query: When was the Amazonian period?
passage: Amazonian (Mars)
The Amazonian is a geologic system and time period on the planet Mars characterized by low rates of meteorite and asteroid impacts and by cold, hyperarid conditions broadly similar to those on Mars today.[1][2] The transition from the preceding Hesperian period is somewhat poorly defined. The Amazonian is thought to have begun around 3 billion years ago, although error bars on this date are extremely large (~500 million years).[3] The period is sometimes subdivided into the Early, Middle, and Late Amazonian. The Amazonian continues to the present day.
passage: Deforestation of the Amazon rainforest
Prior to the 1970s, access to the forest's largely roadless interior was difficult, and aside from partial clearing along rivers the forest remained intact. Deforestation accelerated greatly following the opening of highways deep into the forest, such as the Trans-Amazonian highway in 1972.