Deposition of the uppermost (Croixan) Jordan Sandstone, and the nature of the Cambrian- boundary in the Upper Mississippi Valley

ANTHONY C. RUNKEL Minnesota Geological Survey, 2642 University Avenue, St. Paul, Minnesota 55114-1057

ABSTRACT lowest Jordan lithofacies occurred near the cluded only that the Jordan was deposited in Transcontinental Arch on the western margin a "littoral" (for example, Dott, 1978; The Jordan Sandstone, of Late Cambrian of the embayment, and near the Wisconsin Thomas, 1991) or subtidal shelf (Byers and (Croixan) age, is well known as one of several Arch on the eastern margin. This differential others, 1990) environment. Others have sug- cratonic sheet sandstones in the Upper Missis- erosion marks the earliest known tectonic up- gested that the Jordan was deposited during a sippi Valley that are part of the classic Paleo- lift of the basin's margins relative to the center. transgression (Byers, 1978; Byers and others, zoic "orthoquartzite-carbonate suite." Evi- 1990), during a regression (Raasch, 1951; dence that the Jordan is an entirely marine, INTRODUCTION Raasch and Unfer, 1964; Bunker and others, regressive sequence, rather than transgressive 1988), and during both transgression and re- as commonly assumed, provides new insight Paleozoic strata in the Upper Mississippi gression (Odom and Ostrom, 1978). into the origin of cratonic sheet sandstones. Valley region of the North American craton This study concludes that the depositional The lower half of the Jordan Sandstone is were partly the basis for the development of history of the Jordan Sandstone differs sub- composed of two intercalated lithofacies: (1) the concepts of the orthoquartzite-carbonate stantially from that of other cratonic sheet extensively burrowed, very fine grained sand- suite (Pettijohn, 1957) and of unconformity- sandstones in the Upper Mississippi Valley, stone interbedded with hummocky cross-strat- bounded lithologic sequences (Sloss, 1963). and that the geometry and lateral homogene- ified beds deposited on the offshore shelf and These strata consist of laterally extensive car- ity of sheet sandstone units can be produced (2) fine-grained, burrowed, cross-stratified bonate, sandstone, and shale units that were in different depositional settings. The Jordan sandstone deposited on the lower shoreface deposited on the cratonic shelf over an area consists entirely of marine lithofacies depos- during storms. The upper half of the Jordan of tens of thousands of square kilometers. ited during an overall regression as part of a consists of medium- to coarse-grained sand- The Paleozoic sequence is especially well shoreline system that prograded across the stone deposited on the upper shoreface by tidal known for the several units of enigmatic, craton. The base of the Jordan is conformable and storm-generated currents. This lithofacies quartzose sheet sandstone it contains. Sev- with underlying strata, but the top of the Jor- is characterized by abundant scour surfaces, eral studies over the past 20 yr have recon- dan is unconformable with overlying trans- tidal inlet fills, and very large angular intra- structed the depositional history of some of gressive deposits of Early Ordovician age. clasts of sandstone derived fromincise d beach- the sheet sandstones, such as the Ordovician Recognition of this unconformity as a re- rock on the foreshore. St. Peter Sandstone, and the Cambrian gional feature provides insight into the tec- Lithofacies associations demonstrate that Wonewoc (in Minnesota, the Ironton and tonic history of the craton in this region and the Jordan Sandstone is a regressive sequence Galesville Sandstones) and Mt. Simon For- biostratigraphy across the Cambrian-Ordovi- deposited as part of a shoreline system that mations (Driese and others, 1981; Dott and cian boundary. prograded across the Hollandale embayment, others, 1986; Mossier, 1992). These studies a shallow depression on the cratonic shelf in the concluded that each of these sheet units was STRATIGRAPHY AND STUDY AREA Upper Mississippi Valley region. Progradation deposited during a transgression that fol- was interrupted by transgressive episodes re- lowed an extended period of subaerial ero- This study focused on the Jordan Sand- corded as local tongues of offshore deposits that sion. In general, each consists of fluvial and stone within the Hollandale embayment disconformably overlie shoreface deposits. eolian deposits overlain by strata deposited in (Austin, 1969), a shallow depression that ex- This sedimentologic model contributes to the marine environments. Their sheet geometry tended northward from the and Ozark evaluation of depositional controls in Late is in part the result of fluvial and eolian proc- basins onto the cratonic shelf in northern Cambrian time, and to solving some long- esses that spread sand across the craton land- Iowa, southeastern Minnesota, and south- standing enigmas associated with cratonic ward of the transgressing sea. western Wisconsin (Bunker and others, sheet sandstones. The Upper Cambrian Jordan Sandstone is 1988). The embayment is bordered on the Contrary to the long-held view that the a cratonic sheet sandstone that has remained north and west by the Transcontinental Arch, Cambrian-Ordovician boundary is conform- poorly understood, in part because its origin and on the east by the Wisconsin Arch and able in this region, sedimentologic evidence in- cannot be explained adequately by existing Dome (Fig. 1). In Late Cambrian time the dicates that a regional unconformity separates sedimentologic models developed for such embayment was also flanked by ridges of the Jordan Sandstone from the Early Ordovi- units. Some previous interpretations, based to the west, by headlands cian . Deep incision into the largely on local outcrop studies, have con- and islands of Middle volcanic

Geological Society of America Bulletin, v. 106, p. 492-506, 12 figs., April 1994.

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has the best exposures and a large subsurface data base that includes borehole geophysical logs. Natural gamma logs are especially use- ful in distinguishing lithic attributes of the clastic parts of the Paleozoic section because of the distinctive correlation between grain size and feldspar content (Odom, 1975). For example, feldspathic, very fine grained sand- stone in the Jordan Sandstone is readily dis- tinguishable from the coarser-grained, quartz- ose sandstone (Fig. 2). More than 400 gamma logs and 58 sets of cuttings from boreholes that penetrated at least part of the Jordan Sand- stone were examined. This subsurface infor- mation, together with sedimentologic studies at selected outcrops, provided the basis for detailed analysis of the various lithofacies of the Jordan Sandstone. Most outcrops in Wisconsin and Iowa where a measured section of the Jordan had been published were also examined. These published sections were modified to conform to the lithofacies scheme devised for this study. By including outcrops in these states, it was possible to construct a north-south cross section of the Jordan spanning some 220 km across the Hollandale embayment and a section spanning about 370 km from the Transcontinental Arch to the Wisconsin Figure 1. Early Paleozoic tectonic features of the Upper Mississippi Valley region showing Arch (Fig. 1). location of outcrops and subsurface natural gamma logs used in cross sections and fence diagrams. LITHOFACIES OF THE JORDAN SANDSTONE

