Thiophenes in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

Katsumata, Hideyuki; Shimoyama, Akira

doi:10.2343/geochemj.35.67

Cited by 4 publications

(10 citation statements)

References 22 publications

(47 reference statements)

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“…4(b)) (Mita and Shimoyama, 1999a) and methyldibenzothiophene (Fig. 4(c)) (Katsumata and Shimoyama, 2001). The sensitivity of the index of the free maleimide over that of the bound is reproduced in this case without scattering.…”

Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 72%

“…4, together with isomer ratios of methylnaphthalenes, methylphenanthrenes (Mita and Shimoyama, 1999a) and methyldibenzothiophene (Katsumata and Shimoyama, 2001). We have shown this ratio of bound maleimides to relate to the maturity of organic matter in the Shinjo sediments, and have called it "demethylation index of 2-methyl-3-ethylmaleimide" .…”

Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 95%

“…That finding suggested that the free maleimides are not stable during catagenesis that generated petroleum. In the Kawaruppu sedimentary sequence, where diagenesis is inferred to have taken place evenly over the whole sequence (Mita and Shimoyama, 1999a;Katsumata and Shimoyama, 2001), the depth profiles of free maleimides likely reflect the input of chlorophylls. The decrease in the concentration of free maleimides within the claystone can be related to a smaller input of their precursor chlorophylls into the claystone than into the sediments above and below it.…”

Section: Characteristics Of Free Maleimidesmentioning

confidence: 99%

“…Although bound 2,3-dimethylmaleimide (6) has no corresponding chlorophylls, it can be generated from many bound maleimide structures including bound 2-methyl-3-ethylmaleimide (8) (Barakat and Yen, 1989;Verne-Mismer et al, 1988;Kozono et al, 2001). Therefore, it may be that differences in the precursors, in relation to the massive ex- Mita and Shimoyama (1999a) and (c) from Katsumata and Shimoyama (2001). methyl-3-ethylmaleimide (2), varied up to 10 nmol g -1 . In most sediments the most predominant maleimide was 2-methyl-3-ethylmaleimide (2, 8), which is likely derived from 3-methyl-4-ethyl-pyrrole units (7) included in many chlorophylls and the major sedimentary porphyrins.…”

Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 99%

“…In the present study we analyzed free and bound maleimides in the K/T boundary sediments at Kawaruppu in order to obtain another example illustrating the utility of maleimides as biomarkers, as well as to examine maleimide distribution in a sedimentary sequence differing in maturity from that of the Shinjo sediments. Previous studies indicated that the 65 million year diagenesis has taken place evenly over the sediments throughout the sequence (Mita and Shimoyama, 1999a;Katsumata and Shimoyama, 2001). Organic geochemical studies of amino acids (Mita et al, 1996) and dicarboxylic acids (Mita et al, 1998) in the sediments were discussed as to the possibility of the presence of extraterrestrial organic compounds as well as terrestrial ones.…”

Section: Introductionmentioning

confidence: 99%

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Maleimides in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

et al. 2001

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Maleimides were detected in organic solvent extracts and chromic acid oxidation products of the Cretaceous/Tertiary boundary sediments at Kawaruppu. Free (organic solvent extractable) maleimides consisted of 2,3-dimethylmaleimide and 2-methyl-3-ethylmaleimide, and bound (oxidatively extractable) maleimides of 2-methylmaleimide and its 3-n-alkyl homologs up to C 4 , benzomaleimide (phthalimide) and its methyl homologs. The total concentrations of free and bound maleimides ranged from n.d. to 10 and from 4 to 49 nmol g -1 , respectively. The most abundant compound was 2-methyl-3-ethylmaleimide both in free and bound forms in all the sediments, indicating that the maleimides detected were very likely degradation products of porphyrins and/or chlorophylls. The concentrations of both forms of alkylmaleimides were significantly smaller in the boundary claystone than the sediments above and below it. Their depth profiles agreed with those of pristane plus phytane and n-alkanes, indicating smaller inputs of chlorophylls into the claystone, which relates to the large bio-mass extinction at the end of Cretaceous. The Kawaruppu sequence afforded the first case in which 2-methylmaleimide was the second most abundant maleimide, indicating a mild thermal history of the sediments. The ratios of 2,3-dimethyl-to 2-methyl-3-ethylmaleimide of both free and bound forms showed constant values above and below the boundary claystone, reflecting the uniform diagenesis experienced by the sediments. The ratios exhibited larger values within the claystone, which is possibly related to different precursor chlorophylls caused by the massive extinction of organisms.

