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Baltica is an ancient continental block associated with the core of northeastern Europe. In paleogeographic reconstructions it is treated as a coherent unit over specified intervals, using the surviving rock record rather than present political boundaries to define its identity.

Paleomagnetic poles, ages of deformation and correlations between rock sequences constrain its past position and relation to Laurentia and other continental blocks. Agreement between several independent indicators is stronger than a visual fit of coastlines. Reconstructed arrangements remain hypotheses with stated age ranges and uncertainties; the modern position of Baltica does not determine its ancient orientation.

David A. D. Evans and Ross N. Mitchell combined paleomagnetism with the record of ancient continental margins to reconstruct a core of the supercontinent Nuna. Rotating same-age paleomagnetic poles into a common reconstruction tests whether the proposed continental neighbors share a compatible history. The study compared Siberia, Laurentia and Baltica, using agreement and later divergence of their records to constrain assembly and separation. These magnetic tests complement geological fits rather than assuming that a visually plausible arrangement uniquely reconstructs a vanished supercontinent.^[ref]

A researcher in paleomagnetism and continental reconstruction, including supercontinent histories. Institutional profile: earth.yale.edu/profile/david-evans

A paleomagnetic pole is a reconstructed geomagnetic-pole position inferred from remanent magnetic directions in rocks of a specified age, under a stated field model. In a geocentric axial dipole model, inclination $I$ gives paleolatitude $\lambda$ through $\tan I=2\tan \lambda$.

Oriented samples, age control and corrections for later deformation are essential. Stepwise thermal or alternating-field demagnetization helps separate older magnetization from later overprints. Comparing poles of different ages produces an apparent polar-wander path, which records motion relative to a continental block as well as possible field changes. An axial-dipole direction alone does not fix paleolongitude.^[ref]

The Siberian craton is an ancient, long-lived continental block in northern Asia. Its comparatively stable interior preserves a record that can be used to reconstruct earlier continental configurations, distinct from younger tectonic belts around its margins.

A reconstruction combines dated rock units, structural relationships and paleomagnetic poles. The poles constrain latitude and orientation within a magnetic-field model but generally leave a longitude ambiguity. Consequently, placing the Siberian craton relative to Laurentia or Baltica requires additional geological evidence; a single magnetic direction cannot uniquely determine a complete ancient world map.