Annona Chalk Research Articles

Campanian ammonites from the Annona Chalk near Yancy, Arkansas

Ammonites are abundant in the phosphatic base of the Annona Chalk (Campanian) near Yancy in Hempstead County, Arkansas. The following are described:Pachydiscus(Pachydiscus) sp. (very rare),Placenticerassp. (very rare),Nostoceras(Nostoceras)pulchern. sp. (rare),N.(N.)monotuberculatumn. sp. (scarce),N.(N.)plerucostatumn. sp. (frequent),N.(N.)danei(frequent),Didymocerassp. (rare),Didymoceratoides binodosumn. gen. and sp. (frequent),D. clardyin. gen. and sp. (rare),Baculites taylorensisAdkins, 1929 (abundant),B. crickmayiWilliams, 1930 (common), andBaculitessp. (abundant). The diverseNostocerasassociation is typical of Gulf Coast upper Campanian rocks butDidymoceratoidesis a Western Interior upper middle Campanian genus.Nostoceras(N.)monotuberculatumn. sp., however, is known from a single specimen from the basal upper CampanianDidymoceras stevensonizone in Colorado.

Surface Exposures of Late Cretaceous Strata at Rayburns Salt Dome, Bienville Parish, Louisiana: ABSTRACT

Surface exposures of Cretaceous strata in Louisiana are restricted to isolated occurrences associated with salt domes in the northwestern part of the state. The best known Cretaceous exposures are associated with the Rayburns salt dome in Bienville Parish. Strata exposed at this structure previously have been correlated with formations exposed in southwestern Arkansas, in particular, the Marlbrook Formation and the Saratoga Chalk. Several distinct Upper Cretaceous lithologic units can be identified at the Rayburns locality. Detailed stratigraphic relationships of these units are obscured by the incomplete nature of the exposures and by dense vegetation. Strata on the west side of the outcrop area include a basal olive-gray marl that is locally glauconitic. This unit is thought to correlate with the Brownstown Marl in Arkansas. The basal marl is overlain in part by a massive glauconitic sandstone at the western end of the outcrop area and by a gray chalky marl at the eastern end. These lithologies are thought to correlate with the Buckrange Sand Lentil or basal Ozan Formation exposed in Arkansas. The sandstone and gray chalky marl units are directly overlain by a hard white chalk. This chalk lithology correlates faunally and lithologically with the upper Ozan and the Annona Chalk in Arkansas. Exposures along the east side of the outcrop area, adjacent to an abandoned quarry, are blue-gray marl and chalk whose fauna and lithology correlate with the Saratoga Chalk in southwest Arkansas. The concretionary clays of the Midway Group, of Paleocene age, lie unconformably on the truncated surface of this Saratoga equivalent. The unconformity is marked by a thin layer of bored, calcareous nodules. The uppermost portions of the Navarro Group, which occur elsewhere between Cretaceous and Paleocene strata, have apparently been eroded at this locality. End_of_Article - Last_Page 1212------------

Magnetostratigraphy of Upper Cretaceous Deposits in Southwestern Arkansas and Northeastern Texas: ABSTRACT

Interpretation of preliminary paleomagnetic (a.f. demagnetized) and biostratigraphic data from Upper Cretaceous deposits suggests that the Nacatoch Sand (Navarroan) and the Brownstown Marl (Austinian) of southwestern Arkansas correlate with Guffio (Italy) reversed polarity zones E- and A-, respectively. Other Austinian, Tayloran, and Navarroan Upper Cretaceous deposits (Tokio Formation, Ozan Formation, Annona Chalk, Marlbrook Marl, Saratoga Chalk, Arkadelphia Marl, Gober Chalk, Sprinkle Formation) possess a weak remanent magnetization of normal paleomagnetic polarity. We assume the normal polarity to be primary magnetization, and interpret deposition of the Tokio Formation during the Gubbio long normal zone (Santonian and older), and that of the other units in Gubbio norm l polarity zone B+ (Campanian to early Maestrichtian); this is consistent with previous assignments of the units to stages on the basis of biostratigraphic data. We conclude that the boundary between the Austinian and Tayloran provincial stages approximates the boundary between the Gubbio reverse polarity zone A and the Gubbio normal polarity zone B+. The Tayloran-Navarroan boundary is probably within the upper part of Gubbio normal polarity zone B+. The magnetostratigraphic approach for refinement of the End_Page 764------------------------------ geochronology for Upper Cretaceous deposits in Arkansas and Texas offers another method of dating geologic events in these areas and relating them to events elsewhere. End_of_Article - Last_Page 765------------

