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Climate changes and solar cycles recorded at the Holocene Paraná Delta, and their impact on human population.

Milana JP, Kröhling D - Sci Rep (2015)

Bottom Line: The evolution of this 17,400 km(2) delta enclosed in Plata estuary, can be tracked by a series of 343 successive coastal-ridges showing a c.11 years period, in coincidence with sunspot cycle, also found in some North Hemisphere coastal-ridge successions.Results suggest that aside the solar forcing, both short and medium term climate changes controlled delta evolution.An important learning is that a slight cooling would turn the highly productive pampas, into that unproductive desert and, given the lack of artificial irrigation systems, changing present-day warmhouse into a cooling cycle might be economically catastrophic for the region.

View Article: PubMed Central - PubMed

Affiliation: CONICET - Universidad Nacional de San Juan, InGeo, (5401) San Juan, Argentina.

ABSTRACT
The Paraná delta, growing at a rate of c. 2 km(2) yr(-1) since 6,000 yrs, is one of the most complete records of the Late Holocene in southern South America. The evolution of this 17,400 km(2) delta enclosed in Plata estuary, can be tracked by a series of 343 successive coastal-ridges showing a c.11 years period, in coincidence with sunspot cycle, also found in some North Hemisphere coastal-ridge successions. The Paraná delta shifted from fluvial, to wave-dominated, and back to the present fluvial-dominated delta, in response to climate changes associated with wind activity correlating with South American glacial cycles. The wave-dominated windy period coincides with the activation of the Pampean Sand Sea, suggesting desert conditions prevailed on the Pampas between 5,300 and 1,700 yrs, in coincidence with scarce or absent pre-historic aborigine remains ("archeological silence"). Further warmer and less windy conditions allowed human repopulation. Results suggest that aside the solar forcing, both short and medium term climate changes controlled delta evolution. An important learning is that a slight cooling would turn the highly productive pampas, into that unproductive desert and, given the lack of artificial irrigation systems, changing present-day warmhouse into a cooling cycle might be economically catastrophic for the region.

No MeSH data available.


Related in: MedlinePlus

Detailed coastal ridge mapping showing the development of the succession and erosion & hiatus surfaces shown in Fig. 3.Box 2C shows the interference produced by a paleoisland, while largest paleoisland (Ibicuy67) is portrayed on Fig. 1, and its effect on ridge morphology is observed by sharp curves of box 2D. Box locations on Fig. 1. Map elaborated by the authors using CONAE imagery and graphical software CorelDraw 12.0 TM.
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f2: Detailed coastal ridge mapping showing the development of the succession and erosion & hiatus surfaces shown in Fig. 3.Box 2C shows the interference produced by a paleoisland, while largest paleoisland (Ibicuy67) is portrayed on Fig. 1, and its effect on ridge morphology is observed by sharp curves of box 2D. Box locations on Fig. 1. Map elaborated by the authors using CONAE imagery and graphical software CorelDraw 12.0 TM.

Mentions: Our study was based on the detailed mapping based on aerial photographs and high-resolution satellite imagery, plus field control, of the remains of the original delta structure. The low degree of reworking along the northeast margin allowed mapping a continuous succession of 343 consecutive coastal ridges (Figs 1 & 2), and their significance is the main focus of this paper. The recognition of coastal ridges in the Paraná Delta is not new, and they have been described by several authors as Holocene beach deposits5678, although there was not a detailed mapping, integration, numbering and tracing of these conspicuous ridges (Fig. 2), which are well-defined in remote imagery, but very subtle in the field.


Climate changes and solar cycles recorded at the Holocene Paraná Delta, and their impact on human population.

Milana JP, Kröhling D - Sci Rep (2015)

Detailed coastal ridge mapping showing the development of the succession and erosion & hiatus surfaces shown in Fig. 3.Box 2C shows the interference produced by a paleoisland, while largest paleoisland (Ibicuy67) is portrayed on Fig. 1, and its effect on ridge morphology is observed by sharp curves of box 2D. Box locations on Fig. 1. Map elaborated by the authors using CONAE imagery and graphical software CorelDraw 12.0 TM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526942&req=5

f2: Detailed coastal ridge mapping showing the development of the succession and erosion & hiatus surfaces shown in Fig. 3.Box 2C shows the interference produced by a paleoisland, while largest paleoisland (Ibicuy67) is portrayed on Fig. 1, and its effect on ridge morphology is observed by sharp curves of box 2D. Box locations on Fig. 1. Map elaborated by the authors using CONAE imagery and graphical software CorelDraw 12.0 TM.
Mentions: Our study was based on the detailed mapping based on aerial photographs and high-resolution satellite imagery, plus field control, of the remains of the original delta structure. The low degree of reworking along the northeast margin allowed mapping a continuous succession of 343 consecutive coastal ridges (Figs 1 & 2), and their significance is the main focus of this paper. The recognition of coastal ridges in the Paraná Delta is not new, and they have been described by several authors as Holocene beach deposits5678, although there was not a detailed mapping, integration, numbering and tracing of these conspicuous ridges (Fig. 2), which are well-defined in remote imagery, but very subtle in the field.

Bottom Line: The evolution of this 17,400 km(2) delta enclosed in Plata estuary, can be tracked by a series of 343 successive coastal-ridges showing a c.11 years period, in coincidence with sunspot cycle, also found in some North Hemisphere coastal-ridge successions.Results suggest that aside the solar forcing, both short and medium term climate changes controlled delta evolution.An important learning is that a slight cooling would turn the highly productive pampas, into that unproductive desert and, given the lack of artificial irrigation systems, changing present-day warmhouse into a cooling cycle might be economically catastrophic for the region.

View Article: PubMed Central - PubMed

Affiliation: CONICET - Universidad Nacional de San Juan, InGeo, (5401) San Juan, Argentina.

ABSTRACT
The Paraná delta, growing at a rate of c. 2 km(2) yr(-1) since 6,000 yrs, is one of the most complete records of the Late Holocene in southern South America. The evolution of this 17,400 km(2) delta enclosed in Plata estuary, can be tracked by a series of 343 successive coastal-ridges showing a c.11 years period, in coincidence with sunspot cycle, also found in some North Hemisphere coastal-ridge successions. The Paraná delta shifted from fluvial, to wave-dominated, and back to the present fluvial-dominated delta, in response to climate changes associated with wind activity correlating with South American glacial cycles. The wave-dominated windy period coincides with the activation of the Pampean Sand Sea, suggesting desert conditions prevailed on the Pampas between 5,300 and 1,700 yrs, in coincidence with scarce or absent pre-historic aborigine remains ("archeological silence"). Further warmer and less windy conditions allowed human repopulation. Results suggest that aside the solar forcing, both short and medium term climate changes controlled delta evolution. An important learning is that a slight cooling would turn the highly productive pampas, into that unproductive desert and, given the lack of artificial irrigation systems, changing present-day warmhouse into a cooling cycle might be economically catastrophic for the region.

No MeSH data available.


Related in: MedlinePlus