Earth Science Flashcards
What is the absolute age of the Earth?
4.7 billion years old
Who formulated the Law of Superposition?
Nicolas Steno(1638 - 1686)
A Danish anatomist
Nicolas Steno
The law simply states that, in an undeformed or undisturbed layer of sedimentary rocks
Law of Superposition
The rock layer found at the bottom is the______
Oldest
The rock layer is found at the top is ________
Youngest
Sequence of rock layers
Strata
States that sediments are generally deposited in a horizontal manner
Law of Original Horizontality
In Law of Original Horizontality Steno observed that thin layers of sediments were deposited in a ____________
Horizontal manner
States that, sedimentary rocks and/or sediments extends laterally in all directions until such time that it thins-out or terminated by the edges of a basin in a depositional environment.
Principle of Lateral Continuity
The principle of Cross-cutting Relationship is credited to who?
James Hutton (1726—1797)
Examples of igneous intrusion.
sills and dikes
Igneous intrusion that intersects through a layer of rock, is younger than the rock it cuts through.
Principle of Cross-cutting Relationship
Who observe the Principle of fossil succession?
William Smith (1769-1839)
he was the one who noted that fossil content
existed in a determinable order in rock layers.
Who is this person?
William Smith
states that a rock fragment found inside another rock layer or formation (e.g. sandstone found inside a dike), is older than the rock containing it.
Inclusion
It describes periods of nondeposition and/or erosion which can be observed between two rock layers.
Uncomformities
Types of Unconformities
Disconformity
Nonconformity
Angular unconformity
When an igneous or metamorphic rock is overlain by sedimentary strata, this is called a nonconformity.
Nonconformity
This is characterized by an erosion surface that separates two rock layers of different ages, which are generally parallel with each other.
Disconformity
In a cross-section, disconformities are usually shown by _______
Wavy lines
This type of unconformity is represented by titled sedimentary layers overlain by horizontal sedimentary.
Angular unconformity
