High Resolution images (300 dpi) to accompany ms The enigmatic crustal plateaux and "tessera terrain" of Venus revisited : revision Oct 22nd, 2024 available on Research Gate and on this site
Figure 1 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Principal crustal plateaux on Venus cited in the text, plotted on a base provided by
https://astrogeology.usgs.gov/search/map/Venus/Magellan/RadarProperties/Colorized/
Venus_Magellan_C3-MDIR_ClrTopo_Global_Mosaic_6600m (Magellan Team: Ford et al. (1993).
centred on 0,0 latitude and longitude. Circled letters indicate the principal crustal plateaux. A: Alpha
Regio; F: Fortuna Regio; O: Ovda Regio; P: Phoebe Regio; Te: Tellus Regio; Th: Thetis Regio.
Other labels are A: Atla Regio; B: Beta Regio; T: Themis Regio (BAT). The principal crustal
plateaux are clustered in a single hemisphere (red box), antipodal to the BAT (yellow box).
Maxwell Montes are the white patch just west of Fortuna Regio. Single white asterisk is the
location of Fig. 4A; double white asterisk is the location of Figs 4C and D; # indicates the
approximate centre of the hypothetical giant impact proposed in this contribution.
Principal crustal plateaux on Venus cited in the text, plotted on a base provided by
https://astrogeology.usgs.gov/search/map/Venus/Magellan/RadarProperties/Colorized/
Venus_Magellan_C3-MDIR_ClrTopo_Global_Mosaic_6600m (Magellan Team: Ford et al. (1993).
centred on 0,0 latitude and longitude. Circled letters indicate the principal crustal plateaux. A: Alpha
Regio; F: Fortuna Regio; O: Ovda Regio; P: Phoebe Regio; Te: Tellus Regio; Th: Thetis Regio.
Other labels are A: Atla Regio; B: Beta Regio; T: Themis Regio (BAT). The principal crustal
plateaux are clustered in a single hemisphere (red box), antipodal to the BAT (yellow box).
Maxwell Montes are the white patch just west of Fortuna Regio. Single white asterisk is the
location of Fig. 4A; double white asterisk is the location of Figs 4C and D; # indicates the
approximate centre of the hypothetical giant impact proposed in this contribution.
Figure 2 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Spatial Distribution of "tessera terrain" (red) on Venus. Capital letters indicate purported
"tessera terrain" clusters. I–A: Ishtar–Ananke; O–T: Ovda–Thetis; V–T: Virilis–Themis; A–L:
Alpha Lada; N: Nemesis. Yellow dashed line show approximate contours of the clusters. The
thicker black solid line corresponds to the 0 km contour (6051 km mean planetary radius), the
thinner black solid line-contour +1 km, and the thinner black dashed line-contour -1 km. Includes
the principal crustal plateaux and purported foundered fragments ("inliers"). Taken from Ivanov and
Head (2015a, their figure 2).
Spatial Distribution of "tessera terrain" (red) on Venus. Capital letters indicate purported
"tessera terrain" clusters. I–A: Ishtar–Ananke; O–T: Ovda–Thetis; V–T: Virilis–Themis; A–L:
Alpha Lada; N: Nemesis. Yellow dashed line show approximate contours of the clusters. The
thicker black solid line corresponds to the 0 km contour (6051 km mean planetary radius), the
thinner black solid line-contour +1 km, and the thinner black dashed line-contour -1 km. Includes
the principal crustal plateaux and purported foundered fragments ("inliers"). Taken from Ivanov and
Head (2015a, their figure 2).
Figure 3 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Global correlation chart for Venus. T is the mean model age of the surface (~700 Ma)
and separates the Guineverian and Atlian periods. Note the relative timing of the Global Tectonic
Regime, the Global Volcanic Regime, and the Network Rifting-Volcanism Regime. The formation
and subsequent deformation of the principal crustal plateaux (t as in "tessera terrain") occurred
primarily during the Fortunian period, near the beginning of observable geological history (e.g.
Basilevsky and Head, 1998; Ivanov and Head, 2011). Taken from Ivanov and Head (2015a, their
figure 19). See also Herrick et al. (2023).
Global correlation chart for Venus. T is the mean model age of the surface (~700 Ma)
and separates the Guineverian and Atlian periods. Note the relative timing of the Global Tectonic
Regime, the Global Volcanic Regime, and the Network Rifting-Volcanism Regime. The formation
and subsequent deformation of the principal crustal plateaux (t as in "tessera terrain") occurred
primarily during the Fortunian period, near the beginning of observable geological history (e.g.
Basilevsky and Head, 1998; Ivanov and Head, 2011). Taken from Ivanov and Head (2015a, their
figure 19). See also Herrick et al. (2023).
Figure 4a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
"Tessera terrain" in northern Laima "Tessera"; see Fig. 1 for location. Scale bar is 75
km. NW-SE trending ridges (folds) cut by NE-SW trending high aspect ratio graben. See also
Solomon et al. (1992) and Ivanov and Head (1996).
Image sourced from https://jmars.mars.asu. edu/.
"Tessera terrain" in northern Laima "Tessera"; see Fig. 1 for location. Scale bar is 75
km. NW-SE trending ridges (folds) cut by NE-SW trending high aspect ratio graben. See also
Solomon et al. (1992) and Ivanov and Head (1996).
Image sourced from https://jmars.mars.asu. edu/.
Figure 4b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
"Tessera terrain" in northeastern Ovda Regio. (see Fig. 1 and Appendix Fig. 8F for location and context).
Scale bar is 50 km. NW-SE trending ridges (folds) cut by NE-SW trending high aspect ratio graben, as
distinct from later, wider, "complex" graben (c) at upper left (see also Phillips and Hansen, 1998; Ghent
and Hansen, 1999; Hansen et al., 2000; Ghent et al., 2005; Nunes and Phillips 2007; Hansen and Lopez, 2010).
Image sourced from https://jmars.mars.asu. edu/.
"Tessera terrain" in northeastern Ovda Regio. (see Fig. 1 and Appendix Fig. 8F for location and context).
Scale bar is 50 km. NW-SE trending ridges (folds) cut by NE-SW trending high aspect ratio graben, as
distinct from later, wider, "complex" graben (c) at upper left (see also Phillips and Hansen, 1998; Ghent
and Hansen, 1999; Hansen et al., 2000; Ghent et al., 2005; Nunes and Phillips 2007; Hansen and Lopez, 2010).
