geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

New age for the Skalamælifell excursion and identification of a global geomagnetic event in the late Brunhes chron


, : New age for the Skalamælifell excursion and identification of a global geomagnetic event in the late Brunhes chron.

Sixteen lava flows sampled from isolated hills, including Sk lam lifell hill, on the Reykjanes Peninsula in southwest Iceland record excursional geomagnetic field directions that correspond to virtual geomagnetic poles (VGPs) grouped at 12 S, 25 E in the eastern Pacific Ocean. The VGPs are similar to those obtained in earlier studies of these lavas, for which the name Sk lam lifell excursion was previously assigned. Based on unspiked K Ar dating of nine samples from six hills, it has been accepted for more than two decades that the transitionally magnetized lavas reflect the 41 ka Laschamp excursion. However, nine newAr/Ar incremental heating experiments on four of the transitionally-magnetized lavas give an age of 91 13 ka. Moreover,U Th isochrons determined for two of these lava flows yield a weighted mean age of 96 1 ka (2?). The weighted mean of theAr/Ar andU Th ages is 94.1 7.8 ka (2?), which is more than twice as old as the K Ar data imply. We conclude that the Sk lam lifell excursion is not synchronous with the Laschamp excursion. Rather, the Sk lam lifell excursion likely corresponds to the post-Blake excursion at 94 ka, which coincides with a globally observed low in paleointensity. These findings highlight the potential shortcomings of K Ar dating of young (< 1 ka), low-K basalts, and reinforce the need for multiple independent chronometers when determining ages for geologic events throughout Earth's history.The focus of the study is on the age of the Sk lam lifell excursion. The new age of the excursion is twice as old as published K Ar ages. We point out some pitfalls in using the K Ar technique on young, low-K lavas. We highlight that the 94 ka Sk lam lifell excursion is a global phenomenon..

US$29.90


Other references

Dostal Ondrej, 2004: Paleontology of the Obora area. Permian sediments of the Zbonek-Svitavka horizon are exposed at the locality Obora. Plants are common and more than about two thirds of species were determined for the first time at the locality. Invertebrates are represented by two subphyla (Crus...

Zorman, S.; Rebane, A.A.; Ma, L.; Yang, G.; Molski, M.A.; Coleman, J.; Pincet, F.; Rothman, J.E.; Zhang, Y., 2015: Common intermediates and kinetics, but different energetics, in the assembly of SNARE proteins. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are evolutionarily conserved machines that couple their folding/assembly to membrane fusion. However, it is unclear how these processes are regulated and function. To...

Arce Gómez, E.; Avila Ramírez, L., 1965: Clinical evaluation of Fursemide, a diuretic and saluretic agent. Revista Medica del Hospital General 28(7): 475-489

Liem, R.K., 1973: The story of acupuncture. Hawaii Medical Journal 32(6): 394-395

Ross, G., 1975: Spontaneous elevation of a depressed skull fracture in an infant. Case report. This is a report of an infant with a depressed skull fracture that apparently elevated spontaneously within a period of 4 hours.

Bostem, F.; Lesèvre, N., 1968: Variation under the effect of anoxia, of visual and somesthetic evoked potentials in Papio papio. Journal de Physiologie 60 Suppl 2: 408-408

Gontar' , E.M.; Kuz' min, V.N., 1977: The tannin content of Rumex rechingerianus roots in different habitats and in cultivation. Root tannin content differed with habitat and the differences were retained in cultivated plants grown from seed. [For earlier work see HcA 46, 11735.].

Cao, Q.; Mao, Z-Dao.; Shi, Y-Jia.; Chen, Y.; Sun, Y.; Zhang, Q.; Song, L.; Peng, L-Ping., 2016: MicroRNA-7 inhibits cell proliferation, migration and invasion in human non-small cell lung cancer cells by targeting FAK through ERK/MAPK signaling pathway. To investigate the effects of microRNA-7 (miR-7) on the proliferation, migration and invasion of non-small cell lung cancer NSCLC) cells by targeting FAK through ERK/MAPK signaling pathway. NSCLC tissues and adjacent normal tissues were obtained f...

Dimentberg, R.; Rosman, M., 1993: Peritalar dislocations in children. Five patients with peritalar dislocations were identified in a search for injuries of the talus. We report the mechanism, management, and outcome of their injuries and compare and contrast the injuries with the same injury in adults. To our knowle...

Sakagami S.F.; Yamane S.; Inoue T., 1983: Oviposition behavior of 2 southeast asian stingless bees trigona laeviceps and trigona pagdeni. Intranidal behaviors of 2 southeast Asian stingless bees, T. (Tetragonula) laeviceps Smith and T. (T.) padeni Schwarz are characterized by the following ethological features: relatively simple queen-worker coactions; successive cell construction;...