Chemical differentiation of the Cordillera Paine granite (southern Chile) by in situ fractional crystallization

1984 ◽  
Vol 87 (2) ◽  
pp. 179-195 ◽  
Author(s):  
Peter J. Michael
Keyword(s):  
Fractional Crystallization ◽  
Southern Chile ◽  
Chemical Differentiation

scholarly journals The predation of farmed salmon by South American sea lions (Otaria flavescens) in southern Chile

2009 ◽  
Vol 67 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Juan Vilata ◽  
Doris Oliva ◽  
Maritza Sepúlveda
Keyword(s):  
Prey Size ◽  
South American ◽  
Southern Chile ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
Farmed Salmon ◽  
South American Sea Lion ◽  
Autumn And Winter ◽  
Strong Suspicion

Abstract Vilata, J., Oliva, D., and Sepúlveda, M. 2010. The predation of farmed salmon by South American sea lions (Otaria flavescens) in southern Chile. – ICES Journal of Marine Science, 67: 475–482. The South American sea lion Otaria flavescens is abundant off southern Chile. Because Chilean salmon farming has experienced an explosive growth in the past two decades, interactions between O. flavescens and this industry have increased. Fieldwork, including in situ behavioural observations, was carried out at three salmon farms off southern Chile from May to July 2008. The aim was to analyse possible patterns in the interactions and to evaluate whether they were influenced by the endogenous circa-rhythms of the species, prey size, tidal flux, and the use of an acoustic harassment device (AHD). The results showed that the attacks by O. flavescens followed seasonal patterns, with salmon predated more in autumn and winter, and daily patterns, with more interactions at night. In addition, attacks were more frequent on larger salmon, suggesting the existence of a prey-size preference. More sea lions were sighted at the ebb and flow tide peaks, when currents are stronger, suggesting that currents linked to tidal flux might facilitate the access of the sea lions to the farmed salmon. Although the use of AHDs appeared positive at one site, there is a strong suspicion that their efficacy may be site-specific.

Coexistence in a subtidal habitat in southern Chile: the effects of giant kelp Macrocystis pyrifera overgrowth on the slipper limpet Crepipatella fecunda

2014 ◽  
Vol 95 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Francisco J. Díaz ◽  
Sandra V. Pereda ◽  
Alejandro H. Buschmann
Keyword(s):  
Annual Cycle ◽  
Kelp Forest ◽  
Population Level ◽  
Macrocystis Pyrifera ◽  
Ecological Interactions ◽  
Southern Chile ◽  
Positive Effect ◽  
Neutral Effect ◽  
Slipper Limpet

In many coastal areas substrate is the limiting resource for benthic organisms. Some sessile species can be used as secondary substrate, reducing competition and increasing coexistence. In southern Chile, annual populations of Macrocystis pyrifera recruit and grow on the shells of Crepipatella fecunda. This study describes ecological interactions between the kelp and the slipper limpet over an annual cycle. The degree of kelp overgrowth was established by collecting sporophytes and through in situ submarine photography over a 10 month period (starting when kelp recruits became visible and ending when sporophytes were no longer present). Changes in the biochemical composition of the limpet tissue were also recorded by chemical analyses, to evaluate the potential effects (positive/neutral/negative) of kelp on C. fecunda nutritional condition. The results indicate that both species coexist, although kelp overgrowth may cause a decrease in carbohydrates in C. fecunda tissues, restricted to the period when the kelp forest reaches its maximum biomass. Individually, the short duration of the maximum overgrowth period and the size reached by C. fecunda females (up to 65 mm shell length) may enable rapid limpet recovery, avoiding competitive exclusion. On a population level, the M. pyrifera annual cycle generates the needed ‘break’ for C. fecunda populations, reducing the effects of kelp overgrowth. Thus, in the view of the neutral effect of kelp overgrowth, together with the positive effect of C. fecunda on M. pyrifera recruitment described somewhere else, this ecological interaction can be categorized as commensalism.