rocks to the north, and by ridges of the Bara- Adams, 1978; Davis, 1970). Lithostratigraph- Despite its generally homogeneous tex- boo and related quartzites along the Wiscon- ic evidence presented here and in Smith and ture, four distinct lithofacies of the Jordan sin Arch. others (1993) demonstrates that the Coon Sandstone can be recognized: (1) very fine The Jordan Sandstone is as thick as 35 m in Valley lies unconformably upon medium- to grained, hummocky cross-stratified and bur- the Hollandale embayment and consists coarse-grained sandstone of the Jordan and is rowed sandstone; (2) fine-grained, trough mostly of very fine to coarse-grained sand- transitional with the dolostone of the Oneota cross-stratified and burrowed sandstone; stone (Fig. 2). It grades laterally into sandy above. Because of the nature of these con- (3) medium- to coarse-grained, large-scale dolomite in southern Iowa (Horick and Stein- tacts, together with its generally dolomitic cross-stratified sandstone; and (4) hetero- hilber, 1978) and east of the Wisconsin Arch character, the Coon Valley Member is con- lithic, thinly interbedded sandstone, mud- along the western edge of the Michigan basin sidered the basal member of the Oneota Do- stone, and shale. Typical sections of the Jor- (Smith and others, 1993). The Jordan grada- lomite in this paper. dan Sandstone include lithofacies 1,2, and 3 tionally overlies the St. Lawrence Forma- The Jordan Sandstone has been divided (Fig. 2). Lithofacies 4 was found only at a tion, a unit of siltstone and dolostone depos- into members such as the Norwalk (Stauffer, single outcrop near Rushford, Minnesota. ited mostly in an offshore shelf environment 1925), Waukon (Odom and Ostrom, 1978), (Ostrom, 1964; Webbers, 1972). The Jordan Sunset Point (Raasch, 1951), and Van Oser Lithofacies 1—-Very Fine Grained, is overlain by the Coon Valley Member of the (Stauffer and others, 1939). These units were Hummocky Cross-Stratified and Oneota Dolomite (Fig. 2), which consists of never adequately defined in accordance with Burrowed Sandstone interbedded shale, sandstone, and sandy do- the North American Stratigraphic Code lostone deposited mostly in an intertidal to (1983), and consequently they were not use- This lithofacies consists mostly of feld- supratidal environment (Adams, 1978; Smith ful to this study (Runkel, in press). spathic, very fine grained sandstone charac- and others, 1993). Previous workers have terized by extensively burrowed and struc- placed the Coon Valley Member as the up- METHOD tureless beds (Fig. 3A) intercalated with permost member of the Jordan Sandstone hummocky cross-stratified intervals. Very (for example, Odom and Ostrom, 1978; The interpretation of the depositional his- thin to thin tabular beds of siltstone and shale Mossier, 1987) and as the lowermost member tory of the Jordan Sandstone is based mostly are also common, as well as bioturbated, of the Oneota Dolomite (for example, on data from southeastern Minnesota, which poorly sorted beds that have grain sizes rang-

Geological Society of America Bulletin, April 1994 493

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z some of the structureless very fine grained < w o sandstone, probably were deposited as sus- > oliigO pension fallout during waning-storm and fair- o weather conditions. Much of the burrowed tr o <¿¿¿¿¿¿4 COON VALLEY very fine grained sand, however, was likely O deposited as hummocky cross-strata that were bioturbated during fair-weather conditions.

Lithofacies 2—Fine-Grained, Trough LJU LITHOFACIES 3 Z Cross-Stratified and Burrowed Sandstone o Figure 2. Stratigraphic Z c1o- nomenclature for the Jor- This lithofacies consists mostly of moder- < Q dan Sandstone and basal ately to well-sorted, fine-grained sandstone OC Z LITHOFACIES 2 part of the Oneota Dolo- dominated by wedge sets of trough cross- m < LITHOFACIES 1 mite with a typical section strata from 10 to 30 cm thick (Fig. 3C). Most co from an outcrop 3.2 km cross-strata sets are deeply truncated by < z south of Homer, Minne- overlying sets or by a laterally continuous o < LITHOFACIES 2 û sota, showing lithofacies scour. A typical exposure therefore consists CE defined in this report. In mostly of an amalgamation of small remnants O this and subsequent fig- of trough cross-strata sets that are less than —> ures, feldspathic, very fine half their original thickness. Uncommon fea- LITHOFACIES 1 grained sandstone (litho- tures of this lithofacies include shale drapes facies 1) is shaded. along trough foresets and thin lags of medi- um- to coarse-grained sandstone along scour ,ST. LAWRENCE surfaces. 'FORMATION Skolithos and Arencolites burrows are Eza Burrows Iva^l Trough cross-strata common, both as scattered individual bur- ifty/j Tangential cross-strata rows and as concentrated burrows along in- E Intraclasts ESS thick lines are shale drapes Hummocky tervals of poorly sorted sandstone and silt- |V; Medium to coarse-grained S.S. cross-strata stone, which range in thickness from 2 to 20 Dolostone Fine-grained S.S. cm (Fig. 3D). These intervals in which bur- Ripple cross-strata Pebbles rows are concentrated truncate underlying strata and can be traced laterally for tens of meters across the entire extent of some out- crops. Others are only a few meters long and ing from clay to fine sand. Some thin beds as four hummocky intervals. Each interval are themselves truncated at each end by fine upward from planar-stratified fine- to has a lag of poorly sorted sandstone grading trough cross-strata. very fine grained sandstone to structureless, upward to hummocky cross-strata that are Paleocurrent trends of trough cross-strata very fine grained sandstone and siltstone. truncated by an overlying interval. Within in- of this lithofacies at individual outcrops are The hummocky cross-stratified sandstone dividual amalgamated units, the lags at the either unidirectional or scattered. Trends typically is part of a fining-upward interval base of the lower intervals generally are from all outcrops in Minnesota (Fig. 4A) are that begins with a scour surface overlain by a coarser grained and thicker than those in weakly bidirectional to scattered. In general, poorly sorted lag. Relatively complete inter- overlying intervals. the cross-strata in the northernmost outcrops vals typically include 1-50 cm of lag consist- (Minneapolis-St. Paul area) trend west to ing of intraclasts of siltstone and very fine Interpretation northwest; those to the south in Wisconsin grained sandstone set in a matrix of very fine (Dott, 1978) and Minnesota trend south to to very coarse grained, poorly sorted sand- The very fine grain size, extensive biotur- southwest. stone. The lag deposit is gradationally over- bation, and interbedding of shale, siltstone, lain by 20 cm to 1.5 m of hummocky cross- and hummocky cross-stratified sandstone in- Interpretation stratified, well-sorted, fine- to very fine dicate that lithofacies 1 was deposited in a grained sandstone (Fig. 3B). The hummocky low-energy, marine environment, generally Several features of lithofacies 2 are similar cross-stratified sandstone passes transition- below wave base except during storms. This to those of lower shoreface and inner-shelf ally upward into ripple cross-stratified or lithofacies is similar to deposits of the lower storm deposits in ancient rocks described by structureless, very fine grained sandstone shoreface to offshore transition environment Dott and others (1986), Atkinson and others and siltstone. described by Howard and Reineck (1981) and (1986), Carr and Scott (1990), and Driese and Hummocky cross-stratified intervals com- McCubbin (1982). The hummocky cross- others (1991), and those on the modern At- monly are stacked upon one another in amal- stratified intervals were deposited by oscilla- lantic shelf described by Swift and others gamated units similar to those described by tory currents during storms (Dott and Bour- (1986). These features include the size and Dott and Bourgeois (1982). Amalgamated geois, 1982; Hunter and Clifton, 1982). The type of cross-strata, burrows, evidence of units are as thick as 2 m and contain as many thin beds of shale and mudstone, as well as drastic fluctuations in current velocity, uni-

494 Geological Society of America Bulletin, April 1994

Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/106/4/492/3381867/i0016-7606-106-4-492.pdf by guest on 02 October 2021 Figure 3. (A) Burrowed, very finegraine d sandstone of lithofacies 1. Arrows point to thin shale beds. Stillwater, Minnesota. (B) Hummocky cross-strata of lithofacies 1 (above Jacob's staff). Stillwater, Minnesota. (C) Trough cross-strata of lithofacies 2. About 2.5 km north of Still- water, Minnesota. (D) Concentration of burrows in a poorly sorted, 10-cm-thick interval (within dashed lines) in lithofacies 2. About 1.5 km south of Alton, Minnesota. (E) Scour surfaces (arrows) in lithofacies 3. Along north side of U.S. Highway 14 about 11 km southwest of Winona, Minnesota.

