10.6084/m9.figshare.3453689.v1
Lyal B. Harris
Lyal B.
Harris
Jean H. Bédard
Jean H.
Bédard
Interactions between continent-like ‘drift’, rifting and mantle flow on Venus: gravity interpretations and Earth analogues
Geological Society of London
2016
plate boundary forces
upwelling mantle plumes
Venus
Thetis regiones
displacement
crust
Lakshmi Planum
Archaean greenstone terrains
transcurrent shear zones
High Bouguer anomalies
mantle flow tractions
drift
Bouguer gravity data
Earth analogues Regional shear zones
Geology
2016-06-21 11:37:01
Dataset
https://geolsoc.figshare.com/articles/dataset/Interactions_between_continent-like_drift_rifting_and_mantle_flow_on_Venus_gravity_interpretations_and_Earth_analogues/3453689
<p>Regional shear zones are interpreted from Bouguer gravity data over northern polar to low southern latitudes of Venus. Offset
and deflection of horizontal gravity gradient edges (‘worms’) and lineaments interpreted from displacement of Bouguer anomalies
portray crustal structures, the geometry of which resembles both regional transcurrent shear zones bounding or cross-cutting
cratons and fracture zones in oceanic crust on Earth. High Bouguer anomalies and thinned crust comparable to the Mid-Continent
Rift in North America suggest underplating of denser, mantle-derived mafic material beneath extended crust in Sedna and Guinevere
planitia on Venus. These rifts are partitioned by transfer faults and flank a zone of mantle upwelling (Eistla Regio) between
colinear hot, upwelling mantle plumes. Data support the northward drift and indentation of Lakshmi Planum in western Ishtar
Terra and >1000 km of transcurrent displacement between Ovda and Thetis regiones. Large displacements of areas of continent-like
crust on Venus are interpreted to result from mantle tractions and pressure acting against their deep lithospheric mantle
‘keels’ commensurate with extension in adjacent rifts. Displacements of Lakshmi Planum and Ovda and Thetis regiones on Venus,
a planet without plate tectonics, cannot be attributed to plate boundary forces (i.e. ridge push and slab pull). Results therefore
suggest that a similar, subduction-free geodynamic model may explain deformation features in Archaean greenstone terrains
on Earth. Continent-like ‘drift’ on Venus also resembles models for the late Cenozoic–Recent Earth, where westward translation
of the Americas and northward displacement of India are interpreted as being driven by mantle flow tractions on the keels
of their Precambrian cratons.
</p>