Early in her career Sibley painted realistically, but she later said she had become "bored with complete realism" and moved toward abstraction with "a touch of surrealism". She often quoted
Carl Jung's remark that "crystals and flowers are God's thoughts" and said that such ideas informed her work. Sibley admired
Georgia O'Keeffe and cited her as an influence on works such as
Portrait of a Leaf. Many of her acrylic paintings of the 1970s, including pieces titled
Rocks and
January Morning, were described as blending elements of realism and abstraction in pale, delicate tonalities.
Complexity Series In the late 1970s Sibley developed a body of collage work she called the
Complexity Series. Working painstakingly from photographs and reproductions in her collection of art journals, she cut images into vertical or horizontal strips and interspersed them with fragments from other sources. The resulting collages fused divergent forms, colours and concepts into what one reviewer called "complex accordion images sliding and diverging harmoniously along the picture plane, flickering and elusive". More than sixty of these acrylics and collages were included in her 1978 exhibition at the Santa Rosa City Council Chambers. ==Advocacy and community work==