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Six new U-Pb zircon dates for the Siluro-Devonian magmatism in the south-west Grampian Highlands, Scotland, combined with data from previous studies, reveal a 25 million year magmatic 'flare-up'. The new dates are: Lome Lava Pile 424.96 ± 0.65 Ma; Rannoch Moor Pluton 422.48 ±0.47 Ma; Gleann Chaman Fault-Intrusion, Glencoe 419.4 ±4.8 Ma; Clach Leathad Pluton, Glencoe 417.99 ± 0.46 Ma; Cruachan Intrusion, Etive 414.96 ± 0.38 Ma and Inner Starav Intrusion, Etive 408.12 ± 0.40 Ma. The magmatic 'flare-up' occurred after subduction of Iapetus oceanic lithosphere, and following limited subduction of Avalonian continental lithosphere beneath Laurentia. It was accompanied by dominantly strike-slip faulting, with uplift, the location of which reflected the position of a 'bum' and crustal weakening due to the magmatism. Magmas, dominated by intermediate to silicic compositions, were exceptionally diverse, mainly of high-K calcalkaline I-type revealing an enriched mantle signature (eNd-eSr) and increasing addition of (silicic) aluminous crustal material through time. Paucity of basalt with SiOl S50 wt.% is a key feature, with limited mafic magmatism represented by appinitic (s.l.) rocks. This study concludes that partial melting of enriched sub-continental lithosphere occurred as a consequence of asthenospheric upwelling that followed breakoff and sinking of the subducted oceanic lithosphere. The resulting appinitic melts underplated and intruded predominantly mafic lowermost crust formed by previous magmatic underplating. This mafic lower crust partially melted due to heat and volatiles derived from the mantle-derived (appinitic) magma and a diverse range of intermediate-composition melts formed, with some mixing at depth. The ascent of magma batches to shallow levels from this 'hot zone' was facilitated by active crust-penetrating strike-slip faults and shear zones, with partial melting and assimilation of the silicic mid to upper crust also occurring. Tectonic facilitation of magma ascent resulted in the common eruption of crystal-poor, 'superheated' magmas, often in unusually large volumes. As the 'hot zone' developed with time, there was progressively more input from the silicic crust and fewer appinitic magmas reached shallow levels. The closely spaced development of centred volcanoes with associated plutons let to progressive assembly of the South-west Grampian Batholith in -14 million years. Volcanic activity was inextricably linked and a precursor to pluton development at specific crustal locations. The volcanoes comprise a greater proportion of intermediate magma compositions than the successor plutons, and they reveal a far greater compositional diversity than them. The extreme compositional diversity and the striking paucity of basalt are fundamental characteristics of the magmatism in the 25 million-year flare-up; they indicate mainly crustal recycling rather than a major episode of crustal growth.

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This research examines the composition, sedimentary history and chemical properties of sedimentary organic matter [SOM] and its application in determining the content and source of heavy metals and hydrophobic organic contaminants [HOCs] and their fate in waste disposal sites. Previous research has utilised Oxford Clay (OxC) from across the outcrop. In this study a continuous shallow core of OxC and adjoining Kellaways Sand (KS) from Brogborough, UK was used. This avoided the influence of different sedimentary conditions, thereby reducing the problem of sample variability. Relationships have been made between sedimentary and organic petrology and SOM abundance and metals concentration (V, Cr, Co, Ni, Cu, Zn and As). The co-association/binding of different metals to different types of SOM components from the OxC was shown to be dictated by the depositional environment. The organic rich parts (Total Organic Carbon (TOC) > 5 %) of the OxC displayed positive correlations between the elements V, Co, As and total pyrite % (p<1.1E-3, ? >0.7); however, there was an apparent negative correlation with TOC % (p<4.3E-5, ?<-0.4). This may be because of: 1) the rapid accumulation of the OM reduced the time for development of the pyrite (Ave. dia. =5.3?m, SD=2.4); and/or 2) the insufficient concentration of Fe to allow pyrite formation. This could be due to the high sedimentation rate that accelerates the accumulation of OM, which prevents its decomposition in the water column, as well as reducing the time for pyrite that is entrapped in the marine snow to capture metals from seawater during its settlement. Cu has a significant positive correlation with TOC (p=1.9E-2, ?