Palaeomagnetism of the Late Devonian–Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana

Geuna, Silvana Evangelina; Escosteguy, Leonardo Darío; Miró, Roberto César

doi:10.1016/j.gr.2007.05.006

Cited by 12 publications

(9 citation statements)

References 40 publications

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“…The magnetic components carried by haematite and titanohaematite are used to calculate a paleomagnetic pole for the batholith. This pole fits the 380-360 Myr segment of the apparent polar wander path for the Paleozoic of Gondwana (Geuna et al 2008b). Because it coincides with the crystallization age of 368 Myr obtained on zircons by Dorais et al (1997), this pole position favours the interpretation that the titanohaematite formed during the primary crystallization and cooling and not as a product of a much later hydrothermal alteration.…”

Section: Magnetic Properties Of Achala Batholithsupporting

confidence: 71%

“…The coincidence of the paleomagnetic pole of the Achala batholith with the 380–360 Myr segment of the Apparent Polar Wander Path for the Paleozoic of Gondwana (Geuna et al 2008b) favours the interpretation that the ilmeno‐haematite and haemo‐ilmenite formed early during the crystallization process and during cooling were subjected to a deuteric alteration under slightly more oxidizing conditions than the original magma.…”

Section: Discussionmentioning

confidence: 97%

“…The peculiarity in Achala is to find the exsolved haematite‐ilmenite alone. The absence of large discrete grains of magnetite makes these rocks very interesting from the paleomagnetic point of view because haematite is capable of carrying a very stable CRM acquired during early stages of cooling (Geuna et al 2008b), and this is free of the undesirable masking effects of re‐equilibrated, coarse‐grained, pure magnetite.…”

Section: Discussionmentioning

confidence: 99%

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Magnetic petrology of the Devonian Achala Batholith, Argentina: titanohaematite as an indicator of highly oxidized magma during crystallization and cooling

Geuna

McEnroe

Robinson

et al. 2008

Geophysical Journal International

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S U M M A R YDevonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late-to post-orogenic monzogranites emplaced in a metamorphic-plutonic basement. Two groups of Devonian granitoids are distinguished: (1) metaaluminous to weakly peraluminous, hornblende-biotite bearing granitoids, and (2) peraluminous, biotite-(muscovite) bearing granitoids. Groups 1 and 2 are characterized by accessory phases of sphene-magnetite with high susceptibility, and ilmenite-(monazite-uraninite) with low susceptibility, respectively. The magnetic assemblage of the Group 2 Achala Batholith, predominantly paramagnetic, is the subject of this paper.Forty-three sites were sampled in the Achala monzogranite. Overall, it is weakly magnetic, with a mean magnetic susceptibility of 1.5 × 10 −4 SI. Twenty-one sites showed titanohaematite as the magnetic carrier of a stable remanence. The titanohaematite is an accessory mineral and contains exsolved disc-shaped intergrowths of ilmenite.The weak magnetism of Achala monzogranite facies contrasts with the magnetic character of other Devonian porphyritic, batholithic monzogranites in the region. The virtual absence of magnetite, together with the presence of exsolved titanohaematite and Mn-ilmenite indicate crystallization and cooling under more oxidizing conditions. Oxidizing conditions continued into the subsolidus, causing late-stage reactions of ilmenite host grains to ilmenite + rutile+ haematite, and titanohaematite to ilmenite-poorer haematite + rutile. These reactions resulted in low susceptibility values and a strong reduction of natural remanent magnetization (NRM) intensities.Thermal demagnetization, up to 620-640 • C, isolated steeply dipping, dual-polarity remanence directions. The coincidence of the Achala paleomagnetic pole with the 380-360 Myr segment of the Gondwana Apparent Polar Wander Path and the U-Pb zircon age implies that the remanence was acquired soon after emplacement.

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Section: Magnetic Properties Of Achala Batholithsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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Magnetic petrology of the Devonian Achala Batholith, Argentina: titanohaematite as an indicator of highly oxidized magma during crystallization and cooling

Geuna

McEnroe

Robinson

et al. 2008

Geophysical Journal International

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“…In Table 1 there are 27 PPs selected from different crustal blocks that made up Gondwana. The selection was based on the previous ones carried out by McElhinny et al (2003), Geuna et al (2008) and Torsvik et al (2012). All PPs have quality factors Q ≥ 3 with a maximum Q of 7 ( Van der Voo, 1993).…”

Section: Selection Of Gondwanan Paleomagnetic Polesmentioning

confidence: 99%

The Paleozoic Central Patagonian Igneous Metamorphic Belt: its geodynamic and tectonic interpretation based on Paleogeographic reconstructions

