Fleur De Lys Research Articles

U–Pb ages of some crystalline rocks from the Burlington Peninsula, Newfoundland, and implications for the age of Fleur de Lys metamorphism: Discussion

In a recent paper, Mattinson (1977) reports some U-Pb zircon data from the Burlington Peninsula, Newfoundland, and proposes a synthesis of the isotopic data from this area. His synthesis, albeit tentative, is as follows (the geological units are shown in Fig. 1): (1) ophiolite formation -500-510 Ma ago (basal part of the Snooks Arm Group), followed by deposition of sediments in Arenig time; (2) emplacement of the Cape St. John Group and the Cape Brule porphyry -475 Ma; (3) intrusion of the Burlington granodiorite, Dunamagon granite, and Seal Island Bight syenite -440 Ma ago; and (4) resetting of some mineral ages in the Burlington granodiorite by an event -340 Ma ago. Since the Burlington granodiorite, Seal Island Bight s yenite, and Dunamagon granite are all either preor syn-kinematic intrusions, Mattinson also suggests that both deformation and metamorphism in the Burlington Peninsula had begun by -440 Ma, but not prior to 475 Ma. Mattinson's (1977) data represent a welcome , contribution to the understanding of the evolution I of the region, but we do wish to dispute some of his I findings. To begin with, we take strong exception to what we consider to be a misrepresentation by Mattinson of our Rb-Sr data, which we documented in a preliminary report to the Newfoundland Department of Mines and Energy (Bell and Blenkinsop 1975). Not only does the omission of our inferences give a distorted and unrealistic picture of our findings, but it denies us any credit for earlier drawing conclusions similar to Mattinson's regarding the Cape St. John volcanics. To set the record straight, we quote from our report (the quotation refers only to the Cape St. John volcanics):

Rb–Sr ages of silicic igneous rocks and deformation, Burlington Peninsula, Newfoundland

The Burlington Peninsula, east of the Baie Verte Lineament, is underlain by the Eastern Division of the Fleur de Lys Supergroup, a sequence of metasediments and metavolcanic rocks that is intruded by plutonic masses of granitic to granodioritic composition. This sequence has been designated as Cambrian or older and the deformation and metamorphism in the area interpreted as pre-Ordovician. Recently, however, it has been shown that at least part of the succession is post Lower Ordovician and a mid or late Palaeozoic age has been proposed for the major deformation affecting the area.Rb–Sr ages obtained in the present study area are: (a) whole-rock isochrons—Dunamagon Granite, 413 ± 10 Ma; Cape Brulé Porphyry, 393 ± 25 Ma; Cape St. John Group Ignimbrites, 343 ± 15 Ma and 429 ± 50 Ma; Mic Mac Group Ignimbrite, 375 ± 15 Ma; (b) Biotite ages—Dunamagon Granite, 334, 356 and 358 Ma; (c) Mineral isochron—Burlington Granodiorite, 422 ± 40 Ma. Because of extensive trace element migration in at least some of these units, the interpretation of the ages is complex and does not allow a unique history of the area to be determined. However, the ages do support the proposed mid or late Palaeozoic age for the major deformation and indicate that pre-Ordovician orogeny did not prevail on the scale previously envisaged.

U–Pb ages of some crystalline rocks from the Burlington Peninsula, Newfoundland, and implications for the age of Fleur de Lys metamorphism

U–Pb measurements on minerals from the Burlington Peninsula indicate that volcanic rocks of the Grand Cove Group and the probably cogenetic Cape Brule porphyry have primary crystallization ages of 475 ± 10 Ma (Early Ordovician). Later intrusive rocks, including the Dunamagon granite, the Burlington granodiorite and the Seal Island Bight syenite were intruded between 445 and 435 Ma ago. The Grand Cove Group and the Cape Brule porphyry completely predate deformation and metamorphism of the eastern division of the Fleur de Lys Supergroup; the Seal Island Bight syenite, Burlington granodiorite, and Dunamagon granite were evidently emplaced during the early stages of this orogeny. The new age results therefore suggest that the orogeny is Taconic in the classic sense. Some of the isotope systems show evidence of a strong thermal event about 340 Ma ago (Early Carboniferous, Acadian). This event may have caused resetting of some of the Rb–Sr isochron ages recently reported for this area.

