Welcome to the Explore Batiquitos Lagoon Series!
This series, created with permission from and in correspondence with the Batiquitos Lagoon Foundation, invites you to discover the natural beauty, rich ecology, fascinating geology, and deep history of Batiquitos Lagoon. Each cache offers a chance to explore a unique feature of this vibrant coastal environment. Take your time, look around, and enjoy everything this special area has to offer.
This is an EarthCache, meaning there is no physical container at the posted coordinates!
Welcome to Batiquitos Lagoon
Batiquitos Lagoon is a vibrant coastal wetland teeming with ecological life, but it also preserves important clues to Southern California’s geologic past. Along this trail, a striking sedimentary outcrop reveals evidence of ancient marine environments, tectonic uplift, and the erosional forces that have shaped this landscape over millions of years.
This EarthCache invites you to examine the exposed cliff face, observing its sediment characteristics, texture, and weathering patterns to better understand the dynamic geologic history of this coastal environment.
The Scripps Formation: An Ancient Shallow Ocean
The cliffside rock along this trail belongs to the Scripps Formation, a tan sandstone deposited in a shallow ocean about 45 million years ago, during the middle Eocene epoch. These sands likely accumulated on the sea floor in a relatively calm but consistently active marine setting. Over time, they compacted and lithified into the sandstone visible today.
Unlike many sedimentary rocks that show clear horizontal bedding, the Scripps Formation often appears massive, meaning it looks uniform rather than layered. This can result from constant wave and current action that smoothed out variations, or from rapid burial of sediments that left little time for distinct layering to develop.
Shaping the Landscape: Uplift and Erosion
After its deposition on the seafloor, this formation was slowly uplifted by tectonic forces. The Rose Canyon Fault Zone, a local segment of the broader San Andreas system, played a major role in lifting these rocks. Over millions of years, coastal erosion, gravity, and weathering stripped away the overlying layers, exposing the sandstone at the surface.
What you see today is the result of both long-term geologic construction—deposition and uplift—and ongoing destruction—erosion, weathering, and biological activity.
What to Look For at the Outcrop
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Color and Texture: The sandstone has a tan or pale yellow color, with a gritty feel where it hasn’t been weathered smooth.
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Cracks and Fractures: Look for vertical or diagonal fractures caused by tectonic stress or the gradual drying and shrinking of the rock.
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Vegetation: Plant roots take advantage of cracks, accelerating breakdown by holding water and physically prying apart the rock.
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Erosional Signs: Rounded edges, loose grains, and soft crumbly areas show where the rock is giving way to the elements.
Tasks for This EarthCache
To log this EarthCache, visit the cliffside outcrop and complete the following tasks. Message me your answers via Geocaching or email.
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EarthCache Title: Include "EBL 3 - Scripps Formation Outcrop - GCB5WB4" on the first line of your message.
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Describe the Rock: What is the dominant color of the sandstone? Does it look coarse or fine-grained from where you're standing?
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Search for Layering: Do you see any vertical or horizontal layers in the rock? If not, what does the uniform appearance tell you about how it may have been deposited?
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Fractures and Weathering: Are there visible cracks or plant roots breaking into the rock? How is the surface being weathered over time?
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Geological Interpretation: Based on its massive appearance and the environment, do you think this was formed by wind or water? Explain why and use your observations as evidence.
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Photo Evidence: In your log, attach a photo of yourself or a personal belonging with the outcrop AND the yellow Batiquitos Lagoon Foundation sign post at the coordinates in the background. (Note: photos predating the publication of this EarthCache are not accepted.)