1 / 54

SIO224 Internal Constitution of the Earth

Explore the internal constitution of Earth, mantle dynamics, planetary evolution, and isotope geology principles. Learn about mass and heat transfer, mantle models, planet migrations, core formation, and more.

davidpayne
Download Presentation

SIO224 Internal Constitution of the Earth

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SIO224 Internal Constitution of the Earth Fundamental problem: the nature of mass and heat transfer in the mantle and the evolution of the Earth

  2. Ingredients for a unified mantle model • Seismology:1D and 3D structure of the Earth • Geochemistry: bulk composition of the Earth; heat production; geochemical tracers of “mantle reservoirs” • Mineral physics: thermoelastic properties of materials at high T and P (equations of state); phase transformations; rheology of mantle materials • Geodynamics: flow models, geoid constraints, mantle convection, effects of phase transformations and viscosity variations on convection, thermochemical convection, thermal history.

  3. Shear velocity -- +-1% isovelocity surfaces Includes S and SS cluster analysis data

  4. Origin of the solar system

  5. Solar Systems Form by Accretion

  6. Planetary migration • Giant planets have migrated over time, Uranus and Neptune were closer in but migrated out after Saturn and Jupiter went into 2:1 resonance • Jupiter also migrated slightly inward – interactions with left over material led to late heavy bombardment

  7. Exosolar systems • 2701 known systems, 610 known to have multiple planets (two have 7 planets) • On average, one planet per star and 1 in 5 Sun-like planets have an “Earth-sized” planet in the habitable zone • First planets to be identified were “hot Jupiters” – now known to be not so common • Some systems are not “nebular like” • Maybe planetary interactions are generally more important than in our solar system

  8. Formation of the moon

  9. Meteorites and the composition of the Earth

  10. Timing of core/moon formation

  11. Principles of Isotope Geology: Conventional radiogenic isotope systematics used in geology: 147Sm - 143Nd t 1/2 = 10.6 x 1010 yrs 87Rb - 87Sr t 1/2 = 48.8 x 109 yrs 238U - 206Pb t 1/2 = 4.47 x 109 yrs 235U - 207Pb t 1/2 = 0.704 x 109 yrs 232Th- 208Pb t 1/2 = 14.01 x 109 yrs 187Re - 187Os t 1/2 = 42.3 x 109 yrs 176Lu - 176Hf t 1/2 = 35.7 x 109 yrs

  12. The Law of Radioactive Decay The basic equation: dN dN - µ - l N or = N dt dt 1 ½ ¼ # parent atoms D* = Nelt - N= N(elt -1) age of a sample (t)if we know: D*the amount of the daughter nuclide produced Nthe amount of the original parent nuclide remaining lthe decay constant for the system in question (= ln 2/ t ½) More conventionally, D(present) = Do + D* time 

  13. These systematics are being used as chronometers • model age • isochron age • and as petrogenetic tracers….

  14. Earth composition continued….. • lithophile elements (oxygen, oxides, silicate minerals, Greek lithos - stone) • chalcophile (sulphides, Greek khalkos=copper) • siderophile (metallic, Greek sideros=iron)

  15. Hf is enriched in the silicate mantle after core formation

More Related