The Dellwood Seamount Area, an area of approximately 10,000 square km., about 185 km. west of the northern tip of Vancouver Island is located at or near the northernmost end of the Juan de Fuca plate. The main purpose of the study was to test the hypothesis that the Dellwood Knolls mark the site of a short spreading segment connected to the Explorer Spreading Segment at one end by a transform fault trending along the southwestern slope of Paul Revere Ridge; and meeting the Queen Charlotte right lateral transform fault at the other end. An analysis of more than 950 km. of continuous seismic reflection profiles, in conjunction with other geophysical data, shows that (i) the Revere -Dellwood fault zone is a dextral transform fault zone connecting the Explorer and Dellwood spreading segments. (ii) The Queen Charlotte transform fault dies out at the southeastern end of the Scott Channel near the northeastern end of the Dellwood Spreading Segment. (iii) In the channel between the Dellwood Knolls (one of two possible locations of the Dellwood Spreading Segment), the sediments and volcanic basement are cut by normal faults, a feature which is characteristic of spreading centres with median valleys. The heat flow in this channel and in the Revere - Dellwood fault zone is high. (iv) The lower continental slope sediments west of Queen Charlotte Sound is faulted and crumpled and may be the northerly extension of the Scott Islands fault, zone and a site of slow contemporaneous or recently ceased subduction. The deformation of the thick turbidite sequence in the Winona Basin may also be due to subduction. Basalt from the area is chemically intermediate between tholeiitic and alkalic types. That from the Northwest Dellwood Knolls, however, is least differentiated and less than 1 myr. old in contrast to basalt from the sediment-draped Southeast Dellwood Knolls, the latter basalt having Mn-coating up to 50 mm. thick and is thus relatively old. This suggests that spreading may be occurring at the Northwest Dellwood Knolls and not in the channel between the knolls. The texture of basalts from the Dellwood Seamount Range vary depending on size of pillow and depth below pillow surface, but the mineralogy is essentially similar. An unusual rock probably best described as a plagio-clase-olivine basalt porphyry was also recovered from the Dellwood Seamount Range. Non-volcanic rocks recovered include glacial erratics, an authigenic sandstone comprising glacial fragments in an iron-rich cement, a laminated limonitic sediment and manganese nodules. The Dellwood Spreading Segment may have originated by left lateral transcurrent offset from the Explorer Spreading Segment, the offset caused by a change in the direction of motion of the Juan de Fuca plate. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Approximately 790 kilometers of continuous seismic reflection data were obtained with a 5000 joule Sparker in the Strait of Georgia, southwestern British Columbia. The Strait is a geological boundary between Upper Cretaceous Nanaimo Group rocks of the Vancouver Island area and Late Cretaceous-Early Tertiary continental rocks found in scattered outcrops on the southern mainland. Coast Intrusives form mountains on the mainland northeast of the Strait. The Fraser River has built a large submarine delta across the Strait and is the main source of Recent sediments. Deposition is occurring mainly on the delta front and in deep basins to the northwest. In the basin adjacent to the delta, flat-lying bottomset beds average about 200 meters in thickness. An older layer of bottomset beds in this basin overlies bedrock and extends under the present foreset beds. Thinner sedimentary layers of possible hemipelagic origin overlie Pleistocene banks and ridges along the mainland north of the delta. No significant amounts of Recent sediment are presently accumulating in the Strait south of the delta. Erosion of possible Late Pleistocene deltaic sediments has deepened the Strait in that area. Pleistocene deposits of probable drift, till and interglacial sediments occur mainly along the northeast side of the Strait. One extensive stratified deposit, possibly correlated with exposed Pleistocene deposits on nearby shorelines, may reach 550 meters in thickness. Below the Pleistocene, stratified reflectors, suspected to be Late Cretaceous-Early Tertiary bedrock, unconformably overlie Coast Intrusive bedrock along the mainland shore. The reflectors dip seaward at 8 degrees or more. Along the southwest Island coast Upper Cretaceous bedrock dips into the Strait. Deformation, most severe in the south, decreases northward. Dips of bedrock reflectors become less in mid-Strait before disappearing under delta deposits toward the mainland. Some synclinal and anticlinal folding occurs near mid-Strait. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis advisor: Rudolph Hon / Pleistocene-age terra rossa paleosols are situated on and are intercalated with eolianite and marine carbonate units across the Bermuda Islands. These clay-rich soils were originally thought to the derived from weathering of the volcanic seamount and/or from dissolution of the carbonate units, the paleosols are now believed to be primarily the result of atmospheric dust deposition from Saharan North Africa and the Sahel via long range transport, with some local inputs. If so, these soil units are mixtures of atmospheric deposition during one or more glacial- interglacial cycles. Previous investigations have been conducted on the paleosols to determine their provenance, age, and to identify unique characteristics for island wide mapping. We conducted comprehensive geochemical analyses to determine the degree of chemical weathering and diagenesis, and to identify processes responsible for their formation and development. The paleosols were found to be geochemically similar across all ages, and to show an increased degree of alteration with age rather than with their duration of subaerial exposure, indicating diagenesis by infiltrating meteoric waters as well subaerial weathering. Evidence of paleosol diagenesis suggests vadose flow across the island may not be limited to preferential pathways and that while flow through the limestones is complex, infiltrating waters appear to have allowed for additional alteration of the soils. In addition to the paleosols, clay-rich deposits with paleosol-like textures were identified during coring operations in Harrington Sound and Hungry Bay, beneath present-day sea level. The source and development histories of these materials were previously unknown. Since these clay deposits are situated beneath present-day sea level it is likely that they were deposited and chemically weathered exclusively during glacial low-sea level climate conditions. Geochemical analyses were conducted on the submarine clay samples to determine if they were related to the above-sea level paleosol and to identify their sources. Major and trace element signatures showed the submarine clay deposits to be chemically similar to the paleosols and to be derived from a similar upper continental crust-like parent. Trace element fingerprinting showed the samples to be derived from a parent similar to that of the paleosols; primarily atmospheric dust with some volcanic contributions. These findings provide additional evidence that trade wind vectors for dust transport were present during Pleistocene glacial climate conditions. Weathering indicators reveal the submarine clay samples to be somewhat less weathered than paleosols of similar age and comparable periods of exposure. Like the paleosols, the submarine clays underwent an initial period of rapid subaerial weathering which suggests warm humid climate conditions during glacial low sea level periods. However, the submarine clays did not experience extended periods of diagenesis, which may explain the somewhat lower degree of weathering. Evidence of inputs from the volcanic platform to the paleosols was limited, but comparisons with shallow volcanic rock and highly weathered volcanic residual known as the Primary Red Clay showed some similarities, suggesting that in-situ chemical weathering of the volcanic platform could produce a laterite with some characteristics similar to the Bermuda paleosols. Geochemical analysis of volcanic sands collected at Whalebone Bay showed the igneous fragments to be a result of mechanical weathering and sorting of heavy refractory minerals and we interpret these sediments to be best described as a beach placer deposit. These materials are enriched in insoluble trace elements and REE, and their contribution to the paleosols is limited. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

