U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Directorate Geologic Resources Division Natural Bridges National Monument GRI Ancillary Map Information Document Produced to accompany the Geologic Resources Inventory (GRI) Digital Geologic Data for Natural Bridges National Monument nabr_geology.pdf Version: 2/9/2021 I Natural Bridges National Monument Geologic Resources Inventory Map Document for Natural Bridges National Monument Table of Contents Geologic Resourc..e..s.. .I.n..v..e..n..t.o...r.y.. .M...a..p.. .D...o..c..u..m...e..n...t............................................................................ 1 About the NPS Ge..o..l.o..g..i.c... .R..e..s..o..u...r.c..e..s.. .I.n..v..e..n...t.o..r.y.. .P...r.o..g...r.a..m............................................................... 3 GRI Digital Map an...d.. .S..o..u...r.c..e.. .M...a..p.. .C...i.t.a..t.i.o...n...................................................................................... 5 Index Map .................................................................................................................................................................... 6 Map Unit List ............................................................................................................................. 7 Map Unit Descript.i.o...n..s...................................................................................................................... 8 Qal - Alluvium... .(..Q..u..a..t.e..r..n..a..r.y.)............................................................................................................................................. 8 TRc - Chinle. .F..o..r.m...a..t.i.o..n.. .(.U...p..p..e..r. .T..r.i.a..s..s..i.c..)........................................................................................................................ 8 TRm - Moen.k..o..p..i. .F..o..r.m...a..t.i.o..n.. .(.T..r.i.a..s..s..i.c.)............................................................................................................................. 8 Po - Organ R..o..c..k.. .F..o..r.m...a..t.i.o..n.. .(.P..e..r..m...ia..n..)............................................................................................................................ 9 Pc - Cedar M..e..s..a.. .F..o..r.m...a..t.i.o..n.. .(.P...e..r.m...i.a..n..)........................................................................................................................... 9 Ancillary Source. .M...a..p.. .I.n...f.o..r.m....a..t.i.o..n................................................................................................. 12 Natural Brid..g..e..s.. .N..a..t.i.o..n..a..l. .M...o..n..u..m...e..n..t............................................................................................................................. 12 Report ............................................................................................................................................................. 12 Abstract ......................................................................................................................................... 12 Introduction ......................................................................................................................................... 13 Geologic Overview......................................................................................................................................... 13 History of Natural B..r.i.d..g..e..s.. .N...a..t.io..n..a..l. .M...o..n..u..m...e..n..t. .a..n..d.. .i.t.s.. .b..r.i.d..g..e..s...................................................................... 14 Geology of Natural. .B..r.i.d..g..e..s.. .N...a..t.i.o..n..a..l .M...o..n..u..m...e..n..t............................................................................................ 14 Permian Paleotecto..n..i.c.. .E..l.e..m...e..n..t.s.. .o..f. .S..o..u..t.h..e..a..s..t.e..r.n.. .U...t.a..h................................................................................. 14 Regional Stratigrap..h..y.. .a..n..d.. .S..e..d..m...e..n..t.o..l.o..g..y...................................................................................................... 15 Lower Cutler Beds ............................................................................................................................. 16 Cedar Mesa Sandston..e........................................................................................................................... 16 Organ Rock Formatio.n............................................................................................................................ 17 Moenkopi Formation ............................................................................................................................. 18 Chinle Formation ............................................................................................................................. 19 Wingate Sandstone ............................................................................................................................. 19 Development of Br.i.d..g..e..s................................................................................................................................. 19 Conclusion ......................................................................................................................................... 21 Acknowledgements......................................................................................................................................... 21 List of Figures ......................................................................................................................................... 22 Figure 1. Location of N...a..t.u..r.a..l. .B..r.i.d..g..e..s.. .N..a..t.i.o..n..a..l. .M...o..n..u..m...e..n..t. .i.n.. .U..t.a..h.......................................................... 22 Figure 2. Early Permia..n.. .p..a..l.e..o..t.e..c..t.o..n..ic.. .e..l.e..m...e..n..t.s.. .o..f. .s..o..u..t.h..e..a..s.t.e..r..n.. .U..t.a..h................................................... 22 Figure 3. Eolian featur..e..s......................................................................................................................... 23 Figure 4. Intrepreted e..v..o..lu..t.i.o..n.. .o..f. .t.h..e.. .t.h..r.e..e.. .n..a..t.u..r..a..l .b..r..id..g..e..s..................................................................... 24 Figure 5. The natural .b..r.i.d..g..e..s.................................................................................................................. 26 Figure 6. Geologic ma..p.. .a..n..d.. .c.r..o..s.s.. .s..e..c..t.i.o..n.. .f.o..r. .N..a..t.u..r..a..l .B...r.i.d..g..e..s.. .N..a..t.i.o..n..a..l. .M...o..n..u..m...e..n..t.............................. 28 Figure 7. Generalized. .s..t.r.a..t.i.g..r.a..p..h..y.. .(.7..A..). .o..f. .t.h..e.. .P...a..l.e..o..z.o..i.c.. .a..n..d.. .M...e..s..o..z..o..ic.. .r.o..c..k.. .u..n..i.t.s................................ 29 Figure 8. Early Permia..n.. .d..e..p..o..s..i.t.io..n..a..l. .e..n..v..i.r.o..n..m...e..n..t.s.. .i.n.. .s.o..u..t.h..e..a..s..t.e..r.n.. .U...t.a..h.............................................. 30 Figure 9. Detailed stra..t.ig..r..a..p..h..y. .o..f. .t.h..e.. .C...e..d..a..r. .M...e..s..a.. .S..a..n..d..s..t.o..n..e................................................................ 32 Figure 10. Sand avala.n..c..h..e.. .l.a..y..e..r.s........................................................................................................... 33 Figure 11. A red muds..t.o..n..e.. .l.a..y.e..r.. .u..n..d..e..r.l.a..in.. .a..n..d.. .o..v..e..r.l.a..i.n.. .b..y.. .t.h..e.. .w..h..i.t.e.. .s..a..n..d..s..t.o..n..e.. .f.a..c..ie..s......................... 33 Figure 12. Sand-filled .m...u..d..c..r.a..c..k.. .i.n.. .t.h..e.. .r.e..d.. .m...u..d..s..t.o..n..e.. .f.a..c..ie..s.. .o..f. .t.h..e.. .C...e..d..a..r. .M...e..s..a.. .S..a..n..d..s..t.o..n..e.................. 34 References ......................................................................................................................................... 34 2021 NPS Geologic Resources Inventory Program II GRI Digital Data .C...r.e..d..i.t..s................................................................................................................. 38 2021 NPS Geologic Resources Inventory Program II 1 NABR GRI Map Document Geologic Resources Inventory Map Document Natural Bridges National Monument, Utah Document to Accompany Digital Geologic-GIS Data nabr_geology.pdf Version: 2/9/2021 This document has been developed to accompany the digital geologic-GIS data developed by the Geologic Resources Inventory (GRI) program for Natural Bridges National Monument, Utah (NABR). Attempts have been made to reproduce all aspects of the original source products, including the geologic units and their descriptions, geologic cross sections, the geologic report, references and all other pertinent images and information contained in the original publication. This document contains the following information: 1) About the NPS Geologic Resources Inventory Program – A brief summary of the Geologic Resources Inventory (GRI) Program and its products. Included are web links to the GRI GIS data model, and to the GRI products page where digital geologic-GIS datasets, scoping reports and geology reports are available for download. In addition, web links to the NPS Data Store and GRI program home page, as well as contact information for the GRI coordinator, are also present.