Image sourced from https://jmars.mars.asu. edu/.
Figure 4c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
The western portion of a radar-bright, irregular shaped, sub-circular (concave north), purported
"tessera" small inlier, flanked by radar-dark volcanic plains, the only published, detailed example of
a small inlier (Nunes and Phillips, 2007; Nunes et al., 2004). See Fig. 1 for location. Scale bar is
1250 km. Long ridges are readily visible in the western part of the small inlier, but are muted or less
apparent in the central and eastern parts. White box is the location of the small inlier in D.
Image sourced from https://jmars.mars.asu. edu/.
The western portion of a radar-bright, irregular shaped, sub-circular (concave north), purported
"tessera" small inlier, flanked by radar-dark volcanic plains, the only published, detailed example of
a small inlier (Nunes and Phillips, 2007; Nunes et al., 2004). See Fig. 1 for location. Scale bar is
1250 km. Long ridges are readily visible in the western part of the small inlier, but are muted or less
apparent in the central and eastern parts. White box is the location of the small inlier in D.
Image sourced from https://jmars.mars.asu. edu/.
Figure 4d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of Fig. C illustrating the presence of two orthogonal fabrics, WNW-ESE ridges and NNE-SSW
high aspect ratio graben, in the narrow small inlier (solid box). Note that areally limited
swarms of rectilinear lineaments (graben?), oriented perpendicular to the small inlier, are also
present in the radar dark volcanic plains (dashed box), hence they are post-Global Tectonic Regime
in age (see Fig. 3). As opposed to a small inlier of "tessera terrain", one might interpret these
features as rim-parallel slump scarps in an impact crater wall, cut by later, high aspect ratio graben,
possibly related to blind dykes (see Hanmer 2020 regarding blind dykes). Scale bar is 50 km.
Image sourced from https://jmars.mars.asu. edu/.
Detail of Fig. C illustrating the presence of two orthogonal fabrics, WNW-ESE ridges and NNE-SSW
high aspect ratio graben, in the narrow small inlier (solid box). Note that areally limited
swarms of rectilinear lineaments (graben?), oriented perpendicular to the small inlier, are also
present in the radar dark volcanic plains (dashed box), hence they are post-Global Tectonic Regime
in age (see Fig. 3). As opposed to a small inlier of "tessera terrain", one might interpret these
features as rim-parallel slump scarps in an impact crater wall, cut by later, high aspect ratio graben,
possibly related to blind dykes (see Hanmer 2020 regarding blind dykes). Scale bar is 50 km.
Image sourced from https://jmars.mars.asu. edu/.
Figure 5a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Physiographic provinces of Tellus Regio. See Fig. 1 for location. Note the distinction
between interior vs marginal vs transitional domains (here labelled as terrains), and northern and
southern interior subdomains. Taken from Gilmore and Head (2018, their figure 2).
Physiographic provinces of Tellus Regio. See Fig. 1 for location. Note the distinction
between interior vs marginal vs transitional domains (here labelled as terrains), and northern and
southern interior subdomains. Taken from Gilmore and Head (2018, their figure 2).
Figure 5b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
East-west topographic profile A-A'. See A for location. Vertical arrows correspond to terrain boundaries
indicated in A. Horizontal arrows mark the distance (in kilometers) between successive topographic
lows. Vertical exaggeration 25:1 (top), reduced herein to ~2:1 (bottom) to emphasise subtle true
surface relief. Top is taken from Gilmore and Head (2018, their figure 3).
East-west topographic profile A-A'. See A for location. Vertical arrows correspond to terrain boundaries
indicated in A. Horizontal arrows mark the distance (in kilometers) between successive topographic
lows. Vertical exaggeration 25:1 (top), reduced herein to ~2:1 (bottom) to emphasise subtle true
surface relief. Top is taken from Gilmore and Head (2018, their figure 3).
Figure 6a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
W. Ovda Regio (radar-bright), a crustal plateau surrounded by volcanic plains
(radar-dark). See Fig. 1 for location. Note the uniform isotropic cellular texture of the surface, with
the exception of the anisotropic NW and N margins. White box is the location of B. Scale bar is 750
km. Image sourced from https://jmars.mars.asu. edu/.
W. Ovda Regio (radar-bright), a crustal plateau surrounded by volcanic plains
(radar-dark). See Fig. 1 for location. Note the uniform isotropic cellular texture of the surface, with
the exception of the anisotropic NW and N margins. White box is the location of B. Scale bar is 750
km. Image sourced from https://jmars.mars.asu. edu/.
Figure 6b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed image of the interior of W. Ovda Regio. See also Ivanov and Head (1996). Scale
bar is 100 km. The predominant texture is commonly interpreted in the literature as a fold
interference pattern. Alternatively, it can be described non-genetically as an isotropic cellular
structure comprised of oval features rimmed by narrow troughs, some of which curve through ~180
degrees (white box). The radar-dark material within the troughs is generally interpreted as relatively
late, intra-plateau volcanic plains. These features are characteristic of the interior domains of the
principal crustal plateaux on Venus (see Appendix Figs 1-9). Image sourced from https://jmars.mars.asu. edu/.
Detailed image of the interior of W. Ovda Regio. See also Ivanov and Head (1996). Scale
bar is 100 km. The predominant texture is commonly interpreted in the literature as a fold
interference pattern. Alternatively, it can be described non-genetically as an isotropic cellular
structure comprised of oval features rimmed by narrow troughs, some of which curve through ~180
degrees (white box). The radar-dark material within the troughs is generally interpreted as relatively
late, intra-plateau volcanic plains. These features are characteristic of the interior domains of the
principal crustal plateaux on Venus (see Appendix Figs 1-9). Image sourced from https://jmars.mars.asu. edu/.
Figure 6c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlarged detail of the north margin of W. Ovda Regio. Scale bar is 250 km. Note the isotropic cellular
structure of the interior domain (lower field) vs the broad swath of radial, high aspect ratio graben (upper
field) that overprint an outboard margin-parallel anisotropy (dashed white box). The graben also overprint
the interior domain structure in the west (solid box), and an anisotropy with discrete continuous white
bands in the east (dashed box). Image sourced from https://jmars.mars.asu. edu/.
