Slopes Of Andes Research Articles

Cercomacra manu, a New Species of Antbird from Southwestern Amazonia

Cercomacra manu, a New Species of Antbird from Southwestern Amazonia

Middle Preceramic Public and Residential Sites on the Forested Slope of the Western Andes, Northern Peru

A decade of intermittent archaeological research in the upper Zaña Valley in northern Peru has documented an intensive Middle Preceramic period (ca. 6000—4200 B.C.) occupation in the tropical-forest and thorn-forest ecotone on the western Andean slopes. This research has revealed one stratified nonresidential site (the Cementerio de Nanchoc), characterized by dual earth mounds, and a complex of small, preceramic residential sites in the Nanchoc branch of the valley. The nonresidential site is associated with the production of lime, probably used as a mineral supplement to the diet or as an extractive agent with coca leaves. Evidence recovered from residential sites shows that incipient horticulturists, documented by the presence of several species of cultigens, and unspecialized hunters and gathers lived in scattered households located along small streams in alluvial fans above the valley floor. A unifacial lithic technology and a diversified ground-stone technology attest to an economy primarily adapted to plant resources. The preceramic culture of the upper Zaña Valley is interpreted as a local manifestation of an early western-slope-forest cultural tradition associated with the development of a specialized public precinct and the adoption and intensification of agriculture.

Allozyme Variation and Morphological Relationships of Chenopodium hircinum (s.l.)

The domesticated Andean grain chenopod, Chenopodium quinoa, is sympatric with closely related wild types that are classified as two species. Large-fruited (1.5-1.8 mm diam.), broad- leaved plants are placed with C. quinoa, as either subsp. milleanum or var. melanospermum. Plants with smaller fruits (1.0-1.5 mm) and rhombic to tri-lobed leaves are treated as Andean varieties of C. hircinum, a species originally described from the eastern plains of South America. This alignment was evaluated by comparative analysis of electrophoretic and morphometric data taken from pop- ulations occurring throughout the range of C. hircinum (s.l.). Samples from the eastern Andean slopes and plains of Argentina (C. hircinum s. str.) form a coherent group that is positioned at one extreme in the pattern of leaf and fruit variation. These samples, characterized by small, obtuse-margined fruits and acute, lobed leaves, are linked to material from the high Andes through a series of intermediate Andean samples. Andean material shows a wide range of variation in fruit size and shape. Leaf shape is more conservative, although samples from Bolivia trend toward the acute, tri- lobed condition. In contrast to morphological relationships, allozyme variation is simple and well defined. Andean material is homogeneous (I > 0.98), with unique alleles widely dispersed, mainly in southern populations. Populations of C. hircinum (s. str.) are more variable (I = 0.951) and well differentiated from the highland group (I = 0.825) by a relatively common set of unique alleles. Minimal electrophoretic differentiation among Andean samples indicates that the companion weed of C. quinoa is a single biological entity that may represent an Andean element of C. hircinum,

The War on Drugs: The Peruvian Case

Peru is a Priority Theater in The US War against drugs in that it produces more coca for export to the United States than any other Latin American country. The Huallaga Valley, a remote area about 200 miles northeast of Lima on the eastern Andean slopes, is one of the world's most fertile coca-growing regions. This article focuses on what is known about Peru's coca industry, and the anti-drug efforts that have been undertaken by the US and Peruvian governments. Under President Alan Garcia, elected in 1985, the Peruvian government has been usually cooperative with US anti-drug programs; some explanations for this collaboration will be suggested.Despite the Garcia government's cooperative stance, the results of Peru's war against drugs have been similar to results elsewhere: governments have won some battles, but they are losing the war. Perhaps the most important question raised by the ' Peruvian case is whether the United States should give a higher priority to anti-drug efforts or to counterinsurgency; US policy regarding Peru has appeared to do the latter.