The ophiolites of southern Quebec: oceanic crust of Betts Cove type

The Thetford and Asbestos ophiolites of the Eastern Townships of Quebec (Internal Domain) resemble the Betts Cove ophiolite of Newfoundland in three significant respects: (1) ultramafic cumulate sequences of the ophiolites include units with cumulus orthopyroxene; (2) the 'gabbro' unit is composed of a relatively thin yet compositionally and structurally complex clinopyroxenite–gabbro member which unconformably overlies the ultramafic cumulate sequence; and (3) basaltic rocks associated with the ophiolites have extremely low Ti contents. In contrast, in the Bay of Islands region of western Newfoundland (External Domain) basaltic rocks of the ophiolites of the Humber Arm Allochthon have Ti contents typical of normal oceanic crust; the cumulate sequences rarely contain cumulus orthopyroxene; and the 'gabbro' unit includes a major sequence of cumulus plagioclase-bearing rocks which appear to conformably follow the ultramafic cumulates. The Baie Verte ophiolite of Newfoundland is intermediate in character and location between the Betts Cove and Bay of Islands complexes. All of the ophiolites of the Internal Domain are overlain by sequences having conglomerate, olistostrome, and greywacke units containing abundant clastic material derived from ophiolitic rocks.The homologous nature of the Betts Cove and Thetford ophiolites lends some support to the view that the Fleur de Lys and Caldwell - Chain Lakes orthotectonic zones of the Appalachian system are laterally correlative, and that all ophiolites of the Internal Zone of the Appalachians are allochthonous rather than collapsed in situ small ocean basins. The variation exhibited by the ophiolites of the Appalachian system, even within the Internal Zone, cautions however against a too simplistic view of the role of ophiolites in plate tectonic models of orogenic belts of Appalachian type.

Ophiolitic mélange and its significance in the Fleur de Lys Supergroup, northern Appalachians

Ophiolitic mélange consists of a chaotic mixture of sedimentary rocks and igneous rocks derived from the ophiolite suite of rock units. Its formation involves surficial mass wastage, gravity sliding, and tectonism at consuming plate boundaries. Most worldwide examples relate to ophiolite obduction and the destruction of stable continental margins.The Fleur de Lys Supergroup of the northern Appalachians consists of polydeformed and metamorphosed, mainly clastic sedimentary rocks that accumulated at the Hadrynian to early Paleozoic stable continental margin of eastern North America. Greenschists at or near the top of the succession in the east (Birchy Complex) contain zones of typical ophiolitic mélange. These contain large blocks of serpentinized ultramafic rocks, actinolite–fuchsite alterations of smaller ultramafic blocks, altered gabbro, a variety of clastic sedimentary blocks, and marble. All of the rocks are multideformed and metamorphosed so that the mélange was subjected to the full range of Fleur de Lys deformations.The presence of polydeformed and metamorphosed ophiolitic mélange in the Fleur de Lys Supergroup implies an early disruption or imbrication of its rock units. This disruption and mélange formation are interpreted to be related to transport of ophiolite complexes such as the Bay of Islands Complex across an initially undisturbed continental rise prism, the Fleur de Lys Supergroup. Later polyphase deformation and metamorphism of the Fleur de Lys Supergroup are possible results of continued structural submergence and telescoping of the continental margin beneath a thick cover of transported ophiolite rock units.

Fractionation trends in the Bay of Islands ophiolite of Newfoundland: polycyclic cumulate sequences in ophiolites and their classification

