N. W. Roland's scientific contributions

Publications (12)

Data
During the GEISHA expedition (Geologische Expedition in die Shackleton Range 1987/88), the Pioneers Escarpment was visited and sampled extensively for the first time. Most of the rock types encountered represent amphibolite facies metamorphics, but evidence for granulite facies conditions was found in cores of garnet. These conditions must have bee...
Book
The geological sheet map of the Shackleton Range represents the synthesis of numerous geological research programmes between 1967 and 1989. Such investigations have indicated that the ancient cratonic margin of East Antarctica apparently extended across the central part of the Shackleton Range, dividing it into two distinct belts, a cratonic southe...
Article
During the GEISHA expedition the Pioneers Escarpment was visited and sampled. Most of the rock types encountered represent amphibolite facies metamorphics, but evidence for granulite facies conditions was found in cores of garnet. These conditions must have been at least partly reached during the peak of metamorphism. These rocks are considered to...

Citations

... The geochemistry of the charnockites and associated granitoids is relatively heterogeneous, but they are typically peraluminous to metaluminous and subalkaline with a weak trend to alkaline A-type granites (e.g. Klimov et al. 1964;Ravich & Kamenev 1975;Joshi et al. 1991;Roland 2002Roland , 2004aLi et al. 2003). However, they are not typical A-type granites, being relatively low in Ca, Rb, Nb and Ga, such that they plot as A 2 -type according to the classificaton of Eby (1992), and unlike common A-type granite associations they form a voluminous and extensive magmatic suite, covering an area of at least 15 000 km 2 (Roland 2004a, b). ...
... A similar pattern occurs farther south near Terra Nova Bay and the Deep Freeze Range, where polymetamorphic gneisses with early moderate-P/T parageneses are distinguished from high-T granulites and migmatites (Lombardo et al., 1987;Castelli et al., 1991). Wilson Group gneisses are separated from the Bowers terrane by steeply-dipping faults and shear zones Gibson, 1984;Roland et al., 1984;Sandiford, 1985;Capponi et al., 2002), but the age and tectonic significance of these zones are controversial. In northern Victoria Land the Ross Orogeny resulted in pronounced folding of Lower Ordovician rocks in the Bowers and Robertson Bay terranes (Bradshaw et al., 1985;Gibson and Wright, 1985), in diachronous cleavage development within the Robertson Bay Group (Dallmeyer and Wright, 1992), and ductile thrusting of Wilson Group metamorphic rocks (Kleinschmidt and Tessensohn, 1987;Flöttmann and Kleinschmidt, 1991a;Schüssler et al., 1999). ...
... This unit is considered a tectonic slice with different characteristics from both the Wilson and Bowers terrane lithologies [33,34,43,44,59]. The Dessent Unit is represented by a predominant amphibolite lithology with amphibole biotite schist, mafic granulites, quartzite, marble/calcsilicate rocks, metapelites and metaconglomerates, depending on the location (this study) [33,43,44,62,66,67]. This unit distinctly retains amphibolite Minerals 2020, 10, 908 7 of 32 facies mineral assemblage, such as hornblende + garnet + plagioclase, with overprints of retrograde minerals (greenschist facies), such as chlorite + epidote + muscovite. ...
... After the Ross orogeny, all terranes were intruded by Admiralty intrusives during the Late Devonian (e.g., Capponi et al., 1997). The onset, from the mid-Devonian, of progressive uplift of the terranes accreted to the East Antarctic craton (e.g., Barrett, 1981;Lisker 1996 andRossetti et al., 2003;Lisker et al., 2006) controlled the further evolution of the Ross orogen in the NVL. ...
... We interpret aeromagnetic and gravity data over a larger sector of Victoria Land [Reitmayr, 1997; Chiappini et al., 2002] to advance a new tectonic model for northern Victoria Land terranes by contrasting potential field signatures against geologic and geochemical evidence. [4] Low to high grade metamorphic rocks of the Wilson Terrane are intruded by Cambro-Ordovician Granite Harbour Intrusives [Roland and Olesch, 1997]. These intrusive rocks, of calc-alkaline magmatic arc affinity, may relate to southwestward subduction of the paleo-Pacific plate beneath the East Antarctic Craton [Kleinschmidt and Tessensohn, 1987]. ...
... Fuchsitic quartzites are also known from the Pioneers Group at the Pioneers Escarpment in the northern Shackleton Range (Clarkson et al., 1995;Roland et al., 1995), where they are interlayered with a heterogeneous assemblage of metasedimentary and metavolcanic rocks. The depositional age of the Pioneers Group strata is not known, in part due to pervasive Barrovian-type metamorphism and deformation during the Ross Orogeny (Brommer and Henjes-Kunst, 1999;Zeh et al., 1999Zeh et al., , 2004. ...
... In Oates Land, the Wilson Terrane (Fig. 1) encompasses a low-grade metasedimentary sequence (Berg Group; Skinner et al., 1996) bordered to the west by high grade metamorphic rocks – dominantly psammitic metasediments -of the Wilson Metamorphic Complex. During the Ross orogeny, both Berg Group and high-grade rocks were intruded by mostly undeformed magmas of mafic to granitic compositions (Olesch et al., 1996; Schäfer & Olesch, 1997; Schüssler et al., 1993; Lisker & Olesch, this volume). In late-Ross orogenic time (Flöttmann & Kleinschmidt, 1991) the high-grade rocks were detached and thrust to the west onto the low-grade Berg Group (western branch of the Exiles Thrust System, Flöttmann & Kleinschmidt, 1991, 1993). ...