There is a considerable controversy about whether western Amazonia was ever covered by marine wat... more There is a considerable controversy about whether western Amazonia was ever covered by marine waters during the Miocene [23 to 5 Ma (million years ago)]. We investigated the possible occurrence of Miocene marine incursions in the Llanos and Amazonas/Solimões basins, using sedimentological and palynological data from two sediment cores taken in eastern Colombia and northwestern Brazil together with seismic information. We observed two distinct marine intervals in the Llanos Basin, an early Miocene that lasted ~0.9 My (million years) (18.1 to 17.2 Ma) and a middle Miocene that lasted ~3.7 My (16.1 to 12.4 Ma). These two marine intervals are also seen in Amazonas/Solimões Basin (northwestern Amazonia) but were much shorter in duration, ~0.2 My (18.0 to 17.8 Ma) and ~0.4 My (14.1 to 13.7 Ma), respectively. Our results indicate that shallow marine waters covered the region at least twice during the Miocene, but the events were short-lived, rather than a continuous full-marine occupancy o...
... Wei ZX, Zavada MS, Ming TL. 1992 Pollen morphology of Camellia (Theaceae) and its taxonomic s... more ... Wei ZX, Zavada MS, Ming TL. 1992 Pollen morphology of Camellia (Theaceae) and its taxonomic significance. Acta Bot. Yunnanica 14. ... En (Ch) Icones, Palynology. 8p. of plates follow p. 346 Geog=2 Systematics: ANGIOSPERMAE (THEACEAE: CAMELLIA) ( , 199204182). ...
Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exh... more Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed ...
Http Dx Doi Org 10 1080 00173130701780104, Dec 1, 2007
... MICHAEL S. ZAVADA1,2, STEPHANIE M. MCGRAW2 & MELISSA A. MILLER2 ... Pollen studies in a h... more ... MICHAEL S. ZAVADA1,2, STEPHANIE M. MCGRAW2 & MELISSA A. MILLER2 ... Pollen studies in a hospital air-conditioned room. N. Engl. Allergy Proc., 6, 150152. D'Amato, G., Ruuso, M., Liccardi, G., Saggese, M., Gentili, M., Mistrello, G., D'Amato, M. & Falagiani, P. (1996). ...
Massive hill slope erosion in Madagascar is represented by the widespread gullies called 'lav... more Massive hill slope erosion in Madagascar is represented by the widespread gullies called 'lavaka'. Lavakas may be result of natural processes that involves a combination of continuous tectonic uplift that maintains a high angle of repose, ground water sapping at the soil - saprolite interface, and subsequent collapse of the soil surface due to low grade seismic activity in the
There is a considerable controversy about whether western Amazonia was ever covered by marine wat... more There is a considerable controversy about whether western Amazonia was ever covered by marine waters during the Miocene [23 to 5 Ma (million years ago)]. We investigated the possible occurrence of Miocene marine incursions in the Llanos and Amazonas/Solimões basins, using sedimentological and palynological data from two sediment cores taken in eastern Colombia and northwestern Brazil together with seismic information. We observed two distinct marine intervals in the Llanos Basin, an early Miocene that lasted ~0.9 My (million years) (18.1 to 17.2 Ma) and a middle Miocene that lasted ~3.7 My (16.1 to 12.4 Ma). These two marine intervals are also seen in Amazonas/Solimões Basin (northwestern Amazonia) but were much shorter in duration, ~0.2 My (18.0 to 17.8 Ma) and ~0.4 My (14.1 to 13.7 Ma), respectively. Our results indicate that shallow marine waters covered the region at least twice during the Miocene, but the events were short-lived, rather than a continuous full-marine occupancy o...
... Wei ZX, Zavada MS, Ming TL. 1992 Pollen morphology of Camellia (Theaceae) and its taxonomic s... more ... Wei ZX, Zavada MS, Ming TL. 1992 Pollen morphology of Camellia (Theaceae) and its taxonomic significance. Acta Bot. Yunnanica 14. ... En (Ch) Icones, Palynology. 8p. of plates follow p. 346 Geog=2 Systematics: ANGIOSPERMAE (THEACEAE: CAMELLIA) ( , 199204182). ...
Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exh... more Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed ...
Http Dx Doi Org 10 1080 00173130701780104, Dec 1, 2007
... MICHAEL S. ZAVADA1,2, STEPHANIE M. MCGRAW2 & MELISSA A. MILLER2 ... Pollen studies in a h... more ... MICHAEL S. ZAVADA1,2, STEPHANIE M. MCGRAW2 & MELISSA A. MILLER2 ... Pollen studies in a hospital air-conditioned room. N. Engl. Allergy Proc., 6, 150152. D'Amato, G., Ruuso, M., Liccardi, G., Saggese, M., Gentili, M., Mistrello, G., D'Amato, M. & Falagiani, P. (1996). ...
Massive hill slope erosion in Madagascar is represented by the widespread gullies called 'lav... more Massive hill slope erosion in Madagascar is represented by the widespread gullies called 'lavaka'. Lavakas may be result of natural processes that involves a combination of continuous tectonic uplift that maintains a high angle of repose, ground water sapping at the soil - saprolite interface, and subsequent collapse of the soil surface due to low grade seismic activity in the
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