scholarly journals Hafnium isotope variations in Bure volcanic rocks from the northwestern Ethiopian volcanic province: a new insight for mantle source diversity

2010 ◽  
Vol 105 (3) ◽  
pp. 101-111 ◽  
Author(s):  
Daniel MESHESHA ◽  
Ryuichi SHINJO
Keyword(s):  
Mantle Source ◽  
Volcanic Rocks ◽  
Volcanic Province

A new volcanic province: evidence from glacial erratics in western North Greenland

2000 ◽  
pp. 35-41 ◽  
Author(s):  
Peter R. Dawes ◽  
Bjørn Thomassen ◽  
T.I. Hauge Andersson
Keyword(s):  
Volcanic Rocks ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Common Component ◽  
Volcanic Province ◽  
North West ◽  
North East ◽  
The North ◽  
Surficial Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Thomassen, B., & Andersson, T. H. (2000). A new volcanic province: evidence from glacial erratics in western North Greenland. Geology of Greenland Survey Bulletin, 186, 35-41. https://doi.org/10.34194/ggub.v186.5213 _______________ Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

Petrology of the late Triassic mafic volcanic rocks from the Antalya Complex, southern Turkey: evidence for mantle source characteristics during the Neotethyan rifting

2020 ◽  
Vol 29 (7) ◽  
pp. 1049-1072
Author(s):  
Utku BAĞCI ◽  
Tamer RIZAOĞLU ◽  
Güzide ÖNAL ◽  
Osman PARLAK
Keyword(s):  
Mantle Source ◽  
Volcanic Rocks ◽  
Late Triassic ◽  
Trace Element Geochemistry ◽  
Secondary Phases ◽  
Element Geochemistry ◽  
Source Characteristics ◽  
Enriched Mantle ◽  
Southern Turkey ◽  
Island Basalt

The Antalya Complex in southern Turkey comprises a number of autochthonous and allochthonous units that originated from the Southern Neotethys. Late Triassic volcanic rocks are widespread in the Antalya Complex and are important for the onset of the rifting stage of the southern Neotethys. The studied Late Triassic volcanic rocks within the Antalya Complex are exposed in the southern part of Saklıkent (Antalya) region. They are represented by pillow, massive, and columnar-jointed lava flows with volcaniclastic breccias and pelagic limestone intercalations. Spilitic basalts exhibit intersertal, microlithic porphyritic, and ophitic textures and are represented by plagioclase, pyroxene, and olivine. Secondary phases are characterized by serpentine, calcite, chlorite, epidote, zeolite, and quartz. Based on Zr/Ti vs. Nb/Y ratios, the volcanic rocks are represented by alkaline basalts (Nb/Y = 1.54–2.82). A chondrite normalized REE diagram for the volcanic rocks displays significant LREE enrichment with respect to HREE ([La/Yb]N = 15.14–19.77). Trace element geochemistry of the studied rocks suggests that these rocks are more akin to ocean island basalt (OIB) and were formed by small degrees (~2–4%) of partial melting of an enriched mantle source (spinel + garnet-bearing lherzolite). The volcanic rocks of the Saklıkent region exhibit similarities to the Late Triassic volcanics of the Koçali Complex in SE Anatolia and the Mamonia Complex (Cyprus) in terms of their geochemical features. All evidence suggests that the Late Triassic alkaline volcanics in Antalya, Mamonia (Cyprus), and the Koçali (Adıyaman) Complexes were formed in an extensional environment at the continent-ocean transition zone during the rifting of the southern Neotethyan Ocean.

Geochemistry of Siluro-Devonian Tobique volcanic belt in northern and central New Brunswick (Canada): tectonic implications

1989 ◽  
Vol 26 (6) ◽  
pp. 1282-1296 ◽  
Author(s):  
J. Dostal ◽  
R. A. Wilson ◽  
J. D. Keppie
Keyword(s):  
New Brunswick ◽  
Mantle Source ◽  
Upper Mantle ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Continental Rift ◽  
Basaltic Rocks ◽  
Incompatible Elements ◽  
Tectonic Implications

Siluro-Devonian volcanic rocks of the northwestern mainland Appalachians are found mainly in the Tobique belt of New Brunswick where they consist predominantly of bimodal mafic–felsic suites erupted in a continental-rift environment. The axis of the Tobique rift trends north-northeast – south-southwest, obliquely to the regional northeast–southwest trend of the Appalachians. These geometric relationships are interpreted as being the result of rifting in a sinistral shear regime produced during emplacement of the Avalon terrene. The basaltic rocks are continental tholeiites and transitional basalts derived from a heterogeneous upper-mantle source that was enriched in incompatible elements relative to the primordial mantle. The mantle source was probably affected by the subduction processes.

