Santa Barbara Basin

Country:

USA

Region:

California

Category: mixed varves

Archive type:

marine sediments

Author of images:

Arndt Schimmelmann

Reference:

Schimmelmann, A., I.L. Hendy, L. Dunn, D.K. Pak, and C.B. Lange (2013) Revised ~2,000-year chronostratigraphy of partially varved marine sediment in Santa Barbara Basin, California. Geologiska Föreningen i Stockholm Förhandlingar (GFF), special issue "Varve Genesis, Chronology and Paleoclimate", 135 (3-4), 258-264.

Link to reference or DOI:

http://dx.doi.org/10.1080/11035897.2013.773066

The X-radiographic collage illustrates the undisputed varve structure of the central Santa Barbara Basin from AD 1841 to 2004: (a) contact print of a radiograph showing varves below 1954 AD (image: A. Soutar, Scripps Institution of Oceanography); (b) various radiographs taken between 1987 and 2004 by A. Schimmelmann and C. Lange. Many other radiographic images have been used for multiple independent counting efforts by generations of workers at Scripps Institution of Oceanography. The varve counting error at the 1841 AD level is estimated to be 3 years. Additional correlation graphs are available at the JSR Data Archive at http://www.sepm.org/jsr/data_files/2006_data/2006_data.asp > max. resolution

Color images from two kasten and two piston cores demonstrating the reproducible pattern of event layers (i.e. grey and olive turbidites) within laminated sediment. The various coring locations are within about 2 km from the OPD Hole 893. The diagnostic pattern of event layers is helpful for rapid age assignment. > max. resolution

Overview on a selection of correlated piston and kasten cores from the central Santa Barbara Basin. All kasten and piston cores are routinely missing the topmost ca. 150 varves because the softer and younger sediment can only be recovered with box and multi-corers. A selected depth section is enlarged (red rectangles). The various records are mostly based on radiographs. The rightmost record is based on color photographs and on scanned epoxy-embedded sediment sections. Thin red lines indicate core-to-core correlations of event layers. Indicated ages are traditional ages that had assumed a continuously varved nature of the laminated sediment of the part two millennia. In 2011 it was recognized that the laminated sediment intervals below the ca. 1750 AD level are at best partially and intermittently varved, and that the traditional varve count ages are too young. > max. resolution

Erosion by turbidites of underlying laminations. Images derive from scanning of wet sediment slabs recovered from kasten cores in 2009. > max. resolution