Combined 40Ar/39Ar and (U–Th)/He geochronological constraints on long-term landscape evolution of the Second Paraná Plateau and its ruiniform surface features, Paraná, Brazil

Riffel, Silvana Bressan; Vasconcelos, Paulo M.; Carmo, I. O.; Farley, K. A.

doi:10.1016/j.geomorph.2014.10.041

Cited by 30 publications

(18 citation statements)

References 21 publications

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“…The long history of exposure and weathering obtained from the (U-Th)/He record is compatible with the history of weathering obtained from the 40 Ar/ 39 Ar Mn oxide geochronological record (Vasconcelos et al, 1994(Vasconcelos et al, , 2015Ruffet et al, 1996). Both records confirm that the Carajás surface is one the oldest continuously exposed land surfaces on Earth.…”

Section: Age Vs Elevation Relationships For the Carajás And Itacaiunasupporting

confidence: 82%

“…Finally, goethites from the Itacaiunas Surface display the preferential enrichment in Th vs U observed in the IB duricrusts and in the N1 cangas, common for goethites formed by cementation and pseudomorphic replacement of other minerals (Vasconcelos et al, 2013;Monteiro et al, 2014;Riffel et al 2015). They are also rich in Al and Ti, which is consistent with their mode of formation.…”

Section: The Goethite (U-th)/he Record: Chemical Processes Controllinmentioning

confidence: 54%

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Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Monteiro

Vasconcelos

Farley

et al. 2018

Geochimica et Cosmochimica Acta

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 (U-Th)/He geochronology of goethites in stepped landscapes shows that older surfaces are higher and younger surfaces are lower.  Cosmogenic 3 He in hematites from the Carajás Plateau indicate extremely low rates of erosion.  (U-Th)/He geochronology of goethites reveals that low-lying surfaces are diachronous, younging towards receding escarpments surrounding older plateaus. 2 ABSTRACT (U-Th)/He geochronology of two weathered plateaus in the Carajás Mountains, Pará, Brazil, reveals a history of weathering spanning from ca. 80 Ma to the present for this high elevation (~720 m) land surface. Cosmogenic 3 He measurements of hematite pebbles and blocks cemented onto the plateaus at two sites, N1 and S11D, yield erosion rates as low as 0.09 and 0.08 m.Ma-1 , respectively. Thus, these results confirm that the plateau surfaces are nearly immune to physical erosion for tens of millions of years. (U-Th)/He geochronology of ferruginous duricrusts blanketing the low elevation (250-100 m) plains surrounding the Carajás Mountains yield results consistently younger than ~10 Ma. The geochronology results also reveal that the low elevation plain is diachronous, becoming progressively younger towards the receding plateaus. The spatial distribution of (U-Th)/He ages permits reconstruction of the history of scarp retreat for the Carajás landscape, showing that scarp retreat along major river valleys may have been as fast as 20 km.Ma-1 during tectonically active and humid periods in the Cenozoic. The cessation of scarp retreat at some sites suggests that metamorphosed banded iron-formations and quartzites provide effective barriers to retreating escarpments, helping to preserve some of the oldest continuously exposed land surfaces on Earth.

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Section: Age Vs Elevation Relationships For the Carajás And Itacaiunasupporting

confidence: 82%

Section: The Goethite (U-th)/he Record: Chemical Processes Controllinmentioning

confidence: 54%

Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Monteiro

Vasconcelos

Farley

et al. 2018

Geochimica et Cosmochimica Acta

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“…Australia, Brazil, India, South Africa) will arise from the mapping of relict landforms, whose lateritic cover has been dated using supergene minerals (e.g. Vasconcelos et al ., ,b; Vasconcelos & Conroy, ; Bonnet et al ., , ; Riffel et al ., ; Beauvais et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Cenozoic sediment budget of West Africa and the Niger delta

et al. 2017

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Long-term (10 6-7 yr) clastic sedimentary fluxes to the ocean provide first-order constraints on the response of continental surfaces to both tectonic and climatic forcing as well as the supply that builds the stratigraphic record. Here, we use the dated and regionally correlated relict lateritic landforms preserved over Sub-Saharan West Africa to map and quantify regional denudation as well as the export of main catchments for three time intervals . At the scale of West Africa, denudation rates are low (ca. 7 m Myr À1 ) and total clastic export rate represents 18.5 9 10 3 km 3 Myr À1 . Export rate variations among the different drainage groups depend on the drainage area and, more importantly, rock uplift. Denuded volumes and offshore accumulations are of the same magnitude, with a noticeably balanced budget between the Niger River delta and its catchment. This supports the establishment of the modern Niger catchment before 29 Ma, which then provided sufficient clastic material to the Niger delta by mainly collecting the erosion products of the Hoggar hotspot swell. Accumulations on the remaining Equatorial Atlantic margin of Africa suggest an apparent export deficit but the sediment budget is complicated by the low resolution of the offshore data and potential lateral sediment supply from the Niger delta. Further distortion of the depositional record by intracontinental transient storage and lateral input or destabilization of sediments along the margin may be identified in several locations, prompting caution when deducing continental denudation rates from accumulation only.

