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Copper porphyrins have been isolated from deep-sea sediments collected during six DSDP/IPOD legs. These pigments are present in areas receiving high inputs of terrestrially derived organic matter which is either slowly accumulated, deposited from oxygenated bottom waters, or oxidized before deposition. Such areas include the Cretaceous sediments of the Bay of Biscay, Blake-Bahama basin, and Bermuda; slumped Miocene deposits off Cape Bojador on the west coast of Africa; and lower Pleistocene sediments of the Black Sea. Copper porphyrins are absent from sediments that accumulated under anoxic conditions, of which Cretaceous sediments of the Cape, Angola, and Moroccan basins are examples. Copper porphyrins coexist with products of varying states of chlorophyll diagenesis (ch orins, freebase, nickel, and vanadyl porphyrins) which typically form under reducing conditions. The mass spectral envelope is markedly different from that of nickel and vanadyl porphyrins; copper porphyrins are usually etioporphyrins with carbon numbers of C32 to C23 and a centroid at C28 to C25. The DPEP series is usually absent. In contrast, carbon numbers of C32 to C30 and presence of both the DPEP and etio series are characteristic of nickel and vanadyl porphyrins. Their occurrence with a range of chlorophyll diagenetic products and their distinctive mass spectral envelope suggest that copper porphyrins are derived from a different source. Their association with sediments containing terrestrially derived organic matte which has undergone a period of oxidation suggests that copper porphyrins may be potential indicators of oxidized terrestrial organic matter.
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