Ordovician

Ordovician 520 Appalachian Mountains begin Primitive lisbes... [Pg.245]

Ordovician 500 Myr Diversification of echinoderms, other invertebrate phyla, jawless fishes. Mass extinction at end of period (ca. 85To of all species disappear)... [Pg.39]

If the asteroid-impact theory is correct, the extinctions should be repetitive and the Ir anomaly should be observed in other geological stratigraphic levels corresponding to known extinctions. About five other massive extinctions (besides the one at the end of the Cretaceous Period) have been noted [25]. These come at the end of the Cambrian ( 500 MY ago), the Ordovician (M35 MY age), the Devonian ( 345 MY ago), the Permian ( 230 MY ago) and the Triassic ( 195 MY ago) Periods. [Pg.403]

The Mount Fronsac North (MFN) Zn-Pb-Ag deposit is located approximately 40 km southwest of Bathurst, in the Bathurst Mining Camp (BMC), New Brunswick. The MFN deposit lies stratigraphically in the Brunswick horizon between the Nepisiguit Falls Formation and the Flat Landing Brook Formation of the Ordovician Tetagouche Group (Figs. 1-3). Footwall... [Pg.17]

The crystalline host rocks are covered by Palaeozoic sediments of the Western Interior Basin. These consist of Ordovician... [Pg.53]

The Halfmile Lake deposit consists of massive, breccia, and stockwork Zn-Pb-Cu sulfide mineralization hosted by volcanic and sedimentary rocks of the Ordovician Tetagouche Group (Mireku Stanley 2006 Adair 1992). The main sulphide minerals in the deposit are... [Pg.11]

Cambro-Ordovician altered meta-rhyolitic pyroclastics are host to the Thalanga Zn, Pb and Cu massive sulfide deposit in Queensland (Govett Atherden 1987). Beyond the sub-outcrop gossan zone mineralization is covered by up to 70 m of Tertiary horizontal terrestrial sandstones, conglomerates and siltstones (Campaspe beds). [Pg.49]

Bendigo is a classic example of a low-sulphide gold-quartz deposit located in a folded sequence of sandstone and shale of the Cambrian-Ordovician age (Ramsay et al. 1998 Goldberg et al. 2007). Regional soil geochemistry covers an area of 4,000 km. Sampling Grid 5x5 km. 134 samples were collected as can be seen in Fig. 2, titanium anomalies form sub-... [Pg.104]

VMS deposits of the BMC occur within a Middle-Ordovician bimodal volcanic and sedimentary sequence in the northern Appalachians of New Brunswick, Canada (Goodfellow McCutcheon 2003). Volcanic rocks were emplaced between 472 and 455 Ma within an intra-continental back-arc basin (the Tetagouche-Exploits basin) at the eastern margin of the proto-Atlantic (lapetus) Ocean (van Staal et al. 2003). [Pg.177]

Closure of the Tetagouche-Exploits basin by northwest-directed subduction from the Late Ordovician to Silurian led to incorporation of the back-arc terrain into the Brunswick subduction complex, accompanied by polyphase deformation and dominantly greenschist facies metamorphism (van Staal etal. 2003). [Pg.178]

Geological Setting The IRAC is hosted in folded and faulted sedimentary rocks of Cambrian to lower Ordovician age (Currie 1975). These units are the slaty-limestone of the McKay Group (Cambro-Ordovician), massive limestone of the Ottertail Formation (Cambrian), and the sheared argillaceous rocks of the Cambrian Chanceller Formation (Allan 1914, Aitken Norford 1967). [Pg.185]

Aitken, J.D. Norford, B.S. 1976. Lower Ordovician Survey Peak and Outram Formations, southern Rocky Mountains of Alberta. Bulletin of Canadian Petroleum Geology, 15, 150-207. [Pg.188]

The BSC (part of the Dunnage tectonic Zone) formed in Late Ordovician to Early Silurian (i.e., during the Salinic Orogeny), and contains the accreted and subducted remnants of the Middle to Late Ordovician Tetagouche-Exploits back-arc basin. Consequently, the rocks of the BSC have... [Pg.210]

