The MGSL dredge rock collection currently consists of 751 samples from 436 stations. It is one of the most extensive, systematic collections of young volcanic rocks from along the mid-ocean ridge system. Approximately one quarter of the 70,000 km-long ridge system has been sampled at an average interval of 40 km. The bulk of this unique collection consists of recent, glass-bearing pillow basalts from the Mid-Atlantic ridge system. Dredge samples are identified by a ship symbol, cruise number, and station number. For example, EN-063-01-D refers to the first dredge of R/V Endeavor cruise 63. The current holdings of the dredge collection have been sorted and tabulated by Marsden Squares, which divide the globe in 10° x 10° areas. This sorting allows for rapid determination of core coverage in areas of potential interest. Maps of dredge locations Atlantic Ocean Pacific Ocean Cruise Reports For dredges in collection

To find out if the MGSL holds a dredge sample in a particular area you can use our interactive Filemaker Pro databases. This feature allows you input a specific Marsden Square and retrieve a list of dredges that fall within the area. Use the Marsden Square maps to select the area of interest. The results of the search will include specific information about the dredges such as date of collection, location, water depth, volume and lithology. Click here to use the interactive dredge rock database (UNDER CONSTRUCTION).

You can also search the NGDC database for holdings from many different instutuions. NGDC web site.

The results of a database search provides about dredge lithology based on the convention used by the NGDC for the Marine Core Curators File. Dredge lithology is subdivided into three parts: primary, secondary, and tertiary in order to accommodate both rocks and sediments. The primary descriptor reflects the overall composition of the dredge haul, such as volcanic igneous rocks or plutonic igneous rocks. The secondary descriptor provides a textural term for volcanic or authigenic sediments and the tertiary descriptor is used to identify any biogenic or non-volcanic terrigenous sediment. The NGDC website provides more information about dredge lithology.