Qualla: Cocinetas Basin

Cocinetas Basin: Introduction

Fri, 06 Mar 2026 00:00:00 GMT

Photo credit Monkeysdrawer, CC BY-SA 3.0. Forty million years ago, where the driest desert in Colombia bakes today, the Caribbean Plate was grinding eastward against the edge of South America, wrenching open a depression in the Earth's crust. That depression became the Cocinetas Basin - a small pull-apart basin of roughly 1,000 square kilometers wedged into the extreme northeast corner of Colombia, in the department of La Guajira. Three mountain ranges hem it in: the Serrania de Jarara to the south, the Serrania de Macuira to the north, and the Serrania de Cocinas to the southwest. The Gulf of Venezuela forms its eastern shore. It is one of the most paleontologically significant sites in South America, and from the ground, it looks like nothing at all - flat, scorched, and almost entirely without water.

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Image: Monkeysdrawer | CC BY-SA 3.0

Cocinetas Basin: A Desert Built from Seafloors

Fri, 06 Mar 2026 00:00:00 GMT

Photo credit Luca Oddone, CC BY-SA 3.0. The basin's story begins in the Middle Eocene, around 45 million years ago, when the oldest preserved sediments - the Macarao Formation - were laid down in a shallow sea. Foraminifera-rich sandstones and calcareous siltstones, cross-cut by veins of gypsum, record an environment o...

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Image: Luca Oddone | CC BY-SA 3.0

Cocinetas Basin: The Bone Library

Fri, 06 Mar 2026 00:00:00 GMT

Photo credit Llez (H. Zell)., CC BY-SA 3.0. What makes the Cocinetas Basin extraordinary is not its geology alone but what the geology preserved. The Castilletes and Ware Formations are densely fossiliferous, yielding an astonishing catalog of ancient life. Giant crocodilians once dominated these waters - relatives of Puru...

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Image: Llez (H. Zell). | CC BY-SA 3.0

Cocinetas Basin: When Two Americas Collided

Fri, 06 Mar 2026 00:00:00 GMT

Photo credit Eduard solà, CC BY-SA 3.0. The basin's deepest scientific value lies in its timing. The Cocinetas sits near the Isthmus of Panama, the land bridge that rose from the sea and connected North and South America, triggering the Great American Biotic Interchange - one of the most dramatic episodes of animal mig...

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Image: Eduard solà | CC BY-SA 3.0

Cocinetas Basin: Desert Guardians

Fri, 06 Mar 2026 00:00:00 GMT

Photo credit Wtbarron, CC BY-SA 3.0. The basin sits entirely within the municipality of Uribia, in the Alta Guajira - the driest region in Colombia, where long droughts are common and the landscape more closely resembles the Sahara than the rainforests most people associate with this country. The Wayuu people have l...

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Image: Wtbarron | CC BY-SA 3.0