Geochemistry and origin of volcanic rocks from Tuzo Wilson and Bowie seamounts, northeast Pacific Ocean

1985 ◽  
Vol 22 (11) ◽  
pp. 1609-1617 ◽  
Author(s):  
Brian L. Cousens ◽  
R. L. Chase ◽  
J.-G. Schilling
Keyword(s):  
Mantle Plume ◽  
Mantle Source ◽  
Early Stage ◽  
Source Region ◽  
Volcanic Rocks ◽  
Major And Trace Elements ◽  
Spreading Ridge ◽  
Alkali Basalts ◽  
Stage Of Development ◽  
Juan De Fuca

The origin of the Tuzo Wilson Seamounts, 50 km south of the Queen Charlotte Islands, has been ascribed by various workers to either the Pratt–Welker mantle plume, which has formed the Pratt–Welker seamount chain, or the formation of a new segment of the Explorer–Juan de Fuca spreading ridge system. Abundances of major and trace elements in dredged alkali basalts from Tuzo Wilson and Bowie seamounts (360 km northwest of Tuzo Wilson Seamounts) are typical of alkaline volcanism on ocean islands associated with mantle plumes, but 87Sr/86Sr ratios (0.70252–0.70258) fall within the range of mid-ocean ridge basalts (MORB) from the Explorer and Juan de Fuca ridges. Geochronological and chemical data from the Pratt–Welker, Bowie, and Tuzo Wilson seamounts suggest that the Tuzo Wilson Seamounts are in an early stage of development as a result of activity of the Pratt–Welker mantle plume but that contributions from both a depleted and an undepleted mantle source are necessary to reconcile trace-element and Sr isotope values. Modelling of rare-earth behaviour during partial melting indicates that neither the Tuzo Wilson nor Bowie basalts could be generated from a mantle source similar to that of the Explorer or Juan de Fuca MORB, unless recent metasomatism has enriched the seamounts' source region in incompatible elements.

scholarly journals Evidence for a Carbonatite-Influenced Source Assemblage for Intraplate Basalts from the Buckland Volcanic Province, Queensland, Australia

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 546 ◽  
Author(s):  
Joshua J. Shea ◽  
Stephen F. Foley
Keyword(s):  
Trace Element ◽  
Mantle Source ◽  
Alkali Basalt ◽  
Element Concentration ◽  
Continental Lithosphere ◽  
Alkali Basalts ◽  
Volcanic Province ◽  
Eastern Australia ◽  
Low K ◽  
Similar Enrichment

Eastern Australia contains a widespread suite of primitive (MgO ≥ 7.5 wt.%) intraplate basaltic provinces, including those sited along the longest continental hotspot track on Earth (≈2000 km), the Cosgrove track. The Buckland volcanic province is the most southerly basaltic province on the Cosgrove track before a >1600 km stretch that contains only sparse leucitite volcanism. Buckland is also situated just northeast of the edge of thick cratonic lithosphere where it transitions to a thinner continental lithosphere (<110 km) to the east, which may influence the production of plume-derived melts. Here, analysis of minor and trace elements in olivines in alkali basalts and basanites from the Buckland Province are combined with whole-rock compositions to elucidate the mantle source assemblages, and to calibrate minor and trace element indicators in olivine for application to source mineralogy. Olivine xenocrysts show element concentration ranges typical for peridotites; Mn and Al concentrations indicate that the ambient mantle is spinel, rather than garnet, peridotite. High modal pyroxene content is indicated by high Ni, Zn/Fe, and Fe/Mn in olivines, while high Ti/Sc is consistent with amphibole in the source. Residual phlogopite in the source of the basanites is indicated by low K/Nb in whole rocks, while apatite contains high P2O5 and low Rb/Sr (≥0.015) and Sr/La (≥13). The basanite source assemblage probably contains apatite, phlogopite, olivine, clinopyroxene and orthopyroxene, whereas the alkali basalt source assemblage is probably amphibole, olivine, orthopyroxene and clinopyroxene ± phlogopite ± apatite. Both source assemblages correspond broadly to olivine websterite, with the basanite source lying deeper than that for alkali basalt, explaining the occurrence of phlogopite in the source. This mineralogy, along with whole-rock Ti/Eu, Zr/Hf and P2O5/TiO2 values approaching those of natural carbonatites, provide evidence showing that the Buckland source consists of a peridotite that has interacted with a carbonate-rich melt whose origin may be in the deep lithosphere or asthenosphere beneath the craton. Similar enrichment processes are probably common throughout eastern Australia, controlling trace element characteristics in basaltic provinces. The topography of the underside of the lithosphere may play a significant role in determining mantle source assemblages by diverting and concentrating melt flow, and thus influence the location of basaltic provinces.

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