Zircon ages delimit the provenance of a sand extrudite from the Botucatu Formation in the Paraná volcanic province, Iraí, Brazil

Pinto, Viviane Machado; Hartmann, Léo Afrâneo; Santos, João O.S.; McNaughton, Neal J.

doi:10.1590/0001-3765201520130222

Cited by 10 publications

(3 citation statements)

References 40 publications

(25 reference statements)

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“…and Huab (Namibia, Twyfelfontein fm.) basins (Milner et al 1994;Pinto et al 2015), which themselves were overlain by flood basalts dated at c. 132 Ma indicating an ongoing break-up of southern Gondwana (Lower Cretaceous; Fig. 2d; Renne et al 1996).…”

Section: Evolution Of the Southwestern Gondwanan Mesozoic Successionsmentioning

confidence: 99%

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Mesozoic deposits of SW Gondwana (Namibia): unravelling Gondwanan sedimentary dispersion drivers by detrital zircon

Zieger

Harazim

Hofmann

et al. 2020

Int J Earth Sci (Geol Rundsch)

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The Namibian Mesozoic successions may be remnant of a high dynamic sedimentary system that is characterized by multiple stages of sediment accumulation and erosion with contemporaneous homogenization starting with the deposition of the Permo-Carboniferous Dwyka Group strata and continues at least until the Lower Cretaceous. The Lower Cretaceous sedimentary system is interpreted to have involved at least an area covering the whole SW Gondwana, documenting the sedimentary history during the evolution from an ice house environment to an arid desert. To test the sediment homogenization hypothesis, we applied a combination of isotopic and morphometric data on detrital zircon grains, as well as whole-rock geochemical data of selected Mesozoic sandstones from Namibia. As a base for the interpretation of the detrital zircon age data we compiled a zircon age dataset with c. 44,000 analyses for the southern African region. All samples reveal a major detrital pan-African zircon age peak of c. 0.5-0.7 Ga sourced from the pan-African magmatic events occurring around the Kalahari Craton margin. The lowermost Triassic is characterized by the occurrence of additional Mesoproterozoic and Paleoproterozoic age peaks of c. 1.0-1.2 Ga and 1.8-2.0 Ga with a majority of zircon grains showing angular shapes. The protosource of these grains is interpreted to possibly be the Namaqua Metamorphic Complex and other Paleoproterozoic structural units deformed in course of the Namaqua orogeny. In contrast, other samples show a prominent Permo-Triassic age peak and completely rounded zircon grains, putatively derived from within the Gondwanides volcanic arc. The disparity in the zircon age pattern may point towards a change in provenance and also a change in the whole system of zircon recycling during the Mesozoic southern Gondwana. The Lower Triassic Neu Loore fm. are constrained to more local bedrock sources and short zircon transport distance. In contrast, zircon grains of the Middle Triassic Omingonde, the Jurassic Etjo und the Cretaceous Twyfelfontein formations are an expression for a major recycling and sediment homogenization system. The system was facilitated by an interplay between fluvial and eolian sedimentary transport systems.

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Section: Evolution Of the Southwestern Gondwanan Mesozoic Successionsmentioning

confidence: 99%

“…Sedimentary recycling continued during the Lower Cretaceous and a reworking of Lower Permian strata with Permo-Triassic ash-fall tuffs is suggested by sediments of the Brazilian Lower Cretaceous Botucatu fm. (Canile et al 2016;Pinto et al 2015).…”

Section: Evolution Of the Southwestern Gondwanan Mesozoic Successionsmentioning

confidence: 99%

Mesozoic deposits of SW Gondwana (Namibia): unravelling Gondwanan sedimentary dispersion drivers by detrital zircon

Zieger

Harazim

Hofmann

et al. 2020

Int J Earth Sci (Geol Rundsch)

