Analyses of samples from a 200-cm core of coccolith ooze from the deep tropical Atlantic (00° 07'S, 17° 34'W) show it to be uniformly composed of low-magnesium calcite. The levels of most trace elements were found to be low for pelagic marine carbonate sediments.
Thompson, Geoffrey, and Vaughan T. Bowen. 1969. "Analyses of coccolith ooze from the deep tropical Atlantic." Journal of Marine Research 27, (1). https://elischolar.library.yale.edu/journal_of_marine_research/1140