Earth's Separate Layers Flashcards
What does the segregation of planets from the solar nebula explain?
Various features like bulk density and elemental abundances, and the differentiation of planets into distinct layers.
How do meteorites contribute to our understanding of planetary formation?
They provide samples from disrupted parent bodies, revealing Fe-rich metals, rock-metal mixtures, and volcanic rocks.
What challenges exist in studying Earth’s interior?
Limited direct sampling, with deepest drill holes penetrating only a small fraction of Earth’s radius, and reliance on indirect evidence.
How is Earth’s density estimated?
Density is calculated as Mass / Volume, with volume easily measured and mass calculated using Newton’s laws and Cavendish’s experiment.
What does Earth’s ellipsoidal shape indicate?
The equatorial bulge due to Earth’s rotation suggests mass concentration towards the center, with a lower moment of inertia indicating a dense core.
What do seismic waves reveal about Earth’s interior?
Seismic velocities show density variations, with compressional, shear, and surface waves revealing a liquid layer in the shadow zone
What are the main layers of Earth’s interior?
Crust (continental and oceanic), mantle, outer core, inner core, defined by seismic velocities and density variations.
What is the composition of Earth’s core?
The core consists of iron (Fe) and nickel (Ni) with lighter elements, with the outer core being liquid and the inner core solid due to high pressure.
What are lithophile, siderophile, and chalcophile elements?
Lithophile elements prefer silicate rocks (mantle and crust), siderophile elements favor metallic state (core), and chalcophile elements occur in sulfur-bearing minerals.
How are magmaphile elements distributed?
Magmaphile elements concentrate in silicate liquid during melting, predominantly found in Earth’s crust.
What evidence supports Earth’s formation from meteoritic materials?
Earth’s composition compared to chondritic proportions, suggesting formation from meteoritic materials, though with some uncertainties.
What do radiogenic isotopes suggest about core formation?
Core formation likely occurred rapidly within the first 30 million years due to substantial heat sources.
How does Earth’s crust form?
Through partial melting of Earth’s interior, producing magma that erupts as lava or cools to form plutons, with ocean crust being basaltic and continental crust granitic.
What processes contribute to the formation of continents?
A multistage process involving basaltic layers followed by granite formation, possibly involving recycling of basaltic material or weathering.
How did Earth’s atmosphere and oceans form?
Volatiles like H2O and CO2 released through degassing from rocks, with evidence from xenon isotopes suggesting early formation.
