Summary of deep structure of accreted terranes in the Chugach Mountains and Copper River basin, southern Alaska from seismic refraction results

1989 ◽  
pp. 23-26 ◽  
Author(s):  
G. S. Fuis ◽  
E. L. Ambos ◽  
W. D. Mooney ◽  
N. I. Christensen
Keyword(s):  
River Basin ◽  
Deep Structure ◽  
Seismic Refraction ◽  
Accreted Terranes

Crustal structure of accreted terranes in southern Alaska, Chugach Mountains and Copper River Basin, from seismic refraction results

1991 ◽  
Vol 96 (B3) ◽  
pp. 4187-4227 ◽  
Author(s):  
Gary S. Fuis ◽  
Elizabeth L. Ambos ◽  
Walter D. Mooney ◽  
Nikolas I. Christensen ◽  
Eric Geist
Keyword(s):  
River Basin ◽  
Crustal Structure ◽  
Seismic Refraction ◽  
Accreted Terranes

scholarly journals A long-offset seismic reflection and refraction study of the Gippsland and Bass Basins from onshore recording of a marine air-gun source

1989 ◽  
Vol 20 (2) ◽  
pp. 293
Author(s):  
C.D.N. Collins ◽  
J.P. Cull ◽  
J.B. Willcox ◽  
J.B. Colwell
Keyword(s):  
Deep Structure ◽  
Seismic Refraction ◽  
Reflection And Refraction ◽  
Air Gun ◽  
Long Offset ◽  
Deep Crustal Structure ◽  
Basin Formation ◽  
Seismic Refraction Data ◽  
Marine Air ◽  
Refraction Data

Seismic refraction data were obtained for the Bass and Gippsland Basins during the 1988 cruise of the BMR research vessell "Rig Seismic". Seismic recorders were deployed on land by BMR and Monash University to record long-offset wide-angle reflection and refraction data using the ship's air-guns as the energy source. Preliminary results have now been obtained from these data providing information on deep crustal structure related to the basin formation. Two crustal layers have been detected with velocities of 4.5 km/s increasing to 7.4 km/s (unreversed) at depths exceeding 20 km. Additional data have now been obtained over a traverse length of 170 km to provide constraints on the deep structure of Bass Strait and the Lachlan Fold Belt in Victoria and Tasmania.

Gravity interpretation of the southern Wind River Mountains, Wyoming

Geophysics ◽  
1982 ◽  
Vol 47 (11) ◽  
pp. 1550-1561 ◽  
Author(s):  
Charles A. Hurich ◽  
Scott B. Smithson
Keyword(s):  
River Basin ◽  
Deep Structure ◽  
Sedimentary Rocks ◽  
Gravity Anomalies ◽  
Ductile Deformation ◽  
Gravity Modeling ◽  
Green River Basin ◽  
Green River ◽  
Wind River Range ◽  
Gravity Interpretation

The Wind River range is the largest Laramide uplift in Wyoming and is cored by Precambrian rocks thrust over sedimentary rocks of the Green River Basin to the southwest. The origin of these uplifts is in dispute; it has been ascribed to horizontal compression along thrusts or vertical movement along high‐angle reverse faults. Therefore, the attitude of the bounding fault is critical to understanding the mechanics of deformation. A gravity study based on 1800 stations has been carried out to attack this question and to complement a COCORP deep crustal reflection study. Smoothed free‐air gravity anomalies are highly positive over the Wind River range and near zero over the adjacent margins. Bouguer gravity anomalies range from −252 and −225 mgal in the Green River basin and Wind River basin, respectively, to −150 mgal in the basement core of the Wind River range. The bulk density of sedimentary rocks in the adjacent basins is the critical parameter for gravity interpretation of the deep structure and ranges from 2.25 to [Formula: see text], based on density logs. Gravity modeling demonstrates that most of the +85 mgal gravity anomaly associated with the uplift is caused by the sediment‐basement density contrast, but about 18 mgal has a deeper source. This can be accounted for by offset of more dense middle crust along a thrust fault dipping at about 40 degrees. Three‐dimensional (3-D) modeling confirms this interpretation along the southern part of the range. No significant offset of the Mohorovicic discontinuity can be present. This suggests that the thrust either flattened out or the lower crust deformed by homogeneous ductile deformation. Gravity interpretation gives information on deep structure not found in the COCORP reflection data and further confirms the compressive nature of this Laramide uplift.

Deep Structure and Past Kinematics of Accreted Terranes

Eos ◽  
1990 ◽  
Vol 71 (40) ◽  
pp. 1115
Author(s):  
John W. Hillhouse
Keyword(s):  
Deep Structure ◽  
Accreted Terranes
Sign in / Sign up

Export Citation Format

Share Document