South Coastal Plain Research Articles

Sedimentation in Nha Trang Bay, South Vietnam: ABSTRACT

Nha Trang Bay is an embayment at the mouth of the Cai River on the central coast of South Vietnam. The river is the principal source of sediment to the coastline, but intertidal reefs provide minor amounts of calcareous sand, and the continental shelf supplies some coarse quartz sand. The sediment supply to the coast and its distribution in Nha Trang Bay are closely related to the monsoon climate of the region. Northeast monsoons cause intense rainfall and runoff, combined with a unidirectional wind field causing strong southerly coastal currents. Most of the river sediment enters Nha Trang Bay during monsoons, and the sediment distribution reflects the monsoonal wave and current regime. Approximately one-fourth of the river-supplied sand enters the Nha Trang beach littor l cell, where it is transported south along the coast. Thus, the present configuration and orientation of Nha Trang beach are related also to monsoonal wave conditions. This pattern of sediment dispersion appears to have persisted during the Holocene still-stand of sea level, causing the accretion of an extensive beach-ridge coastal plain south of the river mouth. Similar orientation of the ancient beach ridges suggests that monsoonal waves have been the predominant factor in the development of the coastal plain. End_of_Article - Last_Page 786------------

Sable Island Deep Test of Scotian Shelf: ABSTRACT

Mobil Oil No. 1 Sable Island was drilled to a total depth of 15,106 ft on the Scotian shelf of the Canadian Atlantic offshore. It was the first deep test in the region. The well, on the outer shelf, 190 mi east of Halifax, Nova Scotia, used historic Sable Island as a drilling platform. The exploratory test was drilled into the Lower Cretaceous; thus, it not only documented the extension of the submerged Atlantic coastal plain south of Nova Scotia, but also indicated the presence of a thick Cretaceous sedimentary succession in the region. The well section is predominantly marine clastic rock composed of 4,050 ft of Tertiary and Quaternary, and 11,056 ft of Cretaceous strata. These sequences can be subdivided into 11 units on the basis of sandstone percentage, paleontologic data, and other lithologic criteria. These units indicate the occurrence on this part of the Scotian shelf of fluctuating, mainly marine Cretaceous and Tertiary deposition in littoral to bathyal water depths. Encouraging but noncommercial gas shows were tested in several zones, particularly in the Lower Cretaceous. A trace of oil was recovered on a test at total depth. Porous sandstone is abundant through most of the section. The discovery by the Sable Island well of a thick, marine, Cretaceous-Tertiary section with indications of hydrocarbon generation and potential reservoir beds greatly enhances oil and gas prospects in the Canadian Atlantic offshore and the Scotian shelf in particular. End_of_Article - Last_Page 858------------

Studies On Succession, Distribution, and Phenology of Imported Parasites of Therioaphis Trifolii (Monell) In Southern California

The three introduced hymenopterous parasites of Therioaphis trifolii (Monell) were intensively studied for six years in four major climatic regions of southern California. These regions were the Colorado Desert the south coastal plain (two subdivisions), the western Mojave Desert, and the southern San Joaquin Valley. The studies revealed a succession in predominance of Trioxys utilis Muesebeck over Praon palitans Muesebeck, which dominated in the years immediately following parasite introduction. The status of the three wasps varies from one climate area to another. Trioxys is essentially exclusive in the Colorado Desert valleys and strongly dominant elsewhere. Praon attains its greatest importance in the western Mojave Desert and southern San Joaquin Valley. The third wasp, Aphelinus, reaches its most important status on the south coastal plain and is also relatively important in the western Mojave Desert. Parasite phenologies vary. Trioxys has the ability to be intensively active during the several seasons of the year. Praon is most active in the spring and fall. Aphelinus is relatively most active during the cooler, more humid times of the year. The general importance of these several phenomena to biological control programs is discussed.

The Interrelationships of Hypera Brunneipennis (Coleoptera: Curculionidae) and Bathyplectes Curculionis (Hymenoptera: Ichneumonidae) in Southern California1

Hypera brunneipennis, the Egyptian alfalfa weevil, is now found in southern California in three of the four major alfalfa-producing valleys of the California desert and over much of the south coastal plain. It is attacked in these areas by a Palaearctic ichneumonid, Bathyplectes curculionis, which was originally colonized on this weevil at Yuma, Arizona, and apparently has spread with it in bales of alfalfa hay transported to market, and by natural means. The parasite destroys about one-third of the weevil population annually in the coastal areas, but is of little significance in the desert valleys. Partial immunity, effected through the lethal action of the weevil blood on the parasite's eggs, prevents parasitism by B. curculionis from reaching significantly higher proportions. The parasites originally colonized were obtained from a related alfalfa weevil, Hypera postica, and the partial immunity of H. brunneipennis indicates that the strain of B. curculionis found in southern California is not fully adapted to the latter host. Individual larvae of H. brunneipennis appear to have limited ability to inactivate eggs of this parasite, so that in superparasitized larvae one or more of the supernumerary eggs may escape encapsulation. It is anticipated that a fully adapted strain of B. curculionis will be sought from H. brunneipennis in the Near East.

Fieldwork on aerial discoveries in Attica and Rhodes. Part II. Ancient field systems on Mt. Hymettos, near Athens

The scene of my inquiries in Attica in 1955 was the coastal plain south of Athens, on the very doorstep of the city. The background was formed by the magnificent profile of Hymettos, with its long, impressive, but not forbidding skyline. The bare rounded mountain sides are steep but towards the foot they give place to gentler slopes composed of soil washed down from above; and even the narrow plain itself is tilted towards the sea. The soil of this zone is notably rich, terra rossa and rendzina—some of the best soil near Athens. The importance of this fact would have been as obvious to ancient farmers as it is to those who today are restoring large-scale cultivation to the zone.