Ichnology and Depositional Environments of Upper Cretaceous Chalks, Southwestern Arkansas (Annona Formation; Chalk Member, Saratoga Formation): ABSTRACT

Both Annona and Saratoga chalks were deposited during transgression of middle to outer-continental-shelf environments. The basal contact of each chalk is a discontinuity surface underlain by marl. At these contacts chalk was piped across the discontinuity into marl through omission and postomission-suite burrows. Taxonomic composition of chalk-filled burrows below the Annona basal contact changes along a 60-km outcrop belt from dominance by Thalassinoides in the northeast to dominance by Zoophycos, Planolites, and Chondrites in the southwest. Such change indicates that this discontinuity surface was formed on a relatively steep slope which dipped southwest. Conversely, taxonomic composition of chalk-filled burrows below the Saratoga basal contact is unchanging (primarily ne species of Thalassinoides) over a 90-km outcrop belt, thus indicating that this discontinuity was formed on a relatively shallowly sloping surface. The basal 0.2 to 2.0 m of each chalk is a condensed bed rich in phosphate nodules and glauconite. Saratoga chalk was deposited at shallower depths, is generally much coarser grained, and contains more terrigenous detritus than Annona chalk. Saratoga quartz silt and sand may have been transported from a more shoreward area by poststorm seaward-directed currents. The trace-fossil assemblage within the Annona, consisting primarily of Planolites, Zoophycos, and Chondrites, is similar to that documented from modern deep-sea carbonate oozes. Bioturbation within the Saratoga chalk is preserved only as mottles. Thixotropic preservation and large size burrows in each unit indicate that during deposition these chalks had very soft substrates and that oxygen content was not limiting. End_of_Article - Last_Page 422------------

Stratigraphic Relations of Annona Chalk and Gober Chalk (Upper Campanian) at Type Localities in Northeast Texas and Southwest Arkansas: ABSTRACT

Stratigraphic Relations of Annona Chalk and Gober Chalk (Upper Campanian) at Type Localities in Northeast Texas and Southwest Arkansas: ABSTRACT

Subsurface Upper Cretaceous Stratigraphy of Southwestern Arkansas: ABSTRACT

The subsurface Gulf Series of southwestern Arkansas is characterized by uniformity in lithologic features, a minimum of facies variations except on a local scale, general eastward thinning of units toward a shoreline area, and features typical of neritic, eulittoral to sublittoral, and alluvial to prodeltaic environments. The Woodbine Group of southwestern Arkansas consists of the Lewisville Formation of fluvial to littoral varicolored shale and sandstone and the overlying Eagle Ford Formation of dark gray to black littoral to sublittoral shale. The Woodbine is unconformable on Comanchean rocks throughout the area studied. The Austin Group in this area is represented by the Tokio Formation of littoral to sublittoral ashy sandstone and shales and the Brownstown Formation of more offshore calcareous, glauconitic shale and sandstone. The Taylor Group here consists of the Ozan Formation of slightly calcareous shale and glauconitic sandstone with a basal glauconitic sandstone (Buckrange Sand Lentil) followed above by the neritic Annona Chalk, Marlbrook Marl, and Saratoga Chalk. The Ozan Formation tends to thin southwestward in contrast to the underlying Gulf deposits which generally thicken in that direction. The chalk formations of the Taylor Group mark the onset of large numbers of Senonian planktonic coccoliths and foraminifers in this region. In northeastern Texas the Austin Chalk (Tokio equivalent) represents an earlier Senonian invasion of calcareous planktonic organisms. In this region the Austin and Taylor planktonics are associated with typical benthonic fossils and require a neritic environment. The Navarro Group of southwestern Arkansas consists of the Nacatoch Sand and Arkadelphia Marl. The Nacatoch is neritic, littoral, and sublittoral glauconitic sandstone and shale whereas the Arkadelphia is neritic calcareous shale and marl, in part glauconitic. The base of the Paleocene marine Midway Group is distinct throughout the area studied but there is little or no evidence of an unconformable relation with the Gulf Series. There is some evidence of a paleontologic break at the contact, and it probably should be termed a paraconformity. End_of_Article - Last_Page 2171------------