E

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laminae of larger-scale tangential sets was identified as two outcrops. Another type of medium- to coarse- grained sandstone unit bounded by scoured surfaces has very large scale, low-angle cross-stratification. The best example of this feature is near Weaver, Minnesota (Fig. 5D), where such strata overlie a scour and lag with

n=115 boulder-size intraclasts of sandstone. The Figure 4. Paleocurrent roses showing trends very large scale cross-strata, which are ex- in southeastern Minnesota of (A) plunge of posed laterally for more than 30 m, are about trough axes in lithofacies 2 and (B) plunge of 4.5 m thick. Individual beds are 5 to 60 cm trough axes and dip direction of planar and thick, have a maximum apparent dip of about tangential cross-strata in lithofacies 3. 10° to 20°, and internally are structureless or display faint trough cross-stratification. Very thin mudstone and shale drapes separate some cross-strata. Less well exposed exam- ples of similar cross-strata are at Stillwater, Reno, and two outcrops near Rushford, Min- nesota. Cross-strata at such a large scale may be common in lithofacies 3 but were recog- nizable only in large, laterally extensive out- n=224 crops with a suitable trend of exposure. Cross-stratification trends of lithofacies 3 are bipolar in most outcrops, but unimodal to modal to scattered cross-strata trends, and tween grain size of the intraclast and the size scattered in others. Trends of cross-strata absence of structures indicative of tidal cur- of the clast itself. Those composed of silt- from all outcrops combined are scattered rents. ITie dominance of trough cross-strata stone to fine-grained sandstone typically (Fig. 4B). The large-scale cross-strata near and the abundance of scours imply that this have a long axis of <5 cm, whereas those Weaver trend N 30° E and dip to the lithofacies is composed mostly of an amal- composed of medium- to coarse-grained southeast. gamation of the basal deposits of individual sandstone may be of boulder size (Figs. 5A storm events. Most fair-weather and waning- and 5B). These very large clasts typically Interpretation storm deposits apparently were eroded dur- are tabular, about 10-15 cm thick, as long ing subsequent storms (Kumar and Sanders, as 1.5 m, and internally structureless. A The medium to coarse grain size, abun- 1976), although some burrowed intervals and few of the very large clasts, however, have dance of features suggestive of tidal currents, shale drapes may have formed during fair- stratification that parallels the long axis of channel-shaped scours, and boulder-sized weather conditions when currents were too the clast. sandstone intraclasts are evidence that en- weak to transport fine sand (Dott, 1978). Oth- Individual outcrops typically have five to ergy was higher and water was shallower ers may have developed on topographically ten recognizable scour surfaces that define than for underlying lithofacies. The scour- high parts of an incised shoreface during sandstone units that range from half a meter bounded sandstone units that characterize transgressions (discussed later in this report) to 4 m in thickness. Some units consist en- this lithofacies are interpreted to be an amal- at the same time that lower areas were filled tirely of a poorly sorted, structureless or gamation of truncated tidal-inlet fills. The with very fine sand. crudely horizontally stratified, intraclastic lag units with large-scale, low-angle cross-strata deposit. Other units consist mostly of tabular with shale drapes are similar to deposits pro- Lithofacies 3—Medium- to Coarse-Grained, to elongate wedge sets of trough and tangen- duced by the lateral migration of a tidal inlet, Large-Scale Cross-Stratified Sandstone tial cross-strata from about 20 cm to 1.5 m during which there is erosion on one side of thick that commonly overlie an intraclastic the inlet and episodic accretion on the oppo- This lithofacies composes the upper 6-12 lag. Generally, the lower sandstone units site side (Hoyt and Henry, 1967; Kumar and m of the Jordan Sandstone and differs from within an individual outcrop consist mostly of Sanders, 1974). The large thickness of the in- other lithofacies chiefly by its overall coarser sets of trough cross-strata from 20 to 40 cm dividual strata in these units, their shallow grain size, larger-scale cross-strata, and thick. Larger planar and tangential sets as dip, and the presence internally of trough fewer burrows. Most beds consist of medi- much as 1.5 m thick are more common in the cross-strata indicate that they are lateral ac- um-grained sandstone, but coarse-grained upper sandstone units. Shale and mudstone cretion beds, rather than foreset deposits of a sandstone beds as thick as 2 m are common. drapes, reactivation surfaces, and herring- large dune. Thinner scour-bounded units Abundant scours, some having a broad chan- bone cross-strata are common features in consisting only of massive, coarse-grained, nel shape, also characterize this lithofacies many of these cross-stratified units, particu- intraclastic sandstone are similar to the basal (Figs. 3E and 5A). Most scours are overlain larly in large-scale, tabular sets of tangential part of these large-scale low-angle cross- by a lag of siltstone and sandstone intraclasts cross-strata (Fig. 5C). Compound cross-strat- stratified units; they probably are basal rem- set in a matrix of medium- to very coarse ification in the form of reversely dipping rip- nants of deeply truncated inlet deposits, al- grained sandstone. There is a correlation be- ple cross-strata that interfinger with the lee though some could be fills of temporary

496 Geological Society of America Bulletin, April 1994

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Figure 5. (A) Broad, channel-shaped scour (arrows) with lag of boulder-sized sandstone intraclasts. Along north side of U.S. Highway 14 about 11 km southwest of Winona, Minnesota. (B) Large (1.5 m) tabular sandstone intraclast (arrow) lying among pile of intraclasts along the base of an irregular scour (dashed line). Along north side of U.S. Highway 14 about 11 km southwest of Winona, Minnesota. (C) Reactivation surfaces draped by shale (arrows) on tangential cross-strata. Note thinner sets with opposing dips above. About 3.2 km south of Homer, Minnesota. (D) Large-scale, low-angle cross-strata near top of Jordan Sandstone. Arrows mark the contact between the Jordan Sandstone and Oneota Dolomite at top of photo. About 1.2 km west of Weaver, Minnesota.

breaches in the foreshore, or lags of succes- ebb or flood deltas built out from nearby in- existing inlets became wider or migrated sive storms within a single, more permanent lets, rather than filling the inlet proper. laterally. inlet (El Ashry and Wanless, 1965). Other The large sandstone intraclasts common in Scour-bounded units composed mostly scour-bounded units consisting mostly of this lithofacies are similar in thickness, size, of trough cross-stratified sandstone in sets large-scale sets of cross-strata with tidal-cur- and internal stratification to the carbonate-ce- 20 to 50 cm thick that occur near the lower rent sedimentary structures are similar to mented sandstone beachrock intraclasts in part of this lithofacies have few features basal inlet fills described by Kumar and Sand- Miocene foreshore deposits described by diagnostic of a specific nearshore environ- ers (1974), Hayes (1980), and Donselaar Roep and others (1979). The large size and ment. Their stratigraphic position below (1989). The reactivation surfaces, herring- angularity of most of these clasts indicate that tidal inlet deposits and above lower bone cross-strata, compound cross-stratifica- they were not transported far and there- shoreface sandstone (lithofacies 2) and tion, shale and mudstone drapes, and bipolar fore were most likely derived from beach- their sharp upper and lower contacts sug- cross-strata trends were produced by domi- rock in the splash zone of the foreshore gest that these strata may have been de- nant and subordinate bidirectional tidal cur- area, adjacent to an inlet. Incision of the posited in rip channels scoured into the up- rents flowing through an inlet. Some parts of beachrock may have occurred during per shoreface (compare Hunter and these units may also have been deposited as storms when new inlets were breached and others, 1979; Clifton, 1981).

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NORTH

HAY CREEK, MN

ST. LAWRENCE FORMATION

25-1 20 -6 SCALE DISH ho -2 5 10 15 Kilometers 0 10 Miles

Figure 6. Measured sections of the Jordan Sandstone from north to south through the center of the Hollandale embayment. Note the lateral continuity in succession of lithofacies, which consistently record overall shallowing of depositional conditions. Each outcrop consists of intercalated offshore shelf and lower shoreface deposits (lithofacies 1 and 2), overlain by upper shoreface and tidal inlet deposits (lithofacies 3). Columns are generalized from Runkel (in press).

