Large-Area Photo-Mosaicking tool (LAPM tool)

This paper presents a new tool for large-area photo-mosaicking (LAPM tool). This tool was developed specifically for the purpose of underwater mosaicking, and it is aimed at providing end-user scientists with an easy and robust way to construct large photo-mosaics from any set of images. It is notably capable of constructing mosaics with an unlimited number of images on any modern computer (minimum 1.30 GHz, 2 GB RAM). The mosaicking process can rely on both feature matching and navigation data. This is complemented by an intuitive graphical user interface, which gives the user the ability to select feature matches between any pair of overlapping images. Finally, mosaic files are given geographic attributes that permit direct import into ArcGIS. So far, the LAPM tool has been successfully used to construct geo-referenced photo-mosaics with photo and video material from several scientific cruises. The largest photo-mosaic contained more than 5000 images for a total area of about 105,000 m**2. This is the first article to present and to provide a finished and functional program to construct large geo-referenced photo-mosaics of the seafloor using feature detection and matching techniques. It also presents concrete examples of photo-mosaics produced with the LAPM tool.

Stratigraphic correlation of ODP Site 199-1218 and 199-1219

During Ocean Drilling Program Leg 199 a high-resolution (~1-2 cm/k.y.) biogenic sediment record from the late Paleocene to the early Miocene was recovered, containing an uninterrupted set of geomagnetic chrons as well as a detailed record of calcareous and siliceous biostratigraphic datum events. Shipboard lithologic proxy measurements and shore-based determinations of CaCO3 revealed regular cycles that can be attributed to climatic forcing. Discovering drill sites with well defined magneto- and biostratigraphic records that also show clear lithologic cycles is rare and valuable and creates the opportunity to develop a detailed stratigraphic intersite correlation, providing the basis to study paleoceanographic processes and mass accumulation rates at high resolution. Here we present extensive postcruise work that extends the shipboard composite depth stratigraphy by providing a high-resolution revised meters composite depth (rmcd) scale to compensate for depth distortion within individual cores. The depth-aligned data were then used to generate stacked records of lithologic proxy measurements. Making use of the increased signal-to-noise ratio in the stacked records, we then proceeded to generate a detailed site-to-site correlation between Sites 1218 and 1219 in order to decrease the depth uncertainty for magneto- and biostratigraphic datums. Stacked lithologic proxy records in combination with discrete measurements of CaCO3 were then exploited to calculate high-resolution carbonate concentration curves by regression of the multisensor track data with discrete measurements. By matching correlative features between the cores and wireline logging data, we also rescaled our core rmcd back to in situ depths. Our study identifies lithology-dependent core expansion due to unloading as the mechanism of varying stratigraphic thicknesses between cores.

Lithologic correlation of ODP Leg 115 holes

Whole-core (WC) measurements of low-field magnetic susceptibility (MS) provide an extremely simple, rapid, and nondestructive technique for high-resolution core logging and lithostratigraphic correlation between subsidiary holes at Ocean Drilling Program (ODP) sites. This is particularly useful for reconstructing composite, stratigraphically continuous sequences for individual ODP sites by splicing the uninterrupted records obtained from subsections of offset cores recovered from adjacent holes. Correlation between the WCMS profiles of holes drilled at different sites is also possible in some instances, especially when lithologic variations at each site are controlled by regional paleoceanographic or global (i.e., orbitally forced) paleoclimatic changes. In such circumstances, WCMS may also be used as a proxy paleoclimatic indicator, duly assisting climatostratigraphic zonation of the recovered sequence by more conventional microfossil and isotopic techniques. High-resolution WCMS profiles are also useful in detecting intervals of the recovered sequence affected by drilling disturbance, in the form of contamination by pipe rust or similar metallic artifacts as well as discontinuities related to repenetration of the corer or loss of material between successively cored intervals. Stratigraphic intervals that have been affected by early (suboxic) diagenesis resulting from a high initial organic matter content of the sediment are also readily identified by WCMS logging. The MS signal of horizons affected by suboxic diagensis is typically degraded in proportion to the duration and intensity (related to initial Corg concentration) of organic matter remineralization. The lowering of MS values during suboxic diagenesis results from "dissolution" (bacterially mediated ionic dissociation) of magnetic iron and manganese oxides and oxyhydroxides in the sediment. It is to be hoped that, on future ODP (or similar) cruises, WCMS logging will cease to be regarded as a mere adjunct to paleomagnetic measurements, but rather as a simple, yet powerful, lithostratigraphic tool, directly analogous to downhole geophysical logging tools, and complimentary to shipboard techniques for whole-core measurements of physical properties (e.g., P-wave logging, GRAPE, etc.).