In particular, we can use dust as a tracer of past atmospheric circulation patterns: by comparing the radiogenic isotopic “fingerprint” of places where the dust might have come from with the signal we see in some climate archive, we know that storm systems transported that dust from that known source to our location of interest.Then, we can see how the source areas may have changed over time. My samples come from several ice cores in West Antarctica (WAIS), and we use Sr, Nd, and Pb isotopes to identify the changing dust sources to WAIS on glacial-interglacial and millennial timescales, as well as during even shorter-term events such as volcanic eruptions. LOGAN BRENNER Linsley, de Menocal, B.
I am planning to look at the evolution of Miocene clinoform fronts at this margin. In my last chapter, I am going to evaluate the ocean crustal sites at Reykjanes ridge, offshore Iceland for carbon dioxide sequestration in layers of deep-sea basalt.
This work aims to look for an offshore extension of the onshore Carb Fix project launched in 2007.
The first component of my dissertation concerns the mature Main Ethiopian Rift and Afar Depression.
I used earthquake and continuous data from 100 temporary seismic stations located in the region to investigate the shear velocity and radially anisotropic structure of the uppermost mantle.
This investigation produced estimates of mantle temperature and melt content within the rift and also highlighted the potential location of melt segregation along a steeply dipping lithosphere-asthenosphere boundary.
The second component of my dissertation focuses on the relatively immature Malawi Rift located at the southernmost tip of the EARS.Much of my research focuses on the effects of multiple stressors on the growth and physiology of planktonic microorganisms, which form the base of the marine food web and serve as some of the first bioindicators of change in marine ecosystems.Although the effects of ocean acidification are known for some marine plankton, the interactive effects of ocean acidification and other chemical stressors (e.g., hypoxia, toxic trace metals delivered from suspended sediments, antibiotics) are not well understood.Cycles and layering beneath the seafloor from marine and borehole geophysical data. In my first chapter, I examine the effect of short-term tidal cycles in the ocean.Specifically, I assess triggering of seismic activity related to the true fortnightly and fortnightly modulations of diurnal and semidiurnal tides at the East Pacific Rise through a dataset from an Ocean Bottom Seismometer array that was deployed from October 2003 to January 2007.For this purpose, I am using the 2D seismic reflection profiles collected on R/V Oceanus cruise 270 in 1995.