Lithofacies 4—Thinly Interbedded Driese and others (1981) and Mossier (1992) In addition to composing the basal part of Sandstone, Mudstone, and Shale and modern and ancient deposits elsewhere the Jordan, lithofacies 1 also occurs at strat- described by Reineck and Singh (1975) and igraphically higher levels in the formation as This lithofacies is as much as 1.2 m thick Weimer and others (1982). The heterolithic wedge-shaped units within lithofacies 2 and 3 and consists mostly of lenticular to tabular interbeds, reactivation surfaces with shale (Figs. 6 and 7). In these occurrences the beds of intercalated shale, siltstone, and drapes, and herringbone cross-strata are in- lower contact is always an erosion surface very fine to coarse-grained sandstone. dicative of fluctuating conditions in which that can have as much as 1.5 m of relief over Most sandstone beds are < 10 cm thick and low-energy suspension deposition of clay and horizontal distances of —30 m in outcrop. structureless or crudely horizontally strat- silt alternated with traction deposition of sand The upper contact may be either gradational ified, but ripple cross-stratification, tan- by bidirectional tidal currents. or sharp. The basal part of each unit consists gential cross-strata with clay drapes and of a poorly sorted intraclastic lag capped by reactivation surfaces, and cosets of her- LITHOFACIES ASSOCIATIONS hummocky cross-strata (Fig. 7). The hum- ringbone cross-strata also are present. mocky cross-strata in turn pass transitionally Shale and siltstone beds are less than a A cross section of the Jordan Sandstone upward into mostly structureless, burrowed, centimeter thick and are in sharp contact along an approximately north-south transect very fine grained sandstone. Natural gamma with sandstone beds. This lithofacies is ex- through the Hollandale embayment shows a logs of the Jordan in several boreholes in posed at only one outcrop, where it over- consistent vertical succession of lithofacies southeastern Minnesota show that as many lies and interfingers laterally with planar (Fig. 6). Lithofacies 1 gradationally overlies as three separate units of lithofacies 1 are and tangential cross-strata sets of litho- the St. Lawrence Formation and composes present in individual 25- to 30-m sections. facies 3. the lowermost 1.5 to 6 m of the Jordan sand- Units of lithofacies 1 can be distinguished stone. This lowermost unit is gradationally easily on natural gamma logs because of their Interpretation overlain by as much as 10 m of lithofacies 2. large feldspar content compared to the The uppermost 5 to 12 m of the Jordan, which coarser, feldspar-poor sandstone with which Lithofacies 4 is similar to intertidal to shal- consists of lithofacies 3, and rarely 4, in turn they are intercalated (Odom, 1975) (Fig. 7). low-subtidal deposits of other Paleozoic units is sharply overlain by the Coon Valley Mem- Fence diagrams based on correlated gamma in the Hollandale embayment described by ber of the Oneota Dolomite. logs show that units of lithofacies 1 occur as

498 Geological Society of America Bulletin, April 1994

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SOUTH

WABASHA, MN WEAVER, MN

Figure 6. (Continued).

disconformable tongues that climb diagonally upsection from the base of the Jordan (Figs. NATURAL GAMMA LOG OUTCROP 8 and 9). The tongues generally dip to the (Near Stillwater, MN) south in the northern part of the Hollandale ONEOTA DOLOMITE embayment, arid to the west or southwest in the central to eastern part. Individual tongues r-25 are as much as ~ 15 km wide and have a cres- centic shape in cross sections oriented per- pendicular to strike. They are as much as 12 •20 m thick near the base of the Jordan and thin as they stratigraphically climb up section. JJTHOFACIES 3

They typically pinch out within or near the LITHOFACIES 1 base of lithofacies 3. In contrast, individual

tongues maintain a fairly constant thickness LITHOFACIES 2 along strike and can be traced in the subsur-

face for at least 24 km where borehole geo- LITHOFACIES 1 physical logs are closely spaced. The data base is not yet sufficient to correlate individ- LITHOFACIES 2 ual tongues with confidence for greater dis- tances along strike, so it is uncertain whether LITHOFACIES 1 any single tongue is regionally continuous

across the entire Hollandale embayment. 0 Meters ST. LAWRENCE FM. DEPOSOTONAL SYNTHESIS I- 100 API UNITS

The lateral and vertical associations of Figure 7. Measured section about 2.5 kiti north of Stillwater, Minnesota, showing units of lithofacies indicate that the Jordan Sandstone lithofacies 1 disconformably overlying lithofacies 2. Natural gamma log is from water well about is a regressive unit, generally similar to pro- half a kilometer west of outcrop and shows the pronounced positive signatures associated with grading shoreline deposits described by Hob- lithofacies 1 in contrast to lithofacies 2.

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Figure 8. Fence diagram of the Jordan Sandstone in the Minneapolis-St. Paul area based on correlated gamma logs, showing the shape and strati- graphic arrangement of very fine grained sandstone units. See Figure 1 for location.

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Figure 9. Fence diagram of the Jordan Sandstone in southeastern Minnesota based on correlated gamma logs, showing the shape and strati- graphic arrangement of very fine grained sandstone units. See Figure 1 for location.

day and Home (1977), Roep and others to almost entirely traction deposition of fine lower shoreface deposits (lithofacies 1 and 2) (1979), and Duke and others (1991). The ver- sand in the lower shoreface (lithofacies 2) as in the lower half of the Jordan Sandstone. In tical succession of lithofacies across the Hol- the shoreline prograded. Continued progra- contrast, evidence for tidal currents is com- landale embayment consistently reflects an dation led to the deposition of tidal inlet and mon in upper shoreface and tidal inlet depos- overall shallowing of depositional conditions. upper shoreface deposits (lithofacies 3) and its (lithofacies 3) in the upper half of the Jor- Lithofacies 1 at the basal part of the Jordan intertidal deposits (lithofacies 4) on top of dan. Tidal currents apparently were capable Sandstone records the transition from rela- lower shoreface deposits. of transporting sand only in the relatively tively low energy, offshore shelf deposition of Storm-current-produced features domi- shallow water of the upper shoreface and silt and carbonate (St. Lawrence Formation) nate the record of both offshore transition and within tidal inlets (Klein, 1982), whereas sand

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gressive episodes that interrupted prograda- tion and led to shoreface truncation (Fig. 10) RELATIVE FALL IN SEA LEVEL (compare Clifton, 1981; Cant, 1984; Wright, s.l. 1 1986). Deeper water facies were subse- quently deposited on the incised shoreface as PROGRADATION OF SHOREFACE far landward as previous sites of upper shoreface and tidal inlet deposition. Promi- nent burrowed intervals in cross-stratified sandstone of the lower shoreface (lithofacies 2) may have formed during prolonged periods of nondeposition in topographically high RELATIVE RISE IN SEA LEVEL areas of the shoreface during these transgres- S.l. 2 sive episodes. Stacked units of tidal inlet deposits with beachrock lags (lithofacies 3) may also reflect RETREAT OF SHOREFACE repeated transgressive-regressive episodes. ^-Previous position of shoreface Donselaar (1989) attributed amalgamated tidal inlet fills in the Cliff House Sandstone to episodes of aggradation within inlets alternating with transgressive episodes RELATIVE RISE IN SEA LEVEL when these deposits were partly removed. Because inlet bases are commonly deeper than the foreshore-shoreface boundary, tidal

