Pointe Verte to Tide Head, Chaleaur Bay Area, New Brunswick

University of New Hampshire University of New Hampshire Scholars' Repository New England Intercollegiate Geological NEIGC Trips Excursion Collection 1-1-1973 Pointe Verte to Tide Head, Chaleaur Bay Area, New Brunswick Greiner, H. Follow this and additional works at: https://scholars.unh.edu/neigc_trips Recommended Citation Greiner, H., "Pointe Verte to Tide Head, Chaleaur Bay Area, New Brunswick" (1973). NEIGC Trips. 192. https://scholars.unh.edu/neigc_trips/192 This Text is brought to you for free and open access by the New England Intercollegiate Geological Excursion Collection at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in NEIGC Trips by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. TRIP A-7, by H. Greiner, The University of New Brunswick. POINTE VERTE TO TIDE HEAD, CHALEUR BAY AREA, NEW BRUNSWICK INTRODUCTION Silurian and Devonian sedimentary, extrusive and intrusive rocks of northern New Brunswick occupy the southwest-trending Chaleurs Bay Synclinorium (Poole, W. H., and John Rodgers, 1972). These sediments and volcanics were deposited adjacent to an island arc system with a core of Ordovician and older rocks which had been deformed by the Taconic Orogeny (Bird, J. M. and Dewey, J. F., 1970). This ancient land mass, named “Mirami- chia” by Rodgers (1971, p. 1159), was the source of sediment and the site of volcanoes in the Lower, Middle and Upper Silurian and into the Lower and Middle Devonian. Deep-water turbidite accumulations, probably beginning in the Middle Ordovician (with argillaceous limestone or “ribbon rock” of the Matapedia Group), and continuing through the Silurian, prevailed to the west in the Campbellton-Matapedia area. For much of the area there is a remarkable repetition, almost cyclical in character, in the Middle to Upper Silurian and in thQ Lower Devonian. In both an initial, marine, calcareous siltstone or silty limestone is succeeded by basalt flows, followed by ter restrial redbeds or (for the Devonian) very near-shore sedimenta tion, and ending with orange felsitic extrusions. (Fig. 1.) Middle Devonian sedimentary rocks of the Campbellton Form ation are lacustrine, intermontane conglomerates, sandstones and shales, with a rich fish and plant biota, and a close association with tuffs and agglomerates. The youngest consolidated rocks are redbed conglomerates of Pennsylvanian age, the Bonaventure Formation, which lie with conspicuous angular unconformity on older rocks. They are al most flat-lying, and only rarely faulted. Deformation was in shallow-depth zones and mainly Acadian, although local granitic to gabbroic intrusions occurred as well. Folds are open, and two fault systems dominate, one north-trend ing, the other to the east or northeast. Metamorphism is sub- greenschist (zeolites in Devonian palagonite tuffs are not uncom mon), and contact metamorphism minimal. Axial-plane cleavage is present in many of the Silurian and Devonian pelites. Appala 58 chian deformation was apparently limited to gentle warping; shallow-zone faulting took place in the Dalhousie area, as well. The Ordovician-Silurian contact is probably an angular uncon formity (Fig. 2 and 3). Otherwise all formational contacts of Si lurian units in the Petit Rocher-Charlo areas (but probably not in the West Campbellton) are conformable or disconformable. In deed, the Silurian-Devonian boundary itself appears to be one of conformity, and lies somewhere within a calcareous siltstone- mudstone sequence. As might be expected, facies chnge can be great (Fig. 4). Contacts between the various Devonian sedimentary formations are in general more complex, with much- injection and extrusion of igneous rocks, and interfingering and “pinching-out” of units. The Archibald Settlement Felsites in the Charlo area are con spicuously unconformable, as, indeed, is the Bonaventure Con glomerate. LOG AND STOPS MILEAGE FRIDAY, OCTOBER 12, 1973 0.0. in tersection at King Avenue and Main Street, Bathurst. Turn left onto Route 11. 2.4 Tetagouche River. Middle Ordovician graptolite locale ca. one mile upstream in graphitic slate and chert of the Tetagouche Group. 3.5 Vi mile west to graptolite site. 3.8 Pillow basalt flows, probably Devonian. 