Ordeal by Siege: James Bruce in Pensacola, 1780-1781

Of the aspects of British West Florida attracting the attention of historians none surpasses the siege of Pensacola in 1781. All accounts rely on the reports of combatant participants, but no historian of West Florida has evidently used or perhaps been aware of the observations of one of the many civilian observers trapped by war in Pensacola. He was James Bruce, collector of customs at Pensacola. While enduring with his countrymen the final desperate days of British rule in the province, he wrote six letters to mercantile friends in London. They provide, apart from illuminating details of economic conditions during the siege, insights into the psychology of the besieged. They contain hopes, speculations, and denunciations which have no place in official reports. Nothing is known of Bruce’s origins, although his association with West Florida’s “Scotch” party and his name suggest that he was a Scot. He was a warrant officer in the Royal Navy in 1758, when British land and sea forces captured the French fortress of Louisbourg on Cape Breton Island after a siege of seven weeks. By the end of the Seven Years’ War when Bruce, along with the bulk of wartime servicemen, was demobilized or, to use the term then current, reduced, his naval position was “secretary to a flag officer and commander in chief.“ Association with extremely senior officers, which Bruce’s job would have entailed, may have made it possible for him to aspire to favors normally denied to noncommissioned personnel such as himself

A Letter From West Florida in 1768

It has been generally accepted by historians writing on the subject that “there is little evidence that the inhabitants of West Florida were particularly aware of events such as the Sugar Act, Colonial Currency Acts, Townshend Acts. . .” and that “the inhabitants actually were little aware of the disturbances occurring in the northern colonies. . . .“1 The author of the following letter would not have agreed. His letter demonstrates that he was no Tory, had read Dickinson’s Letter of a Pennsylvania Farmer, and was well aware of the “disturbances occurring in the northern colonies.

Changes in vertical ice extent along the East Antarctic Ice Sheet margin in western Dronning Maud Land – initial field and modelling results of the MAGIC-DML collaboration

Constraining numerical ice sheet models by comparison with observational data is crucial to address the interactions between cryosphere and climate at a wide range of scales. Such models are tested and refined by comparing model predictions of past ice geometries with field-based reconstructions from geological, geomorphological, and ice core data. However, for the East Antarctic Ice sheet, there is a critical gap in the empirical data necessary to reconstruct changes in ice sheet geometry in the Dronning Maud Land (DML) region. In addition, there is poor control on the regional climate history of the ice sheet margin, because ice-core locations, where detailed reconstructions of climate history exist, are located on high inland domes. This leaves numerical models ofregional glaciation history in this near-coastal area largely unconstrained. MAGIC-DML is an ongoing Swedish-US-Norwegian-German-UK collaboration with a focus on improvingice sheet models of the western DML margin by combining advances in modeling with filling critical data gaps regarding the timing and pattern of ice-surface changes. A combination of geomorphological mapping using remote sensing data, field observations, cosmogenic nuclide surface exposure dating, and numerical ice sheetmodeling are being used in an iterative manner to produce a comprehensive reconstruction of the glacial historyof western DML. Here, we present an overview of the project, field evidence for formerly higher ice surfaces and in-situ cosmogenic nuclide measurements from the 2016/17 expedition. Preliminary field evidence indicate that interior sectors of DML have experienced a general decrease in ice sheet thickness since the late Miocene, with potential episodes of increasing thickness in the late Pleistocene (700-300 ka, 250-75 ka). To aid in interpreting these field data, new high-resolution ice sheet model reconstructions, constraining ice sheet configurations during key episodes, are presented

Mid-Pleistocene ice sheet fluctuations from cosmogenic nuclide field constraints in western Dronning Maud Land, Antarctica

