Geology of New Brunswick: field guide to excursions, 1973: Trip A-

Ruitenberg, A.A.

English

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University of New Hampshire University of New Hampshire Scholars' Repository NEIGC Trips New England Intercollegiate Geological Excursion Collection 1-1-1973 Tectonic Evolution and Mineral Deposits of the Northern Appalachians in Southern New Brunswick Ruitenberg, A.A. Follow this and additional works at: https://scholars.unh.edu/neigc_trips Recommended Citation Ruitenberg, A.A., "Tectonic Evolution and Mineral Deposits of the Northern Appalachians in Southern New Brunswick" (1973). NEIGC Trips. 194. https://scholars.unh.edu/neigc_trips/194 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 nicole.hentz@unh.edu. TRIP A-9, by A. A. Ruitenberg, New Brunswick Department of Natural Resources.TECTONIC EVOLUTION AND MINERAL DEPOSITS OF THE NORTHERN APPALACHIANS IN SOUTHERN NEW BRUNSWICKINTRODUCTIONThe complex tectonic history of the Northern Appalachians, in Southern New Brunswick, is reflected in a great variety of miner­al deposits, which occur in several distinct belts. In general, the field trip emphasizes contrasting geologic environments and structures as related to metallization (Fig. 1).CALEDONIA BELTThe oldest rocks containing sulphide deposits of economic in­terest occur in the Caledonia Belt (Fig. 2), which extends for about 160 kilometers along the Bay of Fundy Coast, in SouthernNew Brunswick. This area is mainly underlain by late Precambrian volcanic and sedimentary rocks (Coldbrook Group), in part over- lain by Cambrian, possible Silurian and Carboniferous sedi­mentary and minor volcanic rocks. The Coldbrook Group consists mainly of andesitic, dacitic and rhyolitic flows, tuffs and brec­cias, which have been intruded by granitic, dioritic and gabbroic plutons. In the southeastern part of the belt, arkosic and quart­zitic clastic sedimentary rocks (shallow water environment) are intercalated with the lower part of the volcanic sequence, where­as poorly sorted volcanogenic sedimentary rocks are abundant higher in the section. Volcanic flows and ignimbrites (terrestrial) predominate in the northwestern part of the belt.The Coldbrook Group in the Loch Alva — Kingston Peninsula area (Kennebecasis Deformed Zone), adjacent to the Palaeozoic Mascarene-Nerepis Belt (see next section) have been subjected to intense polyphase deformation probably during the Acadian (Middle Devonian) Orogeny (Ruitenberg et al., 1973). Late Pre­cambrian and Early Carboniferous (and/or Late Devonian) rocks in a broad belt, along the Bay of Fundy, have been deformed by intense cataclasis (Fundy Cataclastic Zone). This deformed zone conforms roughly to a northeast trending upwarped belt, defined by a well developed penetrative cleavage. Effects of at least one, and locally two, subsequent deformation phases have been re-81LIST OF MINERAL DEPOSITST R I A S S I C00* 0990*0C  * * 0 + 0 0 9 0 *9 ,  90* 49 *0+ 0. ***/,M I S S I S S I P P I A N  A N O / O R  P E N N S Y L V A N I A NC o » 0 / 0 » O 9 0 9 0 t |A#VM PM I S S I S S I P P I A Nf  M V  | Afe«*S * * 0 0 9 0 ~ ‘ W O / C O O K  9 0 C » 9L A T E  D E V O N I A N  T O  C A R B O N I F E R O U S] D C /  Q o o ru  momroo/9oL A T E  O E V O N I A N$ 0 0 4 9 9 0 0 0 ,  < 0 + f t 0 m 0 * 0 9 0 ,  m * 00*  r o * o m * c  f O C » 90 4M I O O L E  O E V O N I A NS t  S o o r f o  0 0 9 0 0 / 1 9 0LSZD E V O N I A N  A N D  E A R L I E R"5171EE£Z 5/ 5 9 0 0 0 0 m  m o f » c  * 0 9 9 0 9 * 0 *  0 0 * 0 9 9 * 0 0  § f 0 0 * 9 0  0 0 0  0 , 0 ' , 9 0_________ W  L U W LS F  | F l U M C  MlOOC f O A H A T l O N S SS VE*gl 9 0  • 0I00C6UA9H FORMATI ON 9 » - V A * C t O  FORMATIONO R O O V I C I A N0  C00R 90N  FORMATION0 0 1 * 9 * 0  0 0 4  C 0 U 0 9 0 0 * 9  9 0 0 ,0 * 0 0 9 0 * , ' 0 C 9 $ ,  m i* * * *  r o t e 00, c  ' O d tS 0 , ' 0 € P 0 9 9 «  r o < 9 $* AM/A, m , 0 0 f  $ , / * c , c  0 O 9 C 0 0 0  S V | • 5< //r« , *100* mot* 00X00* *oc9t S M ,  M e 9 C 0* 900,  G r 000 /SM? 9 0 0 9 0 0 9 0 0 0 ,  $ 9 0 0 0  /SN | 9 0 0 9 0 0 * 9 ,  6 9 0 0 0  t  **l? ^ 4 9 0 0 * 9 .  6 9 0 0 0  0O R O O V I C I A N  O R  S I L U R I A NO S  */#/#. 