=1.3), which could be the consequence of Cu being an essential element in OM. The OxC with a lower OM content (TOC < 5 %) showed a different distribution of metals. V, Cr and Cu found in OM was found to have a significant positive correlation with TOC (p<2.9E-2, ?>0.05). The Kellaways Sand core showed that the V, Co, Ni, Cu, Zn and As had a strong connection both with TOC (p<1.6E-3, ?=0.03~37.3) and pyrite (p<4.9E-3, ?=0.23~5.5), suggesting that both OM and pyrite were major metal sinks in Kellaways Sand. The more significant positive correlation between V, Cr and pyrite compared to V, Cr and TOC implies that pyrite contains more V and Cr than did TOC. Other studies used the OxC from Bletchley, the Kimmeridge Clay (KC) from Kimmeridge Bay, Dorset, and Tertiary mud (Wittering Formation-WF) from Whitecliff, Isle of Wight due to their distinctive OM characteristics (AOM rich and/or phytoclast rich). Organic material was isolated for identification and analysis using a novel extraction method (heavy liquid extraction) and traditional methods involving HF digestion. These organic materials were then used to determine influences of extraction on HOCs (toluene and naphthalene) sorption and desorption. Organic petrology classification was applied to identify the various types of isolated OM. AOM from KC displayed a higher sorption capacity (Kd=6,481, 59,670; for toluene and naphthalene, respectively) compared to literature values. AOM rich sorbent extracts demonstrated a higher absorption capacity than the phytoclasts rich sorbents (e.g. WF, Kd=219, 20,661; for toluene and naphthalene, respectively). However, the phytoclast rich sorbent showed a higher sorption/desorption hysteresis capacity for toluene than AOM. Implications of results in landfill design/risk assessment and modelling are discussed.

The influence of lithological heterogeneities, structural discontinuities and discontinuity surface mineralisation upon groundwater migration within the Chalk and the Upper Greensand of southern England has been investigated. Lithological heterogeneities in the Chalk succession include marl seams, hardgrounds, tabular flints and nodular flints. Each of these heterogeneities has a lower intrinsic porosity and permeability than in the calcite rich chalk. The influence that each of these heterogeneities exerts upon groundwater flow is assessed in relation to the porosity and permeability of the Chalk. Clay minerals, iron oxide and dendrites of manganese hydroxide are forms of discontinuity surface mineralisation. The paragenesis of these deposits is predominately from superficial deposits resting on the Chalk. The presence of mineralisation reduces the porosity and permeability of discontinuity surfaces. Mineralisation reduces the exchange between water in discontinuities with that in the matrix. In the matrix, parallel to the discontinuity surface, a zone of enhanced porosity occurs, formed by the dissolution of the Chalk matrix. Parallel to this zone is a zone of reduced porosity which has been formed by the precipitation of calcite as overgrowths upon the matrix. Mineralised discontinuity surfaces provide routes for rapid migration of groundwater in both the saturated and unsaturated zones. There is no discernible relationship between the physical properties of discontinuities (i.e. orientation, dip, dip direction) and the occurrence of mineralisation. The distribution of discontinuities within the Chalk is not uniform. Clusters of similarly orientated discontinuities occur separated by less disturbed material, which causes the Chalk act as an anisotropic aquifer. Solution formed cavities have been observed at the point of intersection between discontinuities, or at the intersection of discontinuities with lithological heterogeneities. The cavities extend laterally along the line of intersection. These cavities allow rapid migration of groundwater within the saturated zone. Inclined solution cavities are formed where the discontinuities have differing orientations or where the lithological heterogeneities are dipping. Such cavities provide preferential routes of groundwater recharge through the unsaturated zone. The Chalk is a less effective aquifer at depth due to the decreased occurrence of solution enhanced discontinuities. The Chalk and Upper Greensand aquifers are not in hydraulic continuity in locations where the basal unit of the Lower Chalk, the Glauconitic Marl is present.