scholarly journals COLLECTION OF FRAGARIA IN CENTRAL AND SOUTHERN CHILE

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1141f-1141
Author(s):  
Thomas M. Sjulin ◽  
J. Scott Cameron ◽  
Carl H. Shanks ◽  
Carlos E. Munoz
Keyword(s):  
Fruit Size ◽  
Soluble Solids ◽  
Considerable Variability ◽  
Southern Chile ◽  
Reproductive Characteristics ◽  
Wide Range ◽  
Very High

In January, 1990, a team of U.S. and Chilean scientists collected native and cultivated Fragaria from central and southern Chile. During the course of this expedition, 363 new accessions of Fragaria were collected. Approximately 2,500 plants of 250 clones were collected from 66 sites in 19 different areas, and 113 seedlots (estimated at over 100,000 seeds) were obtained.Plants were collected from a wide range of habitats, and considerable variability was observed in vegetative and reproductive characteristics. Fruit were round to conical in shape, deep red to white in color, soft to moderately firm, with soluble solids ranging from 5-18%, dull to glossy skin, bland to strong flavor, low to very high aromatics, and difficult to moderately easy capping. Fruit size in situ approached 4 g, while fruit larger than 12 g were found under cultivated conditions. Strawberry aphids (Chaetosiphon fragaefolii) were found on plants in situ and under cultivation. Little or no evidence of other pests were observed on clones collected in situ.

scholarly journals Performance of Satellite-Based Evapotranspiration Models in Temperate Pastures of Southern Chile

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3587
Author(s):  
Italo Moletto-Lobos ◽  
Cristian Mattar ◽  
Jonathan Barichivich
Keyword(s):  
Water Footprint ◽  
Southern Chile ◽  
Productivity Losses ◽  
Lack Of Information ◽  
Irrigation Practice ◽  
Average Water ◽  
In Situ Observations ◽  
Temperate Pastures ◽  
Sustainable Irrigation

Farmers in the temperate zone of southern Chile have started to irrigate historically rainfed pastures during recent years to reduce dairy productivity losses against increasingly severe summer droughts. The lack of information on pasture water requirements (i.e., evapotranspiration), however, hampers the implementation of efficient irrigation programs. Here, we use in-situ observations to evaluate the skill of four remote sensing Surface Energy Balance (SEB) models and two satellite-based global evapotranspiration products (PML_V2 and GLEAM) to estimate actual evapotranspiration (ETa) of pastures in southern Chile during 2014–2017. Daily ETa measured at an evaluation site over the period ranges between 1.2 mm and 6.2 mm day−1 during the growing season (October–March), with an annual maximum of about 4.8 mm day−1 in January and a minimum 0.6 mm day−1 in June. Only the Simplified SEB (SEBS) model and its operational variant (SSEBop) and the PML_V2 global evapotranspiration product perform well, capturing 63–79% of the variance of in-situ evapotranspiration with an error between 0.75 mm day−1 and 1.1 mm day−1. The readily available PML_V2 product can be used as a convenient way to determine average water footprint of pastures and the two SEBs models can be implemented to monitor irrigation requirements in near-real time from field to regional scales. These results demonstrated a high potential of satellite observations for monitoring evapotranspiration and quantify the water footprint of pastures in southern Chile for a sustainable irrigation practice.

Paleomagnetism of Lower Cretaceous rocks from east of the Liquine-Ofqui fault zone, southern Chile: evidence of small in-situ clockwise rotations

1992 ◽  
Vol 113 (4) ◽  
pp. 539-551 ◽  
Author(s):  
Jose Cembrano ◽  
Myrl E. Beck ◽  
Russell F. Burmester ◽  
Constanza Rojas ◽  
Alfredo Garcia ◽  
...  
Keyword(s):  
Fault Zone ◽  
Lower Cretaceous ◽  
Southern Chile

