PALYNOSTRATIGRAPHIC REEVALUATION OF THE MANURIPI-X1 (1541-1150 M INTERVAL), MADRE DE DIOS BASIN, NORTHERN BOLIVIA: RECYCLED DEVONIAN SPECIES AND THEIR IMPLICATION FOR THE TIMING AND DURATION OF GONDWANAN GLACIATION

DI PASQUO, M.M.; WOOD, G.; ISAACSON, P.; GRADER, GEORGE

La Plata

Simposio; XVI Simposio Argentino de Paleobotánica y Palinología; 2015

universidad nacional de La Plata y Museo

The Manuripi X-1 was examined as part of a project to investigate the Devonian/ Carboniferous boundary in Bolivia. A detailed analysis of the 1541-1150 m interval revealed an assemblage of Carboniferous palynomorphs that occurs with recycled Devonian species. The 1535-1387 m interval has abundant reworked Devonian palynomorphs, but the occurrence of the spores Anapiculatisporites ampullaceus, Cordylosporites papillatus, Crassispora scrupulosa, Cristatisporites echinatus, Dibolisporites setigerus, Foveosporites hortonensis, Raistrickia ponderosa, Reticulatisporites waloweekii, Secarisporites undatus, Spelaeotriletes balteatus, and Vallatisporites ciliaris allow the attribution of a mid to late Tournaisian age.This is partially correlated to the PD Zone of Brazil and PC-CM Zones of Europe. The 1328-1315 m interval is characterized by fewer recycled Devonian forms, the persistant occurrence of Cristatisporites menendezii and C. stellatus, and the inception of Crassispora kosankei, Cristatisporites peruvianus, Indotriradites viriosus, Lycospora noctuina and Verrucosisporites morulatus. The in situ taxa are diagnostic of the Tournaisian?early Visean in Bolivia, Peru, Argentina, North America, Europe, and Australia. The 1214-1151 m interval is most similar to the late Visean based on the first appearance of Reticulatisporites magnidictyus (Mag Zone of Brazil). Retispora lepidophyta (latest Famennian) is abundant in the 1432-1387 m interval, and persists up to 1151 m. Other reworked Devonian forms include Ammonidium garrasinoi, Bimerga bensonii, Evittia sommeri, Grandispora pseudoreticulata, Hystricosporites porrectus, Kraeuselisporites explanatus, Maranhites spp., Piloferites pentagonalis, Samarisporites triangulatus, Umbellasphaeridium saharicum. The presence of abundant, thermally-immature recycled species suggest that glacio-fluvial processes eroded Devonian shales from approximately mid Tournaisian to early Visean in the region.