Isotopic Constraints on Earth System Processes

Using isotopes as a tool for understanding Earth processes From establishing the absolute age of the Earth to providing a stronger understanding of the nexus between geology and life, the careful measurement and quantitative interpretation of minor variations in the isotopic composition of Earth’s materials has provided profound insight into the origins and workings of our planet. Isotopic Constraints on Earth System Processes presents examples of the application of numerous different isotope systems to address a wide range of topical problems in Earth system science. Volume highlights include: examination of the natural fractionation of non-traditional stable isotopes utilizing isotopes to understand the origin of magmas and evolution of volcanic systems application of isotopes to interrogate and understand Earth’s Carbon and Oxygen cycles examination of the geochemical and hydrologic processes that lead to isotopic fractionation application of isotopic reactive transport models to decipher hydrologic and biogeochemical processes The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

List of Contributors vii Preface ix About the Companion Website xii Dedication xiii Part I High-Temperature/Deep Earth Processes 1 High-Temperature Kinetic Isotope Fractionation of Silicate Materials 3 Frank M. Richter 2 Ca and K Isotope Fractionation by Diffusion in Molten Silicates: Large Concentration Gradients Are Not Required to Induce Large Diffusive Isotope Effects 27 James M. Watkins, John N. Christensen, Donald J. DePaolo, and Frederick J. Ryerson 3 Calcium Isotope Constraints on Recycled Carbonates in Subduction- Related Magmas 43 Justin I. Simon 4 Reassessing the Role of Continental Lithospheric Mantle in Cenozoic Magmatism, Southwestern North America 57 G. Lang Farmer 5 Rhyolite Ignimbrite Generation in the Northern Andes: The Chalupas Caldera, Ecuador 87 Lisa Hammersley, Donald J. DePaolo, Bernardo Beate, and Alan L. Deino 6 Xenolith Constraints on “Self-Assimilation” and the Origin of Low δ18O Values in Mauna Kea Basalts 133 John C. Lassiter, Danny W. Anderson, Daniel Villanueva-Lascurain, Edward W. Marshall, and Jaime D. Barnes 7 Monitoring Volcanic Activity Through Combined Measurements of CO2 Efflux and (222Rn) and (220Rn) in Soil Gas: An Application to Mount Etna, Italy 167 Salvatore Giammanco and Kenneth W. W. Sims Part II Low-Temperature/Shallow Earth Processes 8 The Carbon Isotope Record and Earth Surface Oxygenation 205 Thomas A. Laakso and Daniel P. Schrag 9 Detrital Garnet Geochronology: A New Window into Ancient Tectonics and Sedimentary Provenance 217 Kathryn A. Maneiro, Michelle K. Jordan, and Ethan F. Baxter 10 A Review of the Development of Cr, Se, U, Sb, and Te Isotopes as Indicators of Redox Reactions, Contaminant Fate, and Contaminant Transport in Aqueous Systems 237 Thomas M. Johnson, Jennifer L. Druhan, Anirban Basu, Noah E. Jemison, Xiangli Wang, Kathrin Schilling, and Naomi L. Wasserman 11 The Effects of Reactive Transport on Sulfur Isotopic Compositions in Natural Environments 271 Alexandra V. Turchyn and Jennifer L. Druhan 12 A Reactive Transport Framework Describing Covariation in the Isotopic Ratios of Multiple Elements in Natural Systems 285 Jennifer L. Druhan and Alexandra V. Turchyn 13 Stable Ca Isotope Fractionation in Cenozoic Marine Mammals: Beyond Biomineralization and Trophic Positioning 301 Cole M. Messa, Kenneth W.W. Sims, Sean R. Scott, and Mark T. Clementz Index 329