Warfare in the West Highlands and Isles of Scotland, c. 1544-1615

Warfare has long been associated with Scottish Highlanders and Islanders, especially in the period known in Gaelic tradition as ‘Linn nan Creach’ (the ‘Age of Forays’), which followed the forfeiture of the Lordship of the Isles in 1493. The sixteenth century in general is remembered as a particularly tumultuous time within the West Highlands and Isles, characterised by armed conflict on a seemingly unprecedented scale. Relatively little research has been conducted into the nature of warfare however, a gap filled by this thesis through its focus on a series of interconnected themes and in-depth case studies spanning the period c. 1544-1615. It challenges the idea that the sixteenth century and early seventeenth century was a time of endless bloodshed, and explores the rationale behind the distinctive mode of warfare practised in the West Highlands and Isles. The first part of the thesis traces the overall ‘Process of War’. Chapter 1 focuses on the mentality of the social elite in the West Highlands and Isles and demonstrates that warfare was not their raison d'être, but was tied inextricably to chiefs’ prime responsibility of protecting their lands and tenants. Chapter 2 assesses the causation of warfare and reveals that a recurrent catalyst for armed conflict was the assertion of rights to land and inheritance. There were other important causes however, including clan expectation, honour culture, punitive government policies, and the use of proxy warfare by prominent magnates. Chapter 3 takes a fresh approach to the military capacity of the region through analysis of armies and soldiers, and the final thematic chapter tackles the conduct of warfare in the West Highlands and Isles, with analysis of the tactics and strategy of militarised personnel. The second part of this thesis comprises five case studies: the Clanranald, 1544-77; the Colquhouns of Luss and the Lennox, 1592-1603; the MacLeods of Harris and MacDonalds of Sleat, 1594-1601; the Camerons, 1569-1614; and the ‘Islay Rising’, 1614-15. This thesis adopts a unique approach by contextualising the political background of warfare in order to instil a deeper understanding of why early modern Gaelic Scots resorted to bloodshed. Overall, this period was defined by a sharp rise in military activity, followed by an even sharper decline, a trajectory that will be evidenced vividly in the final case study on the ‘Islay Rising’. Although warfare was widespread, it was not unrestrained or continuous, and the traditional image of a region riven by perpetual bloodshed has been greatly exaggerated.

Quantifying uplift and denudation of a thermally heterogeneous crust: a detailed multi-thermochronometeric study of central west Britain

Topography is often thought as exclusively linked to mountain ranges formed by plates collision. It is now, however, known that apart from compression, uplift and denudation of rocks may be triggered by rifting, like it happens at elevated passive margins, and away from plate boundaries by both intra-plate stress causing reactivation of older structures, and by epeirogenic movements driven by mantle dynamics and initiating long-wavelength uplift. In the Cenozoic, central west Britain and other parts of the North Atlantic margins experienced multiple episodes of rock uplift and denudation that have been variable both at spatial and temporal scales. The origin of topography in central west Britain is enigmatic, and because of its location, it may be related to any of the processes mentioned above. In this study, three low temperature thermochronometers, the apatite fission track (AFT) and apatite and zircon (U-Th-Sm)/He (AHe and ZHe, respectively) methods were used to establish the rock cooling history from 200◦C to 30◦C. The samples were collected from the intrusive rocks in the high elevation, high relief regions of the Lake District (NW England), southern Scotland and northern Wales. AFT ages from the region are youngest (55–70 Ma) in the Lake District and increase northwards into southern Scotland and southwards in north Wales (>200 Ma). AHe and ZHe ages show no systematic pattern; the former range from 50 to 80 Ma and the latter tend to record the post-emplacement cooling of the intrusions (200–400 Ma). The complex, multi-thermochronometric inverse modelling suggests a ubiquitous, rapid Late Cretaceous/early Palaeogene cooling event that is particularly marked in Lake District and Criffell. The timing and rate of cooling in southern Scotland and in northern Wales is poorly resolved as the amount of cooling was less than 60◦C. The Lake District plutons were at >110◦C prior to the early Palaeogene; cooling due to a combined effect of high heat flow, from the heat producing granite batholith, and the blanketing effect of the overlying low conductivity Late Mesozoic limestones and mudstones. Modelling of the heat transfer suggests that this combination produced an elevated geothermal gradient within the sedimentary rocks (50–70◦C/km) that was about two times higher than at the present day. Inverse modelling of the AFT and AHe data taking the crustal structure into consideration suggests that denudation was the highest, 2.0–2.5 km, in the coastal areas of the Lake District and southern Scotland, gradually decreasing to less than 1 km in the northern Southern Uplands and northern Wales. Both the rift-related uplift and the intra-plate compression poorly correlate with the timing, location and spatial distribution of the early Palaeogene denudation. The pattern of early Palaeogene denudation correlates with the thickness of magmatic underplating, if the changes of mean topography, Late Cretaceous water depth and eroded rock density are taken into consideration. However, the uplift due to underplating alone cannot fully justify the total early Palaeogene denudation. The amount that is not ex- plained by underplating is, however, roughly spatially constant across the study area and can be referred to the transient thermal uplift induced by the mantle plume arrival. No other mechanisms are required to explain the observed pattern of denudation. The onset of denudation across the region is not uniform. Denudation started at 70–75 Ma in the central part of the Lake District whereas the coastal areas the rapid erosion appears to have initiated later (65–60 Ma). This is ~10 Ma earlier than the first vol- canic manifestation of the proto-Iceland plume and favours the hypothesis of the short period of plume incubation below the lithosphere before the volcanism. In most of the localities, the rocks had cooled to temperatures lower than 30◦C by the end of the Palaeogene, suggesting that the total Neogene denudation was, at a maximum, several hundreds of metres. Rapid cooling in the last 3 million years is resolved in some places in southern Scotland, where it could be explained by glacial erosion and post-glacial isostatic uplift.