Geomorphology of the Gran Sabana, Guayana Shield, southeastern Venezuela

Briceño, Henry O.; Schubert, Carlos

doi:10.1016/0169-555x(90)90041-n

Cited by 136 publications

(55 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These silica 'flecks' appear to be precipitating from evaporating silica-rich water, and over time may slowly 'mature' by Ostwaldtype paragenesis to crypto-crystalline chalcedony (Wray, 1999). These observations are similar to those found for silica stalactites elsewhere in the world (Urbani, 1976;Briceño & Schubert, 1990;Carreño & Urbani, 2004;Wiegand et al, 2004).…”

Section: Stalactite Microscopic Examinationsupporting

confidence: 78%

“…However small opal-A stalactites are found at a number of locations around the world (Urbani, 1976;Briceño & Schubert, 1990;Wray, 1997a;Carreño & Urbani, 2004;Wiegand et al, 2004;Young et al, 2009) and their occurrence and formation on quartz sandstones within the Sydney region has previously been discussed (Wray, 1997a(Wray, ,b, 1999. However the presence of alunite within some of these stalactites has not previously been described.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Alunite Formation within Silica Stalactites from the Sydney Region, South-eastern Australia

Wray¹

2011

IJS

View full text Add to dashboard Cite

Section: Stalactite Microscopic Examinationsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Alunite Formation within Silica Stalactites from the Sydney Region, South-eastern Australia

Wray¹

2011

IJS

View full text Add to dashboard Cite

“…Its altitude ranges from 800 to 1500 m a.s.l. and represents an erosion surface developed on the Precambrian Roraima sandstones and quartzites (Briceñ o and Schubert, 1990). Remnants of higher and older erosion surfaces remain in the Gran Sabana as table mountains (tepuis), up to 2700 m altitude.…”

Section: Geography Geology Soils and Vegetationmentioning

confidence: 99%

A palynological record of a secondary succession after fire in the Gran Sabana, Venezuela

Rull

1999

J. Quaternary Sci.

View full text Add to dashboard Cite

Fire has been considered one of the most important factors in the expansion of savannas in the Gran Sabana region. In Urué, an important fire event that occurred before 1.6 kyr BP led to the replacement of ‘primary’ forests by savannas and morichales (monospecific communities of the palm Mauritia). In the present work, the secondary succession after fire is reconstructed by palynological analysis of a previously dated clay core, and the results are compared with those from studies based on present‐day ecosystems. Charcoal analysis is used to infer fire incidence and surface samples are used as modern analogues. The secondary succession is subdivided into seven seral stages: open secondary forests, helechal or dense fern community, transitional savanna, wet savanna with morichales, treeless savanna, wet savanna with morichales, and treeless savanna. Fires were common at the beginning, but climate constituted the main successional control from the transitional savanna stage onwards. The process is characterised by a continuous impoverishment of taxa, but there was a steady increase in Mauritia, due to its ability to colonise new habitats created by disturbances. The conclusions of this palynological reconstruction show good correspondence with present‐day studies on fire ecology. Copyright © 1999 John Wiley & Sons, Ltd.

show abstract

“…Research utilizing Figure 1. Map of northern South America, showing the approximate extension of the Guayana Shield (in grey) and the Precambrian sandstones and quartzites of the Roraima group (in black), on which the tepuis are modelled (Briceño & Schubert, 1990). The region under study (the Venezuelan Guayana) is indicated by a box.…”

Section: Methodsmentioning

confidence: 99%

Additions to the Pantepui pollen flora (Venezuelan Guayana): the Maguire Collection

López-Martínez¹,

Lara²,

Rull³

et al. 2010

Collect. Bot

View full text Add to dashboard Cite

This work is a pollen-morphological study of various plant species from Pantepui (Venezuelan Guayana), a region with high biodiversity and endemism, where global warming is expected to have a high impact. The study consists of a series of morphological descriptions of selected taxa from the Maguire pollen reference slide collection of The New York Botanical Garden (NYBG). The collection was initiated under the supervision of Senior Curator Bassett Maguire to advance systematic, palynological, and medical studies; today it has become also useful for other disciplines such as paleoecology, paleoclimatology or forensic studies. The aim of this pollen-morphological study is to enhance the database of pollen descriptions and illustrations for identification purposes, to be used in the ongoing paleoecological reconstructions and, eventually, in other types of studies using pollen, particularly from the Guayanan tepui summits.Key words: Guayana; Pollen morphology; Taxonomy; Tepuis; Venezuela. ResumenAdiciones a la flora polínica de Pantepui (Guayana venezolana): la colección Maguire.-Este trabajo es un estudio sobre la morfología polínica de varias especies de plantas de Pantepui (Guayana venezolana), una región con elevada biodiversidad y un alto grado de endemismo, donde se espera un fuerte impacto del calentamiento global. El estudio consiste en una serie de descripciones morfológicas de taxones pertenecientes a la colección Maguire de láminas de referencia del Jardín Botánico de Nueva York (NYBG). La colección fue iniciada bajo la dirección del Curador Jefe Basset Maguire con el objeto de avanzar en estudios de sistemática, palinología y medicina; aunque actualmente también resulta útil en otras disciplinas, como por ejemplo la paleoecología, la paleoclimatología o los estudios forenses. El objetivo de este estudio de morfología polínica es aumentar la base de datos de descripciones e ilustraciones polínicas con propósitos de identificación taxonómica, para ser utilizada en reconstrucciones paleoecológicas y otro tipo de estudios actualmente en desarrollo, en particular en las cimas de los tepuis de Guayana.

show abstract

Geomorphology of the Gran Sabana, Guayana Shield, southeastern Venezuela

Cited by 136 publications

References 9 publications

Alunite Formation within Silica Stalactites from the Sydney Region, South-eastern Australia

Alunite Formation within Silica Stalactites from the Sydney Region, South-eastern Australia

A palynological record of a secondary succession after fire in the Gran Sabana, Venezuela

Additions to the Pantepui pollen flora (Venezuelan Guayana): the Maguire Collection

Contact Info

Product

Resources

About