The fractionation range of the cumulate sequence of the allochthonous Bay of Islands ophiolite of the Western Platform of Newfoundland, measured in terms of the FeO(tolal)/MgO ratios of the liquids from which they were derived, encompasses entirely the range of known values exhibited by the overlying dikes and pillow lavas. Cryptic variations within the cumulate sequences are irregular, often inverse, and the crystallization sequences found in the cumulates suggest that they were formed from at least three different basaltic magma types, one of which is unusual in having given rise to co-existing highly aluminous clinopyroxenes and spinels. These features suggest that crystallization of the Bay of Islands plutonic rocks took place in an 'open system' magma chamber that was tapped repeatedly during fractionation to form dike rocks and lavas. Most of the cumulate rocks of the Bay of Islands ophiolite formed according to the crystallization sequence ol–cpx–(opx) or the sequence ol–plag–cpx–(opx). In contrast, the cumulate rocks of the Betts Cove ophiolite, located within the Fleur de Lys orthotectonic zone of the Newfoundland Appalachians, crystallized according to the sequences ol–opx–cpx and ol–cpx–plag. This difference in the nature of the cumulate sequences within the Bay of Islands and Betts Cove ophiolites is also reflected in the Ti characteristics of the basaltic rocks of the ophiolites, and in the morphology of the gabbroic units. Comparison with Mesozoic ophiolites suggests, as a general rule, that within ophiolite cumulate successions there is a tendency for ol–opx sequences to be followed by ol–cpx sequences, and for ol–cpx sequences to be followed by ol–plag sequences. Such a relationship may be related to processes involving remelting of lower-temperature crystallization products in a system open to either continuous or periodic additions of high temperature basaltic liquid. In terms of oceanic structures the Bay of Islands ophiolite corresponds to sonobouy model 2 of Christensen and Salisbury: the basal high velocity layer corresponding to the olivine-gabbro cumulate rocks, and the lower velocity 'gabbroic' layer to the upper part of the olivine-free cumulate sequence and overlying massive uralitized roof gabbro and dike rocks.

$$^{40}Ar/^{39}Ar$$ Age Spectra of Minerals from the Fleur de Lys Terrane in Northwest Newfoundland: Their Bearing on Chronology of Metamorphism within the Appalachian Orthotectonic Zone

$$^{40}Ar/^{39}Ar$$ age spectra have been determined for hornblende, muscovite, and biotite from the Fleur de Lys metamorphic terrane. Age spectra of all samples are undisturbed, and indicate that total-gas ages date times of post-metamorphic cooling. Within the western division of the Fleur de Lys total-gas ages are variable (hornblende 420-386 m.y., muscovite 411-390 m.y., and biotite 386-368 m.y.), but for each mineral phase show a consistent geographic distribution (older ages recorded in the southwest). At each locality examined, hornblende and muscovite have similar total-gas ages which average ~20 m.y. older than biotite dates. Although distinctly younger dates are recorded in the eastern division of the Fleur de Lys (hornblende 364 m.y., biotite 346-342 m.y.), a similar age discordance is observed. The regional distribution of total-gas ages suggests diachronous southwest-northeast post-metamorphic cooling. This diachronisim may be a result of earlier and, in total, more extensive vertical displacement of the southwestern Fleur de Lys terrane. Relatively rapid post-metamorphic uplift is indicated by the limited discordancy of hornblende and biotite total-gas dates at each locality. When combined with regional stratigraphic relations, the data suggest that in the south and southwest, uppermost structural levels of the Fleur de Lys terrane may have been exhumed by ~460-470 m.y. However, the present erosional level diachronously cooled and was exhumed later. The data do not support previous suggestions of Acadian metamorphism within the Fleur de Lys terrane.

Timing and Development of the Orthotectonic Zone in the Appalachian Orogen of Northwest Newfoundland

Examination of part of the Fleur de Lys Supergroup, within the orthotectonic zone of north-west Newfoundland, reveals that regional deformation and metamorphism may not have commenced prior to the Early Ordovician and was not completed until the Devonian. The onset of deformation could have been as young as Llanvirnian.Fleur de Lys metasediments are correlated to the west with moderately deformed and undeformed rocks of the western platform. To the east, they are shown to be in part the lateral age equivalent of ophiolitic rocks. The ophiolites may be fragments of an older foundation to the mafic volcanic and volcanoclastic Baie Verte Group.Polyphase-deformed and regionally metamorphosed terrains (orthotectonic zones) such as the Fleur de Lys, do not form 'instantaneously', but evidently result from a critical sequential and progressive development history, covering a recognizable time span, and probably display characteristics of paratectonic zones at an intermediate stage. Sequential or simultaneous opening and closing of marginal basins is suggested as a mechanism, not only to explain the formation of such zones, but also the regional timing variation that apparently exists within the Appalachian-Caledonian orogen. Such processes are known to have occurred consistently since the Early Tertiary, and can presently be observed along the Western Pacific margin.

