Abstract Details
(2020) Refining the paleosol-CO2 Proxy and the Reconstruction of early-Pleistocene CO2 Levels
Da J, Ji J, Zhang Y, Li G & Meng X
https://doi.org/10.46427/gold2020.508
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14j: Plenary Hall, Tuesday 23rd June 08:00 - 08:03
Jiawei Da
View abstracts at 3 conferences in series
Junfeng Ji View abstracts at 7 conferences in series
Yi Ge Zhang View all 4 abstracts at Goldschmidt2020
Gen Li View abstracts at 2 conferences in series
Xianqiang Meng View abstracts at 2 conferences in series
Junfeng Ji View abstracts at 7 conferences in series
Yi Ge Zhang View all 4 abstracts at Goldschmidt2020
Gen Li View abstracts at 2 conferences in series
Xianqiang Meng View abstracts at 2 conferences in series
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by Mingsong Li on Monday 22nd June 19:13
Jiawei, thanks for this wonderful presentation. Based on your experience, what is the highest time resolution of the paleosol-CO2 proxy dataset? And what is average growth time for one nodule? Thanks again! Mingsong Li (Penn State)
Good questions! The current time resolution is tectonic-scale. However, based on the solid chronology of the eolian depoits from the Loess Plateau, we try to make it to orbital-scale (i.e. G-IG variations). To do that, we have to deal with the widespread contamination of detrital carbonates within the glacial paleosols (i.e. the loess units), because of the weak monsoonal rainfall during the glacials. It usually takes decades for one nodule to grow (Zamanian et al., 2016). However, this is based on a few radiocarbon ages and indirect measures such as ages of the soil profiles, and more work needs to be done in the future.
Jiawei, thanks for this wonderful presentation. Based on your experience, what is the highest time resolution of the paleosol-CO2 proxy dataset? And what is average growth time for one nodule? Thanks again! Mingsong Li (Penn State)
Good questions! The current time resolution is tectonic-scale. However, based on the solid chronology of the eolian depoits from the Loess Plateau, we try to make it to orbital-scale (i.e. G-IG variations). To do that, we have to deal with the widespread contamination of detrital carbonates within the glacial paleosols (i.e. the loess units), because of the weak monsoonal rainfall during the glacials. It usually takes decades for one nodule to grow (Zamanian et al., 2016). However, this is based on a few radiocarbon ages and indirect measures such as ages of the soil profiles, and more work needs to be done in the future.
Submitted by Mingsong Li on Tuesday 23rd June 00:46
MS was used as a proxy of MAP and then it was used to constrain S(z) and to calculate pCO2. Does that mean MS is a function of pCO2?
The answer is no. S(z) is controlled by three major factors: climatic conditions (e.g. MAP, MAT etc.), soil characteristics (e.g. porosity, tortuosity) and biomass (e.g. plant types, root density, etc.). In the case of the paleosol profiles from the Loess Plateau, the soil characteristics and biomass types remained stable throughout the studied time intervals, so the S(z) is predominantly controlled by climatic conditions, and the MS-S(z) correlation is not a surprise. However, we do not suggest a simple MS-S(z) model if the other two factors changed.
MS was used as a proxy of MAP and then it was used to constrain S(z) and to calculate pCO2. Does that mean MS is a function of pCO2?
The answer is no. S(z) is controlled by three major factors: climatic conditions (e.g. MAP, MAT etc.), soil characteristics (e.g. porosity, tortuosity) and biomass (e.g. plant types, root density, etc.). In the case of the paleosol profiles from the Loess Plateau, the soil characteristics and biomass types remained stable throughout the studied time intervals, so the S(z) is predominantly controlled by climatic conditions, and the MS-S(z) correlation is not a surprise. However, we do not suggest a simple MS-S(z) model if the other two factors changed.
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