Provenance, deposition and age of gneiss units from the KTB drill hole (Germany): evidence from SHRIMP and conventional U–Pb zircon age determinations

1997 ◽  
Vol 86 (S1) ◽  
pp. S235-S250 ◽  
Author(s):  
F. Söllner ◽  
D. R. Nelson ◽  
H. Miller
Keyword(s):  
Drill Hole ◽  
Zircon Age ◽  
Age Determinations

Episodic tectono-thermal activity in the southern part of the East Greenland Caledonides

2000 ◽  
pp. 42-49 ◽  
Author(s):  
A. Graham Leslie ◽  
Allen P. Nutman
Keyword(s):  
Thermal Activity ◽  
Isotopic Data ◽  
Zircon Age ◽  
East Greenland ◽  
Original Series ◽  
Age Determinations

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Leslie, A. G., & Nutman, A. P. (2000). Episodic tectono-thermal activity in the southern part of the East Greenland Caledonides. Geology of Greenland Survey Bulletin, 186, 42-49. https://doi.org/10.34194/ggub.v186.5214 _______________ Isotopic data from the Renland augen granites of the Scoresby Sund region (Figs 1, 2) provided some of the first convincing support for relicts of potentially Grenvillian tectono-thermal activity within the East Greenland Caledonides. In Renland, Chadwick (1975) showed the presence of major bodies of augen granite (Fig. 2) interpreted by Steiger et al. (1979), on the basis of Rb–Sr whole rock and U–Pb zircon age determinations, to have been emplaced about 1000 Ma ago.

scholarly journals Cross-continental age calibration of the Jurassic/Cretaceous boundary

2018 ◽  
Author(s):  
Luis Lena ◽  
Rafael López-Martínez ◽  
Marina Lescano ◽  
Beatriz Aguirre-Urrreta ◽  
Andrea Concheyro ◽  
...  
Keyword(s):  
High Precision ◽  
Sedimentary Basins ◽  
Minimum Duration ◽  
Zircon Age ◽  
The Past ◽  
Age Determinations ◽  
Tithonian Stage

Abstract. The age of the Jurassic/Cretaceous boundary has remained elusive for the past decades. In this study we evaluate how well the determined boundary age agrees between two distinct sections from different sedimentary basins, and whether we can constrain a globally valid Jurassic/Cretaceous boundary age. Here we present high-precision U-Pb zircon age determinations on single grains of volcanic zircon of two sections that span the Jurassic/Cretaceous: the Las Loicas section, Argentina, and the Mazatepec section in Mexico. These two sections display well-established primary and secondary stratigraphic markers as well as interbedded volcanic horizons that allow bracketing the age of the Jurassic/Cretaceous boundary at 140.22 ± 0.13 Ma. We also present the first age determinations in the early Tithonian and tentatively propose a minimum duration of ~ 7 Ma for the Tithonian stage.

Rb–Sr contribution to the location of Churchill–Superior boundary in Manitoba

1970 ◽  
Vol 7 (3) ◽  
pp. 1017-1020
Author(s):  
A. Turek ◽  
Z. E. Peterman
Keyword(s):  
Drill Hole ◽  
Hudson Bay ◽  
The South ◽  
Lake Winnipeg ◽  
Hudson Bay Lowlands ◽  
Area North ◽  
Age Determinations

Eight whole-rock Rb–Sr age determinations on basement cores from the Hudson Bay Lowlands define an isochron of 1975 ± 45 m.y. (λRb = 1.39 × 10−11y−1) with an initial 87Sr/88Sr 0.7018 ± 0.0005. The indicated age is characteristic of the Churchill Province and on this basis Would suggest that the boundary between the Churchill and Superior provinces is to the south of the drill hole location. A similar age, 1925 ± 105 m.y. with an initial 87Sr/86Sr 0.7025 ± 0.0007, has been obtained on six whole-rock basement samples from the Minago River – Har-grave River area north of Lake Winnipeg.