Post-Ophiolite Unconformity, Tilt Cove – Betts Cove Area, Newfoundland

Subaerial sediments and silicic and mafic lavas of the Cape St. John Group in northern Newfoundland, were originally interpreted as younger than the Betts Cove ophiolite suite and the Lower Ordovician (Arenig) Snooks Arm pillow lavas and oceanic sediments, but recently have been considered as part of the pre-Ordovician Fleur de Lys Supergroup and hence older than the Snooks Arm Group. The volcanic rocks that underlie the Cape St. John were reinterpreted as a pre-Snooks Arm oceanic foundation to the Fleur de Lys rocks.Our work reaffirms the original interpretation of the Cape St. John rocks as unconformably above the Lower Ordovician pillow lavas and ophiolites and we tentatively correlate them with the Springdale and Mic Mac Groups and other nearby Silurian (?) clastic/volcanic sequences of Old Red Sandstone equivalence. The Cape St. John Group grades northward and westward into polydeformed rocks, hence its re-establishment as a post-ophiolite assemblage bears on the history of deformation of adjacent groups.

The Fleur de Lys Supergroup: stratigraphic comparison of Moine and Dalradian equivalents in Newfoundland with the British Caledonides

Whereas the NW. Fleur de Lys Supergroup shows many general similarities with the Moine and Dalradian, the SE. Fleur de Lys is dominantly volcanic and has no extensive analogues in the British Caledonides. Equivalents of these rocks may be largely covered by younger sequences on the E. side of the Atlantic.

Sub-Cenozoic geology of the British continental margin (lat 50°N to 57°N) and the reassembly of the North Atlantic late Paleozoic supercontinent

Current reconstructions of the late Paleozoic North Atlantic supercontinent show differences in detail, notably at more northerly latitudes. It is clear that the establishment of such geological “tie lines” demands detailed knowledge of the geologic structure of the outer shelves. Data from marine geophysical surveys form speculative sub-Cenozoic geology for the continental margin west of the British Isles. The Great Glen fault is confirmed as a potential offshore structural tie line between the Caledonian and Appalachian orogens, although its relationship with the Cabot fault of Newfoundland remains equivocal. A convergent structural lineament crossing the Irish margin at about lat 53°N has no recognized counterpart in the surficial geology of the mainland, but with the Great Glen fault, it serves to delineate the offshore prolongation of the Irish Caledonides, some elements of which show close similarities to the Fleur de Lys Supergroup of Newfoundland. A more tenuous trans-Atlantic tie line involves correlation of an inferred east-trending fault on the Scottish margin at lat 56°N with the suggested prolongation of the Grenville front across Rockall Bank.

On the Origin and Deformation of the Fleur de Lys Metaconglomerate, Appalachian Fold Belt, Northwest Newfoundland

The results of a study of a deformed metaconglomerate from the Fleur de Lys Supergroup, which occupies the northwest metamorphic zone of the Appalachian–Caledonian orogen in northwest Newfoundland, are described.This Eocambrian conglomerate unconformably overlies a Precambrian basement complex and has previously been interpreted as a glacial deposit. Sedimentological evidence does not support such an interpretation, and the present study shows the conglomerate to be of probable fluviatile origin.The deformation of the deposit, reflected in the state of finite strain of the clasts, is clearly inhomogeneous on all scales. The clasts range from nondeformed to intensely deformed and their shapes vary from oblale to prolate ellipsoids. The finite strain is thought to be due to buckling and three-dimensional differential flattening at the basement-conglomerate interface.

Early Paleozoic ophiolite complexes of the Newfoundland Appalachians as mantle-oceanic crust sequences

