Genesis and distribution of Mississippi Valley-type ore assemblages in Middle Silurian strata, Niagara Peninsula, Ontario /

Presently non-commercial occurrences of Mississippi Valley-type ore assemblages in the Middle Silurian strata of the Niagara Peninsula have been studied. Based on this detailed study, a new poly-stage genetic model is proposed which relates ore mineralization in carbonate environments to the evolution of the sedimentary basin. Sulphide ore mineralization occurred during two episodes: 1. During the late diagenesis stage, which is characterized by compaction-maturation of the sediments, the initial mineralization took place by upward and outward movement of connate waters. Metals were probably supplied from all the sediments regardless of their specific lithologies. However, clay minerals were possibly the main contributors. The possible source of sulphur was from petroleum-type hydrocarbons presently mixed with the sediments at the site of ore deposition. Evidence for this is the fact that the greatest abundance of ore minerals is in petroliferous carbonates. The hydrocarbons probably represent liquids remaining after upward migration to the overlying Guelph-Salina reservoirs. The majority of sphalerite and galena formed during this period, as well as accessory pyrite, marcasite, chalcopyrite, chalcocite, arsenopyrite, and pyrrhotite; and secondary dolomite, calcite, celestite, and gypsum. 2. During the presently ongoing surface erosion and weathering phase, which is marked by the downward movement of groundwater, preexisting sulphides were probably remobilized, and trace amounts of lead and zinc were leached from the host material, by groundwaters. Metal sulphides precipitated at, or below, the water table, or where atmospheric oxygen could raise the Eh of groundwaters to the point where soluble metal complexes are unstable and native sulphur co-precipitates with sphalerite and galena. This process, which can be observed today, also results in the transport and deposition of the host rock material. Breakdown of pre-existing sulphide and sulphate, as well as hydrocarbon present in the host rock, provided sulphur necessary for sulphide precipitation. The galena and sphalerite are accompanied by dolomite, calcite, gypsum, anglesite, native sulphur and possibly zincite.

Dinocyst biochronology and palynofacies : inferred systems tract character of Miocene sequences from New Jersey mid-Atlantic transect (ODP legs 174A and 174AX) /

One of the main objectives of the mid-Atlantic transect is to improve dating resolution of sequences and unconfonnity surfaces. Dinoflagellate cysts from two Ocean Drilling Program boreholes, the onshore Leg 174AX Ocean View Site and Leg 174A continental shelf Site 1071, are used to provide age estimates for sequences and unconfonnities fonned on the New Jersey continental margin during the Miocene epoch. Despite the occasional lack of dinocysts in barren and oxidized sections, dinocyst biochronology still offers greater age control than that provided by other microfossils in marginal marine environments. An early Miocene to late Miocene chronology based on ages detennined for the two study sites is presented. In addition, .palynofacies are used to unravel the systems tract character of the Miocene sequences and provide insight into the effects of taphonomy and preservation of palynomorphs in marginal marine and shelf environments under different ~ea level conditions. More precise placement of maximum flooding surfaces is possible through the identification of condensed sections and palynofacies shifts can also reveal subaerially exposed sections and surfaces not apparent in seismic or lithological analyses. The problems with the application of the pollen record in the interpretation of Miocene climate are also discussed. Palynomorphs provide evidence for a second-order lowering of sea level during the Miocene, onto which higher order sea level fluctuations are super-imposed. Correlation of sequences and unconfonnities is attempted between onshore boreholes and from the onshore Ocean View borehole to offshore Site 1071.

Tourist travel via Grand Trunk Railway System : and connections, including Niagara Falls and Gorge, the Highlands of Ontario, comprising Georgian Bay, Muskoka Lakes ; St. Lawrence River, Montreal, Quebec, the Saguenay River, the Rangeley Lakes, White Mountains, and the Atlantic Sea-Coast /

Previous editions of this work have appeared under the title: Gateways of tourist travel.

Palynology and foraminiferal geochemistry of the Lower Pleistocene Olduvai Subchron (ca. 1.8 Ma) in DSDP Hole 603C, western North Atlantic

Marine palynology and benthic and planktonic foraminiferal geochemistry are combined to reveal long- and short-term (Milankovitch-scale) paleoceanographic changes across the upper half of the Olduvai Subchron (ca. 1.86--1.77 Ma, lower Pleistocene) in DSDP Hole 603C from the lower New Jersey continental rise. Planktonic foraminiferal Mg/Ca ratios reveal annual sea-surface temperatures between 14.5° and 25°C, whereas modern values vary between 16° and 20°e. Despite evidence of downslope transport in much of the studied interval, dinoflagellate cyst and acritarch assemblages appear to reflect fluctuating temperate to subtropical water masses. These assemblages comprise both neritic and oceanic species, and are marked by a transition upsection from warm conditions, dominated by Lingulodinium machaerophorum, Polysphaeridium zoharyi and Cymatiosphaera? invaginata, to cooler conditions dominated by Filisphaera filifera. Combining dinoflagellate cyst proxies with planktonic foraminiferal geochemistry allows downslope transport events to be recognized during glacial episodes, and events dominated by intensified bottom-water circulation during interglacial episodes. Sixtytwo in-situ dinoflagellate cyst and acritarch taxa were recorded including several not previously described.

CENTRAL NORTH ATLANTIC PALEOCEANOGRAPHY DURING THE MIDDLE PLEISTOCENE (ca. 726–603 ka): INSIGHTS FROM THE DINOFLAGELLATE CYST RECORD

Integrated Ocean Drilling Program (IODP) Site U1313, located at the northern boundary of the subtropical gyre in the central North Atlantic, lies within the southern part of the ice-rafted debris belt. Seventy-three palynological samples were studied from an uninterrupted interval ca. 726–603 ka (upper Marine Isotope Stage [MIS] 18 through lower MIS 15) to resolve conflicting paleoceanographic interpretations. Glacial stages were characterized by high productivity surface waters reflecting a southward shift of the Arctic Front. Sea surface salinities (SSSs) and sea surface temperatures (SSTs) were obtained by transfer functions using the Modern Analogue Technique. The lowest SSTs of 9ºC (±1.3) and 10ºC (±1.3) were recorded in glacial MIS 16 and MIS 18 respectively. However, these reconstructions are influenced by abundant heterotrophic taxa and may reflect elevated nutrient levels rather than lowered temperatures. Reworked palynomorphs uniquely indicate a Cretaceous as well as Paleozoic provenance for the first Heinrich-like events.

Extraordinary Narrative of the Prince of Wales' Trip Across the Atlantic (1895)

Detailing what the Prince had to say about his travels.