TY - JOUR
T1 - Unexpected occurrence and significance of zinc alkyl porphyrins in Cenomanian-Turonian black shales of the Demerara Rise
AU - Junium, Christopher K.
AU - Mawson, Deborah H.
AU - Arthur, Michael A.
AU - Freeman, Katherine H.
AU - Keely, Brendan J.
N1 - Funding Information:
Initial funding for the study was provided in the form of a student exchange travel Grant for C. Junium to the University of York by the Worldwide University Network. Continuing funding was provided by the National Science Foundation (NSF EAR05-25464) to M. Arthur and K. Freeman. J. Fulton is gratefully acknowledged for discussion and laboratory assistance. C. Junium thanks the Ocean Drilling Program for samples and the opportunity to participate on Leg 207. We thank P. Schaeffer, R. Ocampo and an anonymous reviewer for constructive comments.
PY - 2008/8
Y1 - 2008/8
N2 - We analyzed alkyl porphyrins in acetone extracts of Cenomanian-Turonian black shales from the Demerara Rise using reverse phase high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. The major alkyl porphyrins comprise mixtures of free base and metallo porphyrins of the C33 bicycloalkanoporphyrin (BiCAP) structural type. The most abundant porphyrins in the sediments are vanadyl complexes, occurring with varying relative amounts of free base porphyrins, nickel complexes and, unexpectedly, zinc complexed C33 alkylporphyrins. The geochemical conditions that favor production of vanadyl, zinc/nickel and free base porphyrins are very different. Although the geochemical conditions that controlled metal availability were highly variable spatially and temporally over the sample interval, the dominant precursor chlorophyll(s) appears to have remained constant, giving rise to limited structural variation with a dominance of BiCAP structures.
AB - We analyzed alkyl porphyrins in acetone extracts of Cenomanian-Turonian black shales from the Demerara Rise using reverse phase high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. The major alkyl porphyrins comprise mixtures of free base and metallo porphyrins of the C33 bicycloalkanoporphyrin (BiCAP) structural type. The most abundant porphyrins in the sediments are vanadyl complexes, occurring with varying relative amounts of free base porphyrins, nickel complexes and, unexpectedly, zinc complexed C33 alkylporphyrins. The geochemical conditions that favor production of vanadyl, zinc/nickel and free base porphyrins are very different. Although the geochemical conditions that controlled metal availability were highly variable spatially and temporally over the sample interval, the dominant precursor chlorophyll(s) appears to have remained constant, giving rise to limited structural variation with a dominance of BiCAP structures.
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U2 - 10.1016/j.orggeochem.2008.04.004
DO - 10.1016/j.orggeochem.2008.04.004
M3 - Article
AN - SCOPUS:47849116980
SN - 0146-6380
VL - 39
SP - 1081
EP - 1087
JO - Organic Geochemistry
JF - Organic Geochemistry
IS - 8
ER -