Spacetime Wrinkles: Defect-Like Textures as a Geometric Origin of Dark-Matter Phenomenology

The dark-matter problem is usually framed as the search for an unseen particle component. This work develops an alternative geometric hypothesis: a significant part of dark-matter phenomenology may arise from persistent defect-like textures in an emergent spacetime medium. Building on the Enchan Field framework, spacetime order is represented by a dimensionless geometric field S(x) whose finite-tension relaxation can support long-lived defect-like configurations, referred to here as spacetime wrinkles. The present work is deliberately formulated as an effective-field research program, not as a completed fundamental theory. In particular, the defect profile and finite-tension dynamics are treated at the effective level, the baryonic anchoring condition remains phenomenological, and a complete relativistic stress-energy and cosmological perturbation treatment remains open. Over the modeled flat-rotation-curve regime, the effective radial ansatz S(r) ≃ ηS ln(r/rcore) produces |∇S| ∝ 1/r and therefore an effective weak-field response scaling as gS ∝ 1/r. Under a gradient-stress scaling analogy, this corresponds to an effective contribution ρwrinkle ∝ 1/r², which yields an enclosed effective mass growing approximately linearly with radius and therefore approximately flat galactic rotation curves. The manuscript does not claim that this profile is a demonstrated three-dimensional vacuum solution of the full theory; it is used as an effective asymptotic description over the relevant galactic regime. To connect the geometric response to baryonic structure, the model introduces a baryonic anchoring condition near the characteristic acceleration scale a0. Combining the anchor condition with the wrinkle response yields the slope-four scaling vflat⁴ ≃ G a0 Mb, providing a candidate geometric route to the Baryonic Tully-Fisher Relation and to the characteristic acceleration scale associated with the Radial Acceleration Relation. At the present stage, this anchoring relation is explicitly treated as a phenomenological bridge rather than a microphysical derivation. Public SPARC-based benchmarks are used as observational targets and consistency checks. The associated Enchan materials reproduce the RAR/MDAR, BTFR, and fixed-rule rotation-curve regularities at the reported level, but these benchmarks do not by themselves establish the spacetime-wrinkle hypothesis or exclude particulate dark matter. The manuscript then defines the major external consistency tests that any viable geometric dark-sector model must pass: cluster collisions and lensing, including Bullet-Cluster-like offsets; CMB temperature and polarization constraints on defect-like networks; early-galaxy structure formation; high-acceleration Solar-System recovery; and derivation of galaxy-scale regularities directly from the finite-tension field dynamics. The Bullet Cluster is treated as a serious compatibility target rather than an already-solved success case, and the CMB behavior of finite-tension wrinkle networks remains a required calculation. Likewise, the high-acceleration suppression used in current effective tests is identified as a phenomenological safeguard rather than a completed derivation from the covariant field equation. A full ephemeris-level treatment remains necessary. The framework is therefore explicitly falsifiable. It fails as a dark-sector interpretation if no finite-tension wrinkle configuration can simultaneously reproduce galaxy-scale regularities while remaining compatible with cluster lensing, CMB constraints, and precision Solar-System gravity. Related Enchan Project Materials The Enchan Field — Core Framework:https://doi.org/10.5281/zenodo.20121394 Enchan Field Notes — Mathematical Precursor:https://doi.org/10.5281/zenodo.17979664 Computational Validation — Deterministic Relaxation Framework:https://doi.org/10.5281/zenodo.18139449 Open Review An open review has been requested through PREreview on August 26, 2026.PREreview: https://prereview.org/preprints/doi-10.5281-zenodo.20257701