Current meter measurements from five moorings in the subpolar North Atlantic east of the Grand Banks of Newfoundland

The southwestern part of the subpolar North Atlantic east of the Grand Banks of Newfoundland and Flemish Cap is a crucial area for the Atlantic Meridional Overturning Circulation. Here the exchange between subpolar and subtropical gyre takes place, southward flowing cold and fresh water is replaced by northward flowing warm and salty water within the North Atlantic Current (NAC). As part of a long-term experiment, the circulation east of Flemish Cap has been studied by seven repeat hydrographic sections along inline image (2003-2011), a 2 year time series of current velocities at the continental slope (2009-2011), 19 years of sea surface height, and 47 years of output from an eddy resolving ocean circulation model. The structure of the flow field in the measurements and the model shows a deep reaching NAC with adjacent recirculation and two distinct cores of southward flow in the Deep Western Boundary Current (DWBC): one core above the continental slope with maximum velocities at mid-depth and the second farther east with bottom-intensified velocities. The western core of the DWBC is rather stable, while the offshore core shows high temporal variability that in the model is correlated with the NAC strength. About 30 Sv of deep water flow southward below a density of sigma-theta = 27.68 kg/m**3 in the DWBC. The NAC transports about 110 Sv northward, approximately 15 Sv originating from the DWBC, and 75 Sv recirculating locally east of the NAC, leaving 20 Sv to be supplied by the NAC from the south.

Hydrographic measurements from C.S.S. Hudson Cruise 82-002, Canadian Technical Report of Hydrography and Ocean Sciences No. 118, 112 pp (digital version)

This archive consists of the hydrographic data collected on Cruise 82-002 of C.S.S. Hudson, April 11 to May 2, 1982. 78 stations were occupied on a line running near 48°N from the mouth of the English Channel to the Grand Banks of Newfoundland. Pressure, temperature and salinity were measured by a Guildline digital CTP system. Salinity, dissolved oxygen, silicate, nitrate and phosphate were measured from water samples collected on the CTP upcasts. CTP and discrete bottle data and associated derived parameters are tabulated at standard levels. This is the digital version of the printed report (of 1989, see further details), published in 2006 with the information system Pangaea.

Jurassic microfossils of DSDP Hole 79-547B

The first marine incursion of the incipient North Atlantic Ocean is recorded in the uppermost Triassic to Lower Jurassic sequence of DSDP Site 547 off central Morocco. A lithologic change from continental red beds below to slope breccias and hemipelagic carbonates above indicates that a carbonate ramp was probably established by Sinemurian time along the Moroccan continental margin and that subsidence in the adjacent basin was rapid in the early phases of continental rift. Foraminifers recovered from the Liassic (Sinemurian-Pliensbachian) basinal deposits are diverse and well preserved. The faunas are compositionally similar to contemporaneous neritic assemblages of Europe and the Grand Banks of Newfoundland. The Middle Jurassic in Hole 547B is characterized by regressive deposits that are poor in foraminifers. The major Late Jurassic "Atlantic" transgression is again represented by basinal deposits consisting of limestone breccias and pelagic carbonates. Foraminifers recovered from this interval are transitional between Late Jurassic assemblages reported from deep-sea deposits in the North Atlantic and typical Late Jurassic neritic assemblages of Europe. The Late Jurassic assemblages of Hole 547B are primarily dominated by nodosariids and spirillinids with moderate abundances of simple arenaceous forms. Nonreticulate epistominids occur very rarely in the Upper Jurassic of Hole 547B. It is tentatively suggested that these represent upper bathyal assemblages.

