Is mycorrhizae present in root structures found in plant fossils of Mongolia in in the Early Cretaceous Period (~100-120 million years ago) ? 

Exquisitely preserved fossil plants were collected in central Mongolia. The specimens collected include wood, roots, leaves, seeds, and pollen and seed cones that date back ~100-120 million years ago from the Early Cretaceous Period. The Mongolian flora is mostly composed of conifers such as the spruce and juniper families which grew in a swamp environment. 

Is there necromass degradation from one species of fungus? What is the chemical signature from what is left over?