Allochthonous terranes in the Andes of Ecuador and northwestern Peru

In Ecuador and northwestern Peru the Andes and adjacent country, particularly on the Pacific side, are composed of at least five distinctive geologic terranes. The terranes are distinguished from one another and from cratonic South America to the east by dissimilar basements, cover rocks, intrusive rocks, and Bouguer gravity anomaly fields.The Piñón terrane, occupying most of coastal Ecuador, has a basaltic basement characterized by the largest known on-land positive Bouguer anomalies in the western hemisphere. The Tahuín terrane occupies most of northwestern Peru and the southwestern corner of Ecuador. The terrane has an especially complex basement and is the site of generally positive Bouguer anomalies. The small Birón terrane has an unusual basement composed in part of cordierite gneiss and amphibolite that give consistent Late Cretaceous K – Ar mineral ages. The wedge-shaped Chaucha terrane lies in part on the western Andean slope, between the oceanic Piñón terrane on the north and the continental Birón terrane on the south. The vast Santiago terrane composes the high Andes of southern Ecuador and northwestern Peru. It is the site of the unique Santiago Formation, a thick succession of Lower Jurassic limestones found nowhere else in the region.Geologic and geophysical evidence supports the view that the five terranes are parautochthonous or allochthonous fragments emplaced against cratonic South America from Middle Jurassic to Late Eocene time. Continental-border subduction alone (at the so-called "Andean margin") may have been an inadequate engine for orogeny. Additional allochthonous terranes perhaps await identification at other places along the Andes. Whether the emplacement of allochthonous terranes has been an important process elsewhere in the tectonic development of the Andes remains to be established. Geologic mapping on the oceanward western border of the Andean orogen, studies of basement petrology and chronology, and paleomagnetic studies are particularly needed.The distribution of mineral deposits (including petroleum) in Ecuador and northwestern Peru is not uniform but is instead related spatially to the five terranes and cratonic South America. This relationship can be useful to prospectors.

Leishmaniasis in different altitudes on Andean slope of Ecuador.

An epidemiological survey was performed in a leishmaniasis-endemic area along highway which was established about 15 years ago on the Andean slope of Ecuador; the area ranged from 300 m to 1, 500 m above sea level. In general survey, 64 (14.3%) of the 446 subjects examined were positive for leishmanial signs. In order to know leishmanial infections in relation to the altitudes of dwelling sites of subjects, analysis was made on 224 children with 5 to 15 years of age. At 4 different sites with 500 m, 1, 000 m, 1, 300 m and 1, 500 m above sea level, the infection rates of the subjects from the individual sites were 17.4, 18.8, 5.6 and 8.8%, respectively. A statistically significant difference was recognized between the altitudes, 500-1, 000 m and 1, 300-1, 500 m (0.01 < p< 0.05, χ2= 5.314), but not between 500 m and 1, 000 m and between 1, 300 m and 1, 500 m. Leishmanial infections of the children who came from forest and highway areas were compared in each altitude. But no significant difference was found between forest and highway dewellers at any study sites.

The spread of the House Sparrow Passer domesticus in Bolivia

Bolivia lies within the Tropics and contains extremes from desert to jungle and from low to high altitudes. House Sparrows entered the south of Bolivia from Argentina about 1930 and have now spread to towns and villages scattered through about half of the country. These are principally in the semi‐arid Andean descents of south and central Bolivia and in the lowlands in Santa Cruz city and certain nearby towns. In the high altiplano they have reached only two cities and are not numerous in either. They appear to be absent from the humid Andean slopes and from most of the eastern and northern lowlands, with the exception of two isolated towns which they could have reached either from Brazil or from elsewhere in Bolivia. House Sparrows do not occur away from human settlements in Bolivia.

Hemispheric differences in face perception at various processing stages

Two hypotheses have attempted to explain the development of Mixed Paleofloras during the Cenozoic in South America. One of them postulates changes in the climatic tolerances of its component taxa and the other calls for the establishment of atmospheric thermal stability (“equable climate”) at the time these floras came into existence. We set out to test these hypotheses using leaf physiognomical analyses for eight Mixed fossil floras of the Cenozoic of Chile and Argentina. In addition to physiognomic analyses of the complete dicotyledonous flora as known from each site, we also evaluated the physiognomic significance of fossil Nothofagus leaves in relation to current Chilean species of the genus. Our results suggest that fossil Nothofagus leaves have a broader climatic envelope relative to the extant species. This divergence could be accounted by differences in their respective climatic tolerances. We postulate that the Mixed Paleoflora evolved in a subtropical climate that extended as far south as 40°S, with relatively warm temperatures and high annual rainfall with little seasonal variation. This climatic scenario is possible only with a much-reduced Andean massif, which would have permitted the spillover of moisture of easterly origin to the Pacific Andean slopes.

Human Impacts and Ecosystem Resilience in the Southern Andes

The shrubby vegetation of the Andean slopes of Central Chile is being subjected to a variety of perturbations caused by human activities. Some perturbations are absorbed; others significantly change the existing vegetation patterns. This paper describes and discusses the results of experiments designed to evaluate the impacts caused by the introduction of rabbits and goats, and by the increasing incidence of fire. The analysis demonstrates that type and degree of impact depends upon the type of stimulus, the relationship to other perturbations, the amount of vegetation cover, and the past history of the area under study. These characteristics are discussed in the context of ecosystem stability and instability.

