Models

Fold-Thrust Belt — Local Isostasy

When ductile flow accommodates isostatic adjustment beneath a fold-thrust belt, subsidence is local and large, producing a narrower, less elevated belt with steeply dipping faults and a complex internal architecture.

Fold-Thrust Belt — Flexural Isostasy

When lithospheric flexure controls isostatic subsidence, basement tilting on tens-of-kilometre scales facilitates outward propagation of the fold-thrust belt, producing a wider, higher belt with simpler architecture and prominent basement-parallel décollements.

Contractional Gravitational Collapse

Convergent gravitational collapse of a deep intracratonic rift basin. The gravitational potential anomaly relaxes inward, simultaneously driving doming in the extensional domain and nappe emplacement in the contractional domain — linking the Entia Dome and Arltunga Nappe Complex.

Narrow Rift — 600°C Moho

Under a colder geotherm representative of modern conditions, extension localises into a narrow rift defined by conjugate normal faults that evolve into listric detachments merging at the brittle-ductile transition.

Wide Rift — 800°C Moho

Under a warmer geotherm representative of Proterozoic conditions, extension distributes across a broad zone, forming a wide rift through distributed upper crustal faulting and ductile flow in the underlying lithosphere.

Narrow Rift Inversion — 600°C Moho

After 60 Myr of tectonic quiescence, the narrow rift is compressed and inverts into a localised orogenic wedge flanked by foreland basins, largely reactivating the pre-existing rift architecture.

Wide Rift Inversion — 800°C Moho

After 60 Myr of quiescence, lithospheric cooling and embrittlement transform the wide rift inversion. Coupling between upper crustal faults and upper mantle shear zones produces a broad, low-relief orogenic plateau with 10–20 km of Moho offset — a framework that may explain distributed shortening in Proterozoic orogens.