19 terms
Earth and Science set #10
Pangaea
a supercontinent comprising all the continents crust of the earth, postulated to have existed 240 million years ago
Pathalassa
a single ocean surrounding Pangea
continental drift
a hypthesis proposed in 1912 by alfred wegner that suggested that 240 million years ago the continents were all part of a super continent called pangea and have drifted to there current location
seafloor spreading
a hypothesis proposed in the 1960's suggesting that magma from earths mantel rises to the surface through rifts or breaks in the mid ocean ridges and hardens to for new seafloor. As the sea floor movces in oppisite dirrections new magma fills in the gaps creates. the old floor is destroyed in the ocean trenches
magnetometer
an instrument used to detect small changes in magnetis feilds
paleomagnetism
the study of earths magnetic core record using data gathered from iron bearing minerals in rocks that have recorded the orientation of the earths magnetis feild at the time of their formation
mid-ocean ridges
chains of under water mountains that run through out the ocean basins of the world these mountins have a rift and a crack running don through the middle of them
ocean trench
the deepest area of the sea where the ocean floor descends back into the internals of the earth
echo sounder
a device used the detect the depth of the water by determining how long it takes for a sound pulse to bounce off the bottom of the ocean and return to the ship, one type is sonar
magma
melted roch within the earth
basalt
an iron containing rock that mackes up the floor of the world's oceans. This rock contains the iron bearing minerals that record the history of the earths magnetic feild this rock is covered in sediments
marianas trench
the deepest portion of the world's oceans located in the western pacific. this is the location where the ocean floor descends back into the earth. the deepest part is called challenger deep and plunges 7 miles
Cygnogathus
a genus of extinct land dwelling animals that existed 251 million years ago. fossil evidence has been found in south africa and south america
Mesosaurus
aquatis relitive of reptiles found as fossils 299 million years agoi in south africa and south america. mesosaurus lived in fresh water lakes and ponds. becasue it is unlikely that the animal could have traveled across the ocean it is supporting evidence the 2 continounts used to be connected
glossoptres
a genus of fossilized woody plants/ferns found as fossils that have been dated to 300-200 million years ago the fossils currently existed on five continents the distidution of this plant was among the first evidence for continental drift
Lystrosaurus
a trassic land reptile whose fossils have been found in india africa and antarica. continetal drift evidence
striations
grooves in the bedrock caused by glaciers
coal
a type of rock formed from the burial and compaction of ptially decompoitsed swamp plants. used to support continental drift theory
magnetic reversal
when the earth's magnetic field changes polarity between normal and reversed it is believed to have fluctuated every 300,000 years in the past.