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Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 72%

Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 95%

Section: Characteristics Of Free Maleimidesmentioning

confidence: 99%

Section: Effect Of Diagenesis Inferred From Alkylmaleimide Ratiomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maleimides in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

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The occurrence and significance of C25HBI in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin, NW China

et al. 2011

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The saline lacustrine deposit of the Oligocene Lower Ganchaigou Formation is the main source rock for the Western Qaidam Basin, NW China. In this study, abundant highly branched isoprenoids with 25 carbon atoms (C 25 HBI) were detected in the upper section of the Lower Ganchaigou Formation. C 25 HBI is a biomarker for diatoms, and can provide information regarding biogeochemical processes during production and preservation of sedimentary organic matter. The carbon isotopic values of C 25 HBI in these source rocks were in the range of -18‰ to -20‰. The relative enrichment in 13 C of C 25 HBI suggests that these isoprenoids were derived from diatom blooms. In this case, the diatoms used HCO 3 -as an additional carbon source to dissolved CO 2 in water column due to their high biological productivity. Conversely, the diatom blooms indicated an abundant nutrient supply to the environment and high primary productivity. Thus, the occurrence of 13 C-enriched C 25 HBI could be an ideal marker for good source rocks. The decreased concentration of CO 2 (aq) in the water column induced by diatom blooms can result in an enrichment in 13 C of organic matter synthesized by primary producers. This may be a possible reason for the occurrence of 13 C-enriched organic matter in the Cenozoic source rocks of the Western Qaidam Basin. Previous studies have shown that the high carbon number n-alkanes sourced from diatoms have no carbon preference. Hence, the sources of n-alkanes in regional source rocks are complex, and should be considered when discussing the sources of organic matter in future studies.

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Cretaceous Records of Diatom Evolution, Radiation, and Expansion

Harwood

Николаев²,

Winter

2007

Paleontol. Soc. pap.

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New information and discussions regarding Mesozoic diatoms presented over the last decade advanced our knowledge of their origin and early history. The oldest confirmed centric diatom fossils are presented here from the earliest Cretaceous, and araphid and raphid pennate diatoms now date from the Late Cretaceous; all from terrestrial sediments. Molecular sequencing helped clarify relationships between diatom lineages, and verify the position of diatoms within the heterokontophytes. Molecular clock approaches estimate a diatom origin near ~135 Ma, but not before 240 Ma. Biomarkers in marine sediments are able to trace a diatom presence back to the mid-Cretaceous, even when siliceous fossils are absent. Seasonal growth and encystment cycles in Late Cretaceous planktonic marine diatoms are now well documented. A biostratigraphic framework for the Late Cretaceous Arctic will aid regional and global biostratigraphic correlations. The systematic position of many new taxonomic groups is now included within a more natural classification scheme that better reflects phylogenetic relationships evident in molecular data and affirmed by biostratigraphic micropaleontology. Discussions regarding the impact of diatoms on several global systems are maturing, as more information becomes available. Four stages in diatom evolution are proposed to explain the history of radiation, extinction, and expansion into new environments and habitats during the Mesozoic.

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Thiophenes in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

Cited by 4 publications

References 22 publications

Maleimides in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

Maleimides in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan.

The occurrence and significance of C25HBI in Cenozoic saline lacustrine source rocks from the Western Qaidam Basin, NW China

Cretaceous Records of Diatom Evolution, Radiation, and Expansion

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