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A composite 11.82 m-long (9876–-67 cal yr BP) sediment record from Yellowstone Lake, Wyoming was analyzed using a robust set of biological and geochemical proxies to investigate the paleoenvironmental evolution of the lake and its catchment in response to long-term climate forcing. Oxygen isotopes from diatom frustules were analyzed to reconstruct Holocene climate changes, and pollen, charcoal, diatom assemblages, and biogenic silica provided information on terrestrial and limnological responses. The long-term trends recorded in the terrestrial and limnic ecosystems over the last 9800 years reflect the influence of changes in the amplification of the seasonal cycle of insolation on regional climate. The early Holocene (9880–6700 cal yr BP) summer insolation maximum and strengthening of the northeastern Pacific subtropical high-pressure system created warm dry conditions and decreasing summer insolation in the middle (6700–3000 cal yr BP) and late (3000–-67 cal yr BP) Holocene resulted in progressively cooler, wetter conditions. Submillenial climate variation is also apparent, with a wetter/cooler interval between 7000 and 6800 cal yr BP and warmer and/or drier conditions from 4500 to 3000 cal yr BP and at ca. 1100 cal yr BP. These data show that the Yellowstone Lake basin had a climate history typical of a summer-dry region, which helps to better define the spatial variability of Holocene climate in the Greater Yellowstone Ecosystem.

16 of the 20 papers presented at the conference have been expanded into chapters. These are divided into four sections: Unconventional mineral deposits - recognition, exploration and economics; Unconventional deposits in low grade environments; Unconventional deposits in physically inaccessible environments; and Unconventional exploration concepts., 16 of the 20 papers presented at the conference have been expanded into chapters. These are divided into four sections: Unconventional mineral deposits - recognition, exploration and economics; Unconventional deposits in low grade environments; Unconventional deposits in physically inaccessible environments; and Unconventional exploration concepts.

Of the 23 papers printed in this volume, those relating to mineral deposits are: Tectonic controls of the time-space distribution of some Proterozoic metal deposits, by Sawkins F.J.; Proterozoic exhalative massive sulphide deposits, by Gale G.H.; The major stratiform lead-zinc deposits of the Proterozoic, by Lambert I.B.; Constraints on genetic modelling of Proterozoic iron formations, by Kimberley M.M.; Proterozoic uranium deposits and the Precambrian atmosphere, by Langford F.F., Of the 23 papers printed in this volume, those relating to mineral deposits are: Tectonic controls of the time-space distribution of some Proterozoic metal deposits, by Sawkins F.J.; Proterozoic exhalative massive sulphide deposits, by Gale G.H.; The major stratiform lead-zinc deposits of the Proterozoic, by Lambert I.B.; Constraints on genetic modelling of Proterozoic iron formations, by Kimberley M.M.; Proterozoic uranium deposits and the Precambrian atmosphere, by Langford F.F.