CONTINUED RETREAT OF SHOREFACE AND inlet deposits can dominate the depositional DEPOSITION OF OFFSHORE LITHOFACIES record of barrier systems that are subjected ON SHOREFACE to erosion during repeated transgressive and regressive episodes. It is uncertain how many transgressions occurred during deposition of the Jordan Sandstone because individual tongues as yet cannot be confidently correlated on a —• — s.l. 3 regional scale. Jordan sections with as RELATIVE FALL IN SEA LEVEL many as three tongues record a minimum S.l. 4 of three transgressions. Given the limited PROGRADATION OF SHOREFACE extent of individual tongues perpendicular OVER OFFSHORE LITHOFACIES to strike (10-15 km), their regional distri- bution across the embayment, and consist- ent dip to the south-southwest, there are Figure 10. Diagrams showing origin of tongues of lithofacies 1 that disconformably overlie possibly tens of tongues across the Hol- shoreface lithofacies. Progradation of the shoreface (stage 1) was interrupted by transgressive landale embayment in the Jordan, record- episodes during a relative rise in sea level (s.l.) when the shoreface was incised and seaward facies ing tens of transgressive events. migrated landward (stages 2 and 3). Subsequent progradation during a relative fall in sea level The disconformities at the base of the (stage 4) led to deposition of coarser-grained shoreface lithofacies on these transgressive tongues. transgressive tongues mark positions of the truncated shoreface in Late Cambrian time. The south to southwest dip of these in the lower shoreface and offshore areas was beachrock on the foreshore of barriers that tongues indicates that the regional shore- transported and deposited mostly during were either breached during storms, or in- line trended roughly northwest and pro- storms when wave base was lowered and cised by migrating inlets. The apparent ab- graded to the southwest, away from the strong surges and littoral currents developed. sence of back-barrier lagoonal deposits, Wisconsin Dome and Arch area. A similar Several features of the upper part of the which commonly overlie inlet and foreshore shoreline trend has been reconstructed by Jordan Sandstone suggest that barrier islands deposits in regressive barrier island se- Dott and others (1986) for older and developed along at least some parts of the quences, suggests either that the back-barrier younger sheet sandstones in the Hollan- Late Cambrian shoreline. Amalgamated deposits are dominated by sandy tidal chan- dale embayment on the basis of trough units of tidal-inlet fills are characteristic of nel fills, which are indistinguishable from in- cross-strata trends and lithofacies map- barrier systems, where only sediments de- let deposits of lithofacies 3, or that they were ping. As a clastic system, the Late Cam- posited in the topographically lowest parts of removed by an erosive event before deposi- brian shoreline prograded as far as south- the shoreline are preserved (McCubbin, tion of overlying Ordovician strata. central Iowa, near the southern margin 1982; Donselaar, 1989). The large intraclasts The wedge-shaped tongues of lithofacies 1 of the Hollandale embayment, where the of sandstone in the upper shoreface and tidal that lie disconformably within lithofacies 2 Jordan is composed mostly of sandy inlet deposits were probably derived from and 3 (Figs. 8 and 9) are the result of trans- dolostone.

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WEST EAST B B' MADISON

Figure 11. Jordan Sandstone measured sections and interpreted natural gamma logs from the approximate center of the Hollandale embayment to the Wisconsin Arch (B-B') and to the Transcontinental Arch (C-C'). See Figure 1 for locations of outcrops and gamma logs.

CAMBRIAN-ORDOVICIAN BOUNDARY in the Coon Valley Member records a gradual The basal part of the Coon Valley Member IN THE HOLLANDALE EMBAYMENT change from clastic deposition during Cam- is characterized by a lag deposit composed of brian time to carbonate precipitation in Early poorly sorted, structureless to crudely strat- The nature of the contact between the Ordovician time. Recently, however, Smith ified sandstone with shale and sandstone in- Jordan Sandstone and the Coon Valley Mem- and others (1993) suggested that local depos- traclasts and pebble-sized clasts of Precam- ber of the Oneota Dolomite has been contro- its of silcrete and a chert pebble conglomerate brian rock. Along the Wisconsin and versial, in part because it approximates the along the Jordan-Oneota contact on the Wis- Transcontinental Arches, the lag is as much Cambrian-Ordovician boundary. Most early consin Arch are evidence of subaerial expo- as 2 m thick and the pebbles are dominantly workers described the contact as unconform- sure of the Jordan in that part of the quartzite and chert. The lag thins toward the able (for example, Ulrich, 1924; Graham, embayment. center of the embayment, and in outcrops 1933; Trowbridge and Atwater, 1934; Powell, Evidence presented here that the Jordan along the Mississippi and St. Croix Rivers, 1935; Stauffer and Thiel, 1941; Raasch, 1951), Sandstone and Oneota Dolomite are sepa- where it is generally less than a meter thick, an interpretation that was based on scanty rated by a regional unconformity includes (1) pebbles in the lag include iron- biostratigraphic control and biased by the a sharp undulatory contact between the Jor- formation, felsic volcanic rocks, chert, vein dogma that system boundaries correspond to dan and Coon Valley Member in most out- quartz, quartzite, and other sandstone clasts unconformities. Most studies over the past 40 crops; (2) a poorly sorted, locally reworked, of probable Proterozoic age. years, however, have concluded that the con- intraclastic lag containing Precambrian peb- Near the margins of the embayment, the tact is conformable (for example, Berg and bles at the base of the Coon Valley; and (3) Coon Valley lag deposit overlies stratigraph- others, 1956; Kraft, 1956; Ostrom, 1970; deep truncation of the Jordan Sandstone near ically lower (and depositionally deeper) parts Davis, 1970; Stubblefield, 1971; Thomas, the margins of the Hollandale embayment in of the Jordan Sandstone (Fig. 11). For exam- 1991). Many of these workers believe that the south-central Wisconsin and along the Min- ple, to the east on the Wisconsin Arch, the gradational decrease in sand content upward nesota River Valley. Jordan is generally < 15 m thick, and the lag

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/LITHOFACIES 3 C B B

•:•;::•: •:••'••'•.Vi ITHOFAP.IFS 1 * AND ' 2.. -v ; •• RYJ ^--^-C-T-'L-' ' •"'

ST. LAWRENCE ft m FORMATION 60f20 60 km TRANSCONTINENTAL OÍ-H WISCONSIN ARCH HOLLANDALE EMBAYMENT 40 mi ARCH Figure 12. Reconstructed stratigraphic cross section of the Jordan Sandstone and top of the St. Lawrence Formation from west to east across the Hollandale embayment. This cross section is based on sections in Figure 11. Note that the Jordan is more deeply truncated on the margins of the Hollandale embayment, where upper shoreface and tidal inlet deposits (lithofacies 3) are locally absent.