Pollen studies in the Junín area, central Peruvian Andes

Research Article| December 01, 1984 Pollen studies in the Junín area, central Peruvian Andes BARBARA C. S. HANSEN; BARBARA C. S. HANSEN 1Limnological Research Center, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar H. E. WRIGHT, JR.; H. E. WRIGHT, JR. 1Limnological Research Center, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar J. P. BRADBURY J. P. BRADBURY 2U.S. Geological Survey, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1984) 95 (12): 1454–1465. https://doi.org/10.1130/0016-7606(1984)95<1454:PSITJA>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation BARBARA C. S. HANSEN, H. E. WRIGHT, J. P. BRADBURY; Pollen studies in the Junín area, central Peruvian Andes. GSA Bulletin 1984;; 95 (12): 1454–1465. doi: https://doi.org/10.1130/0016-7606(1984)95<1454:PSITJA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Laguna Junín is a large lake 675 km long but only 4 m deep, located in the grass-covered altiplano at an altitude of 4,100 m, northeast of Lima. Pollen analysis of a 30-m core indicates that from about 12,000 yr ago until some time after 3,000 yr ago, about 30% of the pollen was carried in by easterly winds from the east Andean forests, which today are at least 600 m lower in elevation. Contemporaneous pollen deposition in lakes on moraines of the last glaciation west of the Junín plain was dominated by local grassland types and had little contribution from this easterly source. At some time after 3,000 yr ago (perhaps about 1,200 yr ago), the pollen influx to Laguna Junín from this distant forest source greatly diminished, perhaps because of deforestation by increased human populations.Between about 12,000 and 24,000 yr ago in the Junín core, the sparse pollen concentration was dominated by grassland types, supplemented by Polylepis/Acaena, Alnus, and Compositae blown in from the sub-puna shrublands that may have occupied much of the east Andean slopes in place of the humid forest that occurs there today. The silty sediment in this section of the core is interpreted as outwash from piedmont glaciers that invaded the plain, especially from the cordillera to the west. These glaciers left a distinctive pattern of moraines and outwash fans, which served to dam tine lake basin.An unconformity in the sediment covers the time from about 24,000 to 39,000 yr ago, when the lake was probably dry. Before this time, the silty sediment and the dominance of grassland and shrubland pollen types indicates an earlier interval of glaciation, recorded on the landscape by an older set of moraines and outwash fans, which initially dammed the lake basin. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The metamorphic “basement” of Ecuador

Research Article| January 01, 1982 The metamorphic “basement” of Ecuador TOMAS FEININGER TOMAS FEININGER 1Département de Géologie, Université Laval, Québec, Québec, Canada G1K 7P4 Search for other works by this author on: GSW Google Scholar Author and Article Information TOMAS FEININGER 1Département de Géologie, Université Laval, Québec, Québec, Canada G1K 7P4 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1982) 93 (1): 87–92. https://doi.org/10.1130/0016-7606(1982)93<87:TMBOE>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation TOMAS FEININGER; The metamorphic “basement” of Ecuador. GSA Bulletin 1982;; 93 (1): 87–92. doi: https://doi.org/10.1130/0016-7606(1982)93<87:TMBOE>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The metamorphic rocks of Ecuador, once thought to constitute a uniform and ancient basement, belong to several distinct units of widely differing ages, compositions, and metamorphic histories. The largest area of metamorphic rocks constitutes an unbroken belt on the eastern Andean slope from the Colombian to the Peruvian border. The bulk of the rocks in this belt are of Cretaceous age, and were metamorphosed in the greenschist facies under a barrovian facies series. Rocks in the extreme north, and those south of lat. 3° 15′S are different, and may be of Paleozoic age. A smaller terrain, on the western Andean slope in southwestern Ecuador, is yet more varied. It includes four metamorphic terrains: the polymetamorphic Piedras Group of Precambrian age; the low-pressure Tahuin Group of Paleozoic age; the high-pressure Raspas Formation of Cretaceous age; and a low-pressure terrain of uncertain age north of the La Palma fault. Several isolated outcrops of metamorphic rocks in Ecuador are of uncertain significance. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Joppini (Hymenoptera: Ichneumonidae) of Tarapaca

Only 2 genera and 4 species of Joppini inhabit northernmost Chile's desertic Tarapaca Province. Carinodes fulgor n. sp. and Thymebatis hichinsi n. sp. are restricted to the west Andean slopes between 3 and 4000 m altitude. Thymebatis hichinsi n. sp. occurs from 0 to 2700 m in scattered oases and fertile river valleys. Carinodes vargasi n. sp. has been collected only from the Azapa Valley near Arica. Thymebatis hichinsi parasitizes an alfalfa cutworm, Copitarsia consueta Walker (Lepidoptera: Noctuidae), but hosts of the other Tarapaca Joppini remain unknown.

