Email: lear@imcs.rutgers.edu
Phone: 732-932-6555 ext. 255 (office);  ext. 227 (lab)
Fax: 732-932-8578

Research Interests:

My research is focussed on understanding the links between geological and biological processes, ocean chemistry and climate change over the Cenozoic (the last 65 million years). I use the chemical composition of biogenic carbonate as "proxies" for past ocean chemistry and temperature.

For example, I have used the Sr/Ca ratios of benthic foraminifera to interpret the seawater 87Sr/86Sr curve in terms of global weathering rates through the Cenozoic (Lear et al. 2003). I am also currently working on a project with Ethan Grossman (Texas A&M) and Yair Rosenthal that uses the Sr/Ca of aragonite molluscs to evaluate changes in both sea surface temperatures and also seasonality through the Cenozoic.

I also use the Mg/Ca ratios of benthic foraminiferal tests as a proxy for past bottom water temperatures. This method was initially developed by Yair Rosenthal (Rosenthal et al. 1997) and we are continually improving this proxy method (e.g., Lear et al. 2002). I have applied this method to a low-resolution record of Cenozoic deep sea temperatures (Lear et al., 2000) and am currently improving the Miocene to Eocene portion of the Cenozoic record using deep sea Pacific sediments collected on Ocean Drilling Program Leg 199, in which I participated. By using multiple sites, the Mg proxy method may be used to track changes in ocean circulation through time. At present, I am evaluating the extent to which changes in ocean circulation may affect global climate. An initial study suggests that the closure of the Panama Gateway had a marked effect on the thermal properties of North Atlantic Deep Water and may have been linked to the Plio-Pleistocene Northern Hemisphere Glaciation (Lear et al. in press). I am now investigating the role of ocean circulation change in the major middle Miocene glaciation of Antarctica.

Peer-reviewed Publications

Lear C.H., Y. Rosenthal and J.D. Wright (in press) The closing of a seaway: Ocean
water masses and global climate change. Earth and Planetary Science Letters. [pdf]

Lear C.H., H. Elderfield and P.A. Wilson (2003) A Cenozoic seawater Sr/Ca record from benthic foraminiferal calcite and its application in determining global weathering fluxes. Earth and Planetary Science Letters 208 69-84. [pdf]

Lear C.H., Y. Rosenthal and N. Slowey (2002) Benthic foraminiferal Mg/Ca-paleothermometry: A revised core-top calibration. Geochimica et Cosmochimica Acta 66 3375-3387. [pdf]

Lear C.H., H. Elderfield and P.A. Wilson (2000) Cenozoic deep-sea temperatures and global ice volume from Mg/Ca in benthic foraminiferal calcite. Science 287 269-272. [pdf]

Non peer-reviwed publications

Lear C.H., H. Elderfield and P.A. Wilson (2003) Fossil thermometers for Earth's climate. Ocean Drilling Program Highlights, edited by Kasey White and Elspeth Urquhart, Ocean Drilling Program, TX. [pdf]