The Pleistocene sediment fill in the trough is 300 to over 1 200 m thick, with local areas of disruption due to excess magmatism relative to spreading rate (2.3 cm/yr) at intervals of about 15 km along the axis. The coexistence of tectonic extension with rapid sedimentation favoured the formation of sheeted sills rather than basalt flows. Circular sediment hills up to 1 200 m in diameter and 120 m high are interpreted as uplifted fault blocks above laccolith intrusions. Massive sulphides with surface exposures at least 100 m long on the peripheries of these hills are composed predominantly of pyrrhotite with less abundant isocubanite, chalcopyrite, sphalerite, arsenopyrite and marcasite, with local barite-rich and polymetallic massive sulphide higher in Zn, Pb, Ag, As, Sb and Sn. It is proposed that the heat to drive the hydrothermal circulation is provided both by regionally extensive sills and by local laccoliths. Reaction of heated sea water with basaltic rocks controls the initial composition of the hydrothermal fluid, but its interaction with sediment in the upflow zone alters its chemistry and enriches the deposits in metals of groups IV, V and VI. The geological setting, associated lithologies and composition of the deposits are generally analagous to Besshi-type deposits, but differences in the tectonic setting of the identified modern deposits and contrasts in morphology and composition imply that the ancient deposits formed within a multitude of oceanic rift environments., The Pleistocene sediment fill in the trough is 300 to over 1 200 m thick, with local areas of disruption due to excess magmatism relative to spreading rate (2.3 cm/yr) at intervals of about 15 km along the axis. The coexistence of tectonic extension with rapid sedimentation favoured the formation of sheeted sills rather than basalt flows. Circular sediment hills up to 1 200 m in diameter and 120 m high are interpreted as uplifted fault blocks above laccolith intrusions. Massive sulphides with surface exposures at least 100 m long on the peripheries of these hills are composed predominantly of pyrrhotite with less abundant isocubanite, chalcopyrite, sphalerite, arsenopyrite and marcasite, with local barite-rich and polymetallic massive sulphide higher in Zn, Pb, Ag, As, Sb and Sn. It is proposed that the heat to drive the hydrothermal circulation is provided both by regionally extensive sills and by local laccoliths. Reaction of heated sea water with basaltic rocks controls the initial composition of the hydrothermal fluid, but its interaction with sediment in the upflow zone alters its chemistry and enriches the deposits in metals of groups IV, V and VI. The geological setting, associated lithologies and composition of the deposits are generally analagous to Besshi-type deposits, but differences in the tectonic setting of the identified modern deposits and contrasts in morphology and composition imply that the ancient deposits formed within a multitude of oceanic rift environments.

The Late Cretaceous to Eocene rocks form part of an accretionary prism complex and host more than 600 known massive sulphide deposits and prospects. Fluid inclusion, stable isotope and whole-rock data all support sea-floor volcanogenesis in both sediment-starved and sedimented mid-ocean ridge settings. Deposits hosted by pillow lavas, massive basalts and mafic tuffs are analagous to Cyprus-type deposits. Those hosted by intercalated slates and greywackes are analagous to Besshi-type deposits. Both types are similar morphologically and are characteristically stratiform to stratabound. They vary in size from under 1 000 000 t to over 5 000 000 t ore, with the largest mostly Besshi-type. Dominant minerals are pyrite, pyrrhotite, chalcopyrite and sphalerite, with minor cubanite, arsenopyrite, tetrahedrite and secondary marcasite. Gangue is mainly quartz and chlorite. Sedimentary features and ubiquitous. The sediment-hosted ores give lower temperature values and higher sulphur and oxygen levels than volcanic-hosted ores, reflecting mixing of hydrothermal fluids with seawater in the sediment pile. Geochemical analyses suggest normal and enriched mid-ocean ridge basalts and low-K arc tholeiites., The Late Cretaceous to Eocene rocks form part of an accretionary prism complex and host more than 600 known massive sulphide deposits and prospects. Fluid inclusion, stable isotope and whole-rock data all support sea-floor volcanogenesis in both sediment-starved and sedimented mid-ocean ridge settings. Deposits hosted by pillow lavas, massive basalts and mafic tuffs are analagous to Cyprus-type deposits. Those hosted by intercalated slates and greywackes are analagous to Besshi-type deposits. Both types are similar morphologically and are characteristically stratiform to stratabound. They vary in size from under 1 000 000 t to over 5 000 000 t ore, with the largest mostly Besshi-type. Dominant minerals are pyrite, pyrrhotite, chalcopyrite and sphalerite, with minor cubanite, arsenopyrite, tetrahedrite and secondary marcasite. Gangue is mainly quartz and chlorite. Sedimentary features and ubiquitous. The sediment-hosted ores give lower temperature values and higher sulphur and oxygen levels than volcanic-hosted ores, reflecting mixing of hydrothermal fluids with seawater in the sediment pile. Geochemical analyses suggest normal and enriched mid-ocean ridge basalts and low-K arc tholeiites.