overlies lower shoreface deposits (lithofacies fore, they suggested that the upper part of the Nonetheless, other major regressive events 2) near Spring Green and in the Madison area Jordan conformably spans the boundary. in the Hollandale embayment, such as those (Fig. 11, B-B'). Near Mazomanie, the Jordan However, a review of the literature in which that occurred immediately prior to deposition is locally missing and the lag overlies offshore identified can be placed in stratigraph- of the Wonewoc and St. Peter Formations shelf deposits of the St. Lawrence Forma- ic context shows that reported Ordovician (Dott and others, 1986), resulted in wide- tion. Similarly, to the west near the Trans- faunas (for example, Stauffer, 1925; Powell, spread incision or nondeposition rather than continental Arch in the vicinity of Mankato, 1935; Stauffer and Thiel, 1941; Raasch and the deposition of a major sandstone unit. The Minnesota (Fig. 11, C-C'), the Jordan is 9-25 Unfer, 1964) were in fact all collected from latest Cambrian fall in sea level therefore m thick and the Coon Valley Member locally above the unconformity, within the Coon must have been accompanied by a large sand lies directly on lower shoreface deposits Valley or younger beds. Conversely all re- supply (Heward, 1981), possibly in response (lithofacies 2). In the center of the embay- ported Cambrian faunas were collected from to uplift and incision of source areas during ment in southeastern Minnesota, northeast- strata beneath the unconformity (for exam- the initial tectonic development of the Hol- ern Iowa, and extreme southwestern Wis- ple, Stauffer, 1925; Stauffer and Thiel, 1941; landale embayment. consin, however, the Jordan is 25 to 35 m Raasch, 1951; Nelson, 1956). It is difficult to attribute the tongues of thick and the Coon Valley lag overlies tidal lithofacies 1 to a specific cause. If the tongues inlet and upper shoreface deposits (litho- CONTROLS ON STRATIGRAPHY are regionally continuous across the Hollan- facies 3). This relationship implies that upper dale embayment, they may have developed shoreface deposits in the upper part of the Lowering of relative sea level that led to in response to decreases in regional sediment Jordan Sandstone were eroded along the progradation of the shoreline across the Hol- supply or in rate of sea-level fall relative to flanks of the Hollandale embayment (Fig. 12) landale embayment and subsequent erosion subsidence. If individual tongues are local in in pre-Coon Valley time, marking the earliest may have occurred at least partly in response extent, they could be the result of changes in known development of the Hollandale em- to a latest Cambrian and early Ordovician the geographic position of rivers providing bayment into a basin in which the margins eustatic fall in sea level, as postulated by Hal- detritus to the shoreline, changes in the pat- were uplifted relative to the center. lam (1984). The Jordan Sandstone lies within terns of tropical storms resulting in locally Pre-Coon Valley erosion was most likely the middle of the North American Sauk III variable scour, or local structural activity related to fluvialincisio n in landward areas as sequence of Sloss (1963), which was depos- (compare Mossier, 1972) that created areas of the shoreline prograded across the Hollan- ited during a transgression. However, latest increased subsidence within the embayment. dale embayment in Late Cambrian time, Cambrian regressive events and/or Cam- leaving a lag that contained the relatively brian-Ordovician unconformities have been DISCUSSION large and resistant Precambrian clasts. Re- described in many parts of North America gional transgression in Early Ordovician time (for example, Lochman-Balk, 1970; Miller, Dott and others (1986), in studying the Or- led to the deposition of intertidal and subtidal 1984) and other continents such as Australia dovician St. Peter and Cambrian Wonewoc strata (Smith and others, 1993), with concur- and Europe (for example, Ripperdan and Formations, developed a sedimentologic rent incorporation of the lag deposits into the Kirschvink, 1992; Nicoll and others, 1992). model in which the spread of sand across the Coon Valley Member. The deposition and preservation of an en- craton by eolian and fluvial processes prior to The fact that the Jordan Sandstone- tirely marine, regressive unit of generally uni- transgressive marine reworking is largely re- Oneota Dolomite boundary is a regional un- form thickness over such a large area in a sponsible for the sheet geometry and matu- conformity has important implications for the shallow, relatively stable cratonic basin such rity of these and other cratonic sandstones. placement of the Cambrian-Ordovician as the Hollandale embayment is unusual. The The sedimentologic model developed here boundary in the Upper Mississippi Valley re- gradient of the alluvial plain landward of the for the Jordan Sandstone shows that cratonic gion. Workers who did not recognize the un- retreating shoreline in latest Cambrian time sheet sandstones share a similar history only conformity believed that Coon Valley-like may have been about the same as the low in that they all are diachronous units depos- strata that yielded Ordovician fossils were gradient of the seaward shelf surface in the ited when there apparently was an abundant transitional with underlying sandstone that embayment. In such a setting, fluvial erosion sediment supply during either a regional produced a Cambrian fauna (for example, in landward areas would be minimal during a transgressive or regressive event. There is no Berg and others, 1956; Ostrom, 1970). There- regression (Posamentier and others, 1992). evidence for fluvial and eolian deposition in

