Time and Geology

novella:
http://highered.mheducation.com/novella/SITELIBDisplay.jsp?mode=SEM&catId=903

10th ed:
http://highered.mheducation.com/sites/007252815x/student_view0/chapter10/multiple_choice_quiz.html

14th ed:
http://highered.mheducation.com/sites/0073369381/student_view0/chapter10/multiple_choice_quiz.html


The Key to the Past

Relative Time
     Principles Used to Determine Relative Age
     Unconformities
     Correlation The Standard Geologic Time Scale

Numerical Age
     Isotopic Dating
     Uses of Isotopic Dating

Combining Relative and Numerical Ages

Age of the Earth
     Comprehending Geologic Time

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What is the difference between the relative age and numerical age?

How to determine the sequence of geologic events? Through dating!
What are the relative dating principles?

How do fossils are used to determine relative age?
How paleontology contributed to the development of the geologic time scale?

What is radioactive decay?
How do radiogenic isotopes can be used to determine numerical age?

What is the age of the Earth?
What is the Earth's major subdivision of geologic time?

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James Hutton  father of geology

 Charles Lyell Principles of Geology Charles Darwin

The concept that geologic processes operating at present are the same processes that operated in the past eventually became known as the principle of uniformitarianism. Basically, history repeats itself.

 The term actualism comes closer to conveying the principle that the same processes and natural laws that operated in the past are those we can actually observe or infer from observation as operating at present. History gives birth to Present.

 Under present usage, uniformitarianism has the same meaning as actualism for most geologists.

numerical age (also known as absolute age )—age given in years or some other unit of time;
e.g. Dec. 10, 1997

 relative time the sequence in which events took place, rather than the number of years involved
e.g. I am born two weeks before Christmas a week after Bonifacio Day.

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 Contacts are the surfaces separating two different rock types or rocks of different ages.

 Formations are bodies of rock of considerable thickness with recognizable characteristics that make each distinguishable from adjacent rock units.

 The subdiscipline of geology that uses interrelationships between layered rock (mostly) or sediment to interpret the history of an area or region is known as stratigraphy (from the Latin word stratum, meaning a thing spread out, or a cover).

The principle of original horizontality states that beds of sediment deposited in water formed as horizontal or nearly horizontal layers.

The principle of superposition states that within a sequence of undisturbed sedimentary or volcanic rocks, the oldest layer is at the bottom and layers are progressively younger upward in the stack.

The principle of lateral continuity states that an original sedimentary layer extends laterally until it tapers or thins at its edges.

 The principle of crosscutting relationships states that a disrupted pattern is older than the cause of disruption. s. The sedimentary beds on either side of the valley appear to have been sliced off, or truncated, by the valley.

 Feature Is Younger Than But Older Than

 Valley (canyon) < Skinner Gulch Limestone
 Foster City Formation < Dike > Hamlinville Formation
Dike < Larsonton Formation > Foster City Formation
 Larsonton Formation < Leet Junction Formation and granite >Dike
Granite < Tarburg Formation >Larsonton Formation

contact metamorphosed (think “seared” or “baked”)

The principle of inclusion states that fragments included in a host rock are older than the host rock.

An unconformity is a surface (or contact) that represents a gap in the geologic record, with the rock unit immediately above the contact being considerably younger than the rock beneath.

An angular unconformity is a contact in which younger strata overlie an erosion surface on tilted or folded layered rock.

A nonconformity is a contact in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rock.

In geology, correlation usually means determining time equivalency of rock units.

Finding physical continuity —that is, being able to trace physically the course of a rock unit—is one way to correlate rocks between two different places.

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Update: SO I PLANNED TO RESUME WRITING THE REMAINING NOTES HERE BUT I WAS REMINDED BY THE LESSONS OF THE BHAGAVAD GITA TO BE IN THE PRESENT.

Which it the right way because this important but as humans we should be in the moment with the current occupations in our life not otherwise. So bye.