Residual barite deposits were derived from the weathering of lower Palaeozoic dolostones. Open-space, Mississippi Valley-type mineralisation in the bedrock was controlled by the intersection of permeable lithologies with late Palaeozoic near-vertical faults or linear zones of intense jointing. Linear trends of residual deposits are the surface expression of these bed-rock controls. A consistent mineralogical and barite textural zonation is disposed about the central structures. Sulphide mineralisation is concentrated about the central structures whereas barite is more widespread. Barite textures vary systematically from coarse bladed near the central structures to fine plumose more distally. Such zoning indicates outward ore fluid flow from the central faults and joint zones., Residual barite deposits were derived from the weathering of lower Palaeozoic dolostones. Open-space, Mississippi Valley-type mineralisation in the bedrock was controlled by the intersection of permeable lithologies with late Palaeozoic near-vertical faults or linear zones of intense jointing. Linear trends of residual deposits are the surface expression of these bed-rock controls. A consistent mineralogical and barite textural zonation is disposed about the central structures. Sulphide mineralisation is concentrated about the central structures whereas barite is more widespread. Barite textures vary systematically from coarse bladed near the central structures to fine plumose more distally. Such zoning indicates outward ore fluid flow from the central faults and joint zones.

The Anvil Range, central Yukan, includes five stratiform Zn-Pb-Ag deposits with measured reserves of 92 200 000 tonnes (4.7% Zn, 3.6% Pb and 50 g/tonne Ag). Isotope studies on sulphur in pyrite, barite and other minerals and lead in galena indicate that the source of the lead is upper crustal and that the deposits were formed in strongly reduced bottom water related to a previously unknown Early Cambrian anoxic event., The Anvil Range, central Yukan, includes five stratiform Zn-Pb-Ag deposits with measured reserves of 92 200 000 tonnes (4.7% Zn, 3.6% Pb and 50 g/tonne Ag). Isotope studies on sulphur in pyrite, barite and other minerals and lead in galena indicate that the source of the lead is upper crustal and that the deposits were formed in strongly reduced bottom water related to a previously unknown Early Cambrian anoxic event.

The deposits occur in the eroded vent of a lower Miocene (23-22 m.y.) ash flow, located in a tilted basin and range fault block, eroded to c 1.7 km below the pre-eruption surface. Correlation of comagmatic ash flow tuff is possible due to the presence of almandine-spessartine garnets of unique composition. It was suggested that a 100 m3 parental magma chamber zoned from rhyolite to dacite was present, initial rhyolitc eruptions being followed by dacitic ashflows, and the dominant ore related intrusions. Multiple trachyandesite injections into the base of the chamber may have caused magmatic fracturing, surging of dacite magma, and exsolution of volatiles, resulting in ash flow eruptions and later mineralisation. Magmatic processes such as late stage convection, magma fracturing and volatile fluxing may have been critical in porphyry Mo mineralisation, with around 125 000 000 tons of 0.3% MoS2., The deposits occur in the eroded vent of a lower Miocene (23-22 m.y.) ash flow, located in a tilted basin and range fault block, eroded to c 1.7 km below the pre-eruption surface. Correlation of comagmatic ash flow tuff is possible due to the presence of almandine-spessartine garnets of unique composition. It was suggested that a 100 m3 parental magma chamber zoned from rhyolite to dacite was present, initial rhyolitc eruptions being followed by dacitic ashflows, and the dominant ore related intrusions. Multiple trachyandesite injections into the base of the chamber may have caused magmatic fracturing, surging of dacite magma, and exsolution of volatiles, resulting in ash flow eruptions and later mineralisation. Magmatic processes such as late stage convection, magma fracturing and volatile fluxing may have been critical in porphyry Mo mineralisation, with around 125 000 000 tons of 0.3% MoS2.