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“…Plateau ages are generally derived using several apparent ages integrated over continuous degassing steps overlapping at 2σ error level and integrating at least 70% 39 Ar released (Fleck, 1977;Maluski, 1985;McDougall and Harrison, 1988). A plateau age is still valid when it integrates 50 % to 70 % of 39 Ar released over at least three continuous degassing steps whose individual ages overlap in the 2σ error (e.g., Vasconcelos, 1999;Li and Vasconcelos, 2002;Vasconcelos and Conroy, 2003;Colin et al, 2005;Li et al, 2007;Feng and Vasconcelos, 2007;Vasconcelos et al, 2013;Riffel et al, 2015;Bonnet et al, 2014;Deng et al, 2016). When more than two degassing steps integrate only 40 to 50% of 39 Ar released in the 2σ level, a "pseudo-plateau" age was preferred (Vasconcelos et al, 2013;Riffel et al, 2015).…”

Section: Cryptomelane Grain Irradiation and 40 Ar / 39 Ar Datingmentioning

confidence: 99%

“…Much work was done for dating weathering profiles on most continents of the tropical belt, using 40 Ar/ 39 Ar dating of K-rich Mn oxides (e.g., Vasconcelos, 1999;Vasconcelos et Conroy, 2003;Beauvais et al, 2008;Bonnet et al, 2016;Deng et al, 2016;Li et al, 2007;Riffel et al, 2015), or (U-Th)/He dating of iron oxy-hydroxides (e.g., Shuster et al, 2005;Vasconcelos et al, 2013;Monteiro et al, 2018;Allard et al, 2018). For instance, ages of cryptomelane formed in situ in lateritic regolith of West Africa and Brazil allowed calibrating continental denudation over geological time scales (Beauvais and Chardon, 2013;Vasconcelos and Carmo, 2018).…”

mentioning

confidence: 99%

Weathering history and landscape evolution of Western Ghats (India) from ⁴⁰ Ar/ ³⁹ Ar dating of supergene K–Mn oxides

Jean

Beauvais

Chardon

et al. 2019

JGS

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Laterites preserved on both sides of the Western Ghats Escarpment of Peninsular India have formed by long-term lateritic weathering essentially after India-Seychelles continental break up following Deccan Traps emplacement (c. 63 Ma ago). Supergene manganese ores of the Western Ghats were formed on Late Archean manganese protores. Among Mn oxides composing the ores, cryptomelane (K-rich Mn oxide) was characterized and dated by 40 Ar/ 39 Ar geochronology. Measured ages complement those previously obtained in other South-Indian manganese ores from the hinterland plateau (Bonnet et al., 2016) and further document three major weathering periods, c. 53-44 Ma, c. 39-22 Ma, and c. 14-10 Ma, the later being documented for the first time in India. These periods coincide with global paleoclimatic proxies and date the lateritic weathering of three successive paleolandscapes of the Western Ghats that evolved under slow denudation (c. 8 m/myr) over the last 44 Myr and were mostly incised during the Neogene (< 22 Ma). That indicates the Western Ghats are a relict of a South Indian plateau preserved at the headwaters of very long east-flowing river systems and above the Western Ghats escarpment. Topography and denudation history of this landscape do not require Neogene tilt of the Peninsula as recently proposed.

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Combined 40Ar/39Ar and (U–Th)/He geochronological constraints on long-term landscape evolution of the Second Paraná Plateau and its ruiniform surface features, Paraná, Brazil

Cited by 30 publications

References 21 publications

Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Cenozoic sediment budget of West Africa and the Niger delta

Weathering history and landscape evolution of Western Ghats (India) from ⁴⁰ Ar/ ³⁹ Ar dating of supergene K–Mn oxides

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Combined 40Ar/39Ar and (U–Th)/He geochronological constraints on long-term landscape evolution of the Second Paraná Plateau and its ruiniform surface features, Paraná, Brazil

Cited by 30 publications

References 21 publications

Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Age and evolution of diachronous erosion surfaces in the Amazon: Combining (U-Th)/He and cosmogenic 3He records

Cenozoic sediment budget of West Africa and the Niger delta

Weathering history and landscape evolution of Western Ghats (India) from 40 Ar/ 39 Ar dating of supergene K–Mn oxides

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Weathering history and landscape evolution of Western Ghats (India) from ⁴⁰ Ar/ ³⁹ Ar dating of supergene K–Mn oxides