Enlarged detail of the north margin of W. Ovda Regio. Scale bar is 250 km. Note the isotropic cellular
structure of the interior domain (lower field) vs the broad swath of radial, high aspect ratio graben (upper
field) that overprint an outboard margin-parallel anisotropy (dashed white box). The graben also overprint
the interior domain structure in the west (solid box), and an anisotropy with discrete continuous white
bands in the east (dashed box). Image sourced from https://jmars.mars.asu. edu/.
Figure 7 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Topographical relief, in kilometers, of the principal crustal plateaux on Venus, plus
Phoebe Regio. White bars in each panel are 500 km scales. Peak elevations of these highlands
generally occur near their margins and form rims. Rim morphology is more prominent for the lower
standing than the higher standing regiones. Ovda Regio, the tallest principal crustal plateau, entirely
lacks a rim because its highest relief is concentrated at the centre of the highland. Contour spacing
is 0.5 km. Taken from Nunes et al. (2004, their figure 1). Image sourced from https://jmars.mars.asu. edu/.
Topographical relief, in kilometers, of the principal crustal plateaux on Venus, plus
Phoebe Regio. White bars in each panel are 500 km scales. Peak elevations of these highlands
generally occur near their margins and form rims. Rim morphology is more prominent for the lower
standing than the higher standing regiones. Ovda Regio, the tallest principal crustal plateau, entirely
lacks a rim because its highest relief is concentrated at the centre of the highland. Contour spacing
is 0.5 km. Taken from Nunes et al. (2004, their figure 1). Image sourced from https://jmars.mars.asu. edu/.
Figure 8 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Various hypotheses of formation of the purported basin-and-dome fold interference
pattern for the interior domain of Ovda Regio (not to scale). (a) Both sets (NW–SE and NE–SW)
were simultaneously formed undergoing a constriction regime in all directions. (b) First a
contraction took place in a unique direction generating a fold set, and later a change in the stress
tensor provides a perpendicular contraction generating the second structure set, providing the
interference with the first one. (c) Initial contraction with a dominant shortening direction generated
a fold set; later the tectonic regime changed to a constriction in all directions; and finally
contraction with a new dominant shortening direction. Taken from Romeo and Capote (2011, their
figure 13).
Various hypotheses of formation of the purported basin-and-dome fold interference
pattern for the interior domain of Ovda Regio (not to scale). (a) Both sets (NW–SE and NE–SW)
were simultaneously formed undergoing a constriction regime in all directions. (b) First a
contraction took place in a unique direction generating a fold set, and later a change in the stress
tensor provides a perpendicular contraction generating the second structure set, providing the
interference with the first one. (c) Initial contraction with a dominant shortening direction generated
a fold set; later the tectonic regime changed to a constriction in all directions; and finally
contraction with a new dominant shortening direction. Taken from Romeo and Capote (2011, their
figure 13).
Figure 9 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Structural map of the purported central "basin and dome" area of Ovda Regio. Taken
from Romeo and Capote (2011, their figure 10). Compare with Appendix Figs 8C and D. Note the
absence of indications of folded layering, e.g. fold closures.
Structural map of the purported central "basin and dome" area of Ovda Regio. Taken
from Romeo and Capote (2011, their figure 10). Compare with Appendix Figs 8C and D. Note the
absence of indications of folded layering, e.g. fold closures.
Figure 10 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Highly simplified time-line comparison of hypothetical global events giving rise to the
principal crustal plateaux and BAT region on Venus during the Global Tectonic Regime vs the later
Network Rifting-Volcanism Regime (NR-V). Inner circle represents the planetary core; outer circles
bound the planetary lithosphere. Not to scale. Left: impact of a large bolide (red arrow) at the outset
of the <1 Ga Global Tectonic Regime (see Fig. 3) generates shock waves (green arrows) that travel
through the lithosphere toward the planetary antipode where they converge and constructively
interfere, instantaneously shattering the dry diabase crust (blue dot); followed by a time dependent
mantle downwelling flow (blue arrow) beneath the antipode to the impact, that drives the tectonic
thickening of weakened, shattered crust (inspired by Jones et al., 2022). Right: Much later, during
the Network Rifting-Volcanism (NR-V) Regime at ~400-100 Ma, upwelling mantle flow beneath
the impact site continues long-term (~10^8 My), and is potentially responsible for magmato-volcanism
in the BAT region (see Fig. 1).
Highly simplified time-line comparison of hypothetical global events giving rise to the
principal crustal plateaux and BAT region on Venus during the Global Tectonic Regime vs the later
Network Rifting-Volcanism Regime (NR-V). Inner circle represents the planetary core; outer circles
bound the planetary lithosphere. Not to scale. Left: impact of a large bolide (red arrow) at the outset
of the <1 Ga Global Tectonic Regime (see Fig. 3) generates shock waves (green arrows) that travel
through the lithosphere toward the planetary antipode where they converge and constructively
interfere, instantaneously shattering the dry diabase crust (blue dot); followed by a time dependent
mantle downwelling flow (blue arrow) beneath the antipode to the impact, that drives the tectonic
thickening of weakened, shattered crust (inspired by Jones et al., 2022). Right: Much later, during
the Network Rifting-Volcanism (NR-V) Regime at ~400-100 Ma, upwelling mantle flow beneath
the impact site continues long-term (~10^8 My), and is potentially responsible for magmato-volcanism
in the BAT region (see Fig. 1).
Appendix Figure 1a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Crustal plateau Alpha Regio (radar-bright) surrounded by regional
volcanic plains (radar-dark). See main text Fig. 1 for location. Scale bar is 750 km. Surface texture
is generally an isotropic cellular structure, except for the western margin. Dashed box is location of
B; solid box is location of C. The WNW-ESE "structural zone" of Gilmore and Head (2000) is
located between the two white boxes. Image sourced from https://jmars.mars.asu. edu/.
Crustal plateau Alpha Regio (radar-bright) surrounded by regional
volcanic plains (radar-dark). See main text Fig. 1 for location. Scale bar is 750 km. Surface texture
is generally an isotropic cellular structure, except for the western margin. Dashed box is location of
B; solid box is location of C. The WNW-ESE "structural zone" of Gilmore and Head (2000) is
located between the two white boxes. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 1b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of the isotropic cellular structure in the northern
part of the crustal plateau. Small, radar-dark, intra-plateau volcanic plains are relatively young with
respect to most adjacent deformation features. Scale bar is 250 km. Image sourced from https://jmars.mars.asu. edu/.