Cretaceous diapiric plutonism in the southern cordillera, Chile

1987 ◽  
Vol 124 (6) ◽  
pp. 569-575 ◽  
Author(s):  
M. Suarez ◽  
M. Herve ◽  
A. Puig
Keyword(s):  
Upper Jurassic ◽  
Southern Chile ◽  
Small Bodies ◽  
North West ◽  
Metasedimentary Rocks ◽  
Rock Types ◽  
Short Period ◽  
Intrusive Rocks ◽  
Quartz Monzodiorites

AbstractThe Castores and probably the Santa Rosa plutons of north-west Isla Navarino, southern Chile, have been emplaced by in situ diapirism into metasedimentary rocks of the Upper Jurassic (?)–Lower Cretaceous Yaghan Formation. For the former, this model is consistent with the concentric foliation paralleling the margin of the pluton and the foliation and stratification planes in the metamorphic aureole. Only the southern part of the Santa Rosa Pluton is preserved, and it has some structures similar to those of the Castores Pluton, which can also be interpreted as produced by an inflating diapir. The main intrusive rocks of these plutons are quartz-monzodiorites and quartz-diorites with synmagmatic foliation. They were preceded by minor bodies of hornblende gabbros, and followed by dykes and small bodies of non-foliated granodiorites. Non-foliated to weakly foliated granodiorites, forming the centre of the Castores Pluton, probably represent a younger intrusive pulse.Twelve K–Ar mineral dates from 10 specimens of plutonic rocks, interpreted as near crystallization ages, span the period 80–90 Ma. These dates do not show the sequence of intrusion of the different rock-types, which may suggest that all of them were intruded and cooled in a short period of time. The timing of emplacement of these plutons in relation to tectonism is difficult to determine; however, a post-tectonic emplacement for at least the Castores Pluton, is proposed.

The Shiant Isles Main Sill: structure and mineral fractionation trends

1996 ◽  
Vol 60 (398) ◽  
pp. 67-97 ◽  
Author(s):  
F. G. F. Gibb ◽  
C. M. B. Henderson
Keyword(s):  
Diffusion Coefficient ◽  
Fractional Crystallization ◽  
Host Rock ◽  
Cation Diffusion ◽  
Stages Of Development ◽  
Calcic Plagioclase ◽  
Sulphide Mineralization ◽  
Mineral Zoning

AbstractThe Shiant Isles Main Sill, of Tertiary age, is a classic example of a composite, differentiated alkaline basic sill. The first unit to be intruded was a 2 m thick olivine teschenite which was emplaced with phenocrysts of olivine (mg> 83) [mg≡ Mg#] and, perhaps, plagioclase. This was intruded by a 24 m thick picrite sill consisting of a mush of melt and suspended olivine phenocrysts (mg> 83) with a D-shaped modal profile. The 140 m thick picrodolerite-crinanite unit was formed by a magma carrying ∼ 10% olivine (mg> 83) as the main phenocryst phase, together with some calcic plagioclase phenocrysts, being emplaced into the top of the picrite unit before the host rock was completely solidified. The olivine phenocrysts settled towards the bottom to form the picrodolerites.In-situdifferentiation processes occurred under conditions of almost perfect fractional crystallization, during which very strongly zoned ophitic crystals of olivine (fayalitic rims) and clinopyroxene (hedenbergitic rims), and zoned laths of plagioclase (anorthoclase rims), formed. The last unit consists of ∼ 2 m of granular olivine picrodolerite which was intruded into the upper crinanites, again before the host rock was fully solid.The mineral zoning patterns are interpreted using published cation diffusion coefficient data, and used to show that the picrite unit might have cooled to the blocking temperatures for Mg and Fe diffusion in < 5 years, and that even the relatively thick crinanite unit cooled very fast, so preserving the zoned Fe-Mg olivine and pyroxene compositions. The compositions of coexisting ilmenites and spinels define a redox trend which initially lies close to fayalite-magnetite-quartz buffer conditions, but later becomes more reducing and approaches magnetite-wustite buffer conditions. The final stages of development occurred during sub-solidus deuteric processes and involved formation of analcime and zeolites, as well as localized sulphide mineralization.

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