5,996 research outputs found
Gradational development of slaty cleavage to schistosity -an example from the Iberian Pyrite Belt, Spain-
The Iberian Pyrite Belt is an Upper Paleozoic succession which has been divided into the Phyllite-Quartzite Group, the Volcanic-Sliceous Complex and the Culm Group in ascending order from base to the top. The contacts among them are conformable. These Groups are tightly folded and metamorphosed un-der low-grade conditions during Hercynian times. The first stage folds of the Volcanic-Siliceous Complex and the Culm Group are associate with slaty cleavages (S1), while the Phyllite-Quartzite Group is asso-ciate with schistosities (S1). Fold analysis using cleavages and minoe folds has been utilized in the analysis of the stratigraphy. This led to systematic horizontal collection of specimens (pelitic rocks). S1 texture is defined by paralled alignment of secondary platy minerals which tend to grow larger and together, forming zonal domains toward the Phyllite-Quartzite Group. The clay matrices change to recrystallized quartz toward the Phyllite Quartzite Group. Textural modifications are evidenced by gradational changes from slaty cleavages to schistosities. This shows that recrystallization is the important deformation mecha-nism responsible for S1 development. It also reflects that the deformation was contemporaneous with metamorphism
Lie algebras of symplectic derivations and cycles on the moduli spaces
We consider the Lie algebra consisting of all derivations on the free
associative algebra, generated by the first homology group of a closed oriented
surface, which kill the symplectic class. We find the first non-trivial
abelianization of this Lie algebra and discuss its relation to unstable
cohomology classes of the moduli space of curves via a theorem of Kontsevich.Comment: This is the version published by Geometry & Topology Monographs on 25
February 200
Igusa quartic and Borcherds products
By applying Borcherds' theory of automorphic forms on bounded symmetric
domains of type IV, we give a 5-dimensional linear system of automorphic forms
of weight 6 on Igusa quartic 3-fold which induces an S_6-equivariant rational
map of degree 16 from Igusa quartic to Segre cubic
- …