The phrase "era of activity" is correct and usable in written English.
You can use it to refer to a specific time period in which something was especially active, energetic, or productive. For example, you could say, "The 1980s marked the beginning of an era of activity in the tech industry."
I'm interested in how organisms adapt to the Anthropocene" — the era of human activity on earth — "as opposed to the Sierra Club 'conserve and preserve' way of thinking".
The Portuguese, who for a century had been seeking a sea route to eastern Asia, finally arrived at Malacca in 1509, inaugurating a new era of European activity in Southeast Asia.
Crustal magnetization of rocks in regions of Mars surface testifies to an era of dynamo activity.
Mars' era of dynamo activity was discovered when the Mars Global Surveyor (MGS) spacecraft dropped to a low orbit during an aerobraking manoeuver and recorded quite high levels of crustal magnetization (Acuña et al. 1999).
Recent scholarship has revealed that the so called period of cessation was actually a thriving era of intellectual activity in the Southern part of Persia where the so called the "School of Shiraz" emerged.
"The new era of distributed activity encourages 'innovation without permission.'".
These discoveries ushered in a new era of high activity in RNA biochemistry and structural biology that, in conjunction with developments in genomics, established groundwork for the ensuing explosion in discoveries of other functional but noncoding RNAs.
So, the SMSBV should be applied wildly even in the era of increasing endovascular activity.
In an era of intensifying human activities on Earth – the "Anthropocene" – societal interactions with post-fire landscapes are becoming commonplace.
Tory rhetoric against end-to-end encryption has also failed to sway increasing numbers of tech companies from deploying zero access architecture as a strategy to safeguard user privacy in an era of government surveillance activities undermining trust in consumer services.