(Table 2) Production parameters of phytoplankton and some associated parameters in the area of the Titanic Polygon

Studies were carried out mostly in the area of RMS Titanic wreck site (41°44'N, 49°57'W) located above the continental slope and the south of the Grand Banks of Newfoundland. In a period from 18.06 to 24.09.2001 five surveys of production characteristics of surface phytoplankton were conducted over 5-9 days. Mean values of these characteristics obtained during the surveys were 9.2-11.7 mg C/m**3 per day for primary production (C_phs), 0.102-0.188 mg/m**3 for chlorophyll a (C_chls), and 4.44-7.42 mg C/mg chl. a per hour for assimilation number (AN). The main reason for low C_phs variability was a significant inverse relationship (R=-0.66) between AN and C_chls found over the research area. When cold shelf waters dominated in the area (27.07 to 19.08.2001), C_chls values for the slope region (0.125+/-0.031 µg/l) and for the outer shelf (0.130+/-0.040 µg/l) were similar. During strengthening of influence of warmer slope waters within area (from 29.08 to 13.09.2001), C_chls concentration within surface waters of the outer shelf was 0.152+/-0.039 µg/l and exceeded one for the slope region (0.094+/-0.004 µg/l) by factor 1.6. Against the background of low Cchls values, the High values of integral primary production in the water column (510-1010 mg C/m**2 per day) at low C_chls values measured within the area were determined both by high assimilation activity of phytoplankton and by the deep (30-40 m) maximum of primary production. Main reasons for formation of such a maximum were high chlorophyll concentration within the layer of the deep chlorophyll maximum (up to 0.5-2.5 µg/l) and in the relatively high solar irradiance within this layer varying from 1.4 to 8.6% of subsurface PAR.

Annotated record of the detailed examination of Mn deposits from JOIDES Preliminary Cruise with M/V Caldrill I on the Blake Plateau

In May 1964 the Institute of Marine Science (University of Miami), Scripps Institution of Oceanography (University of California), Woods Hole Oceanographic Institution, and Lamont Geological Observatory (Columbia University) joined in the establishment of the JOINT OCEANOGRAPHIC INSTITUTIONS DEEP EARTH SAMPLING (JOIDES) program. The long range purpose of this organization is to obtain continuous core samples of the entire sedimentary column from the floors of the oceans. It was decided that initial efforts would be limited to water depths of less than 1000 fathoms (6000 feet), and tentative locations were selected for drilling operations off the eastern, western and Gulf coasts of the United States. Near the end of December 1964 it was found that the M/V Caldrill I, a drilling vessel capable of working to depths of 6000 feet, was to engage in drilling operations on the Grand Banks of Newfoundland during the summer of 1965 for the Pan American Petroleum Corporation. Thus it was agreed to organize a drilling program along the track of Caldrill between California and the Grand Banks. Selection was made of an area on the continental shelf and the Blake Plateau off Jacksonville, Florida. Based upon many previous geological and geophysical investigations by the participating laboratories, a considerable body of knowledge had been gained about this region of the continental-oceanic border. For this initial program of JOIDES, the Lamont Geological Observatory was chosen as the operating institution with J. L. Worzel as principal investigator, and C. L. Drake and H. A. Gibbon as program planners.

(Table 1, page 605) Chemistry of concretions from Grand Lake (GL) and Ship Harbour Lake (SH), Nova Scotia and Mosque Lake (ML), Ontario

Studies by optical microscopy, x-ray diffraction, and electron probe techniques of ferromanganese concretions from three Canadian lakes reveal chemical banding of amorphous hydrated iron and manganese oxides. The average ratio of iron to manganese in concretions from these lakes varies from 0.43 to 2.56. The concentrations of cobalt, nickel, copper, and lead are one to two orders of magnitude below those reported for oceanic ferromanganese concretions.

(Table 3, page 309) Mercury content of concretions from Grand Lake (GL) and Ship Harbour Lake (SH), Nova Scotia and Mosque Lake (ML), Ontario

Ferromanganese concretions from Grand Lake and Ship Harbour Lake in Nova Scotia and Mosque Lake in Ontario are most common in water 0.5 to 2 m deep. X-ray diffraction studies show the ferromanganese portions of the concretions to he amorphous. Petrographic and electron probe studies of the ferromanganese material reveal chemical banding of iron and manganese. Bulk chemical analyses indicate that the Fe:Mn ratios of concretions from different sites within a single lake are similar, whereas concretions from different lakes have characteristic Fe:Mn ratios. Trace element concs are different in different lakes and are generally several orders of magnitude less than those of oceanic nodules.