Joaquín Bastías

Trinity College Dublin

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

David Chew

Trinity College Dublin

Richard Spikings

University of Geneva

Teal R. Riley

British Antarctic Survey

Alex Burton‐Johnson

British Antarctic Survey

Massimo Chiaradia

University of Geneva

Fernando Poblete

University of Chile

Anne Grunow

The Ohio State University

Alexey Ulianov

University of Lausanne

Francisco Hervé

University of Chile

Foteini Drakou

Trinity College Dublin

Cooperative Institutions

University of Chile

National University of Patagonia San Juan Bosco

Consejo Nacional de Investigaciones Científicas y Técnicas

British Antarctic Survey

Ministry of Natural Resources

Universidad Andrés Bello

Chinese Academy of Geological Sciences

Centre National de la Recherche Scientifique

China Geological Survey

Ministry of Civil Affairs

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Re-evaluating the link between the Ellsworth Mountains and East Antarctica in the Neoproterozoic: Implications for the breakup of Rodinia and the existence of Pannotia

Precambrian Research (2024)

Paula Castillo Fernando Poblete Rodrigo Fernández Joaquín Bastías C. Mark Fanning

Our current understanding of the Ellsworth Mountains stratigraphy suggests the oldest sedimentary sequence (Heritage Group) was deposited in a Cambrian rift setting. This early Paleozoic age is then used as a key piercing point to help define Cambrian paleogeography for the southern paleo-Pacific margin of Gondwana, which places the Ellsworth Mountains between southern Africa and East Antarctica as part of West Gondwana. However, U-Pb zircon dating of a micro-diorite from the Heritage Group reveals a crystallization age of 682 ± 10 Ma, challenging chronostratigraphic and tectonic interpretations. Positive εHft and mantle-like δ18O values for these Cryogenian zircons suggest that the rifting, affecting Mesoproterozoic crust, occurred during the Cryogenian rather than in the Cambrian. This finding strongly supports a connection between the Ellsworth-Whitmore Mountain crustal block and the Transantarctic Mountains in East Antarctica prior to the amalgamation of Gondwana. It also facilitates its contextualization during the breakup of Rodinia, likely positioned close to the Shackleton Range as a continuation of the Australia-Antarctic plate, which separated from Laurentia to form the proto-Pacific Ocean in the late Neoproterozoic. This connection is supported by the U-Pb, Hf, and O data in detrital zircon grains from the lowermost units of the Heritage Group, which indicate local, East Antarctic Shield, and probable Laurentian sources. A second magmatic event in the Cambrian (516 ± 7 Ma) is recorded through zircons from a basaltic andesite within the Liberty Hills Formation, which provides an absolute depositional age for this unit. This magmatism is linked to an extensional setting, albeit distinct from that of the Cryogenian micro-diorite. The Cambrian zircons yield elevated δ18O values, indicating a strong sedimentary influence on the magma source and crustal recycling. We interpret this Cambrian extensional magmatism as a result of a tectonic escape following the collision between the East Antarctic Shield and West Gondwana/Indo-Antarctic plates, leading to the formation of Gondwana. This interpretation argues against the hypothetical Pannotia supercontinent and the proposed Cambrian rift between this sector of the paleo-Pacific margin of Gondwana and southern Laurentia.

Rodinia

Link (geometry)

10.1016/j.precamres.2024.107325

Cite

Citations (1)

The Gondwanan margin in West Antarctica: insights from Late Triassic magmatism of the Antarctic Peninsula

EarthArXiv (California Digital Library) (2019)

Joaquín Bastías Richard Spikings Alex Ulianov Teal R. Riley Alex Burton‐Johnson

Triassic orthogneisses of the Antarctic Peninsula provide evidence for the Palaeozoic and Mesozoic geological evolution of southern Gondwana within Pangaea. These rocks are sporadically exposed in southeastern Graham Land and northwestern Palmer Land, although reliable geochronological, geochemical and isotopic data are sparse. We combine new geochronological (LA-ICP-MS zircon U-Pb), geochemical, and zircon (Hf, O) and whole rock isotopic (Nd, Sr and Pb) data to constrain the age and Triassic – Palaeozoic tectonic setting of these rocks. Zircon cores record a Palaeozoic magmatic arc between 252.5 ± 2 and 527.8 ± 6.2 Ma, which was mainly located to the west of the Eastern Palmer Land Shear Zone (Central Domain; Vaughan and Storey, 2000). The arc is considered to be an extension of contemporaneous Palaeozoic arcs that have been identified along the Pacific margin of South America and the Thurston Island Block. Regions to the east of the Palmer Land Shear Zone (Eastern Domain, Vaughan and Storey, 2000) were located distal from the Terra Australis Margin, and possibly resided within Sunsas-aged belts within Pangaea. Triassic continental arc, calc-alkaline magmatism during 223.4 – 203.3 Ma modified the crust of the Antarctic Peninsula on both sides of the Eastern Palmer Land Shear Zone. Magmatic sources included igneous and sedimentary crustal material, which formed by crustal reworking during Sunsas- and Braziliano-aged orogenesis, and Palaeozoic arc magmatism. Arc magmatism accompanied sinistral extension which brought both domains into the arc and resulted in steady oceanward migration of the Triassic arc during the Middle – Late Triassic. We conclude that the Eastern Palmer Land Shear Zone formed in the Triassic, and that both the Eastern and Central Domains are autochthonous to Gondwana.

