scholarly journals Widespread occurrence of silicate-hosted magnetic mineral inclusions in marine sediments and their contribution to paleomagnetic recording

2016 ◽  
Vol 121 (12) ◽  
pp. 8415-8431 ◽  
Author(s):  
Liao Chang ◽  
Andrew P. Roberts ◽  
David Heslop ◽  
Akira Hayashida ◽  
Jinhua Li ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Magnetic Mineral ◽  
Widespread Occurrence ◽  
Mineral Inclusions

scholarly journals Magnetic mineral study of Holocene marine sediments from the Alfonso Basin, Gulf of California - implications for depositional environment and sediment sources

2009 ◽  
Vol 48 (3) ◽  
Author(s):  
L. Pérez-Cruz ◽  
J. Urrutia-Fucugauchi
Keyword(s):  
Marine Sediments ◽  
Gulf Of California ◽  
Depositional Environment ◽  
Magnetic Mineral ◽  
Sediment Sources ◽  
La Paz

Se presentan los resultados del estudio de propiedades magnéticas en sedimentos marinos colectados en la Cuenca Alfonso en la Bahía de la Paz, los cuales se analizan en términos de las fuentes de aporte y el ambiente de depósito en el sur del Golfo de California durante el Holoceno. El control estratigráfico se basa en fechamientos de radiocarbono, que indican una edad para los sedimentos de fondo del núcleo de alrededor de 7597-7831 años cal. B.P. La señal magnética está dominada por minerales de grano fino de titanomagnetitas, los cuales provienen de las secuencias de tobas silícicas expuestas en la Bahía de la Paz. La mineralogía magnética es relativamente homogénea como lo indican las mediciones de propiedades de susceptibilidad magnética, magnetización remanente y coercitividad. Los ciclos de histéresis magnética indican la ocurrencia de componente paramagnéticas y los ciclos correspondientes después de la corrección paramagnética muestran ciclos que saturan en campos bajos y altos valores de magnetización de saturación. Las gráficas de discriminación de estado de dominio magnético empleando cocientes de los parámetros de histéresis muestran que las muestras se agrupan en el campo de dominio pseudos-sencillo, sugiriendo mezclas de dominios sencillo y múltiple. Los registros de susceptibilidad magnética revelan valores altos de factores de dependencia de frecuencia, en particular en el segmento del Holoceno Medio, lo que sugiere contribuciones de minerales superparamagnéticos de grano fino y posible transporte eólico. La presencia de laminaciones finas, características de la secuencia de Alfonso indica condiciones anóxicas en el fondo de la cuenca. El ambiente de depósito durante el Holoceno parece ser dominado por sedimentos detríticos pluviales y sedimentos de grano muy fino y transporte eólico, con menor contribución de sedimentos biogénicos.

Detrital remanent magnetization of single-crystal silicates with magnetic inclusions: constraints from deposition experiments

2020 ◽  
Vol 224 (3) ◽  
pp. 2001-2015
Author(s):  
Liao Chang ◽  
Hoabin Hong ◽  
Fan Bai ◽  
Shishun Wang ◽  
Zhaowen Pei ◽  
...  
Keyword(s):  
Field Dependence ◽  
Remanent Magnetization ◽  
Magnetic Moments ◽  
Magnetic Mineral ◽  
Simple Explanation ◽  
Rolling Ball ◽  
Mineral Inclusions ◽  
Recording Efficiency ◽  
Inclination Shallowing ◽  
Linear Field

SUMMARY Quasi-linear field-dependence of remanence provides the foundation for sedimentary relative palaeointensity studies that have been widely used to understand past geomagnetic field behaviour and to date sedimentary sequences. Flocculation models are often called upon to explain this field dependence and the lower palaeomagnetic recording efficiency of sediments. Several recent studies have demonstrated that magnetic-mineral inclusions embedded within larger non-magnetic host silicates are abundant in sedimentary records, and that they can potentially provide another simple explanation for the quasi-linear field dependence. In order to understand how magnetic inclusion-rich detrital particles acquire sedimentary remanence, we carried out depositional remanent magnetization (DRM) experiments on controlled magnetic inclusion-bearing silicate particles (10–50 μm in size) prepared from gabbro and mid-ocean ridge basalt samples. Deposition experiments confirm that the studied large silicate host particles with magnetic mineral inclusions can acquire a DRM with accurate recording of declination. We observe a silicate size-dependent inclination shallowing, whereby larger silicate grains exhibit less inclination shallowing. The studied sized silicate samples do not have distinct populations of spherical or platy particles, so the observed size-dependence inclination shallowing could be explained by a ‘rolling ball’ model whereby larger silicate particles rotate less after depositional settling. We also observe non-linear field-dependent DRM acquisition in Earth-like magnetic fields with DRM behaviour depending strongly on silicate particle size, which could be explained by variable magnetic moments and silicate sizes. Our results provide direct evidence for a potentially widespread mechanism that could contribute to the observed variable recording efficiency and inclination shallowing of sedimentary remanences.

Magnetic Mineral Diagenesis in a High Temperature and Deep Methanic Zone in Izu Rear Arc Marine Sediments, Northwest Pacific Ocean

2018 ◽  
Vol 123 (10) ◽  
pp. 8331-8348 ◽  
Author(s):  
Myriam Kars ◽  
Robert J. Musgrave ◽  
Tatsuhiko Hoshino ◽  
Ann‐Sophie Jonas ◽  
Thorsten Bauersachs ◽  
...  
Keyword(s):  
High Temperature ◽  
Pacific Ocean ◽  
Marine Sediments ◽  
Magnetic Mineral ◽  
Northwest Pacific ◽  
Northwest Pacific Ocean
Sign in / Sign up

Export Citation Format

Share Document