Microfacies analysis of the lower paleocene beda formation in Western Concession 59 and Block 59F, Sirte Basin, Libya /

The rock sequence of the Tertiary Beda Formation of S. W. concession 59 and 59F block in Sirte Basin of Libya has been subdivided into twelve platformal carbonate microfacies. These microfacies are dominated by muddy carbonates, such as skeletal mudstones, wackestones, and packstones with dolomites and anhydrite. Rock textures, faunal assemblages and sedimentary structures suggest shallow, clear, warm waters and low to moderate energy conditions within the depositional shelf environment. The Beda Formation represents a shallowing-upward sequence typical of lagoonal and tidal flat environments marked at the top by sabkha and brackish-water sediments. Microfossils include benthonic foraminifera, such as miliolids, Nummulites, - oerculina and other smaller benthonics, in addition to dasycladacean algae, ostracods, molluscs, echinoderms, bryozoans and charophytes. Fecal pellets and pelloids, along with the biotic allochems, contributed greatly to the composition of the various microfacies. Dolomite, where present, is finely crystalline and an early replacement product. Anhydrite occurs as nodular, chickenwire and massive textures indicating supratidal sabkha deposition. Compaction, micr it i zat ion , dolomit izat ion , recrystallization, cementation, and dissolution resulted in alteration and obliteration of primary sedimentary structures of the Beda Formation microfacies. The study area is located in the Gerad Trough which developed as a NE-SW trending extensional graben. The Gerad trough was characterized by deep-shallow water conditions throughout the deposition of the Beda Formation sediments. The study area is marked by several horsts and grabens; as a result of extent ional tectonism. The area was tectonically active throughout the Tertiary period. Primary porosity is intergranular and intragranular, and secondary processes are characterized by dissolution, intercrystalline, fracture and fenestral features. Diagenesis, through solution leaching and dolomitization, contributed greatly to porosity development. Reservoir traps of the Beda Formation are characterized by normal fault blocks and the general reservoir characteristics/properties appear to be facies controlled.

Palaeopigment accumulation and implcations for paleolimnology over the lost century for two Ontario lakes

Crawford Lake is a meromictic lake, which is 24 m deep and has an area of 2.5 ha, and has never been reported to have mixed below 16 m. Lady Evelyn Lake, which became a reservoir when a dam was built in 1916, is dimictic with a maximum depth of about 35 m. 1 My research proved that both native chlorophylls and the ratio of chlorophyll derivatives to total carotenoids were better preserved in the shallower lake (Crawford Lake) because it was meromictic. Thus the anaerobic conditions in Crawford Lake below 16 m (monimolimnion) provide excellent conditions for pigment preservation. Under such conditions, the preservation of both chlorophylls and carotenoids, including oscillaxanthin and myxoxanthophyll, are extremely good compared with those of Lady Evelyn Reservoir, in which anaerobic conditions are rarely encountered at the mud-water interface. During the period from 1500 to 1900 A. D. in Crawford Lake, the accumulation rates of oscillaxanthin and myxoxanthophyll were extremely high, but those of chlorophyll derivatives and total carotenoids were relatively low. This was correlated with the presence of a dense benthic mat of cyanobacteria near the lake's chemocline. Competition for light between the deep dwelling cyanobacteria and overlying phytoplankton in this meromictic lake would have been intensified as the lake became more and more eutrophic (1955-1991 A. D.). During the period from 1955 to 1991 A. D., the accumulation rates of chlorophyll derivatives and total carotenoids in the sediment core from Crawford Lake (0-7.5 cm, 1955-present) increased. During this same period, the accumulation rates of cyanobacterial pigments (Le. oscillaxanthin and myxoxanthophyll) declined as the lake became more eutrophic. Because the major cyanobacteria in Crawford Lake are benthic mat forming Lyngbya and Oscillatoria and not phytoplankton, eutrophication resulted in a decline of the mat forming algal pigments. This is important because in previous palaeolimnological studies the concentrations of oscillaxanthin and myxoxanthophyll have been used as correlates with lake trophic levels. The results of organic carbon a13c analysis on the Crawford Lake sediment core supported the conclusions from the pigment study as noted above. High values of a13c at the depth of 34-48 cm (1500-1760 A. D.) were related to a dense population of benthic Oscillatoria and Lyngbya living on the bottom of the lake during that period. The Oscillatoria and Lyngbya utilized the bicarbonate, which had a high a 13C value. Very low values were found at 0-7 cm in the Crawford sediment core. At this time phytoplankton was the main primary producer, which enriched 12C by photosynthetic assimilation.

