Untangling the Impacts of Tectonics on Climate: Lessons From the Northern Andes-Caribbean
Abstract
Two geologic events in the northern Andes-Southern Caribbean region highlight their significance —or lack thereof— in climatic/biotic events of the past. First is the closure of the Isthmus of Panama, regarded by some as the cause of northern hemisphere glaciation. Then, is the rise of the northern Andes and onset of Amazonian drainages. Both of them roughly coincident with the Miocene-Pliocene transition. Both have been regarded as clear examples of tectonics impacting climate. Both events, however, could be older and more complex than previously thought. Climate itself may be playing a trick in both cases. In the case of the Isthmus of Panama, one of the arguments for a Mio-Pliocene closure time is the well dated migration of North American mammals into South America. A contrasting argument is that an older jungle-covered Isthmus could only be used for migration once climate changed (colder, drier), and jungle conditions were replaced by open savannas. In the case of the northern Andes, geologic data suggests elevations gains since Paleocene times for some parts of this mountain range, while palynological and paleobotanical data suggest a surface elevation gain only in Mio-Pliocene times. Climate too, could be playing a trick here. The signal of cooling climatic conditions along an already high established orogen could have been read as the record of surface uplift. While in both cases paleontological and paleoclimatic data support the simultaneity of both events, geologic data suggests otherwise, and therefore no connection between there tectonic events and climate. We use palinspastic reconstructions based on strain data, piercing points and paleomagnetic data to constrain the history of the northern Andes-southern Caribbean region to show that the relationship between climate and tectonics, although undeniable, is complex and treacherous.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGP53A0664M
- Keywords:
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- 1525 Paleomagnetism applied to tectonics: regional;
- global;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 1616 Climate variability;
- GLOBAL CHANGE;
- 8157 Plate motions: past;
- TECTONOPHYSICS;
- 8177 Tectonics and climatic interactions;
- TECTONOPHYSICS