Environment of calcium carbonate deposition west of Andros Island, Bahamas

Abstract

1955 fieldwork. Rezak performed the majority of the ship board analyses, and Neuman and Walter took and cared for the cores. Help also was received with core handling from Donald Stewart in 1955 and from James Double in 1956.Fronr their work leading toward publication of a separate report on the Foraminifera, Ruth Todd and Doris Low have provided information on occurrence of the principal foraminiferal species; and ~iiss Low undertook the onerous responsibility of typing, checking, and processing the often con1plicated pages of this report. Kenneth Lohman studied selected samples for diatoms in the midst of heavy pressure from other work. Biological determinations have also been provided by specialists of the U.S. National 11 useum and other organizations as indicated on tables 3, 10, and 11. The fishes were identified by Leonard Schultz, of the U.S. National Museum, and plankton collections were reported on by David L. O'Berry, of the University of Miami Marine Laboratory. As usual, Frederiek M. Bayer has been a constantly available and generous source of information and advice on ecological subjects.Arrangements for work at Andros Town in 1955 were made by Kay Norton and Arne Lindroth of the Wenner-Gren Foundation. At Andros Town much courteous help was received from Gunnar Lindstrs3m, Kenneth Sundin, and Misse Peterson.Both in 1955 and in 1956, F. G. Walton Sn1ith and Hilary Moore came to the rescue at the crucial mon1ent with marine equipment from the University of Mian1i Marine Laboratory. To them and to G. E. Voss, of the Marine Laboratory, and Robert Ginsburg, of Shell Development Corp., I am warmly grateful for rnany favors and much useful advice. To Farrington Daniels I am also grateful for taking tirne out from a very busy period in Washington, D.C., for discussion of the precipitation problem and for subsequent helpful correspondence.An emergency grant of $785 fron1 the Geological Society of America permitted F. D. Sisler's employment for critically needed bacteriological work until arrangements could be completed for his assignrnent to the U.S. Geological Survey. The Department of Geology, U.S. National Museum, generously provided laboratory space and facilities for his work for the duration of this project.Most of the collaborating authors have read and criticized all sections of the report, and D. L. Graf and R. S. Boardn1an critiqued the entire report. Helpful review of individual sections was made by F.

An optical model for heat and salt budget estimation for shallow seas

“…The salinity change represents then, a maximal salinity change possible for each depth. It is seen that the salinity for these water columns can reach about 46 psu in late spring, and is corroborated from observations [ Smith , 1940; Cloud , 1962]. The roughly concentric arrangement of the isohalines was observed in the pool of hyper‐saline waters, which develops in the summer months off the west coast of Andros (recall Figure 2).…”

“…In addition to being warmer than the surrounding waters, some of these shallow regions are known to produce hyper‐saline waters (waters with salinity greater than 37 psu) due to excessive evaporation. The presence of such hyper‐saline waters as high as 46 psu has been observed by Cloud [1962] and later by many other scientists (Figure 2).…”

The Origin of Carbonate Mud

“…Nevertheless, the origin of carbonate mud remains enigmatic, reflecting a knowledge gap in carbon cycle fluxes and the interpretation of carbonate geochemical records. Much of the debate on the origin of carbonate mud has focused on two mechanisms: (1) primary precipitation of aragonite in the water column, whether via homogeneous precipitation (Cloud et al, 1962;Macintyre & Reid, 1992;Milliman et al, 1993;Shinn et al, 1989) or nucleated on suspended carbonate particles (Morse et al, 2003) or microbes (Robbins & Blackwelder, 1992;Yates & Robbins, 1998), and (2) postmortem disintegration and dispersal of the skeletons of calcifying organisms -particularly calcareous algae and foraminifera-into individual mud-sized carbonate particles (Broecker et al, 2000;Broecker & Takahashi, 1966;Debenay et al, 1999;Lowenstam, 1955;Nelsen & Ginsburg, 1986;Neumann & Land, 1975;Stockman et al, 1967). Both mechanisms conflict with geochemical observations of modern carbonate mud: radiocarbon data preclude water column precipitation (Broecker et al, 2000;Broecker & Takahashi, 1966), while Sr concentration data are inconsistent with algal production (Milliman et al, 1993).…”

Lime muds and their genesis off-Northwestern India during the late Quaternary

“…Lime muds are produced by several mechanisms: mechanical disintegration of biogenic skeletal components, disaggregation of calcareous green algae, inorganic precipitation, bioerosion, erosion of tidal-flat deposits and bio-geochemical processes (Bathurst 1971). The modern settings for lime mud formation are largely confined to carbonate platforms (Bahamas, Florida and Belize) or shallow-water ramps (Persian Gulf) (Ginsburg 1956; Lowenstam and Epstein 1957;Cloud 1962; are reported on the northwestern and southwest Australian margins (James et al 1999(James et al , 2001(James et al , 2004(James et al , 2005Dix et al 2005). Fine-grained carbonates are also common in reef environments (Adjas et al 1990).…”

“…Several researchers have attempted to explain the formation of lime mud in modern carbonate settings. Inorganic formation is favoured by Cloud (1962); Wells and Illing (1964); De Groot (1965); Milliman et al (1993); Dix (2001) and Dix et al (2005), whereas disintegration of codiacean algae and other skeletal materials is favoured by Lowenstam and Epstein (1957); Matthews (1966); Stockman et al (1967); Neumann and Land (1975) and James et al (1999James et al ( , 2001James et al ( , 2004. Lime mud origin has been linked to dense carbonate mud suspensions (whitings) formed from precipitation of fine-grained aragonite in the water column (Broecker and Takahashi 1966;Morse et al 1984;Morse and Mackenzie 1990;Robbins and Blackwelder 1992).…”