TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN PAUL E. OLSEN Bingham Laboratories, Department of Biology, Yale University, New Haven, Connecticut Abstract Newark Supergroup deposits of the Newark Basin 1946), makes this deposit ideal for studying time-facies (New York, New Jersey and Pennsylvania) are divided relationships and evolutionary phenomena. These into nine formations called (from bottom up): Stockton recent discoveries have focused new interest on Newark Formation (maximum 1800 m); Lockatong Formation strata. (maximum 1150 m); Passaic Formation (maximum 6000 m); Orange Mountain Basalt (maximum 200 m); The Newark Basin (Fig. 1 and 2) is the largest of the Feltville Formation (maximum 600 m); Preakness exposed divisions of the Newark Supergroup, covering Basalt (maximum + 300 m); Towaco Formation (max- about 7770 km2 and stretching 220 km along its long imum 340 m); Hook Mountain Basalt (maximum 110 axis. The basin contains the thickest sedimentary se- m); and Boonton Formation (maximum + 500 m). Each quence of any exposed Newark Supergroup basin and formation is characterized by its own suite of rock correspondingly covers the greatest continuous amount - types, the differences being especially obvious in the of time. Thus, the Newark Basin occupies a central posi- number, thickness, and nature of their gray and black tion in the study of the Newark Supergroup as a whole. sedimentary cycles (or lack thereof). In well over a century of study the strata of Newark Fossils are abundant in the sedimentary formations of Basin have received a relatively large amount of atten- the Newark Basin and provide a means of correlating tion. By 1840, the basic map relations were worked out the sequence with other early Mesozoic areas. The (Rogers, 1839, 1840, Cook, 1868) and by 1898, the ma- Stockton, Lockatong, and most of the Passaic Forma- jor rock-stratigraphic subdivisions of the basin section tion are Late Triassic (?Middle and Late Carnian- were delimited and named (Darton, 1890; Kiimmel, Rhaetic) while the uppermost Passaic Formation (at 1897, 1898). Despite this long tradition, fundamental least locally) and younger beds appear to be Early aspects of its historical and structural geology have re- Jurassic (Hettangian and Sinemurian) in age. The mained essentially unexplored. The lithostratigraphy of distribution of kinds of fossils is intimately related to se- the younger sediments, in particular, has received short quences of rock types in sedimentary cycles. shrift. Recently I have revised certain aspects of Newark Basin stratigraphy with an emphasis on the younger INTRODUCTION rocks (Olsen, in press). In the process I haveproposed a number of new formational names (Table 2). Here I will Far from being the consequence of the last gasps of review the formations of the Newark Basin and attempt the Appalachian Orogeny, Late Triassic and Early to place their broader lithostratigraphic features into Jurassic Newark Supergroup basins formed in dynamic biostratigraphic context. association with the opening of the Atlantic Ocean (Sanders, 1974; Van Houten 1977; Manspeizer,Puffer, OVERVIEW OF NEWARK BASIN FORMATIONS and Cousminer, 1978; Olsen, 1978). In addition, Newark Supergroup rocks, once thought to be nearly As currently defined (Olsen, 1978; Van Houten, 1977; barren of fossils, are now known to be exceptionally Cornet, 1977), the Newark Supergroup consists of rich in organic remains (Thomson, 1979), replete with predominantly red elastics and volumetrically minor plants, invertebrates, and vertebrates spanning some 35 basaltic igneous rocks exposed in 13 major and 7 minor million years of the Early Mesozoic (Cornet, 1977). elongate basins preserved in the Piedmont, New Finally, long episodes of unusually continuous England, and Maritime physiographic provinces of deposition coupled with an abundance of laterally eastern North America (Figure 1, Table 1). In general, extensive stratigraphic "marker" beds (McLaughin, the long axes of these basins parallel the fabric of the In W. Manspeizer (ed.), 1980, Field Studies in New Jersey Geology and Guide to Field Trips, 52nd Ann. Mtg. New York State Geological Assoc.iation, Newark College of Arts and Sciences, Newark, Rutgers University, p. 2-39. 