Repositorio
Institucional

Amann, Benjamin

Bertrand, Sebastien

Alvarez-Garreton, Camila

Reid, Brian

Seasonal Variations in Fjord Sediment Grain Size: A Pre-requisite for Hydrological and Climate Reconstructions in Partially Glacierized Watersheds (Baker River, Patagonia)

AMER GEOPHYSICAL UNION

JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE

en

Fjord sediments are increasingly recognized as high-resolution archives of past hydrological and climate variability. Using them as such, however, requires a comprehensive understanding of the variables that affect their accumulation rates and properties. Here, we conduct a spatial and temporal study of sediment samples collected at the head of Martinez Channel (Chilean Patagonia, 48 degrees S), to understand how the fjord's sediments register changes in the hydrology of Baker River, Chile's largest river in terms of mean annual discharge. We apply end-member modeling to particle-size distributions of: (a) river suspended sediments, (b) surface sediments collected along a proximal-distal transect at the fjord head, and (c) fjord sediments collected in a sequential sediment trap at 15-day resolution during two consecutive years. We then validate the use of the grain-size end members for hydrological and climate reconstructions, using a sediment core that covers the last 35 years. Results show that the river suspended sediments and fjord sediments are consistently composed of two grain-size subpopulations. The finest end member (EM1, mode 4.03 mu m) reflects the meltwater contribution, which dominates in all but the winter season. The coarser end member (EM2, mode 18.7 mu m) dominates in winter, when meltwater contribution is reduced, and is associated with rainfall. We show that the fluxes of EM1 and EM2 provide quantitative estimates of baseflow (r = 0.87, p < 0.001) and quickflow (r = 0.86, p < 0.001), respectively. Additionally, we propose that log (EM1/EM2) can be used to reconstruct meltwater production (r = 0.67, p < 0.001) and temperature (r = 0.81, p < 0.001) in the lower Baker River watershed. These results support the use of fjord sediments for quantitative reconstructions of hydrological and climate variability in partially glacierized watersheds.

artículo original

This research was funded by the Special Research Fund of Ghent University (BOF) HYDROPROX project 01N02216 and by the FWO (Flemish Research Foundation) Paleo-GLOFs project G0D7916 N. Camila Alvarez-Garreton was funded by the Center for Climate and Resilience Research (CR2, ANID/FONDAP/15110009) and by the joint research project ANID/NSFC190018. Brian Reid was funded by ANID R20F0002. We would like to thank Elke Vandekerkhove, Loic Piret, and Dawei Liu (RCMG, Ghent University) for assistance in the field, constructive discussions, and comments on an earlier version of this manuscript. We are also grateful to Inka Meyer (RCMG, Ghent University) for sharing her knowledge on grain-size end-member modeling, and to Matthias Troch for discussions. Particular thanks go to Ivan Ernesto Perez Santos (iMAR, Puerto Montt) for providing the deck unit used to operate the acoustic release, and to Romina San Martin and Silvio Pantoja (COPAS Sur-Austral, Universidad de Concepcion) for administrative and equipment support. We would also like to thank Nicola Araneda (CIEP, Coyhaique) for receiving and storing our field equipment. We particularly want to acknowledge the crew of the R/V Sur-Austral (Rodrigo Mansilla and Luis Rogel) for their excellent assistance and company during these field seasons. Finally, we thank Varyl Thorndycraft and one anonymous reviewer for providing comments that improved an earlier version of this manuscript.

Esta investigación fue financiada por el proyecto HYDROPROX 01N02216 del Fondo Especial de Investigación de la Universidad de Gante (BOF) y por el proyecto Paleo-GLOFs de FWO (Fundación Flamenca de Investigación) G0D7916 N. Camila Álvarez-Garreton fue financiada por el Centro de Investigación sobre el Clima y la Resiliencia (CR2 , ANID/FONDAP/15110009) y por el proyecto de investigación conjunto ANID/NSFC190018. Brian Reid fue financiado por ANID R20F0002. Nos gustaría agradecer a Elke Vandekerkhove, Loic Piret y Dawei Liu (RCMG, Universidad de Gante) por su ayuda en el campo, discusiones constructivas y comentarios sobre una versión anterior de este manuscrito. También agradecemos a Inka Meyer (RCMG, Universidad de Gante) por compartir su conocimiento sobre el modelado de miembros finales del tamaño de grano, y a Matthias Troch por las discusiones. Un agradecimiento especial a Iván Ernesto Pérez Santos (iMAR, Puerto Montt) por proporcionar la unidad de cubierta utilizada para operar la liberación acústica, y a Romina San Martín y Silvio Pantoja (COPAS Sur-Austral, Universidad de Concepción) por el apoyo administrativo y de equipos. También agradecemos a Nicola Araneda (CIEP, Coyhaique) por recibir y almacenar nuestro equipo de campo. Queremos agradecer especialmente a la tripulación del B/V Sur-Austral (Rodrigo Mansilla y Luis Rogel) por su excelente asistencia y compañía durante estas temporadas de campo. Finalmente, agradecemos a Varyl Thorndycraft y a un revisor anónimo por brindar comentarios que mejoraron una versión anterior de este manuscrito.

10.1029/2021JF006391

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end-member analysis

sediment fluxes

river suspended sediments

fjord sediments

meltwater

temperature

METEOROLOGICAL DATA

NORTHERN PATAGONIA

REANALYSIS DATA

LAKE-SEDIMENTS

MASS-BALANCE

GRADIENTS

PRECIPITATION

FLUCTUATIONS

GLACIATION

INTENSITY

Geociencias

Multidisciplinario

análisis de miembros finales

flujos de sedimentos

sedimentos suspendidos de ríos

sedimentos de fiordos

agua de deshielo

temperatura

DATOS METEOROLOGICOS

PATAGONIA DEL NORTE

DATOS DE REANÁLISIS

SEDIMENTOS DE LAGOS

EQUILIBRIO DE MASA

GRADIENTES

PRECIPITACIÓN

FLUCTUACIONES

GLACIACIÓN

INTENSIDAD

Seasonal Variations in Fjord Sediment Grain Size: A Pre-requisite for Hydrological and Climate Reconstructions in Partially Glacierized Watersheds (Baker River, Patagonia)

artículo original

version publicada

0

acceso abierto

acceso abierto

Ugent 01N02216

FWO G0D7916 N

ANID-FONDAP 15110009

ANID R20F0002

[ANID NSFC190018

ANID FONDAP 15110009

WOS:000763468400010