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328 W. Manspeizer and Others Although significant variations occur locally, strata within foreland-type folds with axial plane-spaced cleavage have been each basin typically dip about lo0 to 15O toward the border fault, mapped at Lepreau Harbor in the Fundy basin (Stringer and where they are commonly bent into broad synforms and anti- Lajtai, 1979) and in the Jacksonwald syncline along the narrow forms (Fig. 6), termed warps by Wheeler (1939), and/or into neck connecting the Newark and Gettysburg basins (Lucas and more tightly compressed en echelon folds (Davis, 1898). Where- others, 1988); both studies attribute these structures to regional as Wheeler (1939) related the warps in the Newark and Hartford compression, perhaps related to transpression. Triassic cleavage basins to differential dip slip along salients and reentrants of the has also been reported from the Richmond basin of Virginia border fault, later studies by Sanders (1963), Fail1 (1973), Mans- (Shaler and Woodworth, 1989) and the Deerfield basin of Mas- peizer (1980), and Ratcliffe (1980) related folds within these sachusetts (Goldstein, 1975) and in coal seams of the Sanford basins to horizontal stress in a compressional setting. En echelon (Deep River) basin of North Carolina (Reinemund, 1955). USGS LINE 5 ATLANTIS BASIN TERTIARY >- I 7 UPPER CRETACEOUS -T/LK T/UJ LOWER CRETACEOUS I- - 2 UPPER JURASSIC 4- -4 - CRYSTALLINE BASEMENT Figure 7. Seismic-reflection profile and interpreted line drawing of USGS line 5, showing the Atlantis basin near the basement hinge zone. The fan-shaped form of the tilted reflectors and the curved shape of the southeastern fault suggest formation by rotation along a listric fault. Captions and figures from Hutchinson and others, 1986. - , 7
Strata within these Mesozoic basins are also cut by major oblique-trending cross faults, Sanders (1963) reports that in the Newark basin some faults have as much as 20 km of horizontal displacement and 3 km of vertical displacement, and Van Houten (1969) reports that some northeast-trending strike-slip faults in the Newark basin may be part of a strike-slip system involving the Ramapo border fault (Fig. 5). Published geophysical and subsurface data from the Newark-Gettysburg basin (Sumner, 1977; Cloos and Pettijohn, 1973), the Hartford basin (Wenk, 1984), the Durham basin (Bain and Harvey, 1977), and the Sanford basin (Deep River; Randazzo and others, 1970) show that the basement is cut by cross faults creating intrabasin grabens and horsts that, most probably, formed early and concurrently with the onset of sedimentation (see Sumner, 1977; Cloos and Pettijohn, 1973). However, field data (e.g., Faill, 1973; Lucas and ^ -J -r -' 0 I- I- - 2- - 3- - NW Post-Paleozoic activity 329 USGS LINE 9 LONG ISLAND BASIN S P* 400 500 600 others, 1988) also show that some rift-related deformation of the onshore basins postdates the youngest rift strata (Early Jurassic) and may have continued through the Middle Jurassic, when sea- floor spreading and drifting began offshore. Seismic profiles across the passive margin show that, except for intrusions by salt and igneous rocks, the younger drift strata appear essentially undisturbed (Figs. 8,9). That the onshore rift basins have been deformed during the drifting phase is supported by many studies, including McHone and Puffer (this chapter) and Prowell (this chapter). The defor- mational continuum and complexity is documented in field studies of the north-trending Hartford basin, where de Boer and Clifford (1988) and Wise (1982) show that late Triassic faulting was accomplished by oblique slip with a dextral shear component along north-south (grain parallel) fractures in the basement. As S P# 400 500 600 700 I I I I I I 0 T/UK TERTIARY /QUATERNARY T/LK UPPER CRETACEOUS Figure 8. Seismic-reflection profile and interpreted line drawing of USGS line 9, showing the Long Island basin beneath the post-rift unconformity. The low-angle western border fault, tilted (sedimen- tary?) horizons, and high-angle cross faults can be identified on this profile. PRU: post-rift unconformity, T/UK: top of Upper Cretaceous, T/LK: top of Lower Cretaceous, T/UJ: top of Upper Jurassic. Figures and caption from Hutchinson and others, 1986. SE LOWER CRETACEOUS - I - - CRYSTALLINE BASEMENT - 2 5 KM O- -3 - -
Page 1 and 2: The Geology of North America Vol. F
Page 3 and 4: Post-Paleozoic activity SIBERIAN Fi
Page 5 and 6: DETRITAL BASINS :'->: SALT BASINS 0
Page 7 and 8: similar orientations and/or lie alo
Page 9: Post-Paleozoic activity NEWARK BASI
Page 13 and 14: Post-Paleozoic activity USGS LINES
Page 15 and 16: sic marine tongue was speculated to
Page 17 and 18: contours in red are over Jurassic d
Page 19 and 20: crust. A pronounced north-northeast
Page 21 and 22: for relative contributions from iso
Page 23 and 24: Post-Paleozoic activity CULPEPER LI
Page 25 and 26: the basins and also corresponding w
Page 27 and 28: tons (1963), Thayer and others (197
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Page 31 and 32: the north side of the basin. Accord
Page 33 and 34: - 46' - 42O Post-Paleozoic activity
Page 35 and 36: activity was initiated. The initial
Page 37 and 38: percent pyroxene (chiefly augite),
Page 39 and 40: have formed under higher conditions
Page 41 and 42: lines an elongated north-south patt
Page 43 and 44: Several studies of the intrusions w
Page 45 and 46: 0 100 200 300 Miles ^ Figure 27. Ma
Page 47 and 48: tomac Formation. They also report t
Page 49 and 50: REFERENCES CITED ' Post-Paleozoic a
Page 51 and 52: Galton, P. M., 1976, Prosauropod di
Page 53 and 54: - , 1988, Triassic-Jurassic rifting
Page 55 and 56: Bulletin, v. 95, p. 1176-1 187. Res

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