Detail of the isotropic cellular structure in the northern
part of the crustal plateau. Small, radar-dark, intra-plateau volcanic plains are relatively young with
respect to most adjacent deformation features. Scale bar is 250 km. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 1c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
A discrete triangular
subdomain (white box, also the location of D) within the southern interior domain of Alpha Regio.
The scale bar is 100 km. According to Bindschadler et al. (1992a), the subdomain is characterised
by mostly symmetrical "broad arcuate ridges" formed by interference folding.
Image sourced from https://jmars.mars.asu. edu/.
A discrete triangular
subdomain (white box, also the location of D) within the southern interior domain of Alpha Regio.
The scale bar is 100 km. According to Bindschadler et al. (1992a), the subdomain is characterised
by mostly symmetrical "broad arcuate ridges" formed by interference folding.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 1d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of C. The scale bar is 75 km. Note the single, hairpin-like, radar-dark feature left of centre (white box, also the
location of E). Image sourced from https://jmars.mars.asu. edu/.
Detail of C. The scale bar is 75 km. Note the single, hairpin-like, radar-dark feature left of centre (white box, also the
location of E). Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 1e @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Further enlargement of D. The scale bar is 50 km. Close-spaced, radar-bright,
unspecified lineaments are oriented NW-SE and NE-SW. Locally, the latter, adjacent to the radardark
hairpin-like feature in the centre (white box), present a similar curvature to the hairpin-like
feature itself, but the lineaments are clearly discordant to the latter on its north side. Bindschadler et
al. (1992a, their figure 5) suggested that the hairpin-like feature is a fold within an extensive
interference fold pattern. This is geologically improbable, as it would then be the only fold closure
observed in the entire triangular subdomain (see C and D). In addition, it would be an isolated,
intra-folial fold5, in contradiction to the commonly proposed upright dome-and-basin interpretation
of the interior domains of crustal plateaux on Venus. Image sourced from https://jmars.mars.asu. edu/.
Further enlargement of D. The scale bar is 50 km. Close-spaced, radar-bright,
unspecified lineaments are oriented NW-SE and NE-SW. Locally, the latter, adjacent to the radardark
hairpin-like feature in the centre (white box), present a similar curvature to the hairpin-like
feature itself, but the lineaments are clearly discordant to the latter on its north side. Bindschadler et
al. (1992a, their figure 5) suggested that the hairpin-like feature is a fold within an extensive
interference fold pattern. This is geologically improbable, as it would then be the only fold closure
observed in the entire triangular subdomain (see C and D). In addition, it would be an isolated,
intra-folial fold5, in contradiction to the commonly proposed upright dome-and-basin interpretation
of the interior domains of crustal plateaux on Venus. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 2 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Sketch map and topographical profile of the terrains identified within Fortuna
Regio. See main text Fig. 1 for location. Short lines represent structural trends that differ from
terrain to terrain. Discussed in the main text. Taken from Vorder Bruegge and Head (1989, their
figure 3).
Sketch map and topographical profile of the terrains identified within Fortuna
Regio. See main text Fig. 1 for location. Short lines represent structural trends that differ from
terrain to terrain. Discussed in the main text. Taken from Vorder Bruegge and Head (1989, their
figure 3).
Appendix Figure 3a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Western part of Fortuna Regio, a radar-bright crustal plateau. The scale
bar is 250 km. The broad band of anisotropy immediately east of Maxwell Montes (white patch at
left) is the arcuate ridged terrain of Appendix Fig. 2 (large dashed white box). The eastern border of
this image includes the western part of the chevron terrain: note the large "chevron" feature in the
lower right corner (medium dashed white box), and the large crustal block to the north of it (upper
solid white box) with its weakly developed internal fabric elements that contrasts with the adjacent,
well developed, isotropic cellular structure. Note the small, isolated, local swarm of high aspect
ratio graben set within the interior domain (small dashed box at lower right).
Image sourced from https://jmars.mars.asu. edu/.
Western part of Fortuna Regio, a radar-bright crustal plateau. The scale
bar is 250 km. The broad band of anisotropy immediately east of Maxwell Montes (white patch at
left) is the arcuate ridged terrain of Appendix Fig. 2 (large dashed white box). The eastern border of
this image includes the western part of the chevron terrain: note the large "chevron" feature in the
lower right corner (medium dashed white box), and the large crustal block to the north of it (upper
solid white box) with its weakly developed internal fabric elements that contrasts with the adjacent,
well developed, isotropic cellular structure. Note the small, isolated, local swarm of high aspect
ratio graben set within the interior domain (small dashed box at lower right).
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 3b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
The chevron terrain of central Fortuna Regio, located at the lower right corner of A. Principal features
of note include confined anisotropic bands of unknown origin (small dashed white box), plus areas of
unconfined anisotropy (large dashed white box), that deflect around the corners of large rectangular
blocks with weakly developed internal fabric elements of unknown origin (Vorder Bruegge and
Head (1989). Dashed white boxes also indicate locations of C (upper) and E (lower).
Image sourced from https://jmars.mars.asu. edu/.
The chevron terrain of central Fortuna Regio, located at the lower right corner of A. Principal features
of note include confined anisotropic bands of unknown origin (small dashed white box), plus areas of
unconfined anisotropy (large dashed white box), that deflect around the corners of large rectangular
blocks with weakly developed internal fabric elements of unknown origin (Vorder Bruegge and
Head (1989). Dashed white boxes also indicate locations of C (upper) and E (lower).
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 3c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of the chevron terrain of central Fortuna Regio. Scale bar is 100
km. Note confined anisotropic bands of unknown origin (lower left: see E for detailed view), plus
areas of unconfined anisotropy (solid and dashed white boxes; see D for detailed view). The
anisotropy outlines chevron-like shapes that deflect around the corners of large rectangular blocks
with weakly developed internal fabric elements of unknown origin (lower solid white box). Vorder
Bruegge and Head (1989) compared these chevron-like features to tectonic syntaxes, as opposed to
buckle folds. Large solid white box indicates location of D. Image sourced from https://jmars.mars.asu. edu/.