Precambrian Zircon Age of Orthogneiss in the Shuswap Metamorphic Complex, British Columbia

1975 ◽  
Vol 12 (2) ◽  
pp. 326-332 ◽  
Author(s):  
R. K. Wanless ◽  
J. E. Reesor
Keyword(s):  
British Columbia ◽  
Metamorphic Complex ◽  
Gneiss Dome ◽  
Zircon Age ◽  
Core Zone ◽  
The Core ◽  
Basement Rocks ◽  
Proterozoic Basement ◽  
Shuswap Metamorphic Complex ◽  
Age Determinations

Pb-U age determinations carried out on zircon from granodiorite gneiss of the core zone of Thor-Odin gneiss dome have provided isotopic evidence for involvement of Proterozoic basement rocks in the Mesozoic structures of the Shuswap Metamorphic Complex. The study has revealed that the zircons originally crystallized [Formula: see text] ago and suffered an episodic loss of lead [Formula: see text] ago.

scholarly journals Zircon ages delimit the provenance of a sand extrudite from the Botucatu Formation in the Paraná volcanic province, Iraí, Brazil

2015 ◽  
Vol 87 (3) ◽  
pp. 1611-1622 ◽  
Author(s):  
VITER M. PINTO ◽  
LÉO A. HARTMANN ◽  
JOÃO O.S. SANTOS ◽  
NEAL J. MCNAUGHTON
Keyword(s):  
Detrital Zircon ◽  
Lower Triassic ◽  
Flood Basalt ◽  
Early Cambrian ◽  
Ion Microprobe ◽  
Zircon Age ◽  
Volcanic Province ◽  
Igneous Activity ◽  
Botucatu Formation ◽  
Age Determinations

Ion microprobe age determinations of 102 detrital zircon crystals from a sand extrudite, Cretaceous Paraná volcanic province, set limits on the origin of the numerous sand layers present in this major flood basalt province. The zircon U-Pb ages reflect four main orogenic cycles: Mesoproterozoic (1155-962 Ma), latest Proterozoic-early Cambrian (808-500 Ma) and two Palaeozoic (Ordovician- 480 to 450 Ma, and Permian to Lower Triassic- 296 to 250 Ma). Two additional small concentrations are present in the Neoarchean (2.8 to 2.6 Ga) and Paleoproterozoic (2.0 to 1.7 Ga). Zircon age peaks closely match the several pulses of igneous activity in the Precambrian Brazilian Shield and active orogeny in Argentina. A main delimitation of the origin of the sand is the absence of zircon ages from the underlying Cretaceous basalts, thus supporting an injectite origin of the sand as an extrudite that emanated from the paleoerg that constitutes the Botucatu Formation.

U–Pb age determinations on Proterozoic to Devonian rocks from northern Ellesmere Island, Arctic Canada

1987 ◽  
Vol 24 (2) ◽  
pp. 246-256 ◽  
Author(s):  
H. P. Trettin ◽  
R. Parrish ◽  
W. D. Loveridge
Keyword(s):  
Deep Water ◽  
Lower Cambrian ◽  
Crystalline Basement ◽  
Significant Component ◽  
Zircon Age ◽  
Water Basin ◽  
Middle Ordovician ◽  
Late Cambrian ◽  
Deep Water Basin ◽  
Age Determinations

This paper presents age determinations on six units of the Franklinian deep-water basin and the Pearya Terrane of northern Ellmere Island and discusses their tectonic implications.Four different fractions of detrital zircon from the Lower Cambrian Grant Land Formation of the deep-water basin all have average 207Pb/206Pb ages of 2.2–2.4 Ga, suggesting that the sediments were derived mainly from Aphebian–Archean parts of the Canadian Shield rather than from the Neohelikian crystalline basement of Pearya, as assumed earlier. The first evidence for Ordovician arc-type volcanism in the northern part of the deep-water basin is provided by a Llandeilo(?) zircon age of [Formula: see text] but the fault-bounded volcanic unit could be exotic.Four major stratigraphic successions are recognized in Pearya. Present zircon studies confirm that succession I has been affected by a 1.0–1.1 Ga orogeny, as inferred earlier by Sinha and Frisch from a Rb–Sr isochron. A zircon age of [Formula: see text] on a rhyolite demonstrates that succession II extended into the Late Cambrian or Early Ordovician.Granitic intrusions in the Pearya Terrane, at Cape Richards and Cape Woods, are, respectively, Middle Ordovician (463 ± 5 Ma) and Devonian (382 ± 18 Ma or, more likely, 390 ± 10 Ma) in age on the basis of combined zircon and sphene determinations. They are post-tectonic with regard to major deformations in the Middle Ordovician and Late Silurian. Both have a significant component of xenocrystic zircon, which appears to have been derived from succession I of Pearya on the basis of upper intercept ages.