Continental arc

Island arc

Back-arc basin

10.31223/osf.io/8ds42

Cite

Citations (3)

Cretaceous magmatism in the Antarctic Peninsula and its tectonic implications

Figshare (2022)

Joaquín Bastías Richard Spikings Teal R. Riley David Chew Anne Grunow

SM Table 3_Compilation

Peninsula

10.6084/m9.figshare.20286387

Cite

Citations (0)

The Triassic of the Antarctic Peninsula

EGUGA (2019)

Joaquín Bastías Richard Spikings Alexey Ulianov Teil Riley Alex Burton‐Johnson

Peninsula

Source

Cite

Citations (0)

Very low-grade secondary minerals as indicators of palaeo-hydrothermal systems in the Upper Cretaceous volcanic succession of Hannah Point, Livingston Island, Antarctica

Applied Clay Science (2016)

Joaquín Bastías Francisco Fuentes Luis Aguirre Francisco Hervé Alain Demant

Paragenesis

Phenocryst

10.1016/j.clay.2016.07.025

Cite

Citations (12)

Comment on egusphere-2023-1769

Joaquín Bastías David Chew Fernando Poblete Paula Castillo William R. Guenthner

Abstract. While thermochronological studies have constrained the landscape evolution of several of the crustal blocks of West and East Antarctica, the tectono-thermal evolution of the Ellsworth Mountains remains relatively poorly constrained. These mountains are among the crustal blocks that comprise West Antarctica and exhibit an exceptionally well-preserved Palaeozoic sedimentary sequence. Despite the seminal contribution of Fitzgerald and Stump (1991), who suggested an Early Cretaceous uplift event for the Ellsworth Mountains, further thermochronological studies are required to improve the current understanding of the landscape evolution of this mountain chain. We present new zircon (U-Th)/He (ZHe) ages, which provide insights into the landscape evolution of the Ellsworth Mountains. The ZHe ages collected from near the base and the top of the sequence suggest that these rocks underwent burial reheating after deposition. A cooling event is recorded during the Jurassic–Early Cretaceous, which we interpret as representing exhumation in response to rock uplift of the Ellsworth Mountains. Moreover, our results show that, while ZHe ages at the base of the sequence are fully reset, towards the top ZHe are partially reset. Uplift and exhumation of the Ellsworth Mountains during the Jurassic–Early Cretaceous was contemporaneous with the rotation and translation of this crustal block with respect to East Antarctica and possibly the Antarctic Peninsula. Furthermore, this period is characterised by widespread extension associated with the disassembly and breakup of Gondwana, with the Ellsworth Mountains playing a key role in the opening of the far South Atlantic. Based on these results, we suggest that uplift of the Ellsworth Mountains during the disassembly of Gondwana provides additional evidence for major rearrangement of the crustal blocks between the South American, African, Australian and Antarctic plates. Finally, uplift of the Ellsworth Mountains commenced during the Jurassic, which predates the Early Cretaceous uplift of the Transantarctic Mountains. This may indicate that continental scale, rift-related exhumation was diachronous, initiating in the Ellsworth Mountains in the Jurassic and then propagating southwards into the Transantarctic Mountains during the Early Cretaceous.

Peninsula

Sequence (biology)

10.5194/egusphere-2023-1769-rc2

Cite

Citations (0)

The Byers Basin: Jurassic-Cretaceous tectonic and depositional evolution of the forearc deposits of the South Shetland Islands and its implications for the northern Antarctic Peninsula

EarthArXiv (California Digital Library) (2019)

Joaquín Bastías Mauricio Calderón Lea Israel Francisco Hervé Richard Spikings

This paper addresses the Jurassic-Cretaceous stratigraphic evolution of fore-arc deposits exposed along the west coast of the northern Antarctic Peninsula.In the South Shetland Islands, Upper Jurassic deepmarine sediments are uncomformably overlain by a Lower Cretaceous volcaniclastic sequence that crops out on Livingston, Snow and Low islands.U-Pb zircon ages are presented for the upper Anchorage Formation (153.1 ± 1.7 Ma) and the Cape Wallace granodiorite of Low Island (137.1 ± 1.7 Ma) as well as 40 Ar/ 39 Ar ages of 136-139 Ma for Low Island andesites.Data are also presented for a U-Pb age of 109.0 ± 1.4 Ma for the upper volcanic succession of Snow Island.In combination with published stratigraphy, these data provide a refined chrono-and litho-stratigraphic framework for the deposits herein referred to as the Byers Basin.Tentative correlation is explored with previously described deposits on Adelaide and Alexander islands, which could suggest further continuation of the Byers Basin towards the south.We also discuss possible correlation of the Byers Basin with the Larsen Basin, a sequence that shows the evolution of foreland to back-arc deposits more or less contemporaneously with the fore-arc to intra-arc evolution of the Byers Basin.

Forearc

Shetland

Peninsula

10.31223/osf.io/x75p4

Cite

Citations (0)

The Triassic–Cretaceous Tectonomagmatic History of the Antarctic Peninsula constrained by Geochronology, Thermochronology and Isotope Geochemistry

Joaquín Bastías

Thermochronology

Geochronology

Isotope Geochemistry

Peninsula