Developments in Arkansas and North Louisiana in 1963

This report covers that part of the Gulf Coastal Province located in North Louisiana and Arkansas, and the Paleozoic area of northwestern Arkansas. The District includes 26 parishes of North Louisiana and all of Arkansas. There was an over-all increase in drilling activity in 1963 as compared with the previous years. North Louisiana had a record-breaking year in the number of wells drilled. This was due to an increase in development drilling in the Wilcox trend and Saratoga-Annona Chalk areas of Sabine and Caddo Parishes. There was also an increase in exploratory drilling. Arkansas showed an increase in development and a decrease in exploration drilling activity. Fourteen new fields were discovered in North Louisiana and 5 new fields were discovered in Arkansas. Sandstones of the Wilcox formation accounted for the largest number of new-field discoveries in North Louisiana. Four of the new-field discoveries in South Arkansas were in the Nacatoch, Meakin, and Baker sands and the Smackover limestone. In North Arkansas the discovery was in the Atoka (Pennsylvanian) sand. The most important exploration activity in Arkansas was in search of gas in the Arkoma basin in the northwestern part of the state. Exploratory drilling was active in the Wilcox areas in the eastern part of North Louisiana, and in the western part the Saratoga and Annona Chalk areas were most active. Exploration activity will probably remain about the same during 1964 as was present in 1963. Arkansas' most important activity will be centered in the Arkoma basin while activity in North Louisiana will again be centered in the Wilcox, Sligo, Hosston-Cotton Valley, and Saratoga-Annona Chalk areas.

Developments in Arkansas and North Louisiana in 1962

This report covers that part of the Gulf Coastal Province located in North Louisiana and Arkansas, and the Paleozoic area of northwestern Arkansas. The District includes 26 parishes of North Louisiana and all of Arkansas. There was an over-all increase in drilling activity in 1962 as compared with the previous year. In North Louisiana the increase in the number of wells drilled was due to an increase in development drilling in the Wilcox, Monroe Gas Rock, and Saratoga-Annona Chalk areas although there was a decrease in exploratory drilling. Arkansas showed a decrease in both development and exploration drilling activity. Ten new fields were discovered in North Louisiana and 6 new fields were discovered in Arkansas. Sandstones of the Tuscaloosa Formation accounted for the largest number of new-field discoveries in North Louisiana. Four of the new-field discoveries in Arkansas were in sandstones of Pennsylvanian age, one was Silurian, and one was Lower Cretaceous. The most important exploration activity in Arkansas was in search of gas in the Arkoma basin in the northwestern part of the state. Exploratory drilling was dominant in the Wilcox and Tuscaloosa areas in the eastern part of North Louisiana and in the western part the Saratoga and Annona Chalk areas were most active. Interest was again shown in the Hosston and Cotton Valley of Jackson, Lincoln, and Ouachita Parishes. Exploration activity will probably remain about the same during 1963 as was present in 1962. Arkansas' most important activity will be centered in the Arkoma basin while activity in North Louisiana will again be centered in the Wilcox, Tuscaloosa, Hosston-Cotton Valley, and Saratoga-Annona Chalk areas.

Developments in Arkansas and North Louisiana in 1961

This report covers that part of the Gulf Coastal Province located in North Louisiana and Arkansas, and the Paleozoic area of northwestern Arkansas. The district includes 26 parishes of North Louisiana and all of Arkansas. There was an over-all increase in drilling activity in 1961 as compared with the previous year. In North Louisiana the increase in the number of wells drilled was due to increases in both exploration and development drilling, primarily in the shallow Wilcox and Saratoga-Annona Chalk areas. Arkansas showed a decrease in both development and exploration drilling activity. Fifteen new fields were discovered in North Louisiana and 5 new fields were discovered in Arkansas. Sandstones of the Cotton Valley Formation accounted for the largest number of new-field discoveries in North Louisiana. Three of the new-field discoveries in Arkansas were in sandstones of Pennsylvanian age, 1 was Mississippian and 1 was Upper Cretaceous. The most important exploration activity in Arkansas was in search of gas in the Arkoma basin in the northwestern part of the state. Exploratory drilling was dominant in the Wilcox and Tuscaloosa areas in the eastern part of North Louisiana and in the western part the Saratoga and Annona Chalk areas were most active. Interest was again shown in the Hosston and Cotton Valley of Jackson, Lincoln, and Ouachita Parishes. Exploration activity will probably remain about the same during 1962 as was present in 1961. Arkansas' most important activity will be centered in the Arkoma basin while activity in North Louisiana will again be centered in the Wilcox, Tuscaloosa, Hosston-Cotton Valley, and Saratoga-Annona Chalk areas.