6.1 Grants Brook. Ordovician Tetagouche metasedimentaries. Just beyond, cross Rocky Brook-Millstream Fault zone into Silurian siltstone, shale-limestone rocks. Gaspe visible across Chaleur Bay. 9.7 Nigadoo River. Silurian. 14.4 STOP 1 — Limestone Point. Silurian sedimentary rocks lie with probable unconformity on Elmtree (-Teta gouche) phyllite, quartzite, etc., and are unconformably overlain by Devonian andesitic flows. The Silurian sec tion here begins with Lower (but probably not lowest) Silurian redbed rudites, tentatively named the “Pointe 59 G AS P E Upsalquitch DEVONIAN mudstone , shple Rafting \ Ground Sugarloaf Dacite SILURIAN MIDDLE ORDOVICIAN to LOWER SILURIAN ( G AS P E Campbellton f.nmnbellton Formation X n / r X X X X X X X x X X X X andesite, tuff . etc X X X 1f \ A X X x x X X X X X X X X X X X 1 ^ - X X X x X X X Sugarloaf Dacite v v granite, v x v v felsite Balmoral Gabbro Dalhousie CHALE UR BA Y Stewart x Andesite East Charlo v \B ry o n' <7 v V~"hiash| v ^ v vvCreek L v Archibald vFelsite^ \ Fm Nash Creek i Fm. Charlo Charlo Granite v Granite v Balmoral ^ Gabbro 62 SCHEMATIC PANEL DIAGRAM FACIES AND FORMATIONS CHALEUR BAY COASTAL AREAS NORTHERN NEW BRUNSWICK (THICKNESS APPROXIMATE) East Charlo I 2 3 MILE 1 2 3 KILOMETE Belledune Belledune , Point Bonaventure Fm_________ Sunnyside Fm _______ Belledune Fm New Mills Conglomerate amygdaloidal porphyry Chapel Poinl Sandstone Nash Creek Antinouri Limestone Granite Pointe Verte Redbeds Elmtree Group 63 .c a m w. 0) o I 6 o E o c a> c o E c X5 o <D 0) o c O o 0) CO V> c 0) "D o C a> o v 0> c in C • o E o fll ♦“ V w — in a; O ) X) 0 0) E 0 XJ • H •5.6 c - o o T3 £ -O a> l i ■O C/3 2 o 0) </> cr c in UJ o in c H 0) a 3 o jO O m Itin o SH • *- z 0) «n a) a> 3 a> a O o OQ i i — c V in ^ a* — o c ■O c C7> O a> £ 3 cr a •o o <Z °> o <D <_> o o cr (J 55 O k . 11 o CO CO < < U- o -J O ca > 0 ) cr O J-l => Q I cr < CO o a; o-C > > o tJO c o in o o O) <1> c in Is o ^^ nO o S c uo u o o C a> o e § ^ o > in 0) c ? o 13 ■O W. > O a> o o • a> <D o o D ^ m E k. c a> * E : q k . ^ c • d a> E O) — m o X ) c x> Q ~ c c o O c r a> c s| o a> — 2 c o ? u .X: in 0>O ^ cc w •— rnCO CNJ UJ aT o (p s • o c S o ^ o 2 z o j r 2 co 6 \ Tn in CO => •O oc in o • H O c -O • • b , >- o O' D >sCO in in x: TD -x - O O o • - c o cr >S <D <1> o o (V > k. o k. ~ O UJ C7» c o ?? o Q • o Z a> z O e o < - < 6u Q o y £ « "O Z >» «/> 0) ^ - < -C o ! l § cr O Q cr jd < 5 < < CO Z 0 A O c r CO E Q. > 3 O 0 _ j CO UJ UJ Q Q. 0 CO GASPE GASPE PENINSULA v o 10 _ *n (/) e t IA O' — y UJ CJ UJ e t _J *« £3 ^ o 4> r , UJ a u J* o £ >K o * o a> > CO e t c o c o * o o C7» c £ o z < < o o E c/> < % X q . a O CL S.- et D w jt: o O £ . 3 c r n< et Z 1 £ < o O ^UJ L ^ CD </■> <_> U J cr D is 2 0 q : uj > w o UJ 1 O £ if) tf) * - J o 5 " o o < et o o i t K (f> o O u j h- £ <r <r • rH O Ph CD £ O C/3 CD S a CO £ O 03 CD 03O £ O 0 £ • H03 £ O > CD Q 1 £ •r~i03 £ 0 } i £ • *—•05 o > T5O o CO D > > H U« 0 J I f ) o I f) <0 65 66* 59’ 66° 52' LOWER DEVONIAN (?) OR LATER Felsic intrusive and extrusive rocks gronite . granodiorite, felsite .feldspar porphyry .docite stocks, and reloted dykes and sills LOWER,MIDDLE AND UPPER SILURIAN AND LOWER DEVONIAN Greenish - weathering micoceous. silty mudstone and shale, calcareous siltstone and minor conglomerate 2o Thick to medium-bedded sondstone and siltstone, with basal ond mterbedded con glomerate UPPER ORDOVICIAN (?) TO LOWER SILURIAN M a t a p e o ia g r o u p Dork bluish-grey, dense,calcareous argillite la Uncleaved' banded"limestone ond dork shale Foult .with escorpment I SCALE IN MILES 4 7 *5 3 ’ 6 6 *5 9 ’ 66*52' Fig. 4 Ordovician-Silurian-Devonian contact relations, Resti- gouche River estuary, New Brunswick. Verte Redbeds,’ with minor andesitic flows, and is suc ceeded by typical, widespread, nodular “pitroek” lime stone, roughly equivalent to the Gaspe La Vieille Form ation of upper Llandovery-YVenlock age. This is the Nash Creek Limestone. Especially interesting here are the intense slump folds penecontemporaneous with deposition of the sediment. Time permitting, a side trip up the Madran road to the railroad crossing to see a small gabbroic neck — the probable source for the andesite flows — and, farther on, to view the Elmtree metasedimentaries will be made.

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