The use of object-oriented and process-oriented methods for gravity anomaly modeling of sedimentary basins

Journal article

Gravity anomalies have provided some of the most commonly accepted models we have for the density structure, stress state and strength of Earth's crust and lithosphere. Two approaches in the indirect approach to gravity interpretation have been followed. In one, Object-Oriented Gravity Modelling (OOGM), physical models are constructed for the geometry and density of a causative body and a ‘trial and error’ method is used to adjust the shape of a body until a satisfactory fit with observations is obtained. In another, Process-Oriented Gravity Modelling (POGM), one or more geological processes, such as sediment loading are considered, along with the density, and parameters such as the flexural rigidity of the lithosphere are varied until a fit is obtained. Both OOGM and POGM are based on the density structure and so should yield the same results. Curiously though, the two approaches have not yet been compared. We show here that in the case of a rifted continental margin that is subsequently loaded by sediment, OOGM and POGM do, in fact, yield the same gravity anomaly. Therefore, gravity anomalies yield information not only on the physical structure, but geological processes in the past. We attribute this to the presence of an elastic ‘core’ which, irrespective of yielding, imparts on the lithosphere a ‘memory’ and allows gravity measurements made today to be used to infer past geological events.

Authors: Watts, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Geophysical Journal International
• Volume: 215
• Issue: 2
• Pages: 1474–1482
• Publication date: 2018-08-24
• Acceptance date: 2018-08-22
• DOI: 10.1093/gji/ggy353
• EISSN: 1365-246X
• ISSN: 0956-540X
• Keywords: sedimentation; Lithosphere; Isostasy; gravity anomalies; rifted margin