The use of diatom assemblages to determine paleotrophic changes in lakes

The purpose of this study was to develop a classifi cation scheme for l ake trophic status based on the relative abundance of l ake sediment diatom trophic indicator species. A total of 600 diatom frustules were counted from the surface sediments of e a ch of 30 lakes selected to repr e seni~ a continuum from u.lt ra-oligotrophic t,o fairly eutrophic but not hype r-' eutrophic conditions. Published autecological information was used to determine the trophic indicator status of each of the s pecies. A quotieht was derived by dividing the s um of all the e utrophic indicator species by the sum of all oligotrophic indicai.-:.or species. Oligo'- mesotrophic. mesotrophic and meso-eutrophic species were added to both the numerator and denomina tor. Five categories of diatom i.nferred trophic status were recognized : ultra-oligotrophic - 0'-0.2:3, oligotrophic::: 0.24-0 . 70, mesotrophic :: 0.'71 -0.99, meso-elxtrophic :: 1. 00-1. '78 and eutrophic:: 1.. 79-2. 43. But only three of these (oligotrophic:: 0-0.69, mesotrophic ::: 0 . 70'-1.69 j and eutrophic:: 1.70-2.50) proved usef ul. The present study of the relationship between diatom inferred trophic status and the literature-derived trophic status of SO lake s (which were purposely chosen to represent a broad spectrum of lakes in Canada) indicated that: 1) Based on diatom species (assemblages ) it is possible to segregate the lakes from which. th",)se diatoms were taken into three basic categories : o ligotrophic, mesotrophic and eutrophic lake types. ~~) It was not possible t,o separate meso-eutrophic and o l igo-mesotrophic lakes f rom mesotrophic l akes as the the degree of overlap betwee n the diat,om species in these lake types was extremely high. 3) Ha d mo r e ul tra-oligotroph,ic lakes been sampled it might have been possible to more a ccurately s eparate them f rom oligotrophic Jakes. 4 ) Had. more humic lakes been sampled in this s tudy I f eel it would have been possible to identify a unique diatom a ssemblage which would h a ve chara cterized t his lake type . Re gression analyses were performed using the aforementioned diatom inferred trophic index as a f unction of 1) log Sec chi transparency (r = - 0.70) 2) total phosphorus (r = 0. 77 ) and 3) chlorophyll-a (r = 0.74). Once e ach of these rel ationships had been established , it was possible to infer paleotrophic (downcore) changes in an oligotrophic lake (Barbara Lake) and in a eutrophic lake (Chemung Lake) . Barbara Llake was dominated by oligotrophic s pecies and remained oligotrophic throughout the 200-·year history r epresented by i t s 32 em long sediment core. Chemung Lake is currently dominated. by eutrophic species but went through a mesotrophic st,age which was associated with a rise in the water level of the lake followi n g dam construction in its watershed in the early 1.900 J ::;. This was followed by its reversion to it,s present day eutrophic stage (dominated by eutrophic species) possibly as a r esult of shallowing process which can be attributed to " silting' up" of the reservoir and the invasion of the l ake by Myriophyllum spjcatum (Eurasian milfoil) i n the 1970's . In addition, nutrient .:r':l.ch run"'offwhich resulted from increased human a.ctivities associated with cottage development along its shores has contribut ed to its eutrophication. There is some evidence that the rat,e o :f its prog ressive eutrophication has declined during the last decade. This was correlated with legislation enacted in the 60's and 70's in Ontario which was aimed at reducing nutrient loading from cottages.

Welland Canal Survey of Lands George Keefer Esquire

Survey map and description of George Keefer's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; road, road allowance, line between Black and Keefer's land, township line, reservoir, bridges, lock no's. 32, 33, 34, 35, mill. Surveyor notes are seen in pencil on the map. Land is composed of sections of lot no.s 9 and 17 in Thorold. The land is a total of 28 acres, 2 roads, and 12 perches.

Welland Canal Survey of Lands Daniel Shriner 1834

Survey map and description of Daniel Shriner's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; north and south branch of reservoir, line between Bouke and Shriner's land. Surveyor notes are seen in pencil on the map.

