Alpacas and Ecosystems Management

Alpacas are a species that present physiological, anatomical, morphological and behavioural distinctive characteristics compared to other species used in animal production. Empirical observation of a herd, grazing under time management controlled conditions, allowed to approximate some initial observations about the effect of alpacas in the management of ecosystems. Larger green matter availability in the paddocks grazed by alpacas, evident natural weed control, better plants distribution and increasing stocking capacity were the relevant observed issues. It is considered that the special behavioural characteristics of alpacas in terms of excretion habits, low hoof pressure, food conversion efficiency and grazing habits should be factors to be rigourously studied to explore the value of alpacas as an environmentally friendly species.Sustainable farm management, farming systems research, alpacas, Environmental Economics and Policy, Livestock Production/Industries,

Greenhouse Gases and Global Change: A Challenge for Canadian Geoscience

Climate change is the most pressing societal issue of our time. The Canadian geological community is deeply divided as to whether or not anthropogenic carbon dioxide is the principal driver of the global warming that we see around us. As geologists, we have the scientific understanding to be effective stewards of Planet Earth and thus have a critical role to play in the climate change debate. Many of the basic scientific principles in this debate, however, are more a matter of atmospheric physics than classical geology: this may be one reason why so much uncertainty continues in the geological community. Also, we have a professional responsibility to inform ourselves and our colleagues beyond the level of knowledge of the general public. We must apply the precautionary principle in assessing the response of the Earth to human activity. We should learn from the engineering and medical communities that our students should be well educated in fundamental principles and that a balanced assessment of issues should be presented to the public and decision-makers. The scientific debate over climate change should be carried on at mainstream meetings and in the peer-reviewed literature

Pisces IV submersible observations in the epicentral region of the 1929 Grand Banks earthquake

The PISCES IVsubmersible was used to investigate the upper continental slope around 44 ON, 56 W, near the epicentre of the 1929 Grand Banks earthquake. Four dives in water depths of 800-2000 m were undertaken to observe speci3c features identijied with the SeaMARC I sidescan system in 1983. Two dives were made in the head of Eastern Valley where pebbly mudstones ofprobable Pleistocene age were recognized outcropping on the seafloor. Constructional features of cobbles and boulders, derived by exhumation and reworking of the pebbly mudstone, were also observed. These include gravel/sand bedforms (transverse waves) on the valley floor. Slope failure features in semiconsolidated mudstone were recognized on two dives onto the St. Pierre slope. Exposures in these mudstones are rapidly eroded by intense burrowing by benthic organisms

The Gravity Signature of a Large Quaternary Depocentre off Southeastern Canada

New bathymetry, gravity and Pliocene - Quaternary sediment isopach maps have been compiled and gridded for the Scotian margin. A large positive gravity anomaly exists over the Laurentian Fan, which is the major Pliocene - Quaternary depocentre on the Scotian margin. This gravity anomaly is not related to deep structure but can be largely explained by considering the Pliocene-Quaternary sediments as isostatically uncompensated. This implies that the underlying continental margin lithosphère has had considerable strength for at least 3 Ma. Some residual anomalies not accounted for by Pliocene-Quaternary sediment thickness may represent thicker Miocene depocentres, but improved seismic and stratigraphie data are required to assess this possibility. The technique of gravity identification of major sediment depocentres is a useful reconnaissance tool in certain circumstances, such as where there is a topographic expression and the deposit is thick and of major areal extent.On a procédé à la compilation des cartes bathymétrique, de gravité marine et des cartes isopaques des sédiments pliocènes/quaternaires de la marge continentale de Scotian. Il existe une importante anomalie gravimetrique au-dessus du cône Laurentien, principale zone d'accumulation pliocène/quaternaire de la marge continentale de Scotian. L'anomalie gravimetrique n'est pas reliée à la tectonique de fond, mais peut en bonne partie s'expliquer si l'on considère que les sédiments pliocenes/ quaternaires n'ont subi aucune compensation isostatique. Ceci implique que la lithosphère de la marge continentale sous-jacente offre une grande résistance depuis au moins 3 Ma. Certaines anomalies résiduelles non imputables à l'épaisseur de la couverture sédimentaire pliocène/quaternaire pourraient être attribuées aux épaisses zones d'accumulation du Miocène; de meilleures connaissances de la sismicité et de la stratigraphie sont nécessaires pour confirmer cette hypothèse. La technique permettant de déterminer la gravité des zones de grande accumulation est un bon outil de reconnaissance en certains cas, c'est-à-dire lorsqu'il y a un relief d'importance et que le dépôt est épais et d'une grande superficie.Neue Karten der Tiefseelotung, der Tiefsee-Schwere und "isopache" Karten der Pliozân/Quaternàr-Sedimente wurden fur den Konti-nentalsaum von Nova Scotia kompiliert. Eine breite, positive Schwereanomalie besteht ûber dem laurentidischen Fâcher, welcher die Hauptablagerungszone im Pliozân-Quaternâr am Kontinentalsaum von Nova Scotia ist. Dièse Schwereanomalie beruht nicht auf der Tiefenstruktur, sondern kann weitgehend dadurch erklàrt werden, daB die Pliozàn-Quatemàr-Sedimente isostatisch nicht kompensiert waren. Dies bedeutet, dafî die Erdkruste des darunterliegenden Kon-tinentalsaums seit mindestens 3 Ma eine betràchtliche Widerstandsfàhigkeit aufweist. Einige Rest-Anomalien, die nicht auf die Dicke des Pliozàn-Quaternâr-Sediments zurùckgefùhrt werden kônnen, kônnten mit dickeren Ablagerungszonen aus dem Miozân erklàrt werden; doch um dièse Môglichkeit zu bestàtigen, sind verbesserte seismische und stratigraphische Messungen nôtig. DieTechnik, die Schwere von bedeutenden Sedimentablagerungs zonen zu bestimmen, ist unter bestimmten Voraussetzungen ein nùtzliches Erkennungs instrument, wie z.B. wenn ein wichtiges Relief vorhanden ist, und die Ablagerung dick und von grôBeren AusmaBen ist

