Question

"chemical evolution is more and less accepted "explanation of that line.....​

Answer 1

Answer:

The study of the chemical evolution of the mantle is a highly active growth field, fueled by analytical advances enabling the measurement of a wider range of elements and isotopes at unprecedented precisions on ever smaller samples. The refinement of seismic imaging techniques is providing new constraints on mantle structure, and greater emphasis is being placed on understanding Earth in a planetary context. Considerable potential exists in the near term for significant advances in our understanding of mantle structure and evolution of the chemical and physical structure of the Earth since its formation. The mantle is increasingly appreciated as an immense and key part of the Earth system; it is impossible to have a true understanding of any part of the planet or its evolution without consideration of this vast and largely unknown domain. The mantle is the ultimate source and sink of elements to the crust, with complex interactions between the hydrosphere, atmosphere, lithosphere, and perhaps the core, all playing a role in establishing its composition.

Explaition:

The study of the chemical evolution of the mantle is a highly active growth field, fueled by analytical advances enabling the measurement of a wider range of elements and isotopes at unprecedented precisions on ever smaller samples. The refinement of seismic imaging techniques is providing new constraints on mantle structure, and greater emphasis is being placed on understanding Earth in a planetary context. Considerable potential exists in the near term for significant advances in our understanding of mantle structure and evolution of the chemical and physical structure of the Earth since its formation. The mantle is increasingly appreciated as an immense and key part of the Earth system; it is impossible to have a true understanding of any part of the planet or its evolution without consideration of this vast and largely unknown domain. The mantle is the ultimate source and sink of elements to the crust, with complex interactions between the hydrosphere, atmosphere, lithosphere, and perhaps the core, all playing a role in establishing its composition.