Geometric Resolution of the Cosmological Lithium Problem in the Zhang Effective Metric

The standard Big Bang Nucleosynthesis (BBN) framework correctly reproduces primordial deuterium and helium-4, yet overpredicts lithium-7 by roughly a factor of three, known as the cosmological lithium problem. We present a geometric resolution within the rotational-order geometric unification programme built upon the Zhang Effective Metric. A transient energy density sourced by the internal S³ orientation field activates in a narrow temperature band near T≈0.1 MeV during BBN. It locally raises the Hubble expansion rate, shortening the time available for the ³He(α,γ)⁷Be radiative capture reaction that dominates primordial ⁷Li production. Because the geometric contribution peaks after weak freeze-out, the neutron-to-proton ratio, deuterium and ⁴He yields remain consistent with existing tight observational constraints. This mechanism is distinct from exotic decaying-particle solutions and furnishes an early-universe falsifiable test of the framework.