English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The abundant spherules present in the Cretaceous-Tertiary boundary layer at Caravaca are diagenetically transformed to potassium feldspar. Before our study no possible relicts of the precursor material had been reported. but in this paper we describe the presence of cores in these spherules that could represent a relict of the &#194;&#171;unknown precursor&#194;&#187;. These cores are made up of C mixed with Si. Mg. AL Cr. Ca among other elements. Laser Ablation System analysis also reveals an enrichment in pe;E could suggest an extraterrestrial origin for this material. PI. Pd and Ir do not show a chondritic ratio: however. asevere modification of their concentration could be expected during the early diagenetic processes.  Las esf&#233;rulas existentes en la l&#225;mina de sedimento del tr&#225;nsito Cret&#225;cico-Terciario de la secci&#243;n de Caravaca han sido transformadas diagen&#233;ticamente a feldespato pot&#225;sico. En este trabajo se describe la existencia de n&#250;cleos encontrados en el interior de las esf&#233;rulas. los cuales' pueden representar relictos del material precursor. Dichos n&#250;cleos est&#225;n constituidos por C. Si. Mg, AL Cr y Ca entre otros elementos. Se pone de relieve, por vez primera, su notable enriquecimiento en elementos del grupo del platino, cuyas relaciones no condr&#237;ticas pueden ser debidas a la existencia de importantes modificaciones en su concentraci&#243;n inicial causadas por los procesos diagen&#233;ticos y por la existencia de materia org&#225;nica

Platinum-group elements in the cores of potassium feldspar spherules from the Cretaceous-Tertiary boundary at Caravaca (Spain)