages](https://reader034.fdocuments.in/reader034/viewer/2022052523/556572dad8b42a7b518b4f26/html5/thumbnails/12.jpg)