Stable carbon isotope record of terrestrial organic materials for the last 450 Ma yr

Nordt, Lee C.; Tubbs, J. D.; Dworkin, Steven I.

doi:10.1016/j.earscirev.2016.05.007

Cited by 44 publications

(25 citation statements)

References 63 publications

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“…Our results also show good agreement with discontinuous marine and terrestrial CO 2 proxies, suggesting that the validity of the proposed mechanism underlying the effect of CO 2 on δ 13 C p values (Schubert and Jahren, 2018) may be comparable to those of these previously confirmed CO 2 proxies. Compared to these methods, however, our proxy has the advantage of relying upon a substrate (terrestrial fossil organic carbon) that is widely available both spatially and temporally (Strauss and Peters-Kottig, 2003;Nordt et al, 2016), allowing the possibility for a near-continuous reconstruction of CO 2 across the entire evolution of C 3 land plants.…”

Section: Discussionmentioning

confidence: 99%

“…Our approach is centered upon the δ 13 C value of C 3 vascular land plants (hereafter δ 13 C p ), which is available from terrestrial sediments for most of the Phanerozoic (Nordt et al, 2016). Our calculations of CO 2 assumed that global changes in atmospheric composition affect the plant tissues of all terrestrial C 3 plants via the universally shared mechanism of photorespiration.…”

Section: Introductionmentioning

confidence: 99%

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A 23 m.y. record of low atmospheric CO2

Cui

Schubert

Jahren

2020

Geology

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Current atmospheric CO2 concentration is known to be higher than it has been during the past ~800 k.y. of Earth history, based on direct measurement of CO2 within ice cores. A comparison to the more ancient past is complicated by a deficit of CO2 proxies that may be applied across very long spans of geologic time. Here, we present a new CO2 record across the past 23 m.y. of Earth history based on the δ13C value of terrestrial C3 plant remains, using a method applicable to the entire ~400 m.y. history of C3 photosynthesis on land. Across the past 23 m.y., CO2 likely ranged between ~230 ppmv and 350 ppmv (68% confidence interval: ~170–540 ppm). CO2 was found to be highest during the early and middle Miocene and likely below present-day levels during the middle Pliocene (84th percentile: ~400 ppmv). These data suggest present-day CO2 (412 ppmv) exceeds the highest levels that Earth experienced at least since the Miocene, further highlighting the present-day disruption of long-established CO2 trends within Earth’s atmosphere.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A 23 m.y. record of low atmospheric CO2

Cui

Schubert

Jahren

2020

Geology

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“…The δ 13 C composition of amber largely depends on resin biosynthesis, environmental factors that affect the whole plant (e.g., Kohn, 2010), and diagenesis (e.g., Spiker and Hatcher, 1987). Dal Corso et al (2017) reported a minor negative offset between liquidviscous resin and solid ones in case of conifers, while other studies mentioned amber as one of the most enriched in C-13 among all plant carbon sources (e.g., Nordt et al, 2016).…”

