Bauxites : Feedbacks of System Earth at Greenhouse times

• Main Author: Andrea Mindszenty
• Format: Article
• Language: English
• Published: Croatian Geological Survey 2016-02-01
• Series: Geologia Croatica
• Online Access: http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/712

The sedimentary record is an inexhaustible repository of information on global climates. The study of the documents of past climate changes may help to understand not only the causes and presumable effects of the current change, but also to reveal the often complex and subtle mechanisms regulating the system. Ferrallitic soils and soil-derived sediments (=bauxites) are generally considered as best climate-indicators on dry-land. Their frequency distribution through geologic time shows pronounced positive anomalies coincident with greenhouse periods of the Earths’ history. It is proposed that intense ferrallitic weathering instead of being simply the passive product of the greenhouse could be also one of the negative feedbacks of the system counteracting warming by contributing to the pump-down of greenhouse gases from the atmosphere and this way to help to decelerate both the carbon-cycle and the hydrological-cycle. The mass-transfer of oxygen from the atmosphere to the lithosphere is tentatively considered as an additional negative feedback acting to slow down oxidative weathering on land. It is suggested that the study of bauxites and correlative anoxic sediments in the oceans should be used to reveal details of the above complex regulation mechanism.