QUIZ 23 JULY ) What is the earth’s equatorial radius? 2) What is the layer beyond thermosphere? 3) Thickness of continental crust? 4) Composition of oceanic crust? 5) What is the lithosphere? 6) Is an underwater ridge mountain range created at a divergent boundary in the middle of Atlantic ocean

7) What system is formed by oceanic- oceanic convergence? 8) How is Marianas Trench formed? 9) Collision of Asia and India produced? 10) San Andreas Fault is found in? 11) Illustrate the Bowen’s reaction series and indicate trend in temperature, pressure.

METHODS of CORRELATION LITHOSTRATIGRAPHIC – lithologically similar TIME-STRATIGRAPHIC – deposited during same time interval BIOSTRATIGRAPHIC – rocks containing same fossil assemblages

ROCK UNITS - observable stratigraphic bodies having a distinctive lithology and recognizable physical boundaries. FORMATIONS – fundamental rock units, must be thick enough and sufficientl distinctive to be represented on a geologic map MEMBER – lithologically distinct portion of a formation (member of that formation)

GROUP – related formations ma form a group TYPE LOCALITY – site at which a rock unit was first described TYPE SECTION – exposure of rock unit at type locality

ROCK UNITS CORRELATION by LATERAL CONTINUITY - physical continuity; in exposed areas, rock units can be followed on foot or traced visually on aerial photographs - physical continuity; in exposed areas, rock units can be followed on foot or traced visually on aerial photographs

ROCK UNITS CORRELATION by LITHOLOGY - reliable only on local basis - used in conjunction with fossil content and character of adjacent strata

ROCK UNITS CORRELATION by GEOPHYSICAL TECHNIQUES - drilling - electrical conductivity - seismic techniques - natural radiation

TIME-STRATIGRAPHIC UNITS Time Stratigraphic Unit – deposited during a specified time interval and may include a variety of lithologies e.g Cambrian System – deposited during Cambrian Period (Time-Strat Unit vs. Geologic Time Unit)

TIME-STRATIGRAPHIC UNITS CORRELATION by FOSSILS - unique succession of assemblages of fossils Index Fossils: i) Have short time range ii) Have wide geographic distribution iii) Be abundant iv) Be easily identifiable

INDEX FOSSIL e.g - trilobite Olenellus – restricted to Early Cambrian deposits, found in many parts of North America and Europe, is relatively abundant, and has a distinctive morphology

CORRELATION by RADIOMETRIC AGES - Radiometric dating : i) K-Ar: date on mica from a metased rock provides a minimum age for the deposition of original sediment ii) U-Pb: provides minimum age for deposition of original sed iii) Rb-Sr: date for basement rock on w/c sed was deposited

CORRELATION by PALEOMAGNETISM - Measuring direction of magnetization of drill cores taken on oceanic sediments - Involves matching pattern of normally and reversely magnetized as lavas

BIOSTRATIGRAPHIC UNITS ZONE – basic unit of biostratigraphy; bed or group of beds characterized by presence of index fossil or assemblage of fossils Synchronous – beds were deposited contemporaneously e.g Jurassic ammonite zone Homotaxial – strata have the same fossil assemblage but are of not the same age

RELATIONSHIP b/w ROCK UNITS AND TIME-STRAT UNITS FACIES – introduced by Swiss geologist Amanz Gressly in 1838 Amanz Gressly in distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment. - distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment.

LITHOFACIES – rock record of sedimentary environment e.g limestone lithofacies of the Onondaga Limestone in New York State represents a shallow, clear-water environment

BIOFACIES – assemblage of fossils representing a particular sedimentar environment e.g. Onondaga Limestone contains a coralline biofacies representing a shallow, clear water marine environment

TRANSGRESSION – an event during which sea level rises relative to the land; resulting in coastal flooding REGRESSION – lowering of the sea

RECONSTRUCTION OF ANCIENT ENVIRONMENTS SEDIMENTARY ENVIRONMENTS:  Transitional Environment: i) Beaches ii) Tidal Flats iii) Lagoons iv) Estuaries v) Coastal Marshes and Swamp

 Marine Environments  Continental Environments i) streams and rivers ii) lakes iii) swamps, marshes, bogs iv) glaciers

Charles Darwin – 1859, Origin of Species Survival of the fittest.

EVOLUTION Jean de Lamarck – French bilogist, 1809 proposed that characteristics acquired during the life of an organism could be inherited by its offspring. i. e. GIRAFFE

Charles Darwin – 1859, Origin of Species Survival of the fittest.

EVIDENCE FOR EVOLUTION  Similarity in Body Chemistry: - chemical compositions of the blood of many animal groups are strikingly similar - ions present in seawater are also present in blood in approximately the same abundances. - chromosomes of living cells contain DNA and RNA

 Similarity in Body Structure skeletal strucutures of terrestrial and marine vertebrates are remarkably similar

 Presence of Vestigial Structures vestigial structures are small, imperfectly developed parts of organs which were more fully developed in earlier generations.

 Stages in the Growth of an Organism in its development from the embryonic to the mature stage, an organism may undergo changes similar to the evolutionary changes that have occurred during the development to as the biogenetic law.