Detail of the chevron terrain of central Fortuna Regio. Scale bar is 100
km. Note confined anisotropic bands of unknown origin (lower left: see E for detailed view), plus
areas of unconfined anisotropy (solid and dashed white boxes; see D for detailed view). The
anisotropy outlines chevron-like shapes that deflect around the corners of large rectangular blocks
with weakly developed internal fabric elements of unknown origin (lower solid white box). Vorder
Bruegge and Head (1989) compared these chevron-like features to tectonic syntaxes, as opposed to
buckle folds. Large solid white box indicates location of D. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 3d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Further enlarged detail of the
chevron terrain of C. Scale bar is 75 km. Note the contrast between the relatively weak NE-SW
trending internal fabric within the large block of crust (left of centre), the strong anisotropy (right
field), and the isotropic cellular structure (upper left). Image sourced from https://jmars.mars.asu. edu/.
Further enlarged detail of the
chevron terrain of C. Scale bar is 75 km. Note the contrast between the relatively weak NE-SW
trending internal fabric within the large block of crust (left of centre), the strong anisotropy (right
field), and the isotropic cellular structure (upper left). Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 3e @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of B. Scale bar is 100 km. Note the
discrete (confined) anisotropic band of unknown origin (left) that deflects around the corner of a
large rectangular block with weakly developed internal fabric elements of unknown origin (centre),
itself apparently the western member of a group of three blocks. Were they originally contiguous?
The constant width of the anisotropic band around the deflection indicates that, if the anisotropy is
planar, the chevron-like feature is steeply plunging. Intra-plateau volcanic plains that partially
drown the left-most block are labelled vp. Image sourced from https://jmars.mars.asu. edu/.
Detail of B. Scale bar is 100 km. Note the
discrete (confined) anisotropic band of unknown origin (left) that deflects around the corner of a
large rectangular block with weakly developed internal fabric elements of unknown origin (centre),
itself apparently the western member of a group of three blocks. Were they originally contiguous?
The constant width of the anisotropic band around the deflection indicates that, if the anisotropy is
planar, the chevron-like feature is steeply plunging. Intra-plateau volcanic plains that partially
drown the left-most block are labelled vp. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Physiographic provinces of Tellus Regio. See main text Fig. 1 for
location. Note the distinction between interior vs marginal vs transitional domains (here labelled as
terrains), and northern and southern interior subdomains. Taken from Gilmore and Head (2018,
their figure 2).
Physiographic provinces of Tellus Regio. See main text Fig. 1 for
location. Note the distinction between interior vs marginal vs transitional domains (here labelled as
terrains), and northern and southern interior subdomains. Taken from Gilmore and Head (2018,
their figure 2).
Appendix Figure 4b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Tellus Regio, a radar-bright crustal plateau, ~1800 x 1800 km, surrounded by
regional volcanic plains (radar-dark). Scale bar is 750 km. Note the isotropic cellular texture of the
interior domain. Small dashed white box is location of C; large dashed box is location of SW Area A
of Gilmore and Head (2018), see A for context; solid white box is location of Appendix Fig. 5B.
White star is the location of the polygonal feature in Appendix Fig. 5C. Gilmore and Head (2018)
interpreted the round block in the lower left corner (SW Area A in A) as a tectonic indentor that
accreted to the Tellus Regio crustal plateau. However, this would predict a marked regional strain
gradient localised on the impactor margin, which is not readily apparent.
Image sourced from https://jmars.mars.asu. edu/.
Tellus Regio, a radar-bright crustal plateau, ~1800 x 1800 km, surrounded by
regional volcanic plains (radar-dark). Scale bar is 750 km. Note the isotropic cellular texture of the
interior domain. Small dashed white box is location of C; large dashed box is location of SW Area A
of Gilmore and Head (2018), see A for context; solid white box is location of Appendix Fig. 5B.
White star is the location of the polygonal feature in Appendix Fig. 5C. Gilmore and Head (2018)
interpreted the round block in the lower left corner (SW Area A in A) as a tectonic indentor that
accreted to the Tellus Regio crustal plateau. However, this would predict a marked regional strain
gradient localised on the impactor margin, which is not readily apparent.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed image of the northern interior domain (terrain) of Tellus Regio. Scale bar is 75 km.
Dashed white box indicates location of figure 1 in Byrne et al., 2020, who interpreted the surface
textural pattern as an E-W trending fold of layered rocks. However, comparison with Appendix Figs
3C-E suggests that this feature resembles a sub-rectangular block with a relatively weak internal
fabric of unknown origin. Image sourced from https://jmars.mars.asu. edu/.
Detailed image of the northern interior domain (terrain) of Tellus Regio. Scale bar is 75 km.
Dashed white box indicates location of figure 1 in Byrne et al., 2020, who interpreted the surface
textural pattern as an E-W trending fold of layered rocks. However, comparison with Appendix Figs
3C-E suggests that this feature resembles a sub-rectangular block with a relatively weak internal
fabric of unknown origin. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlargement of the central part of C. See also Gilmore and Head
(2018, their figure 4), Byrne et al. (2020, their figure 3). Scale bar is 50 km. The interiors of oval
features contain either radar-bright lineaments at various angles to their margins, or a rubbly
(chaotic) texture (see oval feature in white box; labelled a in C; see E for detailed view). Note that
the oval feature at mid-right in this image (labelled b in C) was interpreted by Byrne et al. (2020,
their figure 4) as a periclinal fold. However, their interpretation of simple sinusoidal antiformsynform
pairs is incompatible with the observed narrow troughs (filled with radar-dark intra-plateau
volcanic plains material) that bound the oval features. Image sourced from https://jmars.mars.asu. edu/.
Enlargement of the central part of C. See also Gilmore and Head
(2018, their figure 4), Byrne et al. (2020, their figure 3). Scale bar is 50 km. The interiors of oval
features contain either radar-bright lineaments at various angles to their margins, or a rubbly
(chaotic) texture (see oval feature in white box; labelled a in C; see E for detailed view). Note that
the oval feature at mid-right in this image (labelled b in C) was interpreted by Byrne et al. (2020,
their figure 4) as a periclinal fold. However, their interpretation of simple sinusoidal antiformsynform
pairs is incompatible with the observed narrow troughs (filled with radar-dark intra-plateau
volcanic plains material) that bound the oval features. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4e @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Further enlargement of the western part of D. Scale bar is 25 km. The interior of this oval feature presents a rubbly (chaotic) texture.
Image sourced from https://jmars.mars.asu. edu/.
