HISTORY OF EARTH Flashcards
THE PRINCIPLE IS THE KEY TO THE PAST QHICH IS BASED ON THE PRINCIPLE THAT NATURALLY LAWS HAVE REMAINED THROUGH OUT TIME
UNIFORMITARIANISM
ALSO KNOWN AS THE DOCTRINE OF UNIFORMITY
UNIFORMITARIANISM
FORMED IN LAYER, PRIVIDE USEFUL INFORMATION IN RELATIVE DATING
SEDIMENTARY ROCKS
THEY ARE FORMED FROM FRAGMENTS OF OTHER TYPES OF ROCKS
SEDIMENTARY ROCKS
NEW SEDIMENTARY ROCKS LAYERS ARE ALWAYS _
FLAT
USED TO DETERMINE WHETHER AN OBJECT OR EVENT IS OLDER OR YOUNGER THAN OTHER OBJECTS OR EVENTS
RELATIVE DATING
ARE DEPOSITED IN THE SEDIMENTARY LAYERS OF ROCKS
FOSSILS
LAWS/IDEAS:
LAW OF ORIGINAL HORIZONTALLY, LAW OF SUPERPOSITION, PRINCIPLE OF CROSS CUTTING RELATIONS, IDEA OF UNCOMFORMITIES
MEANS THAT SEDIMENTARY ROCKS ARE ORIGINALLY FORMED IN HORIZONTAL LAYER
LAW OF ORIGINAL HORIZONTALLY
HORIZONTALLY OCCURS IN AN AREA OF LAND THAT IS FORCES TO BEND, USUALLY FROM FORCES INSIDE THR EARTH PUSHINH ON THEM
LAW OF ORIGINAL HORIZONTALLY
STATES THAT IN ANY UNDISTURBED SEQUENCE OF LAYERS OF ROCKS, THE OLDER LAYER WOULD HE AT THE BOTTOM, AND THE YOUNGER WOULD BE ON THE TOP
LAW OF SUPERPOSITION
THIS STATES THAT ANY TOCKS OR FAULT THAT CUT ACROSS THE OTHER ROCK IS YOUNGER THAN THOSE IT CUT ACROSS
PRINCIPLE OF CROSS CUTTING RELATIONS
ARE SURFACES OF EROSION THAT SEPARATE YOUNGER ROCKS FROM OLDER ONES
IDEA OF UNCOMFOMITIES
METHOD OF MEASURING THE ABSOLUTE AGE OF AN EVENT OR OBJECT
ABSOLUTE DATING
UNSTABLE RADIOACTIVE ISOTOPE
PARENT ISOTOPE
STABLE ISOTOPE PRODUCED BY THE RADIACTIVE DECAY OF THE PARENT ISOTOPE
DAUGHTER ISOTOPE
TIME NEEDED FOR A HALF A SAMPLE OF RADIACTIVE SUBSTANCE
HALF LIFE
THE RATE OF RADIOACTUVE DECAY IS _
CONSTANT
ANOTHER DATING METHOD ACHIEVED BY DETERMINING THE ABSOLUTE AGE OF A SAMPLE
RADIOMETRIC DATING
4 RADIOMETRIC DATING METHODS BASED ON THE ESTIMATED AGE OF AN OBJECT:
POTASSIUM-ARGON, URANIUM-LEAD, RUBIDIUM STRONTIUM, CARBON-14
=USES POTASSIUM-40
=HALF LIFE OF 1.3 BILLION YEARS GA, IT LEAVSS ITS DAUGHTER MATERIAL, ARGON
=USED MAINLY TO DATE ROCKS OLDER THAN 100000 YEARS
POTASSIUM-ARGON METHOD
=USES URANIUM-238 HALF LIFE OF 4.5 GA
=URANIUM-238 DECAYS IN A SERIES OF STEPS WHICH BECOMES LEAD-206
=USED TO DATE ROCKS OLDER THAN 10 MILLION YEARS OLD
URANIUM-LEAD METHOD
=USES RUBIDIUM-87 WHICH FORMS A STABLE DAUGHTER ISOTOPE STRONTIUM-87
=HALF LIFE OF RUBIDIUM IS 49 GA
=USED FOR ROCKS WHICH ARE OLDER THAN 10 MILLION MA
RUBIDIUM-STRONTIUM METHOD
=USES RADIACTIVE ISOTOPE CARBON-14
=HALF LIFE OF 5730 YEARS
=MAINLY USED FOR DATING THINGS THAT LIVED WITHIN THE LAST 50,000 YEARS
CARBON-14 METHOD