Welland Canal Survey of Lands Luke Carrol 1826

Survey map and description of Luke Carrol's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; line between Carrol's and Bowman's land, Reservoir, line between Carrol and Vanevery's land. Surveyor notes are seen in pencil on the map.

Welland Canal Survey of Lands Jacob Bowman 1826

Survey map and description of Jacob Bowman's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; spring, Queenston Road, division of lots, Reservoir. Surveyor notes are seen in pencil on the map.

Welland Canal Survey of Lands George Marlatt 1826, 1831

Two survey maps and descriptions of George Marlatt's land created by The Welland Canal Company. The first is from 1826, as described in the deed of November 21, 1826. The second survey was done on August 29, 1831 by George Keefer. Included is a written description of the land along with a drawing of the land. Noteable features for the first survey (p.85) include; line between Kelly and Marlatt's land, lot division. Noteable features for the second survey (p.87) include; road to Beaverdams, reservoir, bridges, road allowance, lot divisions, line between Kelly and Marlatt's land. Surveyor notes are seen in pencil on the map.See also Page 90-91

Welland Canal Survey of Lands Philip Carrol, 1830, 1846, n.d.

Survey map and description of Philip Carrol's land created by The Welland Canal Company. Included are three written descriptions of the lands along the Northern Reservoir, Southern Reservoir as well as the Canal and Reservoir with a drawing of the aforementioned lands. Noteable features for the Northern Reservoir include; line between Philip Carrol's land and Widow McAlpine's land. The land contains 9 acres, 2 roads and 24 perches of wood land. The survey is dated 1830. Noteable features for the Southern Reservoir include; Road to shorthills, side line North, and Watson's land. This survey is not dated. Noteable features for the Canal and Reservoir include; West line of lot, lot.213. The land contains 9 acres and 5 perches. The surveyor's updates for this survey are dated 1846. Surveyor notes are seen in pencil on the map.See also Pp 109-113

Welland Canal Survey of Lands Jonathan Silverthorn, 1834

Survey map and description of Jonathan Silverthorn's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. The lands surveyed include lots 229 and 230. The land was first surveyed in 1830, then again in 1834, by George Keefer. The original survey only included the feeder and resevoir and wood land, whereas the second survey shows all lands owned by Silverthorn. The land totals 19.2 acres, 2 roads and 32 perches. The land is broken down as follows; 7.6 acres cleared land, canal and towpath, 6.6 acres reservoir - Michael Silverthorn, 5 acres woodland. Surveyor notes are seen in pencil and red pen on the map.See also page 138.

Welland Canal Survey of Lands John Hellems, 1835

Survey map and description of John Hellem's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; W. Crooks land, concession lines, basin, bridges, guard lock, reservoir, tow path, Lyons Creek. The survey was done on three seperate ocassions by George and Samuel Keefer for Hellems lot #26 in Crowland township. Surveyor notes are seen in pencil and red pen on the map.

Welland Canal Survey of Lands Michael and Jacob Silverthorn, 1834

Survey map and description of Michael and Jacob Silverthorn's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. Noteable features include; line between Burger and Silverthorn's land, reservoir, wood land, road leading to Quaker settlement, line between Jacob and Michael Silverthorn's land. The deeds for both lands are dated September 25, 1834. Surveyor notes are seen in pencil on the map.

Welland Canal Survey of Lands Welland Canal Company Land in Thorold, 1834

Survey map of the lands of the Welland Canal Company in Thorold. Created by The Welland Canal Company. Noteable features include; Company's land, reservoir, channel of canal, bridge, Pine street, Mullen street, lot divisions. The plan is titled "Plan of Lands belonging to the Welland Canal Company being the West half of lot no. 29 and the East half of lot no.30 in the township of Thorold, adjoining Marlats Reservoir laid out in town lots, November 24th, 1834". Surveyor notes are seen in pencil on the map.

Welland Canal Survey of Lands Village of Allanburgh, 1833

Survey map and description of the Village of Allanburgh, created by The Welland Canal Company. Included is a drawing of the land. Noteable features include; lot divisions, Welland Canal, Niagara street, Holland road, lock 36 and 37, foundry, Canal street, mill, Canby street, Dover street, Rose street, Helen street, Water street, Falls street, Centre street, Welland street, Hall street, Clifton street, James street, Mary street, Catherine street, J.G. Stockley's land, reservoir, graveyard. Surveyor notes are seen in pencil on the map.