The layered ultramafic-mafic complexes of the Northwest platform and the Fleur de Lys orthotectonic zones of the Newfoundland Appalachians are comparable to layered Tethyan ophiolite suites of the Piedmont Alps, the Dinarides, and the Oman. They can be interpreted as oceanic crust and mantle: the peridotites, with high-pressure mineral assemblages, kaersutite, and titaniferous phlogopite, represent the upper mantle; the overlying gabbros and ‘sheeted’ diabases represent layer 3 of the oceanic crust; and pillow lava, chert, and the greywacke unit represent layers 2 and 1. As oceanic lithosphere the ophiolites may represent an intrasialic small ocean basin rather than a major ocean basin such as the Atlantic or Pacific. The early Ordovician thrust emplacement of the ophiolite sheets followed tectonism and metamorphism of a thick sequence of late Proterozoic-Cambrian clastic sediments (Fleur de Lys supergroup) that was deposited as a marginal wedge during the early stages of the development of the Appalachian geosyncline within a composite ‘North American-European’ continental plate. Their emplacement may reflect an early phase in the closing of an Appalachian ocean basin by underthrusting of the North American plate along a southeasterly (present geographic coordinates) dipping Benioff zone. Final closing of the ocean basin during the late Ordovician was effected by subduction of oceanic crust, also along a southeasterly dipping Benioff zone, during the northwest drift of the European plate. Alternatively, the ophiolites may have been emplaced directly onto the Fleur de Lys rocks either (1) at the time of inception of an ocean-forming ridge within a geosyncline that was initiated on continental sialic basement, or (2) during an ocean-closing phase of drift while a ridge was positioned relatively close to the continental margin, or was newly developing within the margin. The Newfoundland ophiolites may represent the oldest known oceanic lithosphere within the North American continent.

Of the Knowledge of Ourselves and of God: a Fifteenth-Century Spiritual Florilegium. Edited by James WalshS.J. and Eric Colledge. (Fleur de Lys Series, 17). Pp. xxii+68, London: Mowbray, 1961. 7s. 6d.

Of the Knowledge of Ourselves and of God: a Fifteenth-Century Spiritual Florilegium. Edited by James WalshS.J. and Eric Colledge. (Fleur de Lys Series, 17). Pp. xxii+68, London: Mowbray, 1961. 7s. 6d. - Volume 13 Issue 2

THE BEHAVIOUR OF THE GIRAFFE, GIRAFFA CAMELOPARDALIS, IN THE EASTERN TRANSVAAL

SUMMARYThe giraffe in South Africa live entirely in the Eastern Transvaal, a lowveld region primarily of grass or veld with scattered bushes and low trees. The giraffe browse on a wide variety of trees in the spring and fall when few leaves are available, but in summer when all the trees are in foliage they are much more selective. The giraffe spend most of the day and part of the night feeding, especially the early morning and late afternoon. In the summer when food is abundant, the giraffe have more time during the day to chew their cud and lie down.The males spend part of the day fighting with each other. Such matches are seldom serious and often end in sexual play with one male mounting the other. The most common heterosexual activity was the testing of the females' urine by the male. There is no breeding season among giraffe, and the young are born all through the year.Giraffe are usually found in groups or herds, but they do not appear to communicate with each other, although they are capable of making sounds. The herds are loose associations of animals, generally with no definite leadership, and often include both adult males and females. Herds travelled very slowly, and often remained on the farm where they were studied for at least one year.The giraffe on Fleur de Lys farm have become used to farm conditions; they jump fences instead of breaking through them, and drink water from the cattle troughs, often walking among the cattle to do so.

On The Nature And Dignity of Love. By William of St Thierry. On Jesus at Twelve Years Old. By st Aelred of Rievaulx. The School of Self-Knowledge. Translated from Latin by Geoffrey Webb and Adrian Walker. (Mowbray's, Fleur de Lys series; 3s. 6d. each).

On The Nature And Dignity of Love. By William of St Thierry. On Jesus at Twelve Years Old. By st Aelred of Rievaulx. The School of Self-Knowledge. Translated from Latin by Geoffrey Webb and Adrian Walker. (Mowbray's, Fleur de Lys series; 3s. 6d. each).

Fleur de Lys and Calumet: being the Penicaut Narrative of French Adventure in Louisiana

Fleur de Lys and Calumet: being the Penicaut Narrative of French Adventure in Louisiana

Fleur De Lys and Calumet Being the Penicaut Narrative of French Adventure in Louisiana.

Fleur De Lys and Calumet Being the Penicaut Narrative of French Adventure in Louisiana.

Fleur de Lys and Calumet; Being the Penicaut Narrative of French Adventure in Louisiana

Fleur de Lys and Calumet; Being the Penicaut Narrative of French Adventure in Louisiana