Location: Dale Bumpers Small Farms Research CenterTitle: Characteristics of a typical loess profile with a macroscopic tephra layer in the northeast China and the paleoclimatic significance
|JIANG, YING-YING - Shenyang Agricultural University|
|SUN, ZHONG-XIU - Shenyang Agricultural University|
|WANG, QUI-BING - Shenyang Agricultural University|
|SUN, ZHONG-GE - Shenyang Agricultural University|
|JIANG, ZHUO-DONG - Shenyang Agricultural University|
|GU, HONG-YU - Shenyang Agricultural University|
|LIBOHOVA, ZAMIR - Natural Resources Conservation Service (NRCS, USDA)|
Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2020
Publication Date: 11/28/2020
Citation: Jiang, Y., Sun, Z., Wang, Q., Sun, Z., Jiang, Z., Gu, H., Libohova, Z., Owens, P.R. 2020. Characteristics of a typical loess profile with a macroscopic tephra layer in the northeast China and the paleoclimatic significance. Geoderma. 198:105043. https://doi.org/10.1016/j.catena.2020.105043.
Interpretive Summary: Geologic sections provide inforamtion about past climates that can help understand climates of today. In this study, a layer of volcanic ash material was found within a deep profile of sediments. This research was conducted using dating techniques of the layers above and below the volcanic ash layer. Additional analyses were used to look at chemical signatures above the ash layer to help identify the climate that was present after the ash deposition. The climate was warmer and wetter after the volcanic eruption that deposited the ash. Analyzing these well preserved vertical sections can improve our knowledge of soil development, loess formation and deepen our understanding of the potential impact of volcanism on changes in the climate.
Technical Abstract: Tephra layers can serve as ideal datable horizons to provide invaluable datums for supplementing research on loess-paleosol sequences. A typical loess profile interbedded with a macroscopic tephra layer (Dunhua soil profile) was investigated in northeastern China. Geochemical and physical properties of the profile were determined and compared with loess materials from other areas to address its characteristics and potential significance for understanding climate variability. Results showed the tephra layers with overlying loess horizons were uniform in parent material, as inferred from evidence such as uniform Ti/Zr ratios with depth, their similar rare earth element distribution patterns, and major elemental distributions with depth. The volcanic properties in the bottom of the Dunhua profile, including morphology, high phosphate adsorption capacity (PAC) and pH (NaF) values, further supported the speculation that the depositions of loess and volcanic materials were synchronous with pedogenic processes. According to the comparison of magnetic susceptibility of Dunhua with the global d18O curve, the local paleoclimate of the area showed characteristics of a significant increase of warm and wet conditions, which may have been affected by volcanism. Research on the loess profile interbedded with a macroscopic tephra could improve our knowledge of loess formation and deepen our understanding of the potential impact of volcanism on climate changes.