Earth's Layers & Structure
Clue: This process separated Earth's layers based on density as heavier materials were pulled to the center.
Answer: What is density stratification?
Clue: He proposed the continental drift hypothesis in 1912.
Answer: Who was Alfred Wegener?
Clue: Harry Hess proposed this theory in 1960 where new ocean crust forms at spreading centers.
Answer: What is seafloor spreading?
Clue: At this type of boundary, tectonic plates move apart from each other.
Answer: What is a divergent boundary?
Clue: The study of natural permanent magnetism in rocks that provided strong evidence for seafloor spreading.
Answer: What is paleomagnetism?
Clue: Making up 68.1 percent of Earth's mass and 83 percent of its volume, this layer sits beneath the crust.
Answer: What is the mantle?
Clue: The single supercontinent that contained all landmasses 225 million years ago.
Answer: What is Pangaea?
Clue: The process where denser oceanic crust sinks beneath continental crust back into the mantle.
Answer: What is subduction?
Clue: The collision of the Indian and Asian continental plates created this major mountain range.
Answer: What are the Himalayas?
Clue: Stationary concentrations of heat in the mantle that produce volcanic island chains like Hawaii as plates move.
Answer: What are hot spots?
Clue: This rigid outer layer up to 100 kilometers thick includes the crust and uppermost mantle.
Answer: What is the lithosphere?
Clue: The two large subcontinents formed when Pangaea began breaking apart 180 million years ago.
Answer: What are Laurasia and Gondwana Land?
Clue: This extensive underwater mountain system runs down the length of the Atlantic Ocean.
Answer: What is the Mid-Atlantic Ridge?
Clue: At this boundary type, plates slide side by side in opposite directions without creating or destroying crust.
Answer: What is a transform fault boundary?
Clue: Ring-shaped coral reef islands centered over a submerged inactive volcano.
Answer: What are atolls?
Clue: This soft, hot layer of the upper mantle can deform plastically under stress and flows like cold taffy.
Answer: What is the asthenosphere?
Clue: Matching rock types, ancient climates, and these remains on separated coastlines supported continental drift.
Answer: What are fossils?
Clue: The University of Toronto professor who proposed the unified Plate Tectonics Theory in 1964.
Answer: Who was John Tuzo Wilson?
Clue: This famous California fault line is a primary example of a transform boundary.
Answer: What is the San Andreas Fault?
Clue: Flat-topped submerged volcanic mountains whose tops were eroded by wave action.
Answer: What are guyots (or table mounts)?
Clue: Extreme pressure keeps this white-hot inner layer solid despite temperatures around 5,800 degrees Celsius.
Answer: What is the inner core?
Clue: The single vast ocean that surrounded Pangaea.
Answer: What is Panthalassa?
Clue: The primary source of heat inside the Earth that drives mantle convection currents.
Answer: What is radioactive decay?
Clue: Deep ocean trenches and continental volcanic arcs form at this specific boundary type.
Answer: What is an oceanic-continental convergent boundary?
Clue: The 1968 scientific drilling vessel that collected ocean sediment cores supporting plate tectonics.
Answer: What is the Glomar Challenger?