9 1 / 9 9 / 0 0 0C A M B R I A Nm  4, 4 9 0 9 / / 0 C 0 0 0 0  90 0 * 0 0 * 9 0 9 , 9 0 0 1 94P R E C A M B R I A N  O R  E A R L Y  P A L A E O Z O I CP C  3 6 r o o /  9 0  0 0 0  r o / o  9 o 0  0 / o 9 o * * c  r o e  A#P C 2 i$ o / o / , m o f / e  0 0 0  9 / M e / c  m x o o x 9 O C 0 9P R E C A M B R I A NC 0 H 0 9 0 0 0 0  O 0 0  0 9 0 9 / 9 0 0 0 0 0 4  M 0 9 0 0 0 0 / O 9 O O 9 9R i v e *82(/)oCDOO  < LUCD ooLU<<o09 0 0 9 03 1 4 S I W4 0 0 9 00 V I H N 1 1 9 OCMtJ)• Hu*83cognized. The penetrative deformation probably resulted from up- warping or bending (under a lithostatic load), which was produc­ed by vertical movements of basement blocks underlying deform­ed layers (Ruitenberg et al., 1973). Numerous high angle reverse and normal dip-slip faults, and locally low angle thrusts cut ac­ross both the late Precambrian and younger rocks. Latest move­ments along these faults postdate the-cataclastic deformation.Mineral deposits of economic interest occur mainly in the southeastern part of the Caledonia area, which is underlain by highly deformed mafic and silicic tuffs, and associated volcano- genic sedimentary rocks (shallow water environment). Sulphide deposits of two distinct ages have been recognized (Ruitenberg et al., 1972). The Teahan and Lumsden deposits are examples of pyrite-copper-zinc sulphide deposits, which are the earliest known in the area. Small amounts of copper were mined from the Tea­han deposit around 1880. The host rocks are composed of inten­sely sheared and altered andesitic tuff with minor intercalated rhyolite tuff and associated volcanogenic sedimentary rocks. Sills and dykes composed of diabase, diorite and granite occur along the footwalls of these deposits. The deposits are enveloped by a dark green chloritic alteration zone, which is thickest along the hanging wall. The mineralized and chloritized zones are envelop­ed by a wide zone of silicification, talcose and micaceous alter­ations. Clay minerals, epidote and Calcite are also common. It is notable that pyrite is abundant throughout the entire altered zone. Both the altered host rocks and surrounding country rocks show a well developed penetrative cleavage. Intense slip has oc­curred roughly parallel to this cleavage. This produced chevron folds or flexures, which mostly plunge in the regional dip dir­ection of the cleavage. Base metal sulphides are generally con­centrated in axial regions of these cross folds, within the inten­sely altered, pyrite-rich tuffaceous horizons.Deposits related to the final metallization episode are mainly composed of copper sulphides with locally abundant tennantite and tetrahedrite, which occur in brecciated and fractured quartz- carbonate veins. These veins post date the late stage cross folds and they cut across both late Precambrian and early Carbonifer­ous rocks. Examples are the “Vernon” Copper deposit, which was mined around 1865, and several mineralized fracture zones in the Black River and Musquash areas (Ruitenberg, 1969, 1970). The more prominent of these deposits appear to be related to faulted unconformities between Coldbrook Group rocks and Carbonifer­ous sediments.84MASCARENE -  NEREPIS AND ROLLING DAM BELTSThe Mascarene-Nerepis Belt extends from the Passamaquoddy Bay area to the northeast into the Annidale area. It is separated by major faults from the Caledonia Belt to the southeast. The Rolling Dam Belt extends from St. Stephen to the northeast intothe Mount Pleasant area (Ruitenberg, 1967, 1972).The Mascarene-Nerepis Belt is chiefly underlain by intensely deformed Silurian to Lower Devonian andesitic and rhyolitic flows and tuffs, siltstones and slates (shallow marine environ­ment). In the northeastern part of this belt these rocks are locally conformable or in faulted contact with Ordovician graphitic slate, siltstone (generally rich in iron sulphides and oxides), grey­wacke, mafic and silicic volcanic rocks. The Rolling Dam Belt consists largely of Ordovician graphitic slate overlain by Upper Silurian to Lower Devonian greywacke and slate. Both belts un­derwent polyphase deformation during the Acadian (Middle De­vonian) Orogeny (Ruitenberg, 1967, 1968, 1969, 1970, 1972) and Brown and Helmstaedt (1970). The main penetrative phase of this deformation resulted from a northwest-southeast shortening and it was followed by emplacement of a large batholith com­posed mainly of silicic and minor mafic plutonic rocks.Nickel-copper sulfide deposits in gabbro and norite, at St. Stephen in the Rolling Dam Belt, are believed to be the earliest in this area, but the time of emplacement is not certain. The earliest base metal deposits occur in dilatant structures, related to late phase chevron folds, in the Mascarene-Nerepis Belt. Copper sulfides predominate where these structures occur in intensely altered andesitic tuffs, whereas zinc sulfides are most abundant in calcareous siltstones and slates, and rhyolite tuff. Economically the most interesting of these deposits occur in the Annidale-Nere- pis area (Ruitenberg, 1972). Some small gold-arsenopyrite-quartz deposits occur in similar dilatant structures in