Midwinter Breeding by Some Birds in the High Andes of Southern Peru

As far as can be gathered from the very scanty information available, most of the land birds of the high Andes of southern Peru breed during or immediately after the summer rains, between November and April. At this season food, both animal and vegetable, is more readily obtained than in the rest of the year which, away from the humid eastern slopes, is characterized by severe drought. I was therefore surprised recently to obtain proof of midwinter breeding by the three species of birds detailed below. Since little has been published concerning the nesting of these species, I include the details of nest placement. Rhodopis vesper. Oasis Hummingbird. On 5 July 1979 I found a nest containing two recently hatched young birds near Chiguata (Dept. Arequipa) at an elevation of 2,750 m, close to the uppermost limit of the vertical range of the species in this part of Peni. The nest was placed approximately one meter off the ground in the branches of a bush (Tessaria integrifolia) growing near a small stream. Johnson (The birds of Chile and adjacent regions of Argentina, Bolivia and Perui. Vol. 2. Platt, Buenos Aires. 1967) mentioned September to December as breeding dates for the species in northernmost Chile (Arica and Tarapaca), which coincides with my experience at Mollendo, on the Pacific Coast (Dept. Arequipa). I know of no previous record of midwinter breeding by this species in any part of its restricted range along the coast and west Andean slopes of Peni and northern Chile. Metallura phoebe. Black Metaltail. On the same date I also found a nest near the top of a steep, moss-covered bank near Chiguata at 2,720 m altitude. The nest was suspended from overhanging vegetation at the top of the bank, kept permanently damp by water filtering down from the agricultural terraces above. Although its contents could not be checked, the female was sitting on th nest when found, and her subsequent behavior, ext eme agitation and reludtance to leave the area, indicated that it might have contained eggs or

Prehistoric dental calculus gives evidence for coca in early coastal Ecuador

Los CERRITOS, a late Chorrera (Engoroy) cemetery on the Santa Elena Peninsula of Ecuador yielded artefacts and radiocarbon assay which indicate that use of the site began about 840 BC and continued for several years within the Late Formative1. The human skulls from the site are of particular interest because many showed heavy accumulations of supragingival dental calculus (tartar), which contrast with the relatively slight calculus accumulations on the teeth of skulls recovered from the earlier Valdivia (3000–1500 BC) site of Real Alto2, also on the Santa Elena Peninsula. We argue here that the heavy calculus accumulations are the result of habitual, secular coca chewing in late Chorrera times. This diagnosis, in turn, supports the hypothesis of prehistoric trade in coca, probably in exchange for mollusc shells, with inhabitants of the eastern Andean slopes.

GEOGRAPHY AS EXPLORATION AND DISCOVERY

Gold placers attracted initial Spanish settlement to the Antioquia highlands of northwest Colombia. Here there evolved a distinctive culture group, centering on Medellin, that in the nineteenth century fanned out to establish numerous pioneer fronts on Andean slopes. Change has been continuous. Recently Antioqueno colonization has been directed towards the northern tropical lowlands. Medellin, despite locational disadvantages, has become a major industrial center. Through example the author argues for the integrative values of area studies and the significance and rewards of field observation in geography.

Les glaciations quaternaires dans les Cascades et dans les Andes méridionales aux latitudes tempérées : bilan des recherches et comparaisons

Summary. — This paper reviews the main results of recent investigations dealing with Quaternary glaciations in the Cascades (Lat. 47° - 49° N) and in the Southern Andes (Lat. 40° - 42° S). There is evidence that events of the last glaciation were simultaneous in both hemispheres, at least in a gross sense. The monoglacial hypothesis which was recently suggested for the Andes appears to be no longer valid. The Chilean lake region is especially suited, for research in the field of glacial geomor- phology. Precise data regarding correlation between glacial events of the two Andean slopes are still lacking. Consequently, more investigations in the Andes are needed before establishing further comparisons with the northern hemisphere.

A Case of Neo-Feudalism: La Convención, Peru

The province of La Convención, department of Cuzco, in Peru became familiar to citizens of the outside world in the early 1960s, when it was the scene of the most important peasant movement of that period in Peru, and probably in the whole of South America. This might legitimately attract the attention of the social historian. At the same time La Convención is a special version of a more general phenomenon, which ought also to interest the economic historian. It is ‘frontier territory’ in the American sense of the word, i.e. it belongs to the large zone of undeveloped land on the eastern edge of the Andes (the western edge of the Amazon basin) which has come under settlement and cultivation in recent decades, mainly for the cultivation of cash crops for the world market, but also for other economic purposes. Along the Andean slopes there are a number of such regions, into which, in their different ways, landlords and entrepreneurs penetrate with estates and trade, peasants in search of land and freedom. Mostly they are Indian peasants from the highlands, and the socio-economic background of the sierra and altiplano determines to some extent the forms of the new economy which take shape on the semi-tropical and tropical eastern slopes. These vary considerably, as we can tell by the various available monographs.