Giant radiating dyke swarms on Earth and Venus

Ernst, Richard E.; Head, J. W.; Parfitt, E. A.; Grosfils, E. B.; Wilson, Lionel

doi:10.1016/0012-8252(95)00017-5

Cited by 391 publications

(224 citation statements)

References 128 publications

Supporting

Mentioning

219

Contrasting

Order By: Relevance

“…First, it broadly supports the prediction by Ernst and Baragar (1992) and Ernst et al (1995a) that the Mackenzie swarm extended outward from the Canadian Arctic across much of ancestral North America (Laurentia). Second, the extension of the dyke swarm into western Canada means that other continents which may have lain alongside western Laurentia in Middle Proterozoic or later times, and were subsequently rifted away, may contain distal members of the Mackenzie swarm.…”

Section: Regional Significancesupporting

confidence: 75%

“…Many are linked to continental flood basalts, and are attributed to the arrival of a mantle plume head (Campbell and Griffiths, 1990;Ernst et al, 1995a) or a magmatic outburst above a steady-state hotspot (Johnston and Thorkelson, 2000). Anomalously high mantle temperatures and huge volumes of uprising melt, leading to updoming of the crust and outflow of magma from the hot-spot, are the most likely causes of the radiating dyke patterns.…”

Section: Introductionmentioning

confidence: 99%

“…All of the igneous activity is considered to have occurred within a few million years of 1267 Ma (LeCheminant and Heaman, 1989). The large volume of magma, the radial flow pattern, and the inferred short time span of emplacement point to a mantle plume origin (LeCheminant and Heaman, 1989;Ernst and Baragar, 1992;Ernst et al, 1995a).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Schwab

Thorkelson

Mortensen

et al. 2004

Precambrian Research

View full text Add to dashboard Cite

The 1.27 Ga Mackenzie dyke swarm, the largest on Earth, radiates from a point in the western Canadian Arctic and extends across much of the Canadian Shield. Possible western extensions of the swarm are largely obscured by younger sedimentary cover. Paleoproterozoic inliers in northern Yukon host the Bear River dykes (BRD), herein dated by U-Pb baddeleyite and zircon methods at 1268.5 ± 1.5 Ma and 1264.6 ± 1.2 Ma. The BRD share similar geochemical and Nd-isotopic characteristics with the Mackenzie dykes and the coeval Coppermine River basalts, and are regarded as products of the same plume. Hydrothermal activity at ∼1270 Ma in breccia of the Nor mineral occurrence, northwest of the BRD, was probably generated by BRD at depth. The BRD generally strike northwest, approximately 90 • to the orientation predicted by the radiating dyke model. This difference may be explained by an anomalous local stress field at the time of BRD emplacement, or reorientation of BRD during subsequent events of Cordilleran deformation. Using the Nor mineral occurrence as the westernmost locale of Mackenzie dyking, and assuming a model of uniform dyke radiation, the arc of the Mackenzie swarm is at least 50 • greater than previously recognized, bringing the total arc of dyke radiation to >150 • .

show abstract

Section: Regional Significancesupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Schwab

Thorkelson

Mortensen

et al. 2004

Precambrian Research

View full text Add to dashboard Cite

show abstract

“…Drawing analogy to the Earth and Venus (e.g. Ernst et al, 1995), Wilson and Head (2002a) present a model for the emplacement of giant dike swarms on Mars, and demonstrate that such Tharsis radiating swarms can plausibly account for the formation of the radiating graben systems. Such dikes propagate radially away from a central magma reservoir, and if they stall near the surface can create near-surface tensional stress fields that are ultimately compensated for by the development of graben.…”

Section: Model Backgroundmentioning

confidence: 95%

Mangala Valles, Mars: Assessment of Early Stages of Flooding and Downstream Flood Evolution