Lentz, D.R., Goodfellow, W.D., Brooks, E. 1996. Chemostratigraphy and depositional environment of an Ordovician sedimentary section across the Miramichi Group-Tetagouche Group contact, northeastern New Brunswick. Atlantic Geology, 32, 101-122. [Pg.212]

VAN Staal, C.R. 1994. Brunswick subduction complex in the Canadian Appalachians record of the Late Ordovician to Late Silurian collision between Laurentia and the Gander margin of Avalon. Tectonics, 13, 946-962. [Pg.212]

Winchester, J.A. 1998. Geochemical and isotopic (Nd, O) data from Ordovician felsic Plutonic and volcanic rocks of the Miramichi highlands petrogenetic and metallogenic implications for the Bathurst Mining Camp. Canadian Journal of Earth Sciences, 3, 237-252. [Pg.280]

The northern part of the Bendigo-Baiiarat zone consists of an Ordovician fiysch sequence which has been complexly deformed and intruded by late Devonian granitoids. In the south-western part of the study area Tertiary basalt overlies much of the Ordovician sedimentary sequence. Practically all known goldfields and mineralized zones have been discovered in areas where Ordovician sedimentary rocks crop out. [Pg.290]

The aim of the investigation was to outline the most promising areas for gold exploration in Ordovician host rock lying under more recent basalts. According to preliminary data, the thickness of the basalt cover is between 100 and 300 m. [Pg.291]

Fyffe, L.R. PiCKERILL, R.K. 1993. Geochemistry of Upper Cambrian - Lower Ordovician black shale along a northeastern Appalachian transect. Geological Society of America Bulletin, 105, 897-910. [Pg.300]

Zimmermann, U. Bahlburg, H. 2003. Provenance analysis and tectonic setting of the Ordovician clastic deposits in the southern Puna Basin, NW Argentina. Sedimentology, 50, 1079-1104. [Pg.300]

Rice, R.J. van Staal, C.R. 1992. Sedimentological Studies in the Ordovician Miramichi, Tetagouche, and Fournier groups in the Bathurst camp and the Belledune-Elmtree Inlier, northern New Brunswick. In Current Research, Geological Survey of Canada, Paper 92-ID, 257-264. [Pg.418]

Orogen (Williams 1995). The Meguma Terrane is made up primarily of Cambro-Ordovician metasedimentary rocks of the Meguma Group and approximately one third of the terrane has been intruded by Late Devonian granitoid batholiths, the largest of which is the South Mountain Batholith (MacDonald 2001). These basement rocks are overlain by the sedimentary rocks of the Maritimes Basin. [Pg.469]

Wilson, R., Burden, E., Bertrand, R., Asselin, E., McCracken, A. 2004. Stratigraphy and tectono-sedimentary evolution of the Late Ordovician to Middle Devonian Gaspe Belt in northern New Brunswick evidence from the Restigouche area. Canadian Journal of Earth Sdence, 41, 527-551. [Pg.517]

See also in sourсe #XX -- [ Pg.44 , Pg.79 ]

See also in sourсe #XX -- [ Pg.24 , Pg.26 , Pg.28 , Pg.115 , Pg.163 , Pg.197 , Pg.262 , Pg.324 ]

See also in sourсe #XX -- [ Pg.282 ]

See also in sourсe #XX -- [ Pg.9 ]

See also in sourсe #XX -- [ Pg.109 ]

See also in sourсe #XX -- [ Pg.7 , Pg.44 , Pg.49 , Pg.52 , Pg.55 , Pg.57 , Pg.60 , Pg.67 , Pg.70 , Pg.76 , Pg.79 , Pg.80 , Pg.81 , Pg.92 , Pg.127 , Pg.156 , Pg.159 , Pg.160 , Pg.161 , Pg.162 , Pg.165 , Pg.166 , Pg.168 , Pg.176 , Pg.242 , Pg.255 ]

See also in sourсe #XX -- [ Pg.28 ]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...