3 FIELD STUDIES OF NEW JERSEY GEOLOGY AND GUIDE TO FIELD TRIPS SCALE (krn) 0 800 l~*~l'l.l - EXPOSED CS=3> INFERRED Fig. 1 Newark Supergroup of eastern North America. Key to numbers given in Table 1. The Newark Basin is 11. Data from Olsen, 1978. TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN Fig. 2 The Newark Basin. A. Geologic map showing distribution of formations, normal, it is clear many, if not all of them, have some conglomeritic facies (irregular stipple), and major clusters component of strike slip, although the significance of this of detrital cycles in Passaic Formation (parallel black lines) component is unclear. Symbols for the names of structural -- abbreviations of formations and diabase bodies as features used in this paper are as follows: A, Montgomery- follows: 9, Boonton Formation; C, Coffman Hill Diabase; Chester fault block; B, Bucks-Hunterdon fault block; C, Cd, Cushetunk Mountain Diabase; F, Feltville Formation; Sourland Mountain fault block; D, Watchung syncline; E, H, Hook Mountain Basalt; Hd, Haycock Mountain New Germantown syncline; F, Flemington syncline; G, Diabase; Jb, Jacksonwald Basalt; L, Lockatong Sand Brook syncline; H, Jacksonwald syncline; I, Ramapo Formation; 0, Orange Mountain Basalt; P, Passaic fault; J, braided connectoin between Ramapo and Formation; Pb, Preakness Basalt; Pd, Palisade Diabase; Hopewell faults; K, Flemington fault; L, Chalfont fault; Pk, Perkasie Member of Passaic Formation; Rd, Rocky M, Hopewell fault. Hill Diabase; S, Stockton Formation; Sc, carbonate Facies of Stockton Formation; Sd, Sourland Mountain Diabase; Data for A and B from Kimmel, 1897; Lewis and Kimmel, T, Towaco Formation. 1910-1912; Darton, 1890, 1902; Darton, et a]., 1908; Glaeser, 1963; Sanders, 1962; Van Houten, 1969; B. Structural features of the Newark Basin. Faults are all McLaughlin, 1941, 1943, 1944, 1945, 1946a, 1946b; drawn as normal with dots on the down-thrown side; Bascom, et at., 1909; Willard, et al., 1959; Faille, 1963; portions of basin margin not mapped as faults should be Manspeizer, pers. comm.; Olsen, in press, and personal regarded as onlaps. While all the faults are mapped here as observation. Appalachian Orogene (Rodgers, 1970; Van Houten, border the Newark Basin along its northeast and north- 1977). The rocks of these basins present a relatively west margins (Figure 2). The southeastern and unified lithology and structure and unconformably southwestern portions of the Newark Basin overlie and overlie (or intrude) Precambrian and Palaeozoic rocks. are bordered by Palaeozoic and Precambrian rocks of They are in turn overlain by post-Jurassic rocks of the the Blue Ridge and Piedmont Provinces. Newark Basin Coastal Plain, Pleistocene deposits or Recent alluvium sediments rest with a profound unconformity on base- and soils. In addition, early Mesozoic red clastics, ment rocks and mostly dip 5 Â- 25' to the northwest. basaltic volcanics, and evaporites at the base of some se- The entire stratigraphic column reaches a cumulative quences on the continental shelf and also at least 12 trigonometrically calculated thickness of over 10,300 m units recognized beneath the Atlantic Coastal Plain pro- (the sum of the maximum thicknesses of all the forma- bably should be grouped in the Newark Supergroup tions), although the total thickness of sediments actually (Figure 1). deposited at any one spot was probably much less. Red clastics are the dominant sediments; intrusive and ex- Precambrian and early Paleaozoic rocks of the trusive tholeiites are the dominant igneous rocks. The southwestern prongs of the New England Upland oldest sediments are probably middle Carnian (early 5 FIELD STUDIES OF NEW JERSEY GEOLOGY AND GUIDE TO FIELD TRIPS Table 1 Key to Rock-stratigraphic term Bas in name Figure 11 I Age range Carnian- ?Nor ian 1 Chatham Group Deep River Basin (Late Triassic) 2 undifferentiated Davie County Basin Late Triassic 'Carnian (Late 3 undifferentiated Farmville Basin Triassic) 4 small basins south 4 undifferentiated 'PCarnian (Late of Farmville Basin Triassic) Dan River and Danville Carnian- ';Norian Dan River Group I Bas ins (Late Triassic) Tuckahoe and Richmond Basin and 6 Carnian (Late Chesterfield Groups subsidiary basins Triassic) Norian- PSinemurian 7 1 none Culpeper Basin (Late Triassic- Early Jurassic) Carnian (Late Taylorsville Basin Triassic) Scottsville Basin and ?Late Triassic- 9 undifferentiated 2 subsidiary basins Early Jurassic Carnian-Het tangian 10 none Gettysburg Basin (Late Triassic- Early Jurassic) Carnian .Sinemurian 11 none Newark Basin (Late Triassic- Early Jurassic) ?Late Triassic- 12 none Pomperaug Bas in 1 Early Jurassic Hartford Basin and Norian-?Bajocian 13 none subsidiary Cherry (Late Triassic- Brook Basin ?Middle Jurassic) ?Norian- PToarcian 14 1 none Deerfield Basin (Late Triassic- Early Jurassic) ?Middle Triassic- 15 Fundy Group Fundy Basin 1 Early Jurassic Chedabucto Format ion Chedabucto Basin ?Late Triassic- (=Eurydice Format ion?) (=Orpheus Basin?) Early Jurassic TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN Table 2 Baird and Take, Kummel, 1897; 1959; Baird, 1964; (Olsen, in press) Lyman, 1895 Darton, 1890 Colbert, 1965 This Article American New Red Sandstone Newark System Newark System Newark Supergroup (of Newark Basin) (of Newark Basin) (of