Further enlargement of the western part of D. Scale bar is 25 km. The interior of this oval feature presents a rubbly (chaotic) texture.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4f @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlarged detail of the northern interior block domain (terrain) of Tellus Regio, located due east of
D. See also Gilmore and Head (2018, their figure 4). Scale bar is 25 km. Note the abrupt
discordance of close-spaced NE-SW internal, unspecified lineaments of one block (within the white
box) with respect to the WNW-ESE lineaments that dominate the rest of the image. Blocks are
separated by narrow radar-dark troughs filled with intra-plateau volcanic plains.
Image sourced from https://jmars.mars.asu. edu/.
Enlarged detail of the northern interior block domain (terrain) of Tellus Regio, located due east of
D. See also Gilmore and Head (2018, their figure 4). Scale bar is 25 km. Note the abrupt
discordance of close-spaced NE-SW internal, unspecified lineaments of one block (within the white
box) with respect to the WNW-ESE lineaments that dominate the rest of the image. Blocks are
separated by narrow radar-dark troughs filled with intra-plateau volcanic plains.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 4g @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlarged detail
of the northern interior block domain (terrain) of Tellus Regio, located just north of My Guying (see
B for location). Scale bar is 25 km. The oval feature (centre) was interpreted by Cofrade et al.
(2019, their figure 2) as diapiric. Alternatively, compare this feature with the cellular structure in
Appendix Figs 4B-D. Image sourced from https://jmars.mars.asu. edu/.
Enlarged detail
of the northern interior block domain (terrain) of Tellus Regio, located just north of My Guying (see
B for location). Scale bar is 25 km. The oval feature (centre) was interpreted by Cofrade et al.
(2019, their figure 2) as diapiric. Alternatively, compare this feature with the cellular structure in
Appendix Figs 4B-D. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 5a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of the centre part of Appendix Fig. 4B along the northern margin of
the southern interior block domain of Tellus Regio (see Appendix Fig. 4A). According to Gilmore
and Head (2018, their figure 5), the NW-SE trending radar-bright features, separated by commonly
radar-dark narrow troughs, are more highly shortened equivalents of the cellular structure of the
northern interior block domain, to which NE-SE trending high aspect ratio graben are orthogonal.
Image sourced from https://jmars.mars.asu. edu/.
Detail of the centre part of Appendix Fig. 4B along the northern margin of
the southern interior block domain of Tellus Regio (see Appendix Fig. 4A). According to Gilmore
and Head (2018, their figure 5), the NW-SE trending radar-bright features, separated by commonly
radar-dark narrow troughs, are more highly shortened equivalents of the cellular structure of the
northern interior block domain, to which NE-SE trending high aspect ratio graben are orthogonal.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 5b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detail of the eastern margin fold belt of Tellus Regio. See Appendix Figs 4A and B for location.
According to Gilmore and Head (2018, their figure 7), NNE-SSW trending radar-bright ridges are
folds flanked by narrow troughs. High aspect ratio graben orthogonally overprint the folds (white
boxes). Note the northern interior block domain (terrain) texture at mid- to top right. The large
radar-dark patch (centre-left) is an intra-plateau volcanic plain. Image sourced from https://jmars.mars.asu. edu/.
Detail of the eastern margin fold belt of Tellus Regio. See Appendix Figs 4A and B for location.
According to Gilmore and Head (2018, their figure 7), NNE-SSW trending radar-bright ridges are
folds flanked by narrow troughs. High aspect ratio graben orthogonally overprint the folds (white
boxes). Note the northern interior block domain (terrain) texture at mid- to top right. The large
radar-dark patch (centre-left) is an intra-plateau volcanic plain. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 5c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
The eastern limit of the western
margin of Tellus Regio contains an enigmatic polygonal feature (Gilmore and Head, 2018; see
Appendix Fig 4B for location). Scale bar is 75 km. According to Gilmore and Head (2018, their
figure 9), the polygonal feature at lower left (solid white box) is a refolded fold ("orocline")
"buttressed against a ‘core' ~35 km across" whose E-W trending axial trace has been refolded about
a N-S trending fold. Although they report that several other ridges to the south show similar
deformation patterns over a distance of ~200 km, they do not identify or locate them. Alternatively,
the crust immediately south of the "core" is anomalously radar-smooth and could represent a
relatively rigid block. Image sourced from https://jmars.mars.asu. edu/.
The eastern limit of the western
margin of Tellus Regio contains an enigmatic polygonal feature (Gilmore and Head, 2018; see
Appendix Fig 4B for location). Scale bar is 75 km. According to Gilmore and Head (2018, their
figure 9), the polygonal feature at lower left (solid white box) is a refolded fold ("orocline")
"buttressed against a ‘core' ~35 km across" whose E-W trending axial trace has been refolded about
a N-S trending fold. Although they report that several other ridges to the south show similar
deformation patterns over a distance of ~200 km, they do not identify or locate them. Alternatively,
the crust immediately south of the "core" is anomalously radar-smooth and could represent a
relatively rigid block. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
W. Ovda Regio, a radar-bright crustal plateau, ~2200 x 2200 km,
surrounded by regional volcanic plains (radar-dark), showing a well differentiated interior domain
vs marginal domains, especially on the north side. See main text Fig. 1 for location. Scale bar is 750
km. Dashed white box is the location of B. The white star is the location of Appendix Fig. 7.
Image sourced from https://jmars.mars.asu. edu/.
W. Ovda Regio, a radar-bright crustal plateau, ~2200 x 2200 km,
surrounded by regional volcanic plains (radar-dark), showing a well differentiated interior domain
vs marginal domains, especially on the north side. See main text Fig. 1 for location. Scale bar is 750
km. Dashed white box is the location of B. The white star is the location of Appendix Fig. 7.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed image of the interior domain, located top-centre in W. Ovda Regio. Scale bar is 100 km.
White box is location of C. The predominant texture is an isotropic cellular pattern comprised of
oval features rimmed by narrow troughs. Image sourced from https://jmars.mars.asu. edu/.
Detailed image of the interior domain, located top-centre in W. Ovda Regio. Scale bar is 100 km.
White box is location of C. The predominant texture is an isotropic cellular pattern comprised of
oval features rimmed by narrow troughs. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed enlargement of the centre of B. Scale bar is
50 km. Note the isotropic cellular structure comprised of oval features, many of which have
approximately E-W internal, unspecified lineaments, rimmed by NNE-SSW narrow troughs (white
boxes). Image sourced from https://jmars.mars.asu. edu/.
