Earth and Life Processes Discovered from Subseafloor Environments

The Integrated Ocean Drilling Program (IODP: 2000-2013) has provided crucial records of past and present processes and interactions within and between the biosphere, cryosphere, atmosphere, hydrosphere and geosphere. Research in IODP encompasses a wide range of fundamental and applied issues that affect society, such as global climate change, biodiversity, the origin of life, natural hazards involving the study of earthquakes processes, and the internal structure and dynamics of our planet. This compilation of major findings from the 2003-2013/14 phase of IODP, focusing on scientific results rather than description of data acquisition and early inferences, provides invaluable information. Anyone wondering what scientific drilling can achieve will gain quick understanding of the range of questions that are uniquely addressed with this methodology and the ways these data dovetail with other regional information. The excitement of breakthrough findings that occasionally accompanies a drilling project will be evident.

IODP obtained unique records from the global ocean basins during the 2003-2013 program phase. This book highlights findings in three theme areas: Subseafloor life and the marine biosphere; Earth's changing environments; and Dynamics of the solid Earth. Each core or borehole log provides a window revealing insights that no other data achieve.

Donna Blackman's research focuses on oceanic spreading centers, investigating how tectonics, mantle flow, and melting along ridge-transform systems vary and what that tells us about the underlying processes. A variety of geophysical methods are used in this research including mapping of seafloor morphology and geology, modeling of gravity data, and measuring subseafloor physical properties using ocean bottom seismographs, towed hydrophone streamers, and scientific drilling, coring and borehole logging. Computer simulations with colleagues test ideas on how deformation of the mantle and crust might occur. Slowly-spreading oceanic rift zones have recently been recognized to undergo episodes where the balance between magmatic and faulting activity evolves over time. During these 1-2 million year periods, newly formed seafloor develops unusual domal highs that are unroofed via long-lived faulting. Study of these 'oceanic core complexes' provides insight into what controls the magma-faulting balance so a major current focus of my research is to document their structure and, thereby, the processes that are responsible for their formation. Another research focus is how minerals develop a preferred orientation during slow viscous deformation in the deep Earth. Seismic waves propagate at different speeds through aligned versus randomly oriented mineral assemblages, so seismic data can detect subsurface deformation patterns induced by flow beneath the rigid tectonic plates. Mineral deformation modes differ depending on in-situ physical conditions and experimental data are still sparse. Numerical models can test the impact of various possible parameters to illuminate the range of outcomes that could occur in Earth's mantle. An aspect currently under study with colleages at Cornell and Paris is whether mineral alignment could result in strong directional dependence of viscosity, that could feedback and alter the style of upper mantle flow.

Donna started her geologic studies in California (Pasadena City College and University of California Santa Cruz). She worked at the USGS Pacific Marine Geology Branch then moved to the eastern US for graduate school (MIT and Brown University). Postdoctoral work was completed at University of Washington and Scripps Institution of Oceanography. Since 1992, she has been a Research Geophysicist at Scripps, with a 1-yr interlude at Leeds University, U.K., in the mid-'90s. In 2012, she began a 3-year rotation at the US National Science Foundation, serving as a Program Director in the Marine Geology and Geophysics program.