Extent of the Ross Orogen in Antarctica: new data from DSDP 270 and Iselin Bank

2011 ◽  
Vol 23 (3) ◽  
pp. 297-306 ◽  
Author(s):  
N. Mortimer ◽  
J.M. Palin ◽  
W.J. Dunlap ◽  
F. Hauff
Keyword(s):  
Ross Sea ◽  
Drill Hole ◽  
Isotopic Ratios ◽  
Zircon Age ◽  
Late Precambrian ◽  
Victoria Land ◽  
High Grade Metamorphism ◽  
Early Palaeozoic ◽  
Igneous Protoliths ◽  
Drilling Project

AbstractThe Ross Sea is bordered by the Late Precambrian–Cambrian Ross–Delamerian Orogen of East Antarctica and the more Pacific-ward Ordovician–Silurian Lachlan–Tuhua–Robertson Bay–Swanson Orogen. A calcsilicate gneiss from Deep Sea Drilling Project 270 drill hole in the central Ross Sea, Antarctica, gives a U-Pb titanite age of 437 ± 6 Ma (2σ). This age of high-grade metamorphism is too young for typical Ross Orogen. Based on this age, and on lithology, we propose a provisional correlation with the Early Palaeozoic Lachlan–Tuhua–Robertson Bay–Swanson Orogen, and possibly the Bowers Terrane of northern Victoria Land. A metamorphosed porphyritic rhyolite dredged from the Iselin Bank, northern Ross Sea, gives a U-Pb zircon age of 545 ± 32 Ma (2σ). The U-Pb age, petrochemistry, Ar-Ar K-feldspar dating, and Sr and Nd isotopic ratios indicate a correlation with Late Proterozoic–Cambrian igneous protoliths of the Ross Orogen. If the Iselin Bank rhyolite is not ice-rafted debris, then it represents a further intriguing occurrence of Ross basement found outside the main Ross–Delamerian Orogen.

The age and geological history of the Wollaston, Peter Lake, and Rottenstone domains in northern Saskatchewan

1980 ◽  
Vol 17 (3) ◽  
pp. 333-347 ◽  
Author(s):  
G. E. Ray ◽  
R. K. Wanless
Keyword(s):  
Ocean Basin ◽  
Continental Margins ◽  
Zircon Age ◽  
Plate Movement ◽  
Tectonic Model ◽  
Northern Saskatchewan ◽  
History Of ◽  
Successive Generations ◽  
The Relationship ◽  
Age Determinations

Three U–Pb zircon and four K–Ar mineral age determinations from national topographic system (NTS) area Geikie River (SE) in northern Saskatchewan are presented and the geology of the region is described. The area lies within the Churchill Province of the Canadian Precambrian Shield and includes parts of the Wollaston, Peter Lake, and Rottenstone domains; the relationship between the geological histories of these domains and the age determinations is discussed. Zircon age measurements suggest a period of late Archean magmatism ca. 2500 Ma was responsible for both the Wollaston domain granitic basement and a suite of basic plutons in the adjoining Peter Lake domain.The overall lithological differences of the presumed lower Proterozoic supracrustal rocks in the region are examined in the context of a plate tectonic model. This invokes late Archean continental rifting accompanied by limited volcanism close to the present Needle Falls Shear Zone, followed by continental separation and the generation of an Aphebian ocean basin. Deposition of shelf and deeper water sediments along the trailing edge of the Wollaston domain continental margin was followed by reversal of plate movement, oceanic subduction, and the formation of an island-arc complex. This marked the start of the Hudsonian Orogeny and was accompanied by the development of successive generations of granitic material, including the Wathaman batholith. The regional emplacement of this batholith ca. 1865 Ma ago is compared to other volcano-plutonic belts described elsewhere along Cordilleran-type continental margins.

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