# @uscdornsife on Instagram

- **Type:** Image
- **Original URL:** https://www.instagram.com/p/CgcjsrXBM78
- **Gondola URL:** https://gondola.cc/posts/1045594-uscdornsife-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/a317b04125.jpg
- **Posted:** 2022-07-25T19:00:45.000+00:00
- **Account Owner:** USC Dornsife (@USCDornsife) — https://gondola.cc/USCDornsife

## Caption

PhD student Justine Grabiec studies at the USCHelium Lab. Her focus is on California geology and the formation of Southern California, occurring around 100 million years ago. To do this, she explores rocks of the Sierra Nevada and Santa Catalina Island 🌄🏝🪨

🔹 Catalina Island is a unique destination for campers, hikers, and snorkelers. Serving as an environmental and Earth science hub, research takes place on marine & terrestrial ecosystems, sustainability, and geoscience.
🔹 Catalina was home to the Tongva Tribe for thousands of years before settlers arrived. They used rocks to form bowls, hunting tools and as canvases. Tongva petroglyphs (carvings) seen in red.
🔹 According to @catalinaconservancy, “the island ecosystem includes native trees, shrubs, wildflowers, grasses, ferns, mammals, insects, birds, reptiles, amphibians, fungi, and lichens,” like prickly pear cacti, fox, fish, and deer. Buffalo were originally brought to the island in 1920.
🔹 Catalina tends to be arid and dry, except during rainy season. Mud cracks happen when sediment on dry surfaces become saturated by rainfall. Turning to mud, it dries to form intricate patterns.
🔹 Geochemical tools are utilized to understand how & when Catalina became an island. Looking at rocks in the field help understand how they formed. Geoscientists determined this was sedimentary, now metamorphic rock. White layers are a result of hot silica-rich fluid infiltrating and precipitating quartz veins.
🔹 A red colored metamorphic rock rich in mineral garnet. Formed deep below the Earth’s surface it eventually came back by geological forces.
🔹 A deformed layer of chert, a very fine-grained silica forms from settling of diatom and radiolaria skeletons on the seafloor, producing a siliceous ooze. Geologists use folds in chert to understand how much deformation a rock experienced.
🔹 Rocks collected in the field are brought to the lab & crushed into powder for analytical techniques. Using a petrographic microscope to pick through sand-sized mineral grains & moved through a series of geochemical steps to be analyzed on a mass spectrometer.

#USCDornsife #USCWrigley #USCEarth #Geology #CatalinaIsland #SierraNevada

## Stats

- **Views:** 0
- **Likes:** 249
- **Shares:** 0
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## Credits

| Name | Username | Profile | Role |
| --- | --- | --- | --- |
| USC Dornsife | @USCDornsife | https://gondola.cc/USCDornsife | University |
| Michael Silver | @BigEastSilver | https://gondola.cc/BigEastSilver | Social Media Manager |

## Tags

catalinaisland, uscearth, uscdornsife, geology, uscwrigley, sierranevada

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