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“…These basalts form the hills and the bedrock (~ 500 m thick on average, up to several km) below the topsoils, except in the coastal area and the surroundings, where other geological formations emerge, and the more complex geology of the Paraná basin is exposed (see Supplementary file 3). The BSGC also includes intertrap silicified sandstones, composed by quartz (~ 90%), feldspar (~ 5%) and opaque minerals (~ 5%), cemented with chalcedony (Pinto et al 2015), interpreted as an injectite complex formed mostly from the sands of the Botucatú Formation (Pinto et al 2015;Hartmann et al 2012). They are interspersed between the basalts as small mantles, ranging from a few centimetres to a few meters thick (Martins et al 2011;Milani et al 2007;Wildner et al 2006: 32).…”

Section: The Lithic Landscapementioning

confidence: 99%

Raw materials and functional designs of Fishtail projectile points from southern Brazil

Carbonera

Loponte²

2021

JLS

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This study analyses the lithic landscape and the selection of rocks used to manufacture Fishtail points (FP) in southern Brazil, their designs, and some functional aspects. In order to identify the offer of lithic resources, we carried out several surveys throughout 15 months in 47 counties in the Southern Brazil covered by the Botucatú - Serra Geral Vulcano Sedimentary Complex. The lithic composition of numerous hill slopes, fallen rocks, and accumulations of pebbles and boulders in the riversides was evaluated. The results show that basalts (including a small proportion of andesites and rhyodacites-rhyolites), and silicified sandstones, are ubiquitous in the landscape. Conversely, non-translucent cherts are scarce, so their acquisition would have been time-consuming. However, these local cherts were the rocks mostly used to manufacture these points, being another example of the selectivity for high quality rocks by Paleoamerican hunter-gatherers. The same cherts selected in southern Brazil to produce the FP were used to manufacture other point-types by local hunter-gatherers of the early and middle Holocene grouped in the so-called “Umbú Tradition”. Not a single FP of the entire collection analyzed here was made from silicified limestones, which is one of the most common raw materials among the Uruguayan FPs, nor were they made from quartzites as were most of the FPs of the Pampean plains. Regarding to the designs of these projectiles, some morphotypes appear to have been designed to produce multiple injuries through successive thrusts and withdrawals in the bodies of the prey, while in others, the design seems to have favoured penetration and fixation on the prey, suggesting in this case, a single shot technique for each projectile. As the maintenance process unfolded, especially for points below ~ 80 mm in length, they show features that negatively impacted their efficiency, including distinct asymmetries, somewhat open front angles, a decrease in the cutting perimeter and cross-sectional area, an increase in the bevel angle of the blade edges, and a tendency to a conical cross-section. Behaviours intended to counteract these problems were maximizing the length of the leading edge, maintaining the symmetry and the triangular blade resting on straight shoulders, and maintaining the aerodynamic properties as much as it were possible, in order to improve their lethality and the fixation capacity. Beyond these rejuvenation processes, three different morphotypes of points appear to be included within the sample. The first includes points over 120 mm and ~ 80 g in weight, with triangular or slightly lanceolate limbs, which mostly present straight shoulders, but there are also examples of rounded shoulders. The second design corresponds to projectiles between 110 and 87 mm and ~30 g in weight, with triangular or slightly lanceolate blades and straight shoulders. The third design presents the classic shape of these projectiles, with a fish silhouette, with maximum lengths below 90 mm, with a more robust and conceptually different design, where the angles of the edges of the blades and of the shoulders are equal, perhaps with the intention to facilitate the spear withdrawal to produce multiple injuries.

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A review of the curved lithic cleavers from the rainforest of southeastern South America

Loponte

Carbonera

Almeida

et al. 2023

Journal of Archaeological Science: Reports

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Zircon ages delimit the provenance of a sand extrudite from the Botucatu Formation in the Paraná volcanic province, Iraí, Brazil

Cited by 10 publications

References 40 publications

Mesozoic deposits of SW Gondwana (Namibia): unravelling Gondwanan sedimentary dispersion drivers by detrital zircon

Mesozoic deposits of SW Gondwana (Namibia): unravelling Gondwanan sedimentary dispersion drivers by detrital zircon

Raw materials and functional designs of Fishtail projectile points from southern Brazil

A review of the curved lithic cleavers from the rainforest of southeastern South America

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