Sites 336 and 352

Talwani, M.; Udintsev, G.; Bjorklund, K.; Caston, V.N.C.; Faas, R.W.; Hinte, J.E. van; Kharin, G.N.; Morris, D.A.; Muller, C.; Nilsen, T.H.; Warnke, D.A.; White, S.N.

doi:10.2973/dsdp.proc.38.102.1976

Cited by 12 publications

(33 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We identified an up to 1.5 km thick basalt layer (v p =4.7-5.0 km/s) that was drilled by DSDP336 and dated to 43AE3.3 million years (Talwani et al, 1976). The lateral extension across the IFR (SW-NE) was found to be about 200 km and corresponds well with the lateral extension of the NAVP (e.g.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 66%

“…Implementing the results of the Deep Sea Drilling Project, site 336 (DSDP336, location is indicated in Fig. 1b) this layer is identified as basalt: DSDP336, that was drilled in 1974 at 811 m water depth penetrated down to 515 m below sea floor (bsf) and revealed the following results (Talwani et al, 1976): 1-159 m bsf=Plio-Pleistocene; 168-463 m bsf=late Oligocene-late Eocene (both layers with v p =1.6-1.76 km/s); 484-515 m bsf=Basalt (dated to 43 AE3.3 million years).…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

“…The uppermost sedimentary layer (S1) with velocities between 1.7 and 2.0 km/s was dated as Pliocene from the DSDP336 borehole (Talwani et al, 1976) indicating a reactivation of subsidence in the last two million years resulting in a high sedimentation rate. Comparing results of DSDP boreholes from other aseismic ridges, Detrick et al (1977) concluded that parts of the IFR have been at sea level for an abnormally long period of 15 Ma.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

“…An emergent ridge would act as the Thulean land bridge for mammals between Eurasia and America, and also prevent the Arctic and Atlantic waters and the marine fauna from mixing across this boundary. As the basalt (penetrated by DSDP336 and identified in our seismic line) was deposited subaerially (Talwani et al, 1976), the IFR must have subsided by at least 1300 m since the middle Miocene stressing its role for evaluating former global water circulation. The fauna evidence at DSDP sites 336 and 352 (see Fig.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

See 3 more Smart Citations

Crustal structure of the southeastern Iceland-Faeroe Ridge (IFR) from wide aperture seismic data

Bohnhoff¹,

Makris²

2004

Journal of Geodynamics

View full text Add to dashboard Cite

The aseismic Iceland-Faeroe-Ridge (IFR) is of central importance in reconstructing the opening of the North Atlantic Ocean. To investigate the crustal structure of the IFR at its southeastern part we conducted a wide aperture seismic survey across the IFR from the Iceland Basin to the Norway Basin. Seismic energy was generated by two 60-litre sleeve guns and recorded by 42 ocean-bottom seismometers (OBS). Kinematic and dynamic forward modeling by two-point ray tracing was applied to develop a 2D velocity-depth model. The accuracy of the model obtained is better than 5% for both velocity and depth of interfaces. We find a Moho depth of 23 km below the crest of the ridge that decreases to about 15 km at either end of the line. The upper part of the crust exhibits P-wave velocities between 5.7 and 6.3 km/s that increase towards the Norway Basin. The lower crust is more homogeneous with v p ranging from 6.6 to 7.0 km/s. Upper and lower parts of the crust are separated by a first order discontinuity. Amplitudes (P m P) and arrival times (P n ) of wide-angle phases indicate upper-mantle velocities of 7.9 km/s. Furthermore we analyzed PS-converted phases for upper crustal depth levels and find a v p /v s ratio of 1.73 AE 0.04 equal to a Poisson's ratio of 0.25 with no significant lateral variations along the seismic line. On the crest of the ridge we identified a basalt layer embedded within the sedimentary sequence that was also penetrated by deep sea drilling and dated to 43AE 3.3 million years. Below the basalt layer we observed a low-velocity layer that is identified as Mesozoic sediment that was also observed to either end of the basalt. We conclude that the southeastern part of the IFR is composed of stretched continental crust and thus part of Paleo-Europe rather than oceanic crust formed by the Iceland hot spot. This conclusion is supported by the distribution of magnetic anomalies that allow identifying the passive continental margin approximately 100 km to the NW of our seismic line. #

show abstract

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 66%

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

See 2 more Smart Citations

Crustal structure of the southeastern Iceland-Faeroe Ridge (IFR) from wide aperture seismic data

Bohnhoff¹,

Makris²

2004

Journal of Geodynamics

View full text Add to dashboard Cite

show abstract

“…Talwani et al (1975) reported that "...small pockets of gas formed in virtually every core recovered below a depth of 50 meters. All but one sample contained methane, and nearly all gas samples from the Miocene contained traces of ethane.…”

mentioning

confidence: 99%

Organic Geochemistry, Leg 38: Introduction to Studies

Kvenvolden¹

1976

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

Paleogeography and paleobathymetry of the Mesozoic and Cenozoic North Atlantic Ocean

Thiede

1979

GeoJournal

View full text Add to dashboard Cite

The history of the North Atlantic Ocean has been traced quantitatively back in time using age and subsidence of the oceanic crust in an attempt to reconstruct the vertical and horizontal elements of its physiographic evolution. Special emphasis has been paid to the history of the Iceland-Faeroe Ridge and of the epicontintental seas around this young basin. The implications of this evolution for changes in the hydrographic regime and for temporal as well as spatial contraints of the surface and bottom water circulation of the North Atlantic are enormous. During its early history this part of the world ocean was connected to the circum-equatorial Tethys Ocean (Late Jurassic to mid-Cretaceous). However, the formation of a deep water pathway to the South Atlantic towards the end of the Mesozoic and the opening of the Norwegian-Greenland Seas during the Early Cenozoic caused the North Atlantic to become part a longitudinal basin allowing an exchange between the Artic and Antarctic polar water masses.

show abstract

Sites 336 and 352

Cited by 12 publications

References 11 publications

Crustal structure of the southeastern Iceland-Faeroe Ridge (IFR) from wide aperture seismic data

Crustal structure of the southeastern Iceland-Faeroe Ridge (IFR) from wide aperture seismic data

Organic Geochemistry, Leg 38: Introduction to Studies

Paleogeography and paleobathymetry of the Mesozoic and Cenozoic North Atlantic Ocean

Contact Info

Product

Resources

About