Hydraulic Fracturing in the Caddo-Pine Island Field

Abstract The application of the hydraulic fracturing process in the Annona Chalk formation in the Caddo-Pine Island field, Caddo Parish, La., has created a new outlook on the development of this reservoir as an economic source for oil production. The reservoir has been greatly affected by faulting and/or fracturing during its geologic history, and the physical characteristics of the formation have made possible the successful hydraulic fracturing operations. These conditions have also caused the production to vary greatly between wells and have resulted in several different methods of drilling and completion practices by the operators. This paper describes briefly the geology, development history, present drilling and completion practices, and the results of the hydraulic fracturing process in stimulating the production from this reservoir. In order to show results of the various completion techniques, production histories on several wells are presented and comparisons of the production from individual or groups of wells before and after fracturing operations are discussed. Introduction The Caddo-Pine Island field is located approximately 15 miles north of the City of Shreveport in Caddo Parish, La., and Marion County, Tex., and is shown geographically in Fig. 1 which covers a portion of the Ark-La-Tex Area. Although production has been obtained from several horizons, ranging in depth from the Nacatoch sand at 800 ft to the Hosston or Travis Peak which is found at 2,500 ft near the crest of the dome of the Lower Cretaceous beds, this paper will deal mainly with the development and production of the Annona Chalk reservoir. The production from the Chalk is associated with faulting and natural fracturing of the formation and is found in several fields in North Louisiana. The discovery well in the Caddo-Pine Island field was the Savage Bros. & Morrical No.1 Offenhauser, which was completed March 28, 1905, in the Annona Chalk at a depth of 1,556 ft. The well was located near Oil City, La., in the center of the NE ¼ of the SW ¼ of Sec. 1, T20N, RI6W, and had an initial production of 5 B/D of 34° gravity oil. The well was considered non-commercial by the operators and was soon plugged and abandoned. However, this discovery led to further development. By the close of 1907 23 wells had been drilled -eight of which produced oil, 11 produced gas, and four were abandoned. Development of the field continued at a rapid pace during the following years, and by 1918 the production reached a peak of 11 million bbl/year.

Correlation of the Pecan Gap, Wolfe City, and Annona Formations in East Texas

The Pecan Gap chalk of East Texas has been correlated, in previous publications,(FOOTNOTE 3) with the Annona chalk of northeastern Texas and southern Arkansas. Detailed surface mapping of a belt of Cretaceous rocks in eastern and northeastern Texas shows that the Pecan Gap chalk thins and disappears north and east and that the Wolfe City sand, which underlies the Pecan Gap chalk, is to be correlated with the Annona chalk.

Notes on the Taylor and Navarro Formations in East-Central Texas

The relations of the Taylor and Navarro formations from Collin County to Travis County are briefly described and graphically shown in the accompanying map and diagram. The Pecan Gap tongue of the Annona chalk is shown to extend into, instead of above the top of, the Taylor marl as far south as Rockwall County. The Wolfe City sand member of the Taylor is recognized as far south as Hill County, and marl of uppermost Taylor age is shown to overlie the Pecan Gap and its equivalent, the Marlin chalk. Three new members of the Taylor are recognized, the Marlin chalk of Falls and Limestone counties, the Lott chalk of Falls and Bell counties, and the Durango sand of McLennan and Falls counties. The base of the Navarro is placed at the base of the zone of Exogyra cancellata, which s shown to correspond with the base of a sandy marl from Kaufman County to Milam County and to be a probable unconformity at least as far south as Falls County. The upper Navarro rests unconformably on the lower Navarro and cuts it from the section south of Milam County.

Notes on the Stratigraphy of the Upper Cretaceous Formations of Texas and Arkansas

The stratigraphic relations of the formations of the Gulf series (Upper Cretaceous) in Texas and Arkansas are briefly described in the text and are graphically represented in a correlation chart. Two new units, the Tokio and Ozan formations, are recognized (in collaboration with C. H. Dane) in the Arkansas section. A new name, Gober, is proposed for a tongue of the Austin chalk, which was previously incorrectly correlated with the Annona chalk. A new formation name, Olmos, is given to the coal series, in the Rio Grande section in Maverick County, Texas. Several important unconformities are recognized in the Gulf series. The Gulf series is shown to be separated from the Comanche series below, and from the Midway (Eocene) above, by important unconformities. An attempt is made to show the age relations of the formations by means of heavy numbered lines. The divergence of these lines shows the thickening, and their convergence the thinning, of the series. The thinning of the series is attributed in part to actual thinning of the deposits and in part to the presence of unconformities.