by Ignacio Jara
We started our fieldwork close the hamlet of Toconce on the western slopes of the Chilean Andes (22°S). At close 3300 meters inwards a higher house the ocean score (m), this expanse represents the upper altitudinal limits of the Atacama Desert where summertime rains allow the institution of perennial shrubs, the pasture lands for these llamas (Lama glama).
Ancient agricultural practice — still used inwards the highlands of northern Chile — can last seen inwards these tillage terraces about Toconce village. Pre-Columbian crops such equally maize, quinoa as well as potatoes are cultivated inwards stone terraces over canyon slopes. The purpose of environmental alter inwards the emergence as well as development of pre-Columbian agriculture inwards this arid share is a topic of electrical flow inquiry as well as 1 of the subjects of my postdoc project.
The showtime days of fieldwork were spent sampling fossil rodent middens. Midden collection took house inwards an around six-million-year-old (late-Miocene) ignimbrite outcrop inwards a higher house 3300 m. Visible at the centre of this pic equally a massive white as well as pinkish plateau, this volcanic deposit forms business office of the Toconce Formation at the western pes of the Altiplano. Volcanic as well as tectonic activeness inwards this expanse extends dorsum to the Tertiary catamenia (66 to 2.6 1 thou k years ago).
My showtime rodent midden! These deposits are usually found within stone shelters, cracks or at the bottom of big boulders, the most mutual places where rodents brand their nests. In arid regions similar northern Chile, these remnants are preserved for thousands of years amongst lots of macro as well as microscopic organic remains including pollen, which I volition utilization to reconstruct past times climates.
Fossil middens are packs of faecal pellets, flora as well as animate existence remains, as well as soil preserved inwards crystalized urine. Apart from their disturbing scent, they save a paleoenvironmental dot extending over the really brief lifespan of an private rat. For this reason, nosotros collected to a greater extent than than xxx middens such equally the 1 pictured here. To decide the historic catamenia of these smelly deposits, nosotros volition engagement them individually amongst radiocarbon techniques.
A chirihue (yellow finch) of the Sicalis genus (left). This various grouping of Andean birds typically own got thick, freeze-proof plume designed to grapple amongst mountainous conditions.
Built-in adobe (clay used equally a edifice material) amongst light, yet durable wooden cactus beams — this 1675 CE Catholic church building is the icon of Chiu Chiu (2400 m) as well as a national monument since 1951. We stopped at Chiu Chiu to remainder earlier heading upwards to the Altiplano.
After our successful sense of collecting middens, nosotros moved upwards to the Altiplano. In the epitome on the right, the high-Andean plateau unfolds inwards front end of a immature Pleistocene lava dome.
Initially, our destination was to gear upwards our tents as well as run inwards a minor lake at 4300 m called Laguna Segunda. Unfortunately, Laguna Segunda was completely dry out when nosotros arrived, as well as thence nosotros could simply collect samples from the dried lake surface. Photo courtesy of Eduardo Godoy Tapia.
Despite our unsuccessful lake hunt, nosotros retrieved 2 sets of peat cores from a bofedal (high-Andean peatland) close El Tatio geothermal expanse at 4300 m (right). Hopefully, paleorecords similar this 1 volition render novel insights into the hydrological development of this region. Photo courtesy of Eduardo Godoy Tapia.
In add-on to peat cores nosotros also obtained a curt sediment heart from a shallow lake at the centre of our bofedal. Pollen analyses from lake or peat sediments offering to a greater extent than continuous records than rodent middens. However, radiocarbon dates from lake sediments inwards the Altiplano are sometimes inaccurate due to contamination amongst inorganic carbon. This dubiety way that complementing unlike types of paleoecological archives is critical inwards obtaining detailed climate histories from this region. Photo courtesy of Eduardo Godoy Tapia.
In the arid western margins of the Altiplano, bofedales render H2O resources for a considerable reveal of birds as well as mammals such equally the herd of vicuña (Vicugna vicugna) seen inwards this photo.
Ignacio A. Jara
CEAZA Scientific Centre, Chile
If you lot own got questions or comments concerning Ignacio's post, delight larn out a comment below, or transportation him an email. You tin also connect amongst him on Twitter.
