Chemostratigraphic evidence of higher-plant evolution in the Taranaki Basin, New Zealand

• Published in: Organic geochemistry Vol. 23; no. 5; pp. 429 - 445
• Main Authors: Killops, S.D., Raine, J.I., Woolhouse, A.D., Weston, R.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-05-1995; Elsevier Science
• Subjects: angiosperm/gymnosperm index; angiosperms; Applied sciences; Crude oil, natural gas and petroleum products; diterpanes; Earth sciences; Earth, ocean, space; Energy; Exact sciences and technology; Fuels; Geology and geochemistry. Geological and geochemical prospecting. Petroliferous series; gymnosperms; higher plants; Hydrocarbons; Prospecting and exploration; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Sedimentary rocks; Taranaki Basin; triterpanes; New Zealand; Australasia; North Island; diterpanes; triterpanes; Taranaki Basin; angiosperms; gymnosperms; higher plants; angiosperm/gymnosperm index; Mesozoic; Paleogene; swamps; Tertiary; biomarkers; Paleocene; concentration; Eocene; Cretaceous; chromatograms; terpanes; Spermatophyta; Taranaki
• ISSN: 0146-6380; 1873-5290
• DOI: 10.1016/0146-6380(95)00019-B

Correlation between palynological and biomarker records of higher-plant development during the Cretaceous and Paleogene in Taranaki Basin, New Zealand is good. Gymnosperms, particularly podocarps, were the chief members of coastal plain swamp flora during the Late Cretaceous, and contributed significant quantities of diterpanes, often dominated by isopimarane, to organic-rich sediments. Angiosperms increased in relative abundance through the Paleocene and became the dominant higher plants in the Eocene; their contributions to coaly sediments are characterized by various triterpanes, particularly 18α(H)-oleanane and its C
24 A-ring degraded counterpart. This change in dominance of higher-plant groups can be followed by the use of an angiosperm/gymnosperm index (AGI) based on the relative concentrations of selected triterpanes and diterpanes in
m
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191 and
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123 mass chromatograms. Plant biomarker distributions do not provide as precise age indications as do pollen assemblages, but they may be more representative of the vegetation growing in a particular area of a peat swamp.