UCD Geology Faculty, Staff and Students made the first departmental gift to the Mondavi Center campaign. Inside the Mondavi, see if you can find our name engraved on the wall (hint: it‘s hidden among the dendrites). Outside the Mondavi, in Symphony Grove, have a seat on the bench bearing our name.

Dendrites. Take a closer look at the sandstone on the Mondavi Center walls. People often comment on the pretty "fossil ferns". The fern-like forms you see on the rock are actually dendrites – from the Greek word “dendrites”, meaning “of a tree”. Made of iron and manganese oxides, they record the passage of fluids through the sandstone rock. These rocks were quarried in India. Deposited in a shallow seaway more than 1,800,000,000 years ago, these rocks are more than 1.4 billion years older than the first ferns.

Need to pick up some tickets to a show? Well, while you're waiting in line you can impress your fellow arts patrons! Geologists classify rocks as igneous, sedimentary & metamorphic. The corner of the ticket office at the Mondavi Center shows that each rock type can be used for building stones. The dark igneous rock cooled from a melt, or magma, forming beautiful, iridescent crystals of plagioclase feldspar. The light colored sandstone is a sedimentary rock deposited 1.8 billion years ago in a shallow seaway. The dark slate walkway is a metamorphic rock formed when a mudstone was buried deeply enough to be heated to temperatures where the clay mineral in the mudstone started to crystallize into changed forms (metamorphosed) and formed new minerals.

"Igneous, sedimentary, metamorphic, oh my!"
Now that you've got everyone-in-line's attention, it's time to show off!

The polished pearl-blue slabs forming the ticket counters and walls separating various front entries to the Mondavi Center is know as Larvikite, deriving its name from the type-locality near Larvik located in the Oslo district of southern Norway. Larvikite is an igneous rock formed during slow cooling and crystallization of Ca-Na-Al-Si rich magma deep in the Earth’s crust. The rock is composed almost entirely of coarse-grained anorthoclase feldspar and is formally classified as an “alkali monzonite.” The pearly to vitreous luster and chatoyant-like appearance, commonly referred to as pearl-blue iridescence, opalescence, or labradorescence, is caused by “exsolution” within anorthoclase crystals producing a submicroscopic intermixture of potash feldspar and oligoclase.

But wait! There's more...
The color banding seen in some of the polished slabs of sandstone used to face the Mondavi Center are caused by red iron oxide minerals that precipitated from waters that moved through the sandstone - sometimes dissolving and sometimes precipitating iron minerals. This type of banding is called Liesegang banding and forms in response to diffusion controlled movement of iron and oxygen through the rock.

The slate walkways and floor of the Mondavi center were mined in India (your knowledge will astound and amaze your new-found friends!). Slates make nice building stones because they can break along planes of weakness (cleavage) where soft, platy minerals like mica and chlorite grow during metamorphism. The planer nature of the cleave planes is obvious in the edges of the slabs used to construct the planters

Pshew! There sure is a lot of Geology crammed into this one area. Need to take a break from the tour? Let's head on over to Mondavi Park to rest awhile on one of those nice sandstone benches. Oh! Why lookie-here! I spy with my little eye...

Heavy minerals. Waves washing back and forth across a beach or water flowing down a river bed can sort mineral grains by their density. That is how placer gold deposits form. You may have seen black sand concentrations at the beach or in a dry river bed. The black minerals are generally made of iron and titanium and include magnetite and ilmenite, which are more dense than the lighter colored quartz and feldspar sand grains. The black patches on this sandstone are heavy minerals concentrated by this same mechanism.

Trace fossils. If we look closely at the sandstone blocks that form the rock walls in the garden, we can see the traces left by animals that crawled on and burrowed through the mud looking for something to eat. These marks are called trace fossils. Animals complex enough to do things like crawl and feed did not evolve until about 600 million years ago. We don’t know where this sandstone is from, or what the true age is, but the presence of these trace fossils tells us it has to be at least a billion years younger than the 1.8 billion year old sandstone used to face the Mondavi Center.

The rocks...they talk to us.....