The Trans-Amazon Drilling Project (TADP) is motivated by two big questions about the history and future survival of the world's largest and most diverse rain forest. What are the origins of Andean/Amazon biodiversity and to what extent did climate, hydrologic, and geologic events drive diversification? How can an improved understanding of the biotic and geologic history of the Amazon inform and animate its conservation? 

The key to answering the first question was to recover high-quality, deep drill cores from basin sediments across the Amazon. In trying to meet this goal, TADP faced multiple large challenges, including funding, contracting a drilling company with experience in the Amazon, identifying appropriate drill site locations, obtaining environmental permits and landowner permissions, mobilizing equipment and personnel, and housing and feeding personnel over the 1.5-years duration of the field operations at remote project locations. These problems were compounded by the Covid-19 global pandemic, which delayed field operations, and its associated macroeconomic effects including labor shortages, supply chain disruptions, and inflation.

Given the magnitude of the project and its challenges, the multiplicity of international partners and funding sources, the vast scope of the region and its relatively remote locations, we feel fortunate to have successfully recovered two long drill cores and to have negotiated access to a third drill core taken for mineral exploration purposes, from the far western Acre, far eastern Marajó, and central Amazonas basins, respectively. These drill cores are the single most important accomplishment of the TADP to date as they are the first and only records of their kind from the Amazon and will serve as important archives for scientific study (by us and by others) for decades to come.

As of the time of this report, we have successfully completed field work. We have described, sampled, and analyzed the drill core from the Amazonas basin. The Acre drill core was shipped to the Continental Scientific Drilling (CSD) Facility at the University of Minnesota, and in August 2024 our team spent one month logging, scanning, and sampling that core. The Marajó drill core is currently being shipped to the CSD Facility, and we plan to log, scan, and sample that core in August 2025. At this time, with most sample analyses just getting underway on our first drill core, we are only beginning to see the first scientific fruits of our labor. 

The Amazonas Basin drill core from Autazes, Brazil includes a 399-meter sediment sequence of Cretaceous to near-modern age, unconformably overlying Paleozoic sediments that contain economic potash deposits formed as ancient evaporative sediments. The Paleozoic sediments are host to a series of meters-thick diabase sills that are part of the world's largest terrestrial "Large Igneous Province," known as the Central Atlantic Magmatic Province (CAMP). The intrusion of CAMP magmas was likely responsible for the mass extinction at the Triassic-Jurassic boundary, 201 million years ago. The basalts from Autazes differ in composition from those found elsewhere and provide information about the nature of the mantle mega-plume/hotspot eruption that was responsible for CAMP. Additional studies of the contact metamorphism between the sills and organic-rich host carbonate and evaporite sediments will provide insight into the possible release of climate-forcing volatile gases and the mass extinction killing mechanism.

Analyses of pollen, U/Pb and Nd isotopes, luminescence, and major element composition of the upper section of the Autazes drill core are nearly complete. Key conclusions (with still-tentative age dates) from these studies are: (1) the oldest sediments above the major unconformity are Aptian age (~120 Ma); (2) the proto-Andes were already connected by a river to the Amazonas basin by ~110 Ma, then alternately disconnected (by intervening sediment capture in lakes, wetlands, or pirate rivers) and reconnected to the Andes at two later times; (3) the penultimate Andean connection began ~28 Ma, then ceased again sometime before the latest Andean connection began ~6 Ma. The hydrologic disconnect between these two periods may have been brought about by southward expansion of the large Pebas wetland/lake. These dates and provenance information, if confirmed, have important implications for the tectonic history of the Andes, the drainage history of the Amazon basin, the history of formation of the Amazon delta and fan, and the biotic diversification of the tropical rain forest. 

In addition to major scientific outcomes, the project has brought together more than 50 scientists from nine countries and contributed to the training and professional development of several dozen early career scientists. Brazilian colleagues have developed extensive outreach materials in Portuguese on topics related to the project, including for teachers, students, land managers, government officials, and public agencies, and they held workshops and training courses in each drilling location. Articles and short videos were developed for Brazilian TV and newspapers, and the project was featured in a 2024 documentary on the Amazon for German TV.

Last Modified: 01/31/2025
Modified by: Sherilyn C Fritz