2005

View full text Add to dashboard Cite

Abstract. The Mangala Valles system is an~900 km fluvially carved channel system located southwest of the Tharsis rise and is unique among the martian outflow channels in that it heads at a linear fracture within the crust as opposed to a collapsed region of chaos as is the case with the circum-Chryse channels. Mangala Valles is confined within a broad, north-south trending depression, and begins as a single valley measuring up to 350 km wide that extends northward from a Memnonia Fossae graben, across the southern highlands toward the northern lowlands. Approximately 600 km downstream, this single valley branches into multiple channels, which ultimately lose their expression at the dichotomy boundary. Previous investigations of Mangala Vallis suggested that many of the units mapped interior to the valley were depositional, related to flooding, and that a minimum of two distinct periods of flooding separated by tens to hundreds of millions of years were required to explain the observed geology. We use infrared and visible images from the THermal EMission Imaging System (THEMIS), and topographic data from the Mars Orbiting Laser Altimeter (MOLA), to investigate the nature of the units mapped within Mangala Vallis. We find that the geomorphology of the units, as well as their topographic and geographic distribution, are consistent with most of them originating from a single assemblage of volcanic flow deposits, once continuous with volcanic flows to the south of the Memnonia Fossae source graben. These flows resurfaced the broad, north-south trending depression into which Mangala Vallis formed prior to any fluvial activity. Later flooding scoured and eroded this volcanic assemblage north of the Mangala source graben, resulting in the present distribution of the units within Mangala Vallis. Additionally, our observations suggest that a single period of catastrophic flooding, rather than multiple periods separated by tens to hundreds of millions of years, is consistent with and can plausibly explain the interior geology of Mangala Vallis. Further, we present a new scenario for the source and delivery of water to the Mangala source graben that models flow of groundwater through a subcryosphere aquifer and up a fracture that cracks the cryosphere and taps this aquifer. The results of our model indicate that the source graben, locally enlarged to a trough near the head region of Mangala, would have required less than several days to fill up prior to any spill-over of water to the north. Through estimates of the volume of material missing from Mangala (13,000-20,000 km 3 ), and calculation of mean discharge rates through the channel system (~5 · 10 6 m 3 s )1 ), we estimate that the total duration of fluvial activity through the Mangala Valles was 1-3 months. Notation:Parameter: Definition (Units); H:water head height in aquifer above base of cryosphere fracture (m); lateral length scale of aquifer (m); P atm : atmospheric pressure (500) (Pa);pressure at bottom of cryosphere fracture (Pa);pressure in unsaturated portion...

show abstract

“…These patterns are observed on both Earth and Venus and are considered to be the result of subhorizontal propagation in different directions from a shallow source region (see Ernst et al [1995] for a review). Maps of such dike swarms often show a systematic change in propagation direction with distance from a radial to a subparallel geometry.…”

Section: Introductionmentioning

confidence: 99%

Calculation of dike trajectories from volcanic centers

Meriaux

Lister

2002

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Patterns of dike swarms around volcanic centers or above mantle plumes are interpreted by a mechanical analysis of regional and dike-induced stresses, in which dike emplacement is controlled and guided by the stress state. Comparisons of dike patterns with patterns of principal-stress trajectories caused by a source and a regional stress system are commonly used to infer paleostresses. However, dike trajectories are determined by a complex interaction between dike-induced stresses and the source/ regional stress system. We present numerical calculations based on a novel boundary-integral formulation, which examines the simultaneous effects of regional stresses, magma pressure, and dike injection on the local stress state around a continuously curving dike. Dike paths are calculated from the condition that dikes propagate by mode I failure. Our results suggest that the magnitude of the regional stresses would be 2 -5 times higher than previous estimates based on principal-stress trajectory analysis.

show abstract

Giant radiating dyke swarms on Earth and Venus

Cited by 391 publications

References 128 publications

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Mangala Valles, Mars: Assessment of Early Stages of Flooding and Downstream Flood Evolution

Calculation of dike trajectories from volcanic centers

Contact Info

Product

Resources

About