The phrase "age marking" is correct and usable in written English.
It can be used in contexts related to identifying or indicating the age of something, such as in educational settings or developmental psychology.
Example: "The study focused on age marking in children's language development to understand how they acquire new vocabulary."
Alternatives: "age indication" or "age identification".
The space age marked the dawn of many daring runway fashions.
The atomic age marked the start of the cold war, fought hot in proxy wars from Vietnam to Afghanistan, with blood spilt by the superpowers' hi-tech weaponry.
The ideal of the melting pot, they insist, has become obsolete in an age marked by the anti-assimilationist doctrines of multiculturalism and the hard facts of globalization.
But this big, baggy, but ultimately extremely moving meditation on encroaching age marked a long-overdue return to the writer's Boltonian roots.
Their musical proficiency and advanced age marked out The Stranglers, who formed in 1974, as outsiders when the punk movement exploded.
These stories, though crudely written, provide glimpses of how the common people spoke and behaved in an age marked by warfare and new religious movements.
The psychological structure of hope, directed as it is towards a powerful figure in a stance of supplication, helps to explain why faith is still possible in an age marked by scientific rationality.
"The recent announcement that a second EPR [new-generation nuclear reactor] is to be constructed in France also illustrates this new industrial age marked by the development of CO2-free energy and the revival of nuclear power.
It would end in a sorry, grasping old age, marked by an incivility to service people (flight attendants, doctors' secretaries) and a dye job that wasn't what it used to be.
The Victorian era in English history is often referred to as a 'golden age', marked by unique and historic achievements in the field of engineering and technology.