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commonly interrupted by transgressive per Cambrian lithofacies: Wisconsin Geological and Natural the Jordan Sandstone, and such processes History Survey Field Trip Guidebook 3, p. 52-66. were not necessarily responsible for spread- events when the shoreface was truncated and Byers, C. W„ Dott, R. H., Jr., and Smith, G. L., 1990, Cambro- Ordovician sequence stratigraphy and paleogeography on the ing the sand across the craton in a sheet-like offshore lithofacies migrated landward. craton and eastern passive margin of North America: 13th International Sedimentologic Congress Abstracts of Papers, fashion during Jordan time. It is possible that The contact between Cambrian and Or- p. 138-139. sand was dispersed to the shoreline in a dovican strata in the Hollandale embayment Cant, D. J., 1984, Development of shoreline-shelf sand bodies in a Cretaceous epeiric sea deposit: Journal of Sedimentary Pe- braided sand plain and eolian dune system as is an unconformity, which forms the bound- trology, v. 54, p. 541-556. ary between the regressive Jordan Sandstone Carr, D. L., and Scott, A. J., 1990, Late storm-dom- proposed by Dott and others (1986) for other inated shelf sand ridges, Sacramento Mountains, New Mex- sheet sandstones, but it is also possible that below, and the transgressive Oneota Dolo- ico: Journal of Sedimentary Petrology, v. 60, p. 592-607. Clifton, H. E., 1981, Progradational sequences in Miocene shoreline sand was transported to the shoreline by a mite above. Deep incision of the Jordan near deposits, southeastern Caliente Range, California: Journal of few major streams and subsequently dis- the Transcontinental and Wisconsin Arches Sedimentary Petrology, v. 51, p. 165-184. Davis, R. A., Jr., 1970, Prairie du Chien Group in the Upper Mis- persed along the shoreline by littoral cur- indicates that the development of the Hollan- sissippi Valley: Wisconsin Geological and Natural History Survey Information Circular 11, p. 35-44. rents. Regardless, after the sand reached the dale embayment into a basin that was sub- Donselaar, M. E., 1989, The Cliff House Sandstone, San Juan Ba- sin, New Mexico: Model for the stacking of "transgressive" coast it had to have been dispersed seaward siding relative to its margins began in latest barrier complexes: Journal of Sedimentary Petrology, v. 59, and spread across the cratonic shelf entirely Cambrian or Early Ordovician time. p. 13-27. Dott, R. H., Jr., 1978, Sedimentology of Upper Cambrian cross- by marine processes such as downwelling This study shows that the laterally uni- bedded sandstone facies as exemplified by the Van Oser Sand- stone: Wisconsin Geological and Natural History Survey storm currents (Swift and Thorne, 1991). form, regionally extensive cratonic sheet Field Trip Guidebook 3, p. 52-66. Sand dispersion both along the shore and in a sandstones of the Upper Mississippi Valley Dott, R. H., Jr., and Bourgeois, J., 1982, Hummocky stratification: Significance of its variable bedding sequences: Geological So- seaward direction would have been enhanced region were produced in regressive as well as ciety of America Bulletin, v. 93, p. 663-680. Dott, R. H„ Jr., Byers, C. W„ Fielder, G. W., Stenzel, S. R., and by the alternating episodes of shoreface pro- transgressive settings. These units share a Winfree, K. E., 1986, Aeolian to marine transition in Cambro- gradation and retreat that characterize the Ordovician cratonic sheet sandstones of the northern Missis- similar history only in that they are diachro- sippi Valley, USA: Sedimentology, v. 33, p. 345-367. history of the Jordan. nous units deposited during a change in sea Driese, S. G„ Byers, C. W., and Dott, R. H., Jr., 1981, Tidal de- posits in the basal Upper Cambrian Mt. Simon Sandstone in For the Jordan Sandstone, shoreface sand level accompanied by an abundant supply of Wisconsin: Journal of Sedimentary Petrology, v. 51, sand. The apparent frequency of storms rel- p. 367-381. would have been potentially subjected to Driese, S. G„ Fischer, M. W., Easthouse, K. A., Marks, G. T., many cycles of erosion and deposition by ative to aggradation rate and the alternating Gogola, A. R., and Schoner, A. R., 1991, Model for genesis of shoreface and shelf sandstone sequences, southern Appa- storms, as well as transportation along shore, episodes of transgression and regression that lachians: Paleoenvironmental reconstruction of an Early Si- lurian shelf system, in Swift, D.J.P., Oertel, G. F., Tillman, shoreward, and seaward during transgres- characterize the depositional history of the R. W., and Thome, J. A., eds., Shelf sands and sandstone Jordan would have contributed to the ex- bodies: International Association of Sedimentologists Spe- sions and regressions (Swift and Thorne, cial Publication 14, p. 309-338. 1991), before final burial. These conditions treme textural maturity and to the near ab- Duke, W. L., Fawcett, P. J., and Brusse, W. C., 1991, Prograd- ing shoreline deposits in the Lower Medina Group, would have contributed greatly to sandstone sence of shale in this and perhaps other Pa- Ontario and New York: Storm- and tide-influenced sedimen- maturity by rounding quartz grains and leozoic sheet sandstones. tation in a shallow epicontinental sea, and the origin of enig- matic shore-normal channels encapsulated by open shallow- abrading less durable minerals, especially marine deposits, in Swift, D.J.P., Oertel, G. F., Tillman, R. W., and Thome, J. A., eds., Shelf sands and sandstone feldspar grains (Odom, 1975), to the very fine ACKNOWLEDGMENTS bodies: International Association of Sedimentologists Special grain size or finer fractions. The near absence Publication 14, p. 339-378. El Ashry, M. T., and Wanless, H. R„ 1965, Birth and early growth of shale beds throughout much of the Jordan The early stages of this study were sup- of a tidal delta: Journal of Geology, v. 73, p. 404-406. Graham, W.A.P., 1933, Petrology of the Cambrian-Ordovician con- and other cratonic sheet sands (Dott and oth- ported by the Legislative Commission on tact in Minnesota: Journal of Geology, v. 41, p. 468-486. ers, 1986) may reflect a different consequence Hallam, A., 1984, Pre-Ouatemary sea-level changes: Annual Re- Minnesota Resources and the Minnesota De- views of Earth and Planetary Sciences, v. 12, p. 205-243. of these conditions—the dominance of storm partment of Natural Resources, Division of Hayes, M. O., 1980, General morphology and sediment patterns in tidal inlets: Sedimentary Geology, v. 26, p. 139-156. over fair-weather deposits in shoreface litho- Waters. G. B. Morey of the Minnesota Ge- Heward, A. P., 1981, A review of wave-dominated clastic shoreline facies. In the Jordan and other Paleozoic deposits: Earth-Science Reviews, v. 17, p. 223-276. ological Survey provided thoughtful discus- Hobday, D. K., and Home, J. C., 1977, Tidally influenced barrier units, strata deposited under fair-weather sion throughout the course of this study. island and estuarine sedimentation in the Upper Carbonifer- ous of southern West Virginia: Sedimentary Geology, v. 18, conditions are common in lithofacies depos- Robert H. Dott, Jr., and Roderick W. Till- p. 97-122. Horick, P. J., and Steinhilber, W. L., 1978, Jordan aquifer of Iowa: ited landward or seaward of the shoreface, man were the GSA reviewers. Iowa Geological Survey Miscellaneous Map Series 6. and these strata contain a significant compo- Howard, J. D., and Reineck, H., 1981, Depositional facies of a high- energy beach to offshore sequence: Comparison with a low- nent of shale (Mossier, 1992; Smith and oth- energy sequence: American Association of Petroleum Geol- ers, 1993). REFERENCES CITED ogists Bulletin, v. 65, p. 807-830. Hoyt, J. H., and Henry, V. J., Jr., 1967, Influence of island migra- Adams, R. L., 1978, Stratigraphy and petrology of the lower Oneota tion on barrier island sedimentation: Geological Society of Dolomite (Ordovician), south-central Wisconsin: Wisconsin America Bulletin, v. 78, p. 77-86. CONCLUSIONS Geological and Natural History Survey Field Trip Guidebook Hunter, R. E., and Clifton, H. E„ 1982, Cyclic deposits and hum- 3, p. 82-90. mocky cross-strata of probable storm origin in the Upper Cre- Atkinson, C. D., Goesten, M.J.B.G., Speksnijder, A., and Vander- taceous rocks of the Cape Sebastian area, southwestern Or- The Jordan Sandstone was deposited dur- vlugt, W., 1986, Storm-generated sandstone in the Miocene egon: Journal of Sedimentary Petrology, v. 52, p. 127-143. Miri Formation, Seria Field, Brunei (Northwest Borneo), in Hunter, R. E„ Clifton, H. E., and Phillips, R., 1979, Depositional ing a Late Cambrian regression that may Knight, R. J., and Mclean, J. R., eds., Shelf sands and sand- processes, sedimentary structures, and predicted vertical se- stones: Canadian Society of Petroleum Geologists Mem- quences in barred nearshore systems, southern Oregon have been the result of a eustatic fall in sea oir 11, p. 213-240. Coast: Journal of Sedimentary Petrology, v. 49, p. 711-726. Austin, G. S., 1969, Paleozoic lithostratigraphic nomenclature for Klein, G. dev., 1982, Probable sequential arrangement of deposi- level accompanied by uplift of marginal areas southeastern Minnesota: Minnesota Geological Survey Infor- tional systems on cratons: Geology, v. 10, p. 17-22. that triggered an increase in the supply of mation Circular 6, 11 p. Kraft, J. C., 1956, A pétrographie study of the Oneota-Jordan con- Berg, R. R., Nelson, C. A., and Bell, W. C., 1956, Upper Cambrian tact zone, in Sloan, R., and Schwartz, G. M., eds., Lower sand to the Hollandale embayment. Each rocks in southeast Minnesota, in Sloan, R., and Schwartz, Paleozoic geology of the Upper Mississippi Valley: Geolog- G. M., eds., Lower Paleozoic geology of the Upper Missis- ical Society of America Annual Meeting, 1956, Field trip section of the Jordan records a shallowing- sippi Valley: Geological Society of America Guidebook Se- guidebook, p. 1-15. upward transition from offshore shelf to ries Field Trip 2, p. 1-23. Kumar, N., and Sanders, J. E., 1974, Inlet sequence: A vertical Bunker, B. J., Witzke, B. J., Watney, W. L., and Ludvigson, G. A., succession of sedimentaiy structures and textures created by shoreface to tidal inlet deposition in a barrier 1988, Phanerozoic history of the central midcontinent, United the lateral migration of tidal inlets: Sedimentology, v. 21, States, in Sloss, L. L., ed., Sedimentary cover—North p. 491-532. shoreline. Offshore transition and lower American craton, United States: The geology of North Amer- Kumar, N., and Sanders, J. E., 1976, Characteristics of shoreface shoreface lithofacies are dominated by storm ica, DNAG Volume D-2: Boulder, Colorado, Geological So- storm deposits: Modem and ancient examples: Journal of ciety of America, p. 243-260. Sedimentary Petrology, v. 46, p. 145-162. deposits. Progradation of the shoreline was Byers, C. W., 1978, Depositional environments of fine-grained Up- Lochman-Balk, C., 1970, Upper Cambrian faunal patterns on the