Detailed enlargement of the centre of B. Scale bar is
50 km. Note the isotropic cellular structure comprised of oval features, many of which have
approximately E-W internal, unspecified lineaments, rimmed by NNE-SSW narrow troughs (white
boxes). Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Further enlargement of the cellular structure in C. Scale bar is 25 km. WNW-ESE
trending lineaments of unspecified origin are confined to the interiors of the oval features (white
box is the same location as the right-hand box in C). The lineaments are truncated at contacts with
stringy textured NNE-SSW trending corridors of lineaments that appear to be deformation zones of
unknown nature (and vorticity; see Hanmer, 1990; Hanmer and Passchier, 1991 for brief
explanation of vorticity). This could be described as a coherent breccia of blocks, bounded by
anastomosing corridors of localised deformation. Image sourced from https://jmars.mars.asu. edu/.
Further enlargement of the cellular structure in C. Scale bar is 25 km. WNW-ESE
trending lineaments of unspecified origin are confined to the interiors of the oval features (white
box is the same location as the right-hand box in C). The lineaments are truncated at contacts with
stringy textured NNE-SSW trending corridors of lineaments that appear to be deformation zones of
unknown nature (and vorticity; see Hanmer, 1990; Hanmer and Passchier, 1991 for brief
explanation of vorticity). This could be described as a coherent breccia of blocks, bounded by
anastomosing corridors of localised deformation. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6e @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlarged detail of the north margin of W.
Ovda Regio. Scale bar is 250 km. Note the isotropic cellular structure of the interior domain (lower
field) vs the broad swath of radial, high aspect ratio graben (upper field) that overprints an outboard
margin-parallel anisotropy (dashed white box). The graben also overprint the interior domain
structure in the west (left solid white box; see F for detailed view), and an anisotropy with discrete
continuous white bands developed in the interior domain in the east (right solid white box; see G for
detailed view). Image sourced from https://jmars.mars.asu. edu/.
Enlarged detail of the north margin of W.
Ovda Regio. Scale bar is 250 km. Note the isotropic cellular structure of the interior domain (lower
field) vs the broad swath of radial, high aspect ratio graben (upper field) that overprints an outboard
margin-parallel anisotropy (dashed white box). The graben also overprint the interior domain
structure in the west (left solid white box; see F for detailed view), and an anisotropy with discrete
continuous white bands developed in the interior domain in the east (right solid white box; see G for
detailed view). Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6f @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Further enlarged detail of E. Scale bar is 100 km. Note the isotropic cellular
structure, typical of the interior domain, somewhat flattened in places and extensively overprinted
by the broad swath of penetratively developed radial ribbon-style graben. Solomon et al. (1992)
identified this as a type area for their "linear trough terrain", i.e. "tessera terrain".
Image sourced from https://jmars.mars.asu. edu/.
Further enlarged detail of E. Scale bar is 100 km. Note the isotropic cellular
structure, typical of the interior domain, somewhat flattened in places and extensively overprinted
by the broad swath of penetratively developed radial ribbon-style graben. Solomon et al. (1992)
identified this as a type area for their "linear trough terrain", i.e. "tessera terrain".
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 6g @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Another enlarged detail of E. Scale bar is 100 km. Note the marked WNW-ESE trending anisotropy,
including distinct bands of unknown origin with radar-bright cores and radar-dark margins,
extensively overprinted by the broad swath of radial ribbon-style graben.
Image sourced from https://jmars.mars.asu. edu/.
Another enlarged detail of E. Scale bar is 100 km. Note the marked WNW-ESE trending anisotropy,
including distinct bands of unknown origin with radar-bright cores and radar-dark margins,
extensively overprinted by the broad swath of radial ribbon-style graben.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 7 @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlarged detail of the interior block domain of W. Ovda Regio; see Appendix
Fig. 6A for location. Scale bar is 25 km. The oval feature (centre) was interpreted by Cofrade et al.
(2019) as diapiric. Alternatively, compare this feature with the isotropic cellular structure in
Appendix Fig. 6B. Image sourced from https://jmars.mars.asu. edu/.
Enlarged detail of the interior block domain of W. Ovda Regio; see Appendix
Fig. 6A for location. Scale bar is 25 km. The oval feature (centre) was interpreted by Cofrade et al.
(2019) as diapiric. Alternatively, compare this feature with the isotropic cellular structure in
Appendix Fig. 6B. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Ovda Regio, a radar-bright crustal plateau composed of two lobes with
extensive areas of isotropic cellular texture within the interior domains, separated by a complex
corridor with abundant radar-dark, "intra-tessera" volcanic plains, all flanked by anisotropic
marginal domains. See main text Fig. 1 for location. Scale bar is 750 km. Note the presence of
penetratively developed high aspect ratio graben on the northwestern margin. Dashed white boxes
are locations of E (top left), F (upper top right) and C (lower top right); solid white box is location
of B. Image sourced from https://jmars.mars.asu. edu/.
Ovda Regio, a radar-bright crustal plateau composed of two lobes with
extensive areas of isotropic cellular texture within the interior domains, separated by a complex
corridor with abundant radar-dark, "intra-tessera" volcanic plains, all flanked by anisotropic
marginal domains. See main text Fig. 1 for location. Scale bar is 750 km. Note the presence of
penetratively developed high aspect ratio graben on the northwestern margin. Dashed white boxes
are locations of E (top left), F (upper top right) and C (lower top right); solid white box is location
of B. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Northern half of the western lobe of Ovda Regio. Scale bar is 500 km. The area in the
solid white box was interpreted bySolomon et al. (1992) as illustrating "sigmoid folds" formed by
E-W directed "compression" (see also Harris and Bedard, 2014a, their figure 9.5). Alternatively, one
can compare the large chevron-like structures, and their tighter equivalents to similar features in
Fortuna Regio (Appendix Figs 3B-E), where chevron-like features formed at the corners of large,
relatively stiff crustal blocks. As in Appendix Fig. 3E, the chevron-like features in this view do not
show apparent axial widening or thickening, suggesting that they are steeply plunging. Note the
isotropic cellular texture in left field (dashed white box). The progressive eastward development of
anisotropy between the two boxes suggests that the folds developed after the cellular structure (cf.
the opposite temporal sequence to that proposed by Solomon et al. (1992, their figure 12).
Image sourced from https://jmars.mars.asu. edu/.