Cenezoic Geology of Southeastern Alabama, Florida, and Georgia

Cenezoic sediments underlie the entire southeastern part of the Coastal Plain south of the Cretaceous outcrop. The Paleocene series consists chiefly of marine clastic deposits in southwestern Alabama and the Panhandle of Florida, limestone in southeastern Alabama, and dolomite and anhydrite in Peninsular Florida. The Eocene series consists chiefly of marine clastics with limestone at the top. In Peninsular Florida the entire series ins non-clastic. The Oligocene series is predominantly limestone where present but is absent in eastern Georgia and the eastern and central part of Peninsular Florida. The Miocene series consists chiefly of marine clastic deposits. In Georgia and Florida the lower part is a marl which grades into a limestone in places. Post-Miocene deposits are chiefly clastics. The coastal terraces have a mantle of Pleistocene marine sand and the stream terraces a mantle of Pleistocene fluvial clastics. Pleistocene limestone is present in southern Florida. The thickness of Cenezoic deposits ranges from less than 2,000 feet in an area in the northern part of the Florida Peninsula to more than 5,500 feet in southwestern Alabama and in southern Florida. The southeastern Coastal Plain includes parts of two distinct sedimentary provinces, one of marine clastic sediments in the eastern part of the northern Gulf Coast area, and another of marine non-clastic sediments, chiefly carbonates and anhydrite, in Peninsular Florida.

Geology and ground-water resources of Puerto Rico

Puerto Rico, the easternmost and smallest of the Greater Antilles, has an axis of deformed and metamorphosed volcanic rocks of Upper Cretaceous age, intruded by dioritic rocks during the Antillean revolution. The hard-rock core is flanked on the north and south by limestones and clastic rocks of late Oligocene and early Miocene age, which have been gently arched and uplifted. Similar rocks were deposited in late Miocene or early Pliocene time along the west coast. During the Quaternary the island has been separated from the other major Antillean islands by faulting and has been arched, uplifted, and tilted to the northeast. Alluvium and littoral deposits have partially filled the valleys and have formed coastal plains on the north and south.The Upper Cretaceous volcanic and associated rocks yield small supplies of water to wells in most places. The Tertiary limestones yield large supplies in some places on the north, south, and west coasts. The Quaternary sands and gravels are the most important aquifers. They yield about 200 million gallons a day to wells in the main south coastal plain alone. The water is used largely for irrigation. A total of perhaps 250 to 300 million gallons a day is pumped from wells in the island, and moderate to large additional supplies are available in some places.

A Study of the Life-history and Control ofCerambyx dux, Fald., a Pest of certain Stone-fruit Trees in Palestine

A long-horned beetle,Cerambyx dux, Fald., is a very serious pest of apricots, peaches, and grafted and wild almonds in Palestine. Its ravages are most probably not confined to these trees and further investigations will undoubtedly enlarge the already important list of food-plants. In localities around Jerusalemsuch as Beit-Jala, Artas, Bethlehem, El Maliha, and Ein Karim (approximate altitude 2,600 feet above sea-level), this pest has been allowed to establish itself over a long period of time and to such an extent that, if immediate and rigid control measures are not undertaken by the growers, apricot and peach trees will, sooner or later, disappear from these localities. These fruit trees can be cultivated without irrigation, which is of great advantage in Palestine, where water is scarce; the fruit fetches good prices both in the local markets and also in Egypt. Their cultivation is therefore of vital importance,especially to the population of the hill country, where conditions of life are difficult and every kind of loss is accentuated. In Jersualem, where almonds, apricots and peaches are planted in household-gardens, not a single healthy tree can be found, and many of them have already succumbed to the attacks of this beetle. In the coastal plain the writer has found this insect in almond trees at Haifa and in apricot and almond trees in villages north of Acre. No records are available of its presence in the coastal plain south of Haifa or in the Jordan Valley.

Pre-Cretaceous Rocks Found in Wells in Gulf Coastal Plain South of Ouachita Mountains

Deep wells that have been drilled in the part of the Gulf Coastal Plain south of the Ouachita Mountains have passed through gently inclined Cretaceous strata and entered Paleozoic rocks. The Paleozoic floor, which is relatively smooth, has a steep southerly dip; therefore, it has not been reached by wells at great distances from the mountains. It has, however, been reached at many places in a wide southwestward trending belt that extends from Oklahoma into Texas. The wells that are described in this paper include a few in southwestern Arkansas, a few in southeastern Oklahoma, and several in Grayson, Fannin, Lamar, and Red River counties, Texas. The Paleozoic rocks that have been penetrated by these wells are similar in character and age to the Paleozoic rocks exposed in t e Ouachita Mountains. Some of the wells in the counties adjacent to Red River in Texas have entered pre-Carboniferous rocks. Areas of such rocks are perhaps southwestward extensions of the exposure of rocks of this age in the Ouachita Mountains in Oklahoma. The other wells within the area described entered rocks that are assigned to the Carboniferous or simply to the Paleozoic. There seems to be no evidence that any of the wells entered pre-Cambrian rocks. The western boundary of the Ouachita Mountain facies of rocks seems to pass in a southerly direction through the western part of Grayson County, Texas. West of this boundary are Paleozoic rocks that are similar to those exposed in the Arbuckle and the Wichita Mountains and Criner Hills. This boundary, the writers believe, is marked by a southwestward continuation of the Choctaw fault from Oklahoma. The axis of the Ouachita geosyncline--the geosyncline in which the rocks of the Ouachita Mountain facies were deposited--has an east-west trend in Arkansas, but it swings toward the southwest in Oklahoma and crosses Red River into Texas. The part of the geosyncline extending from Arkansas across Oklahoma into Texas thus displays an arcuate form.