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craton: Geological Society of America Bulletin, v. 81, Posamentier, H. W., Allen, G. P., James, D. P., and Tesson, M., districts of southeastern Minnesota [M.S. thesis]: Iowa City, p. 3197-3224. 1992, Forced regressions in a sequence-stratigraphic frame- Iowa, University of Iowa, 154 p. McCubbin, D. G., 1982, Barrier-island and strand plain facies, in work: Concepts, examples and exploration significance: Swift, D.J.P.,andThorne,J. A., 1991, Sedimentation on continental Scolle, P. A., and Spearing, D., eds., Sandstone depositional American Association of Petroleum Geologists Bulletin, margins, I: A general model for shelf sedimentation, in Swift, environments: American Association of Petroleum Geolo- v. 76, p. 1687-1709. D.J.P., Oertel, G. F., Tillman, R. W., and Thome, J. A., eds., gists Memoir 31, p. 247-270. Powell, L. H., 1935, A sfudy of the Ozarkian fauna of southeastern Shelf sands and sandstone bodies: International Association Miller, J. F., 1984, Cambrian and earliest Ordovician conodont ev- Minnesota: St. Paul Institute of Science Museum Bulletin of Sedimentologjsts Special Publication 14, p. 3-31. olution, biofacies and provincialism: Geological Society of No. 1, 80 p. Swift, D.J.P., Thorne, J. A., and Oertel, G. F., 1986, Fluid proc- America Special Paper 196, p. 13-65. Raasch, G. O., 1951, Revision of the Croixan Dikelocephalidae: esses and sea-floor response on a modern storm-dominated Mossier, J. H., 1972, Paleozoic structure and stratigraphy of the Illinois State Academy of Science Transactions, v. 45, shelf: Middle Atlantic shelf of North America: Part II: Re- Twin Cities region, in Sims, P. K., and Morey, G. B., eds., p. 85-95. sponse of the shelf floor, in Knight, R. J., and Mclean, J. R., Geology of Minnesota: A centennial volume: Minneapolis, Raasch, G. O., and Unfer, C., Jr., 1964, Transgressive-regressive eds., Shelf sands and sandstones: Canadian Society of Petro- Minnesota, Minnesota Geological Survey, p. 485-497. cycles in Croixan Sediments (Upper Cambrian), Wisconsin: leum Geologists Memoir 11, p. 191-211. Mossier, J. H., 1987, Paleozoic lithostratigrapWc nomenclature for Kansas Geological Survey Bulletin 169, p. 427-440. Thomas, D. A., 1991, Lithostratigraphy, petrology, diagenesis, and Minnesota: Minnesota Geological Survey Report of Investi- Reineck, H. E., and Singh, I. B., 1975, Depositional sedimentary environments of deposition of the Upper Cambrian Jordan gations 36, 36 p. environments: New York, Springer Verlag, 439 p. Sandstone [M.S. thesis]: Duluth, Minnesota, University of Mossier* J. H., 1992, Sedimentaiy rocks of Dresbachian age (Late Ripperdan, R. L., and Kirschvink, J. L., 1992, Paleomagnetic re- Minnesota, 206 p. Cumbrian), Hoilandale Embayment, southeastern Minneso- sults from the Cambrian-Ordovician boundary section at Trowbridge, A. C., and Atwater, G. I., 1934, Stratigraphicproblems ta: Minnesota Geological Survey Report of Investigations 40, Black Mountain, Georgina Basin, western Queensland Aus- in the Upper Mississippi Valley: Geological Society of Amer- 71 p. tralia, in Webby, B. D., and Laurie, J. R., eds., Global per- ica Bulletin, v. 45, p. 21-80. Nelson, C. A., 1956, Upper Croixan stratigraphy, Upper Missis- spectives on Ordovician geology: Rotterdam, The Nether- Ulrich, E. O., 1924, Notes on new names in the table of formations sippi Valley: Geological Society of America Bulletin, v. 67, lands, Balkema, p. 93-103. and on physical evidence of breaks between Paleozoic sys- p. 165-183. Roep, Th. B., Beets, D. J., Dronkert, H., and Pagnier, H., 1979, A tems in Wisconsin: Wisconsin Academy of Sciences, Arts, Nicoll, R. S., Nielson, A. T., Laurie, J. R., and Shergold, J. H., prograding coastal sequence of wave-built structures of and Letters Transactions, v. 21, p. 71-107. 1992, Preliminaiy correlation of latest Cambrian to Early Or- Messinian age, Sorbas, Almeria, Spain: Sedimentary Geol- Webbers, G. F., 1972, Paleoecology of the Cambrian and Ordovi- dovician sea level events in Australia and Scandinavia, in ogy, v. 22, p. 135-163. cian strata of Minnesota, in Sims, P. K., and Morey, G. B., Webby, B. D., and Laurie, J. R., eds., Global perspectives on Runkel, A. C., in press, Revisions to the stratigraphic nomenclature eds., Geology of Minnesota: A centennial volume: Minneap- Ordovician geology: Rotterdam, The Netherlands, Balkema, of the Jordan Sandstone, Upper Mississippi Valley region: olis, Minnesota, Minnesota Geological Survey, p. 474-484. p. 381-394. Shorter contributions to the geology of Minnesota: Minnesota Weimer, R. J., Howard, J. D., and Lindsay, D. R., 1982, Tidal flats North American Commission on Stratigraphic Nomenclature, 1983, Geological Survey Report of Investigations. and associated tidal channels, in Scolle, P. A., and Spearing, North American Stratigraphic Code: American Association Sloss, L. L., 1963, Sequences in the cratonic interior of North D., eds., Sandstone depositional environments: American of Petroleum Geologists Bulletin, v. 67, p. 841-875. America: Geological Society of America Bulletin, v. 74, Association of Petroleum Geologists Memoir 31, p. 191-245. Odom, I. E., 1975, Feldspar grain-size relations in Cambrian are- p. 93-114. Wright, R., 1986, Cycle stratigraphy as a paleogeographic tool: Point nites, Upper Mississippi Valley: Journal of Sedimentary Pe- Smith, G. L., Byers, C. W., and Dott, R. H., Jr., 1993, Sequence Lookout Sandstone, southeastern San Juan Basin, New trology, v. 45, no. 3, p. 636-650. . stratigraphy of the Lower Ordovician Prairie du Chien Group Mexico: Geological Society of America Bulletin, v. 97, Odom, I. E., and Ostrom, M. E., 1978, Lithostratigraphy, petrol- on the Wisconsin Arch and in the Michigan basin: American p. 661-673. ogy, and sedimentology of the Jordan Formation near Mad- Association of Petroleum Geologists Bulletin, v. 77, p. 49-67. ison, Wisconsin: Wisconsin Geological and Natural History Stauffer, C. R., 1925, The Jordan Sandstone: Journal of Geology, Survey Field Trip Guidebook 3, p. 23-45. v. 33, p. 699-713. Ostrom, M. E., 1964, Pre-Cincinnatian Paleozoic cyclic sediments Stauffer, C. R., and Thiel, G. A., 1941, The Paleozoic and related in the Upper Mississippi Valley: A discussion: Kansas Geo- rocks of southeastern Minnesota: Minnesota Geological Sur- logical Survey Bulletin 169, p. 381-398. vey Bulletin 29, 261 p. Ostrom, M. E.,' 1970, Sedimentation cycles in lower Paleozoic Stauffer, C. R., Schwartz, G. M., and Thiel, G. A., 1939, The St. rocks of western Wisconsin: Wisconsin Geological and Nat- Croixan classification of Minnesota: Geological Society of ural Histoiy Survey Information Circular 11, p. 10-34. America Bulletin, v. 50, p. 1227-1243. MANUSCRIPT RECEIVED BY THE SOCIETY MARCH 15,1993 Pettijohn, F. J., 1957, Sedimentaiy rocks (2nd edition): New York, Stubblefield, W. L., 1971, Petrographic and geochemical examina- REVISED MANUSCRIPT RECEIVED JULY 17,1993 Harper, 718 p. tion of the Ordovician Oneota Dolomite in the building stone MANUSCRIPT ACCEPTED AUGUST 9,1993

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