Vizán¹

2022

Preprint

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In the southwestern margin of the North Patagonian Massif there is a NW 26 SE belt of igneous and metamorphic rocks defining a limit between the North Patagonian Massif and southern Patagonia (including the Deseado Massif), named the Central Patagonian Igneous Metamorphic Belt (CPIMB). The objective of this paper is to better understand the geodynamic and tectonic processes that generated its rocks and structures. More specifically, explanations are offered for different questions: 1) the aforementioned belt corresponds to a collisional or accretionary orogen? 2) during which geological event it was built? 3) how was the South American plate driftting during that process? 4) why the foliation of the rocks of one of its localities presents a different structural attitude than others? To answer these questions, paleogeographic reconstructions were performed based on paleomagnetic data ranging from ca.415 Ma to ca.305 Ma. Through these reconstructions and considering the middle and upper Paleozoic rocks located in a central area of this deformational belt (the Taquetrén range) and the geological background of several authors, it was possible to separate the processes involved in two tectonic cycles: the Chanic (late Devonian) and the Gondwanan (Carboniferous-Permian) events. The CPIMB presents rocks from an ancient orogen that was built mainly during the Chanic event. In the Taquetrén range the orogenic process would extend between approximately 400 Ma and about 360 Ma. Based on the data of this area, the Chanic orogen collapsed between about 360 Ma and about 330 Ma as the result of an abrupt change in the movement of South America along with all the other continents that constituted Gondwana. From a global geodynamic perspective, it is known that Pangea formed on a mantle super downwelling, where subduction zones surrounded this supercontinent. This caused magmatic processes in its margins and, in the Taquetrén range, triggered a plutonic emplacement in the old structures of the previous metamorphic rocks of the orogen at about 315 Ma. In these plutonic rocks, a Gondwanan tectonic event is recorded at about 300 Ma. During this event, a suggested transpressive deformation could have determined the assembly of southern Patagonia with the rest of the lithospheric domains of South America. This tectonic event ended in the central area of CPIMB before the intrusion of non-deformed batholiths during the Permian.

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“…6B). The main systems crop out in North and South America, with well-developed examples including the Early Pennsylvanian Juru a Sandstone Formation (the Solimões Basin, Brazil; Elias et al, 2007), the Pennsylvanian Tyrwhitt and Tobermory Sandstone Formations (the Rocky Mountain Supergroup, Canada; Stewart & Walker, 1980) and the Pennsylvanian-Middle Permian Cangapi Formation (the Cuevo Group, Tarija Basin, Bolivia and Argentina; Hern andez & Echevarr ıa, 2009), the Late Carboniferous-Early Permian Patqu ıa Formation (the Paganzo Group, Paganzo Basin, Argentina; Caselli & Limarino, 2002;Geuna et al, 2010). In Saudi Arabia, the Carboniferous-Permian Unayzah Formation constitutes an economically important gas reservoir succession (Melvin & Heine, 2004;Melvin et al, 2010).…”

Section: Evolution Of Aeolian Sand Systems Through Earth Historymentioning

confidence: 99%

Archean to Recent aeolian sand systems and their sedimentary record: Current understanding and future prospects

et al. 2014

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The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand-sea or dunefield (erg) deposits, whereas coastal systems are primarily known from the Cenozoic. The complexity of aeolian sedimentary processes and facies variability are under-represented and excessively simplified in current facies models, which are not sufficiently refined to reliably account for the complexity inherent in bedform morphology and migratory behaviour, and therefore cannot be used to consistently account for and predict the nature of the preserved sedimentary record in terms of formative processes. Archean and Neoproterozoic aeolian successions remain poorly constrained. Palaeozoic ergs developed and accumulated in relation to the palaeogeographical location of land masses and desert belts. During the Triassic, widespread desert conditions prevailed across much of Europe. During the Jurassic, extensive ergs developed in North America and gave rise to anomalously thick aeolian successions. Cretaceous aeolian successions are widespread in South America, Africa, Asia, and locally in Europe (Spain) and the USA. Several Eocene to Pliocene successions represent the direct precursors to the presentday systems. Quaternary systems include major sand seas (ergs) in low-lattitude and mid-latitude arid regions, Pleistocene carbonate and Holocene-Modern siliciclastic coastal systems. The sedimentary record of most modern aeolian systems remains largely unknown. The majority of palaeoenvironmental reconstructions of aeolian systems envisage transverse dunes, whereas successions representing linear and star dunes remain under-recognized. STATE OF THE SCIENCEtemporal transition between different mechanisms of accumulation and preservation; and (iv) is it reasonable to assume that the deposits of preserved aeolian successions necessarily represent an unbiased record of the conditions that prevailed during episodes of Earth history when large-scale aeolian systems were active, or has the evidence to support the existence of other major desert basins been lost for many periods throughout Earth history?

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Palaeomagnetism of the Late Devonian–Early Carboniferous Achala Batholith, Córdoba, central Argentina: Implications for the apparent polar wander path of Gondwana

Cited by 12 publications

References 40 publications

Magnetic petrology of the Devonian Achala Batholith, Argentina: titanohaematite as an indicator of highly oxidized magma during crystallization and cooling

Magnetic petrology of the Devonian Achala Batholith, Argentina: titanohaematite as an indicator of highly oxidized magma during crystallization and cooling

The Paleozoic Central Patagonian Igneous Metamorphic Belt: its geodynamic and tectonic interpretation based on Paleogeographic reconstructions

Archean to Recent aeolian sand systems and their sedimentary record: Current understanding and future prospects

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