Climatic and ecological history of Pantepui and surrounding areas

2019 ◽  
pp. 33-54
Author(s):  
Valentí Rull ◽  
Encarni Montoya ◽  
Sandra Nogué ◽  
Elisabet Safont ◽  
Teresa Vegas-Vilarrúbia
2018 ◽  
Vol 482 (1) ◽  
pp. 75-92 ◽  
Author(s):  
Ferenc Fedor ◽  
Zoltán Máthé ◽  
Péter Ács ◽  
Péter Koroncz

AbstractBoda Claystone is a very tight clayey rock with extreme low porosity and permeability, nano-size pores and small amounts of swelling clays. Due to this character it is ideal as a potential host rock for research into the possibilities of high-level waste deposition in geological formation. Though the research started more than 30 years ago, the genesis, the geotectonic history of the Boda Claystone Formation (BCF) and the geology of surrounding areas has only been sketched out recently. On the basis of research of the past few years the process of sedimentation of different blocks was able to be reconstructed. Equipment and methodological developments were needed for the investigation of reservoir geological and hydrodynamic behaviour of this rock, which began in the early 2000s. Based on them the pore structure and reservoir could be characterized in detail. Only theoretical approaches were available for the chemical composition of free porewater. Traditional water-extracting methods were not adaptable because of excessively low porosity and nano-scale pore size distribution. Hence, new ways have to be found for getting enough water for analysis. These new results of BCF research help to prepare more sophisticated and directed experiments, in which there is a great interest internationally.


1995 ◽  
Vol 68 (1) ◽  
pp. 131 ◽  
Author(s):  
Eva Cheung Robinson ◽  
Madhav Gadgil ◽  
Ramachandra Guha

BioScience ◽  
2019 ◽  
Vol 69 (7) ◽  
pp. 508-522
Author(s):  
Jennifer L Silcock ◽  
Rod J Fensham

AbstractThe ecological history of rangelands is often presented as a tale of devastation, where fragile drylands are irreversibly degraded through inappropriate land use. However, there is confusion about how to recognize and measure degradation, especially in low-productivity environments characterized by extreme natural variability and where abrupt and comprehensive management upheavals preclude benchmarks. These issues have important consequences for rangeland management programs, which are typically founded on presumptions of substantial and ongoing degradation from former “natural” states. We explore complementary approaches to critically assess degradation: the historical record, long-term grazing exclosures, surveys for potentially rare and sensitive plant species, and assessment of water-remote areas in relation to rare plant occurrence. Employing these approaches in inland Australia, we show that prevailing paradigms have become entrenched despite being inconsistent with empirical evidence. Our methodology can be applied to drylands with abrupt changes in management and contentious ecological narratives.


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