Thermoluminescence and Optically Stimulated Luminescence Measured in Marine Sediments Indicate Precipitation Changes Over Northeastern Brazil

Author(s)

Mendes, Vinicius R. ^{[1, 2]} ; Sawakuchi, Andre O. ^[1] ; Chiessi, Cristiano M. ^[3] ; Giannini, Paulo C. F. ^[1] ; Rehfeld, Kira ^{[4, 5]} ; Mulitza, Stefan ^[6]

Affiliation

^[1] Univ Sao Paulo, Dept Sedimentary Geol, Luminescence & Gamma Spectrometry Lab LEGaL, Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Inst Marine Sci, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Sch Arts Sci & Humanities, Santos - Brazil

^[4] Heidelberg Univ, Inst Environm Phys, Heidelberg - Germany

^[5] British Antarctic Survey, Cambridge - England

^[6] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany

• Document type: Journal article
• Source: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY; v. 34, n. 8, p. 1476-1486, AUG 2019.
• Web of Science Citations: 0

Abstract

Marine sediment cores offer a great number of proxies for reconstructions of past environmental conditions, such as ocean temperature, salinity, primary productivity, stratification of the upper water column, and continental precipitation. Up to date, continental precipitation archived in marine sediment cores is reconstructed based mainly on the hydrogen isotopic composition of plant-wax compounds (i.e., n-alkane delta D) or on the ratio between terrigenous and marine sediments expressed as elemental ratios (e.g., ln (Fe/Ca)). Although these proxies provide reliable precipitation reconstructions, there are some inherent limitations, as plant-wax dD application depends on the availability of n-alkanes in marine sediments and elemental ratios can be influenced by other factors like the relative sea-level, primary productivity, and postdepositional processes. Here we introduce new precipitation proxies based on optically stimulated luminescence and thermoluminescence signals of quartz and feldspar. The rationale is that when precipitation changes over the catchment through time, different sediment sources regarding weathering intensity and parent rock types are drained, supplying sediments with varying signals of luminescence to the ocean. We compared our new proxy records with records of well-established proxies, for the same (ln (Fe/Ca)) and neighboring (n-alkane dD) marine sediment cores. The comparison among all proxies as well as with a state-of-art transient climate model run (TraCE-21ka) demonstrates that the new proxies accurately constrain precipitation changes over northeastern Brazil for the last 30,000 years. The main advantage of these new proxies relies on their fast response to precipitation changes over the continent. Furthermore, they are straightforward to measure and not expensive. (AU)

• FAPESP's process: 13/21942-4 - Quaternary sedimentary record of Parnaíba river basin, Piauí, Northeastern Brazil: a multi-proxy study for climate changes research
• Grantee: Vinícius Ribau Mendes
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM)
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: Research Grants - Research Program on Global Climate Change - Young Investigators - Phase 2
• FAPESP's process: 09/53988-8 - Acquisition of a luminescence dating system and a precision microsampler for the study of environmental changes in the Quaternary period
• Grantee: Paulo César Fonseca Giannini
• Support Opportunities: Multi-user Equipment Program