Northern half of the western lobe of Ovda Regio. Scale bar is 500 km. The area in the
solid white box was interpreted bySolomon et al. (1992) as illustrating "sigmoid folds" formed by
E-W directed "compression" (see also Harris and Bedard, 2014a, their figure 9.5). Alternatively, one
can compare the large chevron-like structures, and their tighter equivalents to similar features in
Fortuna Regio (Appendix Figs 3B-E), where chevron-like features formed at the corners of large,
relatively stiff crustal blocks. As in Appendix Fig. 3E, the chevron-like features in this view do not
show apparent axial widening or thickening, suggesting that they are steeply plunging. Note the
isotropic cellular texture in left field (dashed white box). The progressive eastward development of
anisotropy between the two boxes suggests that the folds developed after the cellular structure (cf.
the opposite temporal sequence to that proposed by Solomon et al. (1992, their figure 12).
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8c @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed image of the interior domain of the eastern lobe of Ovda Regio (see A for location). See
also Romeo and Capote (2011; main text Fig. 9). Although described by these authors as illustrating
a dome-and-basin interference fold pattern, fold closures are not apparent. Scale bar is 100 km.
Image sourced from https://jmars.mars.asu. edu/.
Detailed image of the interior domain of the eastern lobe of Ovda Regio (see A for location). See
also Romeo and Capote (2011; main text Fig. 9). Although described by these authors as illustrating
a dome-and-basin interference fold pattern, fold closures are not apparent. Scale bar is 100 km.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8d @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlargement of C, further affirming the absence of a dome-and-basin interference fold pattern.
Scale bar is 50 km. Image sourced from https://jmars.mars.asu. edu/.
Enlargement of C, further affirming the absence of a dome-and-basin interference fold pattern.
Scale bar is 50 km. Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8e @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed enlargement of the top left corner of A. Scale bar is 50 km. See also
Solomon et al.,1992, Romeo and Capote, 2011 and Hansen, 2006. On the one hand, both Solomon
et al. (1992) and Hansen (2006) reported the presence of ENE-WSW low amplitude, open folds and
NNW-SSE high aspect ratio graben from this field of view. On the other hand, Romeo and Capote
(2011) reported more intense deformation and thrusting associated with tight folding.
Image sourced from https://jmars.mars.asu. edu/.
Detailed enlargement of the top left corner of A. Scale bar is 50 km. See also
Solomon et al.,1992, Romeo and Capote, 2011 and Hansen, 2006. On the one hand, both Solomon
et al. (1992) and Hansen (2006) reported the presence of ENE-WSW low amplitude, open folds and
NNW-SSE high aspect ratio graben from this field of view. On the other hand, Romeo and Capote
(2011) reported more intense deformation and thrusting associated with tight folding.
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 8f @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Detailed enlargement of the radar-bright northeastern margin of the eastern lobe of Ovda Regio, flanked by
radar-dark regional volcanic plains. See A for location. The scale bar is 250 km. Note the anisotropy
of the marginal domain (right field; dashed white box) vs the cellular structure of the interior
domain (left field; solid white box). The marginal domain presents margin-parallel ridges,
interpreted in the literature as folds, cross-cut perpendicularly by penetratively developed high
aspect ratio graben (see Fig 4B in main text, itself located at the centre of the marginal belt shown
here, for a detailed view), which are generally absent in the interior domain. Multiple studies have
represented this part of the marginal domain as a type area for classical "tessera terrain" (e.g.
Phillips and Hansen, 1998; Hansen et al., 1999; Ghent and Hansen, 1999; Hansen, 2007c; Hansen
and Lopez, 2010). Image sourced from https://jmars.mars.asu. edu/.
Detailed enlargement of the radar-bright northeastern margin of the eastern lobe of Ovda Regio, flanked by
radar-dark regional volcanic plains. See A for location. The scale bar is 250 km. Note the anisotropy
of the marginal domain (right field; dashed white box) vs the cellular structure of the interior
domain (left field; solid white box). The marginal domain presents margin-parallel ridges,
interpreted in the literature as folds, cross-cut perpendicularly by penetratively developed high
aspect ratio graben (see Fig 4B in main text, itself located at the centre of the marginal belt shown
here, for a detailed view), which are generally absent in the interior domain. Multiple studies have
represented this part of the marginal domain as a type area for classical "tessera terrain" (e.g.
Phillips and Hansen, 1998; Hansen et al., 1999; Ghent and Hansen, 1999; Hansen, 2007c; Hansen
and Lopez, 2010). Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 9a @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Thetis Regio, a radar-bright crustal plateau, ~2200 x 1800 km,
surrounded by radar-dark regional volcanic plains. See main text Fig. 1 for location. Scale bar is
750 km. Dashed white box is location of B. Note the isotropic cellular texture of the interior domain
(mid-field solid white box), identified by Ivanov and Head (2011) as a type area for "tessera
terrain", and the contrast with the NE-SW trending anisotropy in the SW part of the crustal plateau
(lower-field solid white box). To the north of the interior domain is a marginal domain with a
WSW-ESE trending, margin-parallel anisotropy (top-field solid white box).
Image sourced from https://jmars.mars.asu. edu/.
Thetis Regio, a radar-bright crustal plateau, ~2200 x 1800 km,
surrounded by radar-dark regional volcanic plains. See main text Fig. 1 for location. Scale bar is
750 km. Dashed white box is location of B. Note the isotropic cellular texture of the interior domain
(mid-field solid white box), identified by Ivanov and Head (2011) as a type area for "tessera
terrain", and the contrast with the NE-SW trending anisotropy in the SW part of the crustal plateau
(lower-field solid white box). To the north of the interior domain is a marginal domain with a
WSW-ESE trending, margin-parallel anisotropy (top-field solid white box).
Image sourced from https://jmars.mars.asu. edu/.
Appendix Figure 9b @ 300 dpi : The enigmatic crustal plateaux and "tessera terrain" of Venus revisited
Enlargement of the
eastern part of the interior domain (see A for location), highlighting the isotropic (solid white box)
and anisotropic (flattened?) cellular structure of the interior domain (dashed white box), all
overprinted by a broad swath of penetratively developed, high aspect ratio graben. Scale bar is 250
km. Image sourced from https://jmars.mars.asu. edu/.
Enlargement of the
eastern part of the interior domain (see A for location), highlighting the isotropic (solid white box)
and anisotropic (flattened?) cellular structure of the interior domain (dashed white box), all
overprinted by a broad swath of penetratively developed, high aspect ratio graben. Scale bar is 250
km. Image sourced from https://jmars.mars.asu. edu/.
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