The Pre- Carboniferous rocks of the western Cobequid Hills, Avalon zone, Nova Scotia

Pre-Carboniferous rocks of the western Cobequid Hills outcrop north of the Cobequid Fault, are cut by several major east-west faults, and are onlapped unconformably to the north by the Late Carboniferous Cumberland Group. The oldest rocks comprise the Late Hadrynian Jeffers Formation. In the south, this unit consists of mafic and felsic volcanic rocks, interbedded with mudstones and carbonates, that are overlain by turbidites. To the north, the Jeffers Formation consists of a thick sequence of felsic volcanogenic turbidites. This stratigraphic succession of volcanic rocks passing up into turbidites differs from some other Late Hadrynian Avalonian sequences In the predominance of sedimentary rocks, but does resemble the Georgevllle Group of the Antigonish Highlands. Mafic dykes and sills, and associated porphyritlc rbyolite Intrusions, Intruded the Jeffers Formation prior to the formation of a regional flat-lying cleavage. The Late Hadrynian Jeffers Brook Pluton, which post-dates this cleavage, consists of diorite with marginal granitic phases that also occur as dyke-like intrusions beyond the main pluton. Several smaller intrusions petrographically similar to the Jeffers Brook Pluton also occur. At least two series of later dykes, probably pre-Silurlan in age, cut the Jeffers Formation and the Late Hadrynian intrusions. The Silurian Wilson Brook Formation outcrops only at the extreme northern edge of the Cobequid Hills: it consists of fossiliferous fine-grained sandstones and shales which overlie thin rhyolites, basalts and red clastic sediments. This sequence is very similar to the lower part of the Arisaig Group north of the Antigonish Highlands to the east. It is overlain unconformably by the Devono-Carboniferous Fountain Lake Group of volcanic rocks and by Carboniferous sedimentary rocks which are significantly deformed only near the Cobequid Fault. Carboniferous granite plutons appear spatially related to the Kirkhill and Cobequid Faults. They are in places foliated and contain abundant mafic sills and dykes that appear to reflect continuing motion on the Cobequid Fault during emplacement and cooling of the granites. RÉSUMÉ Dans l'Ouest des Honts Cobequid, les roches précarbonifères affleurent su nord de la Faille de Cobequid, sont recoupées par plusieurs failles majeures de direction est-ouest et sont recouvertes en discordance, au nord, par le Groupe de Cumberland d'âge tardicarbonifère. Les roches les plus vieilles englobent la Formation de Jeffers du Tardihadrynien. Au sud, cette derniére se compose de volcanites mafiques et felsiques interlitées avec des mudstones et des carbonates, le tout couronne de turbidites. Vers le nord, la Formation de Jeffers renferme une pulssante assise de turbidites volcanogènes felsiques. Cette succession stratigraphique de volcanites passant vers le haut à des turbidites différe certes de quelques autres séquences tardihadrynlennes avalonlennes par la prédominance, en son sein, de roches sédimentalres male rappelle aussi le Groupe de Georgevllle dans les Monts Antigonish. La mise en place de dykes et filons-couches mafiques, ainsi que des intrusifs de rhyollte qui lcur sont associés. eut lieu avant la formation d'un clivage régional horizontal. Le Pluton tardihadrynien de Jeffers Brook, qui est postérieur à ce cllvage, est formé de diorite avec des phases granitiques marginales qui se présentent aussi au-delà du pluton principal sous formé d*intrusions ressemblant à des dykes. On rencontre aussl plusieurs intrusifs plus petlis mais de pétrographle similaire au Pluton de Jeffers Brook. Au molns deux ensembles de dykes plus tardlfs. probablepent d'âge presilurien, recoupent la Formation de Jeffers et les intrusifs tardlhadryniens. On n'observe la Formation silurienne de Wilson Brook qu'a la llsiere la plus au nord des Monts Cobequid: elle englobe des grès fins fosslliferes et des argilites qui recouvrent, tous deux, de minces rhyolites, basaltes et sédiments clastiques rouges. Cette séquence rappelle fortement la partie inférieure du Groupe d'Arisaig au nord des Monts Antigonish plus à l'est. Bile est recouverte en discordance par le Groupe de volcanites dévono-carbonifères de Fountain Lake et par des roches sédimentalres carbonifères qui ne sont déformées de façon importante qu'auprés de la Faille de Cobequid. Les plutons granitiques carbonifères semblent rattachés dans l'espace aux failles de Kirkhill et Cobequid. lis sont folies par endroits et contieiment d'abondants filons-couches et dykes mafiques qui semblent tradulre le jeu continu de la Faille de Cobequid durant la mise en place et le refroidissement des granites. [Traduit par le journal