Section: Carbon Isotopic Composition Of Ambermentioning

confidence: 99%

The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago

Kocsis

Usman

Jourdan

et al. 2020

Earth-Science Reviews

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In this study we intend to provide an overview on fossilized tree resins (amber) commonly found in Southeast Asia, more particularly in the Indo-Australian Archipelago (IAA). These remains are often referred in literature as "Indonesian amber", "Borneo amber" or simply as "dammar". They are very common in the region and the Brunei Sultanate is no exception as most of its Neogene sedimentary successions contain amber-rich layers. Although amber is a common fossil in the country and in northern Borneo, to our knowledge it has not been studied in great detail so far. Here we present an account on the "Borneo Ambers" from Brunei, regarding their stratigraphic origin, basic physical properties, their interaction with the biosphere and their botanical origin using Fourier-transform infrared spectroscopy (FTIR). Additionally, a number of ambers and modern tree resins were analysed for their carbon isotope composition and a few were tested with gas chromatography. We discuss the results in a regional and global context, in comparison with available data from the IAA. The ambers come from four different lithostratigraphic units with an age range of 12 to 3 million years (middle Miocene to Pliocene). Recently reworked ambers from the coast, ambers from younger alluvial deposits, and several modern tree resins from Dipterocarpaceae and Araucariaceae (Agathis borneensis) were also included in the study. The more than 60 FTIR analyses of modern and fossil specimens suggest that all the Brunei ambers were produced by trees of Dipterocarpaceae. There is no indication of Agathis in the fossil record, in agreement with their lower abundance in the forests of Borneo. Modern and fossil dipterocarp resins were found to be different based on the following criteria: (1) Different reactions to solubility, hot needle and UV tests with faster reaction time and less fluorescence for the modern ones; (2) Clear distinction based on certain FTIR absorbance band ratios, mostly by those that represent carboxylic acids and esters (e.g., ~1700 and 1243 cm-1); (3) Modern resin yielded on an average 3 ‰ lower δ 13 C values, (4) Gas chromatography data reflect maturation differences among the samples. Although there is some overlap in the chemical results between the two groups, generally all these differences reflect different maturation stages of the resinous material and point towards loss of low δ 13 C components from the organic structure of the resin. The minor timewise decreasing trend in average δ 13 C from the late middle Miocene to late Miocene can be explained by (1) gradual changes in local environmental conditions, and/or (2) increased amount of less mature specimens among the younger samples. In contrast, the highest obtained δ 13 C values were found in the youngest Pliocene ambers. Instead of maturation bias this can be linked to environmental factors such as cooler-drier climate with increased seasonality, probably reflecting the onset of the northern hemisphere glaciation.

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“…The stable carbon isotope composition (δ 13 C) of terrestrial plants is one of the primary means for tracking changes in Earth's carbon cycle and climate before the instrument record (Nordt et al, 2016;Strauss and Peters-Kottig, 2003). Diagenetic alteration of organic substrates presents a fundamental limitation for interpreting δ 13 C signals from deep-time (i.e., pre-Quaternary) records (Jones, 1994;Tu et al, 2004;Baczynski et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

The effect of diagenesis on carbon isotope values of fossil wood

Lukens

Eze

Schubert

2019

Geology

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The carbon isotope (δ13C) value of modern and fossil wood is widely used as a proxy for environmental and climatic change. Many researchers who study stable carbon isotopes in modern and recently deceased trees chemically extract cellulose (δ13Ccell) rather than analyzing whole wood (δ13Cwood) due to concerns that molecular variability across tree rings could influence δ13Cwood values, and that diagenesis may preferentially degrade cellulose over lignin. However, the majority of deep-time researchers analyze δ13Cwood without correcting for possible diagenetic effects due to cellulose loss. We measured δ13Ccell, δ13Cwood, and cellulose content of 38 wood fossils that span ∼50 m.y. in age from early Eocene to late Miocene, using variability across such a large range of geologic ages and settings as a natural laboratory in diagenesis. For comparison with our measurements, we produced a literature compilation of 1210 paired δ13Ccell and δ13Cwood values made on fossil and modern trees. We report that, on average, the apparent enrichment factor (ε) between δ13Ccell and δ13Cwood (ε = δ13Ccell – δ13Cwood) is 1.4‰ ± 0.4‰ larger in deep-time samples than Holocene wood, and this can be explained by loss of cellulose during degradation, independent of atmospheric chemistry or climate conditions during growth. A strong linear correlation exists between δ13Cwood and δ13Ccell in both deep-time (r2 = 0.92) and Holocene (r2 = 0.87) samples, suggesting that either substrate can provide a reliable record of environmental conditions during growth. However, diagenetic effects must be corrected if δ13Cwood values are compared to extant trees or across long time scales, where cellulose content may vary.

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Stable carbon isotope record of terrestrial organic materials for the last 450 Ma yr

Cited by 44 publications

References 63 publications

A 23 m.y. record of low atmospheric CO2

A 23 m.y. record of low atmospheric CO2

The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the Indo-Australian Archipelago

The effect of diagenesis on carbon isotope values of fossil wood

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