A new Late Cretaceous to Present APWP for Asia and its implications for paleomagnetic shallow inclinations in Central Asia and Cenozoic Eurasian plate deformation

Abstract

Based on a compilation of 533 Cretaceous to present-day paleomagnetic poles obtained from both sedimentary and igneous rocks, we present a new analysis of the so-called "Asian inclination anomaly" and demonstrated the anomaly to be twofold: a 2 nd -order anomaly, characterized by high paleolatitudes in Indochina and low paleolatitudes over Tibet and Central Asia, is superimposed on a 1 st -order anomaly, characterized by Cenozoic low paleolatitudes found all over north-eastern Asian stable blocks. The analysis herein convincingly shows that the Europe Apparent Polar Wandering Path (APWP) can no longer be used to interpret paleomagnetic data East of the Urals, including interpretation of Asian Tertiary deformation related to the India-Asia Collision. We thus construct a new APWP for East Asia, based on paleopoles from blocks assumed to be stable. This new APWP is consistent with and reinforces previous analyses of Asian tectonics, such as the age (~55 Ma) and locus (~5-10° N) of the Indo-Asian collision, the lateral extrusion of SE Asian continental blocks, and the intracontinental shortening in Central Asia. Possible origins of the 1 st -order paleolatitude anomaly are: (1) a geomagnetic origin, due to long-lasting non-dipolar contribution to the magnetic field, and (2) a tectonic hypothesis, in which a newly defined East Asia plate was located ~10° farther south than expected from the current Europe APWP.Based on a set of 6 new reconstructions from 90 Ma to Present, we show that our tectonic model reconciles geophysical, geological and tectonic observations throughout Eurasia, from Siberia to Europe, including kinematics in the Arctic Ocean, up to northwestern Arctic Alaska. Beyond possible occurrences of non-dipolar field contribution and/or local inclination flattening in the sedimentary data, our model leads us to conclude that Cenozoic tectonics is the dominant contributor to the observed 1 st -order ~10° low paleolatitude anomaly over Asia during the Tertiary.

Magnetic mineral diagenesis

“…For example, systematically shallow inclinations have led to questioning of the GAD hypothesis and invocation of persistent ancient non-axial dipole field geometries (e.g., Chauvin et al, 1996;van der Voo and Torsvik, 2001). In tectonic studies, shallow inclinations have been suggested to indicate major paleolatitude differences between the past and present, which implies significant poleward tectonic transport (Kent and Irving, 2010;Tan et al, 2010;Lippert et al, 2011;Cogné et al, 2013;Muttoni et al, 2013). These issues make it important to have methods to detect and correct for inclination shallowing.…”

Paleomagnetism of Upper Cretaceous red-beds from the eastern Qiangtang Block: Clockwise rotations and latitudinal translation during the India–Asia collision

“…However, recent geological studies show that the Eurasian plate was probably not a rigid plate during the Cenozoic, and relative tectonic movements may still have occurred between the European and the Siberian blocks. Thus the use of European poles would induce a greater intracontinental shortening estimate in Asia when paleomagnetic data are compared (Yegorova and Starostenko, 1999;Trifonov, 2004;Dupont-Nivet et al, 2010a, b;Cogné et al, 2013). Cogné et al (2013) constructed a new APWP for Eastern Asia using the paleomagnetic data obtained from the Siberian Craton, Amuria, the Korean Peninsula and the North and South China blocks.…”

Caracterização sismológica da crosta sob o perfil PABBRISE : uma aproximação por função do receptor e razão espectral H/V

“…Boa parte desses persistiu, em pulsos descontínuos, desde o Cretáceo até o Neógeno. A correlação desses processos com a origem e evolução do Sistema de Riftes Cenozoicos do Sudeste do Brasil atualmente é aceita com certo consenso entre os pesquisadores do tema (Almeida & Carneiro, 1998;Riccomini, 1989;Riccomini et al 2004;Zalán & Oliveira, 2005;Cogné et al, 2011Cogné et al, , 2013Zalán, 2012), entretanto o mesmo não ocorre com relação aos mecanismos formadores e modificadores destas feições geomorfo-estruturais.…”

“…A sedimentação foi essencialmente continental, o que resultou em pacote sedimentar com espessura máxima de 800-850 m no depocentro, próximo à porção centronordeste da bacia (Riccomini, 1989;Marques, 1990;Riccomini, et al, 2004;Carvalho, et al, 2011;Cogné, et al, 2013). Em sua porção sudoeste, atravessada pelo perfil sísmico, o pacote sedimentar não ultrapassa 200 m de espessura (Carvalho, et al, 2011).…”

“…Recentemente, após análise de afloramentos e perfis sísmicos da Bacia de Taubaté, Cogné, et al (2013) sugerem que a mesma seja do tipo afastamento, formada durante o Paleógeno sob tensões transtrativas, com o principal tensor horizontal na direção NE-SW. No entanto, é definido como rifte clássico, em que há somente reativação de zonas de cisalhamento direcionais (verticalizados) do cinturão Ribeira.…”