K—Ar age, composition, and origin of Mesozoic mafic rocks related to Ferrar Group, Pensacola Mountains, Antarctica

Ford, A. B.; Kistler, Ronald W.

doi:10.1080/00288306.1980.10424146

Cited by 51 publications

(25 citation statements)

References 38 publications

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“…At least one dyke is reported from Rosser Ridge, Cordiner Peaks, intruding the Devonian Dover Sandstone and interpreted as Jurassic in age (Ford et al 1978;Ford & Kistler 1980). Both Pecora Escarpment sills and Cordiner Peaks dyke were interpreted by Ford & Kistler (1980) to belong to the Ferrar Group on age and compositional grounds. Furthermore, the Cordiner Peaks is interpreted to be part of a swarm of dykes associated with the Dufek and Forrestal intrusions that have been imaged aeromagnetically (Ferris et al 2003).…”

Section: Pensacola Mountainsmentioning

confidence: 99%

“…Furthermore, the Cordiner Peaks is interpreted to be part of a swarm of dykes associated with the Dufek and Forrestal intrusions that have been imaged aeromagnetically (Ferris et al 2003). Sr isotope data for a Pecora Escarpment sill and the Rosser Ridge dyke give εSr 183 values of 85 and 116 respectively (Ford & Kistler 1980).…”

Section: Pensacola Mountainsmentioning

confidence: 99%

“…The north of the mountain range is dominated by the Dufek and Forrestal gabbro intrusions, which according to the geophysical interpretation of Ferris et al (1998) together cover some 6 600 km 2 and are thought on grounds of composition and age to be part of the Ferrar intrusive episode (Ford & Kistler 1980;Minor & Mukasa 1997).…”

Section: Pensacola Mountainsmentioning

confidence: 99%

“…The sills were dated at 195±5 Ma using K-Ar determinations on pyroxenes and plagioclases (Ford & Kistler 1980). At least one dyke is reported from Rosser Ridge, Cordiner Peaks, intruding the Devonian Dover Sandstone and interpreted as Jurassic in age (Ford et al 1978;Ford & Kistler 1980). Both Pecora Escarpment sills and Cordiner Peaks dyke were interpreted by Ford & Kistler (1980) to belong to the Ferrar Group on age and compositional grounds.…”

Section: Pensacola Mountainsmentioning

confidence: 99%

“…At Pecora Escarpment, several sill leaves intrude gently dipping Permian sediments of the Pecora Formation. The sills were dated at 195±5 Ma using K-Ar determinations on pyroxenes and plagioclases (Ford & Kistler 1980). At least one dyke is reported from Rosser Ridge, Cordiner Peaks, intruding the Devonian Dover Sandstone and interpreted as Jurassic in age (Ford et al 1978;Ford & Kistler 1980).…”

Section: Pensacola Mountainsmentioning

confidence: 99%

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On the long-distance transport of Ferrar magmas

Leat

2008

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Abstract:The distribution and geochemical relationships of the Early Jurassic Ferrar large igneous province (LIP) are examined and it is concluded that they support the lateral flow model for the emplacement of the province, with a source along the strongly magmatic Early Jurassic Antarctica-Africa rifted margin. Published data and new analyses from the Pensacola Range are used to show that the dominant magma type in the Ferrar, the Mount Fazio chemical type (MFCT) occurs in the Theron Mountains, Shackleton Range, Whichaway Nunataks, Pensacola Mountains (all Antarctica), and South Africa, as well as well-known outcrops in Victoria Land, Antarctica, southeast Australia and New Zealand. Chemical compositions are shown to be somewhat varied, but similar enough for them to be considered as representing closely related magmas. Examination of geochemical trends with distance from the interpreted magma source indicates that Mg# and MgO abundances decline with distance travelled, and it is argued that this is consistent with the lateral flow model. The Scarab Peak chemical type (SPCT) occurs as sills in the Theron Mountains and Whichaway Nunataks, and as lavas in Victoria Land, is geochemically very homogeneous. Despite this, Mg#, MgO, Ti/Y and Ti/Zr all fall with distance from the interpreted source, consistent with fractional crystallisation occurring during the lateral flow of the magmas. Flow took place in dykes or (more likely) sills. No feeder dyke swarm has been identified. The distances flowed, at least 4 100 km for MFCT and 3 700 km for SPCT are the longest interpreted lateral magma flows on Earth.End of abstract

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Section: Pensacola Mountainsmentioning

confidence: 99%

Section: Pensacola Mountainsmentioning

confidence: 99%

Section: Pensacola Mountainsmentioning

confidence: 99%

Section: Pensacola Mountainsmentioning

confidence: 99%

Section: Pensacola Mountainsmentioning

confidence: 99%

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On the long-distance transport of Ferrar magmas

Leat

2008

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Petrology and geochemistry of the Batchingou anorthositic suite rocks (Bana volcano‐plutonic complex, Cameroon Volcanic Line): Inference on their origin and relation with host granites

et al. 2022

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This study focusses on field mapping, petrographic description, and geochemical analyses of the Batchingou anorthositic suite rocks (Bana Plutono-volcanic Anorogenic Complex, Cameroon Volcanic Line). This suite consists of gabbroic (gabbro, gabbronorite, norite, and anorthosite) and charnockitic (mangerite, jotunite, enderbite, and monzogranite) rocks and intrude Ypresian granites (51 ± 1 Ma), within an elliptically shaped corridor of 1200 Â 600 m 2 . Gabbroic rocks evolved by crystal fractionation of olivine, hypersthene, augite, plagioclase, and ilmenite following the path: gabbro ! gabbronorite ! norite ! anorthosite. There is little or no crustal assimilation in this suite, contrarily to the charnockitic suite which likely evolved from a jotunite melt by assimilation of the Pan-African granito-gneissic basement rocks. Anorthosite has high Eu/Eu* (2.04-2.66), typical of anorthosites formed as cumulates. The La/Ta ratios (9.75-20.1 in gabbro, 21-45 in anorthosite and 23-76 charnockitic rocks), La/Yb N (4.2-19.5), Nb/U (22-90), and Nb/Th (5-23) suggest that the parental magma of the Batchingou anorthositic suite rocks is an alkaline basaltic melt deriving from a garnet-bearing asthenospheric mantle, but was variably modified during ascent by lithospheric spinel lherzolites and crustal rocks. The Batchingou gabbro has characteristics of evolved tholeiites and match the composition of the Laramie high-Al gabbro, whereas jotunite shows compositional affinity to ferrodiorites from Proterozoic anorthosite complexes. The gabbro Ni (19-39 ppm) and Cu (44-118 ppm) contents are low, indicating that their parental melt is not primitive. The Batchingou anorthositic suite differentiated from a different magma batch postdating the host granitoids and is similar to the anorthosite dykes of the Mboutou ring complex (Cameroon) and most of the ring complexes of the Aïr Province (Niger).

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