The East Antarctic Ice Sheet (EAIS) is generally assumed to have been relatively insensitive to Quaternary climat echange. However, recent studies have shown potential instabilities in coastal, marine sectors of the EAIS. In addition, long-term climate reconstructions and modelling experiments indicate the potential for significant changes in ice volume and ice sheet configuration since the Pliocene. Hence, more empirical evidence for ice surface and ice volume changes is required to discriminate between contrasting inferences. MAGIC-DML is an ongoing Swedish-US-Norwegian-German-UK collaboration focused on improving ice sheetm odels by filling critical data gaps that exist in our knowledge of the timing and pattern of ice surface changes along the western Dronning Maud Land (DML) margin and combining this with advances in numerical techniques. As part of the project, field studies in the 2016/17 and 2017/18 austral summers targeted selected sites spanning accessible altitudes in the Heimefrontfjella, Vestfjella, Ahlmannryggen, Borgmassivet, and Kirwanveggen nunatakranges for in situcosmogenic nuclide sampling. Comparing concentrations of nuclides with widely differing half-lives in bedrock and erratics from a range of altitudes above modern ice surfaces can provide information on ice sheet fluctuations and complex burial and exposure histories, and thus, past configurations of non-erosive ice. Quartz-bearing rock types were sampled and analyzed for 10Be (t1/21.4 My),14C (t1/25.7 ky),26Al (t1/2705ky), and 21Ne (stable), and mafic lithologies for36Cl (t1/2301 ky). Results thus far for 3210Be and 26Al isotope pairs complemented with seven21Ne measurements have yielded some consistent patterns of paleoglaciation for the western DML margin. Eight out of fourteen bedrock samples from high-elevation (1700-2238 m a.s.l.) ridges and summits return some of the oldest exposure ages in Antarctica and have consistent 10Be,26Al, and 21Ne minimum apparent exposure ages of 1.8-4.1 Ma. Initial results therefore indicate that parts of the ice sheet marginal to the Antarctic plateau, along the Heimefrontfjella range, generally have experienced a decrease in ice thickness since the late Miocene. Another six bedrock samples (1556-1732 ma.s.l.) fall in the 300-700 ka range, and they all show significant burial. At face value, perhaps this indicates aregional ice sheet surface above 1700 m a.s.l. for much of the Plio-early Pleistocene. All other samples analyzedto date are erratics from lower elevation and more coastal sites (10 from nunataks at 553-1400 m a.s.l., and 6 froma surface moraine at 1385 m a.s.l.), exhibiting ages between 59 and 275 ka, save for two (4 and 6 ka). Whereas almost all of the nunatak erratics (including the young ones) show significant burial durations, five of the six surface moraine samples do not. These 2016/17 field samples are not yet leading to conclusive age constraints but already start to paint a picture of the western DML margin being relatively stable although there was possibly one or more episodes of relatively limited ice thickening during the last 700 ka

James Thompson, Pensacola\u27s First Realtor

The accompanying document was published first in the New York Journal, November 5, 1767, and was reprinted without alteration half a dozen times. It appeared for the last time on March 24, 1768. It is the first known private advertisement for real estate in the history of the British colony of West Florida. James Thompson, the man who submitted it, was not the first land speculator in the province, but, in his search for customers among the general public in other parts of America, his readiness to cultivate customers of limited means, and his care to advertise property as attractively as possible, his methods resemble those of a modern realtor

Paleoglaciological study of Borgmassivet, Dronning Maud Land, East Antarctica, using WorldView imagery

Paleoglaciological reconstructions based on glacial geological and geomorphological traces are the basis for testing and constraining numerical models of ice sheet extent and dynamics. In MAGIC-DML (“Mapping, Measuring and Modelling Antarctic Geomorphology and Ice Change, in Dronning Maud Land”) we aim to reconstruct the timing and pattern of ice surface elevation changes since the mid-Pliocene across western Dronning Maud Land, East Antarctica. The choice of study area is motivated by an absence of empirical field data and considerable ice sheet model uncertainties. We present a remote sensing-based mapping of glacial geomorphology and structures on the ice sheet surface for a coastal-inland transect including Ahlmannryggen-Borgmassivet-Kirwanveggen using high-resolution WorldView imagery. The primary aim of the study is to map traces of a thicker ice sheet on nunatak slopes that were formerly partly or entirely covered during surface highstands. Panchromatic and multispectral images were analysed in a multi-step procedure using ArcGIS, including image processing and mosaicking, visual feature recognition, and mapping. The identification of crucial landforms (such as till veneers and erratic boulders) required the adoption of some assumptions to differentiate, for example, till from regolith. Where patterned ground was mapped, we infer a presence of till rather than regolith since subglacial erosion is more likely to produce fine material than subaerial weathering. Huge boulders on plateau surfaces are mapped as erratics because they could not have been delivered by slope processes to local highpoints. Sediment veneers with ridges were mapped as till because the ridges are inferred to originate from reworking by ice. However, because of the necessity to invoke assumptions and the absence of crosscutting relationships between landforms, we are unsure of the reliability of derived paleo-ice sheet reconstructions. At face value, the data indicates thicker ice in the past from the altitude above present ice surface of till cover and erratics on some nunataks. Mapping and landform interpretations will be verified during the MAGIC-DML 2017-18 field season. The mapping of structures on the ice sheet surface is used to (i) infer ice flow characteristics; This was possible by assessing the distribution of primarily blue ice areas, crevasse fields, and supraglacial moraines, and by analysing their connection to wind directions and ablation rates; and (ii) yield target field routes to potential cosmogenic nuclide (CN) sampling locations along vertical transects on nunataks. The timing derived from CN dating will permit the delineation of ice sheet surface elevations as targets for ice sheet modeling