- Geological Collections
- Dredged Rocks
Overview of the Dredged Rock Collection
Dredged rock material in the Collection dates from the early part of the 1900s. The Collection has slowly evolved from individual bags of rock to thousands of wooden storage boxes full of rock, housed on tall metal shelves.
The Scripps Institution of Oceanography dredged rocks collection consists of more than 4,000 dredge hauls and related archive materials resulting from published research, donated by investigators specializing in paleoceanography, sedimentary/igneous petrology, and geochemistry.
Dredged rocks are collected by dragging an open steel box with an attached chain bag along the ocean bottom behind a ship. Rocks in a dredge haul frequently weigh hundreds of pounds and a single leg of an expedition often collects and returns in excess of 15 tons of material. The rocks from the hauls are curated and stored in wooden boxes. The dredged rock collection is currently in the middle of being moved. The collection is waiting for completion of a new butler building under construction at our off-site facility at Elliott Field Station. The building is 9,000 square feet and will be filled with 10-foot-high steel shelves, on which the collection will be ordered chronologically.
The Scripps Institution of Oceanography Collection includes rocks from a wide variety of physiographic provinces throughout the Pacific, Indian, and Atlantic oceans. All major tectonic features, including hot spots, island chains, seamounts, and abyssal plains are represented and rock types include drowned coral reef rocks, ice-rafted rocks, and manganese nodules as well as very rare igneous, metamorphic, and mantle rocks. Scientists use a wide variety of methods to subsample and analyze the rock samples, like thin sections, isotope analysis, chemical analysis, among others, to get a greater understanding about formation and metamorphic processes, geochemical, sedimentary processes and properties, for mineralogy, petrology, geophysical, paleoceanography studies and much more.
Carl Hubbs and Roger Revelle provided rock materials from expeditions off Mexico during the 1940s and 1950s. During that same period, Francis Shepard dredged many regions along the California coast. Edwin Allison collected samples throughout the Pacific concentrating on foraminiferal studies during the 1960s. During the same decade, Albert Engel dredged and collected extensive volcanic and metamorphic rocks from throughout the Pacific as well as related continental material from Africa and North America.
In the 1960s and '70s William Menard surveyed and dredged seamounts, formulating early ideas about oceanic plate subsidence. Harmon Craig used dredge samples and samples from Pacific islands for his pioneer work on helium isotope systematics and their use as tracers of magma processes. Gustaf Arrhenius collected and studied manganese and other metal oxides/hydroxides from throughout the Pacific, creating a basic understanding of the geochemistry of sediments.
During the last few decades, E. L. Winterer, Rodey Batiza, Peter Lonsdale, Paterno Castillo, Sherman Bloomer, Robert L. Fisher, James Natland, Robert Stern, and James Hawkins have extensively dredged the East Pacific Rise, parts of the Pacific Antarctic Ridge and Indian Ocean ridge, as well as other plate boundaries such as the Tonga, Mariana, and Philippine Trenches, various fracture zones, seamounts and back arc basins. These expeditions have contributed many tons of basaltic and ultramafic rock to the collection.
Deep Sea Drilling Building-East, Rooms 100, 202, 205, 206. (Map)
Elliott Field Station, Marine Geology Collections Building, 10203 Pomerado Rd, San Diego, CA 92131.