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DSDP drilling activities in the Black Sea afforded an opportunity to continue the study of early chlorophyll diagenesis. Since the usual mass spectrometric analysis of thermally labile nonvolatile geochlorins was inadequate for our study, a new analytical mass spectrometric method based on a novel synthesis of a new class of compounds, the silylated hydroxyaluminum chlorins, was developed. Twenty-five core samples, ranging from 0 to 1062 meters depth of burial (Pleistocene to Miocene) were analyzed. Shallow sediment samples contained chlorins with characteristics similar to those reported for the Pleistocene samples from Leg 15 Site 147 (Baker and Smith, 1973). Chlorins gave way to free-base porphyrins with increasing depth of burial, and small amounts of nickel porphyrins were found in deeper sediments. The importance of depth of burial as a factor in maturation is re-emphasized by these data. All shallow samples (0-400 m) contain chlorins; however, intermediate diagenetic products (free-base porphyrins) occur in Site 380 samples at 484-1016 meters depth of burial. These deeper samples, containing the i n t e r m e d i a t e d i agene t i c p r o d u c t s , can stratigraphically correlated with shallower samples of Site 381 where only chlorins are found. Small amounts of nickel porphyrin were found in Pleistocene samples at and below 484 meters of burial. The distribution of these porphyrins with respect to other pigments present and the geologic age of the enclosing sediments suggest that they are more characteristic of the Pliocene and Miocene sediments than the overlying Pleistocene sediments. Because the distribution of these particular nickel porphyrins do not fit into the expected sequence typical of early and intermediate chlorophyll diagenesis, it is suspected that they migrated from older deeper sediments.

Early and Intermediate Chlorophyll Diagenesis of Black Sea Sediments: Sites 379, 380, and 381