Sediment transport processes at the head of Halibut Canyon, Eastern Canada margin: An interplay between internal tides and dense shelf water cascading

European Geosciences Union General Assembly 2013, 7-12 April, Vienna, Austria.-- 1 pageTo investigate the processes by which sediment is transported through a submarine canyon incised in a glaciated margin, the bottom boundary layer quadrapod RALPH was deployed at 276-m depth in the West Halibut Canyon (off Newfoundland) during winter 2008–2009. Two main sediment transport processes were identified throughout the deployment. Firstly, periodic increases of near-bottom suspended-sediment concentrations (SSC) were recorded associated with the up-canyon propagation of the semidiurnal internal tidal bore along the canyon axis, carrying fine sediment particles resuspended from deeper canyon regions. The recorded SSC peaks, lasting less than 1 h, were observed sporadically and were linked to bottom intensified up-canyon flows (~ 40 cm s− 1) concomitant with sharp drops in temperature. Secondly, sediment transport was also observed during events of intensified down-canyon current velocities that occurred during periods of sustained heat loss from surface waters, but were not associated with large storm waves. High-resolution velocity profiles throughout the water column during these events revealed that the highest current speeds (~ 1 m s− 1) were centered several meters above the sea floor and corresponded to the region of maximum velocities of a gravity flow. Such flows had associated low SSC and cold water temperatures and are interpreted as dense shelf water cascading events channelized along the canyon axis. Sediment transport during these events was largely restricted to bedload and saltation, producing winnowing of sands and fine sediments around larger gravel particles. Analysis of historical hydrographic data suggests that such gravity flows are not related to the formation of coastal dense waters advected towards the outer shelf that reached the canyon head. Rather, the dense shelf waters appear to be generated around the outer shelf, where convection during winter is able to reach the sea floor and generate a pool of near-bottom dense water that cascades into the canyon during one or two tidal cycles. A similar transport mechanism is likely to occur in other submarine canyons along the eastern Canadian margin, as well in other canyoned margins where winter convection can reach the shelf-edgePeer Reviewe

Relationships between tree stand density and burn severity as measured by the Composite Burn Index following a ponderosa pine forest wildfire in the American Southwest

The Trigo fire burned 5548 ha of the Manzano Mountains in central New Mexico in 2008. The fire burned with mixed severity through ponderosa pine (Pinus ponderosa) stands on the Cibola National Forest and private lands. The burned area exhibited a range of stand densities enabling this research to quantify the relationship between variation in tree density and burn severity using the Composite Burn Index (CBI) severity classification. Across 90 CBI plots, high tree density was strongly associated with high burn severity. The CBI method allowed classification of burn severity to a range of forest vertical fuels strata. Tree mortality and duff consumption are two attributes that recorded higher severity in plots with higher tree densities. The CBI approach is designed for rapid on-the-ground assessments; to compliment this procedure a rapid visual classification of stand density was tested to determine its accuracy for land managers. This visual assessment correlated well with quantitative measurements of tree density. Since density classes were also highly correlated with CBI scores they may therefore be a good predictor of burn severity in a stand. This is a more rapid way for land managers to categorize stand density than traditional density measurements. These findings demonstrate that reducing tree density in southwestern ponderosa pine stands may significantly lower burn severity resulting from wildfire