Maloof Home

Adam Maloof
Assistant Professor of Geosciences (Geology)

Department of Geosciences
213 Guyot Hall
Princeton University
Princeton, NJ 08544

Phone: (609) 258-2844
E-Mail: maloof@princeton.edu

Carbonate muds deposited in peritidal environments have high preservation potential and are abundant throughout the geologic record. Much of what we know about pre-Mesozoic ocean chemistry, carbon cycling, and global change is derived from isotope and trace element geochemistry of platform carbonates. My group is working on a long-term project to address two fundamental questions in process sedimentology and biostratigraphy on the Great Bahaman Bank. Our aim is to apply the knowledge we attain in the modern carbonate environment to our understanding of ancient carbonate stratigraphic records.

1. Paleomagnetic data from carbonate muds would allow us to place records of paleolatitude, paleogeography, and perturbations to the geomagnetic field in the context and relative chronology of chemostratigraphy. Many workers, however, have questioned the origin of magnetization in carbonates, suggesting that much of the magnetite found in ancient carbonates may have been modified during burial diagenesis or precipitated by migrating pore-fluids millions of years after deposition. Are modern carbonate muds on Andros Island magnetic? If so, do the carbonates preserve an accurate record of the orientation of the local geomagnetic field? What are the effects of facies variation and bioturbation on the magnetic directions and magnetic moments of carbonate samples? Is the magnetic mineralogy of Andros carbonates dominated by hematitic Saharan dust or by bacterial magnetite concentrated in Algaecyanobacterial filaments? Understanding the origin of magnetization in modern carbonates will help us understand the source and reliability of magnetization in ancient limestones and dolostones.

2. In siliciclastic river systems, sediments often accumulate by lateral aggradation of point bar deposits in migrating meandering streams. In this scenario, vertical facies variation may reflect either a stochastic process like stream migration, or a periodic process such as astronomical forcing of global sea level, or a combination of the two. Determining the relative importance of these sedimentary processes will influence the way we interpret lithological, isotopic, and paleomagnetic time series from ancient laminated carbonates.

Why is the Three Creeks area channelized, while much of western Andros Island is not? Are the channels incised in bedrock, do they sweep back and fort across the platform as terrigenous meandering channels typically do, and how significantly have they changed since this part of the carbonate platform was flooded ~3000 years ago. Do meter-scale parasequences record information about periodic external forcing of sea level and sediment delivery (e.g. Milankovitch) or are the parasequences the result of stochastic internal variability such as the migration of meandering channels? Did the advent of mangroves in the Cretaceous / Early Tertiary help stabilize channels? Answers to these questions will help us interpret the chemostratigraphic time series we rely on to understand basic Earth history and global change.

This work is part of a truly multi-disciplinary collaboration with John Grotzinger, Bob Kopp, David Fike and Joe Kirschvink at Caltech, Ben Weiss at MIT, Hojatollah Vali at McGill University and Tanja Bosak at Harvard University.