Late Mesozoic sedimentation in the northern Antarctic Peninsula and its relationship to the southern Andes

Farquharson, Gordon

doi:10.1144/gsjgs.139.6.0721

Cited by 47 publications

(37 citation statements)

References 19 publications

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“…Aitkenhead (1975) regarded the latter as the youngest member of the volcanic succession on Trinity Peninsula. In conjunction with the revized sedimentary stratigraphy at Longing Gap, NE of Larsen Inlet (Farquharson 1982), it is suggested that arc-building activity in this area reached a climax in Lower Cretaceous times. The chief evidence for Jurassic magmatism rests with K-Ar ages of 158-169 Ma for the plutonic complex round Mount…”

Section: Trinity Peninsulamentioning

confidence: 94%

Rb-Sr geochronology of Graham Land, Antarctica

Pankhurst¹

1982

JGS

154

116

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Thirty-five new Rb-Sr whole-rock and mineral isochrons are reported for igneous rocks from Graham Land. Magmatism was essentially continuous but peaks of activity occurred in early Jurassic, early Cretaceous, late Cretaceous and Eocene times. The oldest dated granite is Triassic (209 ± 3 Ma). Volcanic rocks were erupted throughout this history and some previously supposed Upper Jurassic volcanic rocks must be mid-Cretaceous or younger. A change in magma type, from uniformly acid to predominantly basic or intermediate, combined with westward migration of the arc, may be partly responsible for previously reported transverse geochemical variations. There is a marked trend of decreasing initial 87 Sr/ 86 Sr ratio of the plutonic rocks with time, from c. 0.707 to 0.704, although volcanic rocks tend to have higher values. This trend is ascribed to the waning influence of an, as yet unidentified, pre-magmatic crustal basement, due to increasing depth of magma generation. Close parallels to the observed age pattern imply continuity of the Andean belt through southern South America into Graham Land back to early Mesozoic times and are not compatible with reconstructions of Gondwana in which the Antarctic Peninsula is located W of South America.

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Section: Trinity Peninsulamentioning

confidence: 94%

Rb-Sr geochronology of Graham Land, Antarctica

Pankhurst¹

1982

JGS

154

116

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“…The geology of eastern Graham Land has been closely correlated with the successions of Patagonia from the Ordovician at the time of the Famatinian arc (Riley et al 2012b) to at least the Middle Jurassic during the extensive felsic volcanism associated with the Chon Aike silicic large igneous province and subsequently from the Late Jurassic to the Early Cretaceous (Farquharson 1982).…”

Section: The Eastern Domainmentioning

confidence: 99%

Autochthonous v. accreted terrane development of continental margins: a revised in situ tectonic history of the Antarctic Peninsula

Burton‐Johnson

Riley

2015

JGS

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The allochthonous terrane accretion model previously proposed for the geological development of the Antarctic Peninsula continental margin arc is reviewed in light of recent data and the geology is reinterpreted as having evolved as an in situ continental arc. This is based upon the following factors: (1) the presence of Early Palaeozoic basement and stratigraphic correlation of sequences between the autochthonous and previously proposed allochthonous terranes; (2) isotopic evidence for similar deep crustal structure across the different terranes; (3) ocean island basalt magmas and deep marine sedimentary rocks formed during continental margin extension within the previously proposed accretionary wedge sequence (i.e. not formed against an active oceanic arc); (4) the distribution of magnetic susceptibility measurements and aeromagnetic data locating the palaeo-subduction zone along the west of the Peninsula; (5) a lack of clear palaeomagnetic distinction between the terranes. The following alternative tectonic history is proposed: (1) amalgamation and persistence of Gondwana; (2) subsequent silicic large igneous province magmatism and extension; (3) development and history of Andean subduction until its cessation in the Cenozoic. A number of features in the Antarctic Peninsula correlate with those of other circum-Pacific margins, supporting a global evaluation of allochthonous v. autochthonous margin development to aid our understanding of crustal growth mechanisms.

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“…Cretaceous to Paleogene strata accumulated during thermal subsidence of the basin (Hathway, 2000), with sediment being shed from the Antarctic Peninsula to the west as indicated by palaeocurrent directions and provenance studies (Farquharson, 1982;Ineson, 1989;Pirrie, 1991). Wood is abundant within these marine sequences and is considered to have been derived from the treeforming elements of the vegetation from the Antarctic Peninsula.…”

Section: Geological Setting and Palaeoenvironmentmentioning

confidence: 99%

Taxonomic turnover and abundance in Cretaceous to Tertiary wood floras of Antarctica: implications for changes in forest ecology

Cantrill

Poole

2005

Palaeogeography, Palaeoclimatology, Palaeoecology

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Based on the temporal distribution, abundance, and taxonomic composition of wood floras, four phases of vegetation development are recognized through the Cretaceous to Early Tertiary of the Antarctic Peninsula: (1) Aptian to Albian communities dominated by podocarpaceous, araucarian, and minor taxodiaceous/cupressaceous conifers with rare extinct gymnosperms (Sahnioxylon). (2) Progressive replacement of these communities in ?Cenomanian to Santonian times by angiosperms, most without modern analogues. (3) Increasing dominance of angiosperms becoming important both in terms of diversity and abundance towards the mid-Late Cretaceous. (4) Modernization of the flora during the Campanian to Maastrichtian with the extinction of earlier forms, appearance of the Nothofagaceae and diversification of associated elements. These patterns broadly follow trends seen in the leaf and palynological record but with some important differences.During the Cretaceous, conifer composition undergoes a change whereby Phyllocladoxylon-type woods increase relative to the older Podocarpoxylon forms. During the Paleocene to Eocene period, a marked extinction in wood types occurs associated with an increase in the abundance of nothofagaceous wood. Detailed examination of wood abundance and distributions from sections within Maastrichtian and Paleocene formations points to strong environmental control on taxonomic compositions. Similar differences are encountered when comparing coeval floras from different geographic regions and palaeoenvironments. D

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Late Mesozoic sedimentation in the northern Antarctic Peninsula and its relationship to the southern Andes

Cited by 47 publications

References 19 publications

Rb-Sr geochronology of Graham Land, Antarctica

Rb-Sr geochronology of Graham Land, Antarctica

Autochthonous v. accreted terrane development of continental margins: a revised in situ tectonic history of the Antarctic Peninsula

Taxonomic turnover and abundance in Cretaceous to Tertiary wood floras of Antarctica: implications for changes in forest ecology

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