Building velocity‐depth models for 3-D depth migration

Wyatt, Kay Dautenhahn; Wyatt, Steven B.; Towe, Susan K.; Layton, Jesse; Seggern, D. H. von; Brockmeier, Craig A.

doi:10.1190/1.1437045

Cited by 9 publications

(3 citation statements)

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“…Examples of allochthonous salt sheets overlying pinched-off stems are common in the Gulf of Mexico (Wyatt et al, 1993;Diegel et al, 1995;Fletcher et al, 1995;Rowan, 1995) and Red Sea (Heaton et al, 1995) and have also been observed by us on proprietary seismic data from the North Sea, northwest Germany, and west Africa. However, the mechanism for diapiric pinch-off is unknown.…”

Section: Stage 5: End Of Navajo Sandstone Depositionmentioning

confidence: 59%

Structure and evolution of Upheaval Dome: A pinched-off salt diapir

Jackson¹,

Schultz-Ela²,

Hudec³

et al. 1998

Geological Society of America Bulletin

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Upheaval Dome (Canyonlands National Park, Utah) is an enigmatic structure previously attributed to underlying salt doming, cryptovolcanic explosion, fluid escape, or meteoritic impact. We propose that an overhanging diapir of partly extrusive salt was pinched off from its stem and subsequently eroded. Many features support this inference, especially synsedimentary structures that indicate Jurassic growth of the dome over at least 20 m.y. Conversely, evidence favoring other hypotheses seems sparse and equivocal. In the rim syncline, strata were thinned by circumferentially striking, low-angle extensional faults verging both inward (toward the center of the dome) and outward. Near the dome's core, radial shortening produced constrictional bulk strain, forming an inwardverging thrust duplex and tight to isoclinal, circumferentially trending folds. Farther inward, circumferential shortening predominated: Radially trending growth folds and imbricate thrusts pass inward into steep clastic dikes in the dome's core. We infer that abortive salt glaciers spread from a passive salt stock during Late Triassic and Early Jurassic time. During Middle Jurassic time, the allochthonous salt spread into a pancake-shaped glacier inferred to be 3 km in diameter. Diapiric pinch-off may have involved inward gravitational collapse of the country rocks, which intensely constricted the center of the dome. Sediments in the axial shear zone beneath the glacier steepened to near vertical. The central uplift is inferred to be the toe of the convergent gravity spreading system.

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Section: Stage 5: End Of Navajo Sandstone Depositionmentioning

confidence: 59%

Structure and evolution of Upheaval Dome: A pinched-off salt diapir

Jackson¹,

Schultz-Ela²,

Hudec³

et al. 1998

Geological Society of America Bulletin

View full text Add to dashboard Cite

show abstract

“…In order to facilitate the imaging of the subsurface structures it is necessary to build accurate models that permit rapid calculation within 3D data sets. Triangulated surfaces show interesting advantages in this respect (Dautenhahn Wyatt et al 1994). The approach proposed here to 3D data modelling and ray-tracing includes several basic steps ( Fig.…”

Section: Model Building Methodologymentioning

confidence: 99%

“…7). Within each tetrahedron, the velocity at each point is obtained by linear interpolation between the vertex values and therefore the curvilinear ray-path can be calculated (Dautenhahn Wyatt et al 1994). This linear velocity interpolation implies that there also exists a linear gradient in the velocity field and hence a circular segment describes the ray-path within each tetrahedron.…”

Section: D Ray-tracingmentioning

confidence: 99%