Preface
As the showtime yr of my postdoc at the Centre for Advanced Studies inwards Arid Zones in La Serena, Chile, was coming to an end, nosotros went on our showtime plain trip to northern Chile. We explored the highlands of the Atacama Desert as well as the Altiplano (Fig. 1) inwards Dec 2019 to collect 2 unlike types of paleoecological archives: fossil rodent middens as well as lake sediments. These samples volition travel the heart cloth for my postdoc project, which focuses on reconstructing the in conclusion 4,000 years of climate development of this fascinating region. |
Fig. 1. Location of the highlands of Atacama Desert and Altiplano, Chile |
Instrumental climate records inwards Chile — and the Southern Hemisphere inwards general — are lean as well as really curt inwards time, which implies that climate projections for these regions rely almost alone on brief as well as incomplete datasets. As such, paleoclimate studies similar the 1 I am conducting are highly relevant today because they offering a longer-term climate context to empathize electrical flow changes as well as trends.
After our render from the field, I spent some fourth dimension reviewing the photographs taken during our trip. I was really pleased to run across that the spectacular landscapes, rich biodiversity, as well as prominent geology nosotros witnessed were sharply captured inwards our pictures. I am really happy to introduce a pick of these pictures complemented past times brief notes describing our activities, experiences as well as cardinal information taken inwards the field. I promise you lot bask this photographic journey!
Our journey
The greenish cushion flora at the centre of the pic inwards a higher house is a massive yareta (Azorella compacta). This fellow member of the Apiaceae menage unit of measurement thrives at altitudes equally high equally 5200 m, which makes it 1 of the woody plants living at the highest elevations inwards the planet. Frequently used inwards Andean pop medicine for its positive wellness effects, yaretas tin withstand freezing temperatures spell benefiting from the monsoonal atmospheric precipitation that nurtures the Altiplano during the austral summer. Pollen grains of this species preserved inwards middens or lake sediments tin as well as then last used equally an indicator of past times monsoonal activity.
Our working squad gathered for a terminal pic on the roadside. This sense was simply possible amongst the collaboration of an amazing grouping of people. From left to right: myself, Eduardo Godoy, Esteban Honores, Antonio Maldonado, Gissel Alday as well as Horacio Molina. My particular gratitude goes to Dr. Antonio Maldonado, caput of the Paleoecology laboratory at CEAZA, for his assistance inwards the field.
Afterword
We returned to La Serena afterwards driving for over 16 hours through northern Chile. We were tired but satisfied amongst a truck total of middens as well as sediment, which I volition analyze over the course of written report of the adjacent 2 years. Finally, I cannot avoid mentioning that this plain sense happened during hard personal times equally my manly mortal parent passed away a few days earlier nosotros departed from La Serena. I would similar to dedicate this photographic trouble organization human relationship to his memory, without his endless back upwards I would non last writing these words.
For to a greater extent than information close paleoenvironmental inquiry conducted inwards the Andes of Northern Chile, hither are a few recommended readings:
- Jara, I.A., Maldonado, A., González, L., Hernández, A., Sáez, A., Giralt, S., Bao, R. as well as Valero Garcés, B.L., 2019. Centennial-scale atmospheric precipitation anomalies inwards the southern Altiplano (18° S) propose an extratropical driver for the South American summertime monsoon during the belatedly Holocene. Climate of the Past, 15(5), pp.1845-1859.
- De Porras, M.E., Maldonado, A., De Pol‐Holz, R., Latorre, C. as well as Betancourt, J.L., 2017. Late Quaternary environmental dynamics inwards the Atacama Desert reconstructed from rodent midden pollen records. Journal of Quaternary Science, 32(6), pp.665-684.
- DÃaz, F.P., Latorre, C., Maldonado, A., Quade, J. as well as Betancourt, J.L., 2012. Rodent middens reveal episodic, long‐distance flora colonizations across the hyperarid Atacama Desert over the in conclusion 34,000 years. Journal of Biogeography, 39(3), pp.510-525.
Ignacio A. Jara
CEAZA Scientific Centre, Chile
If you lot own got questions or comments concerning Ignacio's post, delight larn out a comment below, or transportation him an email. You tin also connect amongst him on Twitter.