PPT-Radiogenic isotopic evolution of the mantle and crust

Matt Jackson and Bill McDonot SrNd isotope plot Global OIB ocean island basalts hotspots and MORB midocean ridge basalt We will model SrNd isotopic evolution by crustmantle differentiation. Earth’s thermal evolution poorly understood. - parameterized models yield contrasting predictions w.r.t. onset of plate tectonics. - possibility of discontinuous transitions. Models of continental growth are widely disparate due to:. Chapter 6. Isotope Geochemistry. In isotope geochemistry, our primary interest is not in dating, but using the time-dependent nature of isotope ratios to make inferences about the nature of reservoirs in the Earth and their evolution.. Inferred by Seismology. Nozomu. Takeuchi. (ERI, . Univ. of Tokyo). Importance of Directional Measurements. . from geophysicists’ point of view. (2) Improvements of Neutrino Flux Modeling. . Selwyn’s career goal #__: What does the . asthenosphere. have to do with earthquakes, crustal motions, and mantle convection?. Upper crust. Lower crust. Upper mantle. Upper crust. Lower crust. Upper mantle. Th. . contents. (just a review of noble gas reservoirs....). 2013. 10. . 30. @Workshop on . Particle Geophysics, Sendai. Hirochika SUMINO. Geochemical Research Center (GCRC). University of Tokyo. Cover a wide mass range.. It’s going to be . a WILD RIDE!. Journey to the Center of the Earth. Imagine if you will…... You are a Geologist* and have been given the task of traveling to the center of the Earth. You have a specially designed Earthship that will take you to the core. Your Earthship, . Layers of the Earth. 1. 2. / . 24. 3. / . 24. Plate Tectonics. Earth’s lithosphere is broken up into plates. Hot, weak asthenosphere allows for plates to move. Plates are in motion and continually changing in shape and size. Records of continental growth. Continental crust. Cratonic. mantle. Convecting. mantle. Atmosphere. Two Big Themes. Preservation . vs. Production. Uniformitarianism. . vs. . Catastrophism. Continental Crust. Zones. Lecture 44 . How were the continents created?. So far, we have talked about the when, but not the how.. Today, there are 3 main mechanisms by which new crust is created:. Rifting (e.g., African and Rio Grande Rifts) and divergent plate boundaries (North Atlantic Tertiary Province is an example).. Define: . 1.) Mineral - a naturally occurring, inorganic crystalline material . with a . unique chemical . composition. , and a regular repeating pattern. . 2. .) Viscosity - a measure of a fluid’s resistance to flow. COMMON plumeswere initially thought to consist of primitive mantle (e.g., Schilling, 1973). As we found, mixing be-tween primitive and depleted mantle can explain the Sr and Nd isotopic compositions 1 TWTT0 s 10 s -wave reflection profile over ~1,000 km Goals: . Review isotopic and geophysical data, discuss elements of crustal structure. build a composite picture of the crust . compare results to mineral trends and tectonic features of successively younger events. Lecture . 29. Isochrons. This equation has the form . y = a + bx. .. Plotting the radiogenic isotope ratio against the parent daughter ratio, the intercept with be . R. 0. . and the slope will be . e.