The bathymetry, magnetic anomalies, gravity anomalies and sediment layer is presented to support a young Western Mediterranean no older than 25 million years and an Eastern Mediterranean as old as 200 million years. A buried salt layer is detected in seismic reflection profiles lying below a sediment cover whose base is 4 to 5 million years in age. The seafloor in the eastern Mediterranean is being actively deformed by compressional folding and thrusting beneath the Mediterranean Ridge. The Western Mediterranean opened by rifting and is floored by oceanic crust.

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In recent years the United States Navy has concentrated most of its Anti-Submarine Warfare (ASW) research and development efforts toward passive sonar. Its ability to locate enemy targets without being detected gives the passive sonar system a supreme strategic advantage over its active counterpart. One aspect of passive sonar signal processing is the time delay estimation of an underwater acoustic wavefront. From this estimation the location and velocity of the radiating source (target) can then be determined. This report compares two popular methods of estimating time delay utilizing computer simulations of each: the cross correlator and the beamformer.

Approved for public release; distribution is unlimited / LosCon, the software program developed for the author's thesis and tested at sea, is designed to help the ASW commander regain tactical control in a loss of submarine contact situation. Persistent detection and cueing in the battlespace depend on utilizing contact reports from a network of combatant platform and offboard sensors. LosCon, an extended Kalman filter-based program modeled after MTST (Maneuvering Target Statistical Tracker), can integrate the sensor network very efficiently. Kalman filtering is a method of recursively updating the position of an evading target and accuracy of that position using imperfect measurements. Lines of bearing to the contact with associated standard deviation bearing errors and positions with their standard deviation range errors are the measurements LosCon uses to generate an ellipse of the submarine's likely position or AOU (Area Of Uncertainty). LosCon will also generate an expanded AOU for any future time, allowing commanders to correctly estimate the size of the search area. The effectiveness of the sea shield concept depends on the ability of organic forces to deny the enemy tactical control of the battlespace area. Incorporating the information generated by LosCon would assist ASW commanders in maintaining undersea superiority. / Ensign, United States Navy

Approved for public release, distribution unlimited / The Anti-Submarine Warfare screen design simulation is a program that provides a model for operations in anti-submarine warfare (ASW). The purpose of the program is to aid ASW commanders, allowing them to configure an ASW screen, including the sonar policy, convoy speed, and the number of ships, to gain insight into how these and other factors beyond their control, such as water conditions, impact ASW effectiveness. It is also designed to be used as a training tool for ASW officers. The program is implemented in Java programming language, using the Multi Agent System (MAS) technique. The simulation interface is a Horizontal Display Center (HDC) which is very similar to a MEKO200 class Frigate Combat Information Center's (CIC) HDC. The program uses Extensible Markup Language (XML) files for reading data for program scenarios; parameters are initialized before each run time begins. The simulation also provides all the output data at the end of run time for analysis purposes. The program user's goal, and the purpose of the program, is to decrease the number of successful attacks against surface vessels by changing the configuration parameters of the ASW screen, to reflect sonar policy, convoy speed or number of ships in the simulation. Ongoing use of the program can provide data needed to anticipate required operational needs in future ASW situations. / Lieutenant Junior Grade, Turkish Navy

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