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2003 (June): Boulder-gravel hummocks and wavy basal till contacts: products of subglacial meltwater flow beneath the Saginaw Lobe, south-central Michigan, USA. Boreas, Vol. 32, pp. 328-336. Oslo. ISSN 0300-9483.Hummocky terrain composed of boulder gravel and a wavy contact between stratified till and sand are described and explained as products of subglacial meltwater activity beneath the Saginaw Lobe of the Laurentide Ice Sheet in south-central Michigan. Exposures and geophysical investigations of hummocky terrain in a tunnel channel reveal that hummocks ($100 m diameter) are glaciofluvial bedforms with a supraglacial melt-out till or till flow veneer. The hummocky terrain is interpreted as a subglacial glaciofluvial landscape rather than one of stagnant ice processes commonly assumed for hummocky landscapes. Sandy bedforms at another site are in-phase with a wavy contact at the base of a stratified till exposed for 50 m along the margin of a tunnel channel. The 0.4 m thick stratified till is overlain by up to 5 m of compact, pebble-rich, sandy subglacial melt-out till. The contact between the till and sand has a wave form with a 0.5 m amplitude and 3-5 m wavelength. Bedding within the stratified till, sandy bedforms and melt-out till are mostly in-phase with each other. Clasts from the overlying stratified till penetrate and deform the underlying sand recording recoupling of the ice to its bed. Ice ripples cut into the base of river ice have a similar morphology and are considered analogs for cavities cut into the base of the glacier and subsequently filled with sand. Subglacial meltwater activity was not coeval at each study site, indicating that subglacial meltwater played important roles in the evolution of the subglacial environment beneath the Saginaw Lobe at different times.

ABSTRACT. The Burroughs Glaci er, so uth-east A laska, is a slow-m ov in g remnant ( 14 X 3 km. ) of a much more ex tensive glacier. It is n ow entirely b elow th e firn line; ablat ion has revealed ice structures and fabri c once 300 m. or more below the g lacier surfacc .A t the present glacie r surface three kinds of ice are iden tified -foliated ice, coarse-grained border ice and very coarse-grained basal ice.Two systems of fine-grained foliation a re present. Differential m ovem ent in the g lacier has caused recrystallization a long closely spaced p lanes. At the g lac ier surface thi s produces a steeply d ipp ing longitud in a l foliation. A gently dippin g foliation , hav ing a reg iona l trough-like structure, may be associated with form er stratification p lanes or with former spoon-shaped sh ear su rfaces.T he optic ori entation of cr ystal s in the coarser layers of the foliated ice shows three weak maxima, and in th e fin er layers a singl e weak maximum , correspond ing to one of the coarse layer maxima, a nd normal to the gently d ipp in g foliation p lane. Th e other maxima in th e coarse layers a re orientated close to the poles of principal fracture planes .In the coarse ice the fabric shows a pattern w ith three maxima similar to that obta in ed in torsion shear exper iments. I n th e glacier the pattern may be formed by shear near the glacier bottom o r a long gent ly dipping foliation planes. Grain -size increases towards the glacier te rminus, especially in th e stagnant ice zone .Structura l ev idence suggcsts that in th e earl y stages of the Little Ice Age the ice Row was from west to eas t. Later it was to cast and west from an ice crest in the upper Burroughs G lacier. Structures produced by present movement have b een supe rimposed on o lder structures. R ESUME. L e glacier Burroughs, dans le Sud-Est de l'Alaska, es t un r este ( 14 X 3 km ) it mouvement lent d ' un glacier b eaucoup p lus important. 11 est maintenant entierement en -dessous de la li gne de nevc ; I'ablation a mis en evid ence des structures et des tex tures d e g lace, qui on e ex istees it 300 m au moin s e n-dessous d e la surface d u g lacier.Actue ll ement on peut id entifi er 3 sortes de g lace it la surface d u g lac ier: g lace feuill etce, g lace bordiere it gros gra ins, g lace d e fond it tres g ros grains.O n constate la presence d e 2 systemes d e foliation a gra in s fins. D es mouvements differentiels dans le glacier ont cause des recristallisation le long de p lans rapproches. Ceci se traduit a la surface du glac ier par une foliation it fort pendage longitud in a l. Vne foli at ion a faibl e pendage ayant une structure locale en form e d e c reux p eut etre assoc iee avec d 'a nci ens plans d e stratification ou avec d ' a n c iennes surfaces d e c isa illem en t en forme de cui ll er.L'ori entat ion optique d es cr istau x dans les couc h es it gros gra ins d e la g lace feuill etee , pn'sente 3 faibl es maxima et un se ul faibl e maximum dans les cr istaux a gra ins fins; ce max imum est perpend ic...

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Strandlines and related features representing former high glacial-lake levels possibly related to the Glenwood and Calumet phases of glacial Lake Chicago were identified from Oceana County north to Benzie County in the northwestern lower peninsula of Michigan. Lacustrine features occur as far as 25 km inland from the Lake Michigan shore at altitudes above the rebounded water planes of glacial Lake Algonquin and the Nipissing Great Lakes identified by earlier investigators.In order to determine if the water planes identified in this study and those of previous investigators represent the Glenwood and/or Calumet phases, water-plane altitudes are compared with a height/distance curve for the highest level of the Lake Algonquin water plane constructed by J. W. Goldthwait. The Goldthwait curve north of his zero isobase indicates the nature of glacial isostasy for the northern Lake Michigan basin following the development of the Glenwood and Calumet phases. The rebounded water planes of both the Glenwood and Calumet phases should follow exponential curves similar to that of Lake Algonquin but at higher altitudes.The water-plane data were projected onto a vertical plane oriented perpendicular to Goldthwait's Lake Algonquin isobases in the northern part of the Lake Michigan basin and parallel to the axis of Lake Michigan in the southern part of the basin. From Ludington north to Frankfort, Michigan, the array of water-plane altitudes is diffuse but has an upper boundary that corresponds to a theoretical Glenwood II water plane. Only two sites occur at elevations high enough to be attributed to a Glenwood I water plane. Lacustrine features that occur at lower altitudes within the array, but above the Algonquin level, are within range of a theoretical Calumet water plane.Correlation of water-plane data with either the Glenwood or Calumet phase will probably remain unclear until ages are determined for many of the features.

In considering acts of military intervention by foreign powers which occurred in Mexico during the Mexican Revolution, one is apt to think of the years 1914, 1916 and 1919, when U.S. forces invaded or occupied portions of Mexican territory. There was, however, one case of intervention of this sort during the revolution in which U.S. military personnel were not involved–the landing of a small party of British marines belonging to the H.M.S. “Shearwater” at the port of San Quintín on the northwest coast of the Baja Californian peninsula in April 1911.The British landing at San Quintm constituted a vestige or remnant of "gunboat diplomacy", an aspect of English foreign policy that had originated in the age of Palmerston and which reflected the unrivaled naval supremacy enjoyed by Great Britain during the period extending from the defeat of Napoleon in 1815 to the end of the Second World War. The episode represented, in a rather overt way, the hard-nosed attitude characteristic of British foreign policy at that time with regards to Latin America in general and other so-called "backward" regions of the globe.

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