the Rolling Dam Belt, but no base metal deposits are known to be associated with these structures in this belt. The intimate relationship of the va­rious types of metallic minerals to certain well defined rock types, suggests that the metallic sulfides were originally deposited with the hostrocks and subsequently remobilized. Heat and hydrother­mal fluids, generated by emplacement of the pluton, were pro­bably responsible for the remobilization of the metallic minerals.The latest deposits were formed during early Carboniferous time and are associated with north-northwest trending zones of intense wrench and block faulting (rifts), close to the contact of85the major batholith. The base metal tin-tungsten-molybdenum deposits at Mount Pleasant are the largest known of these dep­osits and occur in intensely fractured and silicified rhyolitic frag­mental rocks (Ruitenberg, 1967, 1972; Parrish and Tully, 1971). Numerous smaller tin, silver-base metal and copper-molybdenum deposits occur in and along silicic stocks and dykes, which were emplaced during this period.MONCTON -  SUSSEX BELTNumerous interesting mineral deposits occur in Carboniferous rocks of southeastern New Brunswick. Limited time available for this field trip does not permit intensive examination of the geo­logic environment of these deposits. The following is a brief re­sume.Gypsum has been produced at Hillsborough for many years. Limestone is being quarried at Havelock. Great thicknesses of salt and potash have been intersected by diamond drilling in the Penobsquis-Plumweseep areas near Sussex. Economically inter­esting amounts of celestite and barite have been discovered at Upper Dorchester. Albertite (solid asphalt) was formerly mined at Albert Mines. The Stony Creek oil field is situated about five miles north of this occurrence.The most interesting metallic mineral deposits are cupriferous (chalcocite and malachite) sandstones in the Dorchester, New Horton and Goshen areas. These deposits appear to be associated with the first grey (channel) sandstone sequence overlying Hope-well red beds (van de Poll, 1973).SCHEDULE AND DIRECTIONSOctober 11:P.M.(1) Lecture Tectonic History and Mineral Deposits, Northern Appalachians in Southern New Brunswick, Hopewell RocksMotel, 8 P.M.(2) The itinerary can be modified to meet specific interests of participants.October 12:A.M.(1) Albert Mines — brief stop at albertite occurrence and near­by outcrop with numerous palaeoniscid fish skeletons first discovered by Greiner (1961).88(2) Old Teahan Mine — intensely altered and mineralizedrocks at the old mine site will be compared with nearby country rocks. Effects of penetrative deformation and sub­sequent deformation will be demonstrated.(3) Bennett Lake — rhyolitic and andesitic tuffs of the Cold-brook Group are well exposed along Highway 114 in this area. The well developed penetrative cleavage in these rocks was produced by intense cataclasis (Fundy Cataclas­tic Zone). The well developed crenulation cleavage res- sulted from a second deformation.P.M.(4) Old Annidale Copper Mine — Effects of cross-folding onthe distribution of copper sulphides in andesite tuffs will be demonstrated. It is notable that pyrite-rich slates on the footwall of the deposit have been similarly deformed, but contain no copper sulphides.October 13:A.M.(5) Black River — sedimentary and volcanic rocks of the Mis- pec Group (Early Carboniferous or Late Devonian) are to the north in faulted contact with Coldbrook (Late Precam­brian) volcanics. These rocks form part of the Fundy Cata­clastic Zone and have been affected by two phases of de­formation. An interesting occurrence of copper sulphides is exposed in fractured Mispec rocks close to this faulted contact. Further north in this section, deformed Coldbrook rocks have been thrust over sedimentary rocks of possible Silurian age, which show no effects of penetrative deform­ation.A.M. -  P.M.(6) Mount Pleasant — Cross-cutting relationships of variousrock types in this volcanic complex will be examined. Ef­fects of several metallization and alteration phases will be shown.P.M.(7) Digdeguash River at Rolling Dam (7a) and Tryon (7b) Ty­pical Ordovician and Upper Silurian — Lower Devonian facies will be compared. Effects of polyphase Acadian (Middle Devonian) deformation on various lithologies willbe demonstrated.87

Tectonic Evolution and Mineral Deposits of the Northern Appalachians in Southern New Brunswick

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Tectonic Evolution and Mineral Deposits of the Northern Appalachians in Southern New Brunswick

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