Trace-element mobility during low-grade metamorphism and silicification of basaltic rocks from Saint John, New Brunswick

1983 ◽  
Vol 20 (3) ◽  
pp. 431-435 ◽  
Author(s):  
J. Dostal ◽  
D. F. Strong
Keyword(s):  
New Brunswick ◽  
Rare Earths ◽  
Low Grade ◽  
Element Mobility ◽  
Upper Carboniferous ◽  
Basaltic Rocks ◽  
Trace Element Mobility ◽  
Saint John ◽  
Ree Patterns ◽  
Basaltic Lavas

Upper Carboniferous basaltic lavas from Saint John, New Brunswick were metamorphosed under prehnite–pumpellyite conditions and some were also affected by extensive silicification. Silicification led to simple dilution of relatively immobile elements such as rare earths, Y, Zr, Hf, Th, and Sc. The chondrite-normalized REE patterns of the silicified rocks are parallel to those of basalts.

Mineralogic reaction zones at a calc-silicate/metapelite interface: an example of trace element mobility in a metamorphic environment

1994 ◽  
Vol 58 (391) ◽  
pp. 205-214 ◽  
Author(s):  
J. V. Owen ◽  
J. Dostal ◽  
B. N. Church
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Rare Earths ◽  
Fluid Phase ◽  
Aqueous Fluid ◽  
Silicate Rock ◽  
Element Mobility ◽  
Trace Element Mobility ◽  
Reaction Zones ◽  
Incompatible Trace Elements

AbstractMetasomatic interaction on a cm scale between calc-silicate pods and the enclosing sillimanite + biotite + tourmaline gneiss at Partridge Breast Lake, northern Manitoba, Canada, led to the development of an inner (by calc-silicate rock), hornblende-rich reaction zone and an outer, biotite-rich zone. The boundary between the reaction zones is interpreted as the original calc-silicate/metapelite interface. Compared with its metapelitic protolith, the biotite zone shows a two- to twenty-fold depletion in the concentrations of incompatible trace elements (notably the light rare earths, U, Th, Nb, Ta, Zr and Hf). In contrast, the relative concentrations of trace elements remained nearly constant during the mineralogical transformation of the calc-silicate rock to the hornblende zone. The depletion of trace elements in the biotite zone is attributed to the dissolution of accessory phases (e.g. monazite). Although stable at the metamorphic conditions (∼600–650°C at ∼ 4.5 kbar) prevalent during metasomatism, Mg-rich tourmaline is absent in the biotite zone, suggesting that either the pH or composition (e.g. the (Al + Si)/(Ca + Mg + Fe) ratio) of the aqueous fluid phase was inappropriate for the preservation of this mineral.

scholarly journals Reassessment of vertebrate ichnotaxa from the Upper Carboniferous ‘Fern Ledges’, Lancaster Formation, Saint John, New Brunswick, Canada

2016 ◽  
Vol 52 ◽  
pp. 021 ◽  
Author(s):  
Matthew R. Stimson ◽  
Randall F. Miller ◽  
Spencer G. Lucas
Keyword(s):  
New Brunswick ◽  
New Combination ◽  
Upper Carboniferous ◽  
Invertebrate Paleontology ◽  
Saint John ◽  
Nomina Dubia

Vertebrate ichnotaxa described by George Frederic Matthew in 1910 from the Upper Carboniferous (Lower Pennsylvanian) ‘Fern Ledges’ of Saint John, New Brunswick, were dismissed as dubious trackways by previous authors. Thus, three new ichnospecies Matthew described appeared in the 1975 Treatise on Invertebrate Paleontology as “unrecognized or unrecognizable” and were mostly forgotten by vertebrate ichnologists. These traces include Hylopus (?) variabilis, Nanopus (?) vetustus and Bipezia bilobata. One ichnospecies, Hylopus (?) variabilis, here is retained as a valid tetrapod footprint ichnotaxon and reassigned to the ichnogenus Limnopus as a new combination, together with other poorly preserved specimens Matthew labeled, but never described. Nanopus (?) vetustus and Bipezia bilobata named by Matthew in the same paper, have been reexamined and remain as nomina dubia. 

Age of the Brookville Gneiss and associated rocks, southeastern New Brunswick

1982 ◽  
Vol 19 (11) ◽  
pp. 2158-2166 ◽  
Author(s):  
William J. Olszewski Jr. ◽  
Henri E. Gaudette
Keyword(s):  
New Brunswick ◽  
Source Area ◽  
Head Group ◽  
Low Grade ◽  
Tectonic Event ◽  
Cape Breton Island ◽  
Eastern Margin ◽  
Saint John ◽  
Loss Event ◽  
Single Zircon

The Brookville Gneiss is a medium- to high-grade quartz–feldspar–biotite and hornblende–quartz–feldspar–biotite gneiss found north and northeast of Saint John, New Brunswick. The Green Head Group, a sequence of low-grade metasediments, surrounds the Brookville Gneiss. Analyses of zircons with euhedral to subhedral overgrowths and rounded to subrounded cores from the Brookville Gneiss yield an upper intercept age on concordia of 1641 Ma, considered to be the age of the source area for the zircons. The zircon analyses also indicate two Pb-loss events at approximately 780 and 370 Ma. These ages are confirmed by zircon analyses of a quartz diorite gneiss from Green Head Island, which yields ages of 827 and 333 Ma. A small euhedral single zircon from the Brookville Gneiss, believed to be formed during metamorphism, gives a concordant age of 814 Ma corresponding to the first Pb-loss event. Rb–Sr whole-rock analyses of a granite from the east side of Musquash Harbour southwest of Saint John give an age of 392 Ma and an initial Sr ratio of 0.7187 substantiating the second Pb-loss event.The results indicate that the Brookville Gneiss and Green Head Group are older than 800 Ma and probably younger than 1200 Ma. The zircon source area age (1641 Ma) and first Pb-loss event (800 Ma) are similar to ages found in rocks of the eastern margin of the Appalachian orogen from Massachusetts and Cape Breton Island, respectively. They suggest a setting and tectonic event correlated in time for the Late Precambrian of the eastern margin distinct from the younger so-called "Avalonian."

Boninites as windows into trace element mobility in subduction zones

2010 ◽  
Vol 74 (2) ◽  
pp. 684-704 ◽  
Author(s):  
Stephan König ◽  
Carsten Münker ◽  
Stephan Schuth ◽  
Ambre Luguet ◽  
J. Elis Hoffmann ◽  
...  
Keyword(s):  
Trace Element ◽  
Subduction Zones ◽  
Element Mobility ◽  
Trace Element Mobility

Timing and Extent of Drift of Shortnose Sturgeon Larvae in the Saint John River, New Brunswick, Canada

2013 ◽  
Vol 142 (3) ◽  
pp. 717-730 ◽  
Author(s):  
Sima Usvyatsov ◽  
Jeffrey Picka ◽  
Andrew Taylor ◽  
James Watmough ◽  
Matthew Kenneth Litvak
Keyword(s):  
New Brunswick ◽  
Shortnose Sturgeon ◽  
Saint John
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