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

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.

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Palaeoenvironmental significance of storm coquinas in a Lower Cretaceous coastal lagoonal succession (Vectis Formation, Isle of Wight, southern England)

Geological Magazine ◽

10.1017/s0016756800003782 ◽

2000 ◽

Vol 137 (2) ◽

pp. 193-205 ◽

Cited By ~ 13

Author(s):

JONATHAN D. RADLEY ◽

MICHAEL J. BARKER

Keyword(s):

High Resolution ◽

Principal Components ◽

Lower Cretaceous ◽

Coastal Lagoons ◽

Trace Fossils ◽

Isle Of Wight ◽

Southern England ◽

Desiccation Cracks ◽

Stratigraphic Framework

Thin bioclastic limestone beds (‘coquinas’) in the Vectis Formation (Wealden Group, Lower Cretaceous) of the Isle of Wight, southern England, exhibit a range of biofabrics and internal stratigraphies. These features are attributed to both simple and complex storm deposition of allochthonous biogenic and siliciclastic materials in coastal lagoons and on adjacent mudflats. These modes of deposition facilitated preservation of dinosaur trackways, desiccation cracks, shallow-tier trace fossils and in situ bivalve colonies through rapid burial. The coquinas thus preserve a record of surficial muds, commonly lost through reworking. The principal components of the coquinas comprise dispersed elements from within the argillaceous ‘background’ facies. Some of these beds are laterally traceable for up to 27 km, providing the foundations for a high-resolution event-stratigraphic framework.

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Stitch in the ditch: Nutzotin Mountains (Alaska) fluvial strata and a dike record ca. 117–114 Ma accretion of Wrangellia with western North America and initiation of the Totschunda fault

Geosphere ◽

10.1130/ges02127.1 ◽

2019 ◽

Vol 16 (1) ◽

pp. 82-110 ◽

Cited By ~ 3

Author(s):

Jeffrey M. Trop ◽

Jeffrey A. Benowitz ◽

Donald Q. Koepp ◽

David Sunderlin ◽

Matthew E. Brueseke ◽

...

Keyword(s):

Fault Zone ◽

Lower Cretaceous ◽

Volcanic Rocks ◽

Alkali Feldspar ◽

Upper Jurassic ◽

Sediment Provenance ◽

Lake Formation ◽

Beaver Lake ◽

Channel Bar ◽

Marine Basin

Abstract The Nutzotin basin of eastern Alaska consists of Upper Jurassic through Lower Cretaceous siliciclastic sedimentary and volcanic rocks that depositionally overlie the inboard margin of Wrangellia, an accreted oceanic plateau. We present igneous geochronologic data from volcanic rocks and detrital geochronologic and paleontological data from nonmarine sedimentary strata that provide constraints on the timing of deposition and sediment provenance. We also report geochronologic data from a dike injected into the Totschunda fault zone, which provides constraints on the timing of intra–suture zone basinal deformation. The Beaver Lake formation is an important sedimentary succession in the northwestern Cordillera because it provides an exceptionally rare stratigraphic record of the transition from marine to nonmarine depositional conditions along the inboard margin of the Insular terranes during mid-Cretaceous time. Conglomerate, volcanic-lithic sandstone, and carbonaceous mudstone/shale accumulated in fluvial channel-bar complexes and vegetated overbank areas, as evidenced by lithofacies data, the terrestrial nature of recovered kerogen and palynomorph assemblages, and terrestrial macrofossil remains of ferns and conifers. Sediment was eroded mainly from proximal sources of upper Jurassic to lower Cretaceous igneous rocks, given the dominance of detrital zircon and amphibole grains of that age, plus conglomerate with chiefly volcanic and plutonic clasts. Deposition was occurring by ca. 117 Ma and ceased by ca. 98 Ma, judging from palynomorphs, the youngest detrital ages, and ages of crosscutting intrusions and underlying lavas of the Chisana Formation. Following deposition, the basin fill was deformed, partly eroded, and displaced laterally by dextral displacement along the Totschunda fault, which bisects the Nutzotin basin. The Totschunda fault initiated by ca. 114 Ma, as constrained by the injection of an alkali feldspar syenite dike into the Totschunda fault zone. These results support previous interpretations that upper Jurassic to lower Cretaceous strata in the Nutzotin basin accumulated along the inboard margin of Wrangellia in a marine basin that was deformed during mid-Cretaceous time. The shift to terrestrial sedimentation overlapped with crustal-scale intrabasinal deformation of Wrangellia, based on previous studies along the Lost Creek fault and our new data from the Totschunda fault. Together, the geologic evidence for shortening and terrestrial deposition is interpreted to reflect accretion/suturing of the Insular terranes against inboard terranes. Our results also constrain the age of previously reported dinosaur footprints to ca. 117 Ma to ca. 98 Ma, which represent the only dinosaur fossils reported from eastern Alaska.

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First fossil liverwort with in situ flask-shaped receptacles from the Lower Cretaceous of Inner Mongolia, China

Cretaceous Research ◽

10.1016/j.cretres.2020.104684 ◽

2021 ◽

Vol 119 ◽

pp. 104684

Author(s):

Ruiyun Li ◽

Xiaoqiang Li ◽

Xuelian Wang ◽

Bainian Sun

Keyword(s):

Lower Cretaceous ◽

Inner Mongolia

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

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315414000228 ◽

2014 ◽

Vol 95 (1) ◽

pp. 25-33 ◽

Cited By ~ 1

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.

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Piezomagnetic In-situ Stress Monitoring and its Application in the Longmenshan Fault Zone

Acta Geologica Sinica - English Edition ◽

10.1111/1755-6724.12321 ◽

2014 ◽

Vol 88 (5) ◽

pp. 1592-1602 ◽

Cited By ~ 3

Author(s):

Chongyuan ZHANG ◽

Manlu WU ◽

Qunce CHEN ◽

Chunting LIAO

Keyword(s):

Fault Zone ◽

In Situ Stress ◽

Stress Monitoring ◽

Longmenshan Fault Zone ◽

Longmenshan Fault

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COLLECTION OF FRAGARIA IN CENTRAL AND SOUTHERN CHILE

HortScience ◽

10.21273/hortsci.25.9.1141f ◽

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.

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