Geology and Magnetite Deposits of the Franklin Quadrangle and Part of the Hamburg Quadrangle, New Jersey GEOLOGICAL SURVEY PROFESSIONAL PAPER 638 Geology and Magnetite Deposits of the Franklin Quadrangle and Part of the Hamburg Quadrangle, New Jersey By DONALD R. BAKER and A. F. BUDDINGTON GEOLOGICAL SURVEY PROFESSIONAL PAPER 638 A study of the rocks, structure, and magnetite deposits of an area in northern New Jersey UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. 76-606118 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Pf.ge Abstract.__________________________________________ 1 Hardyston Quartzite and unconformity on Precambrian Introduction and acknowledgments.__________________ 1 rocks.-______-_______-__---_-----------_--------- 27 Geography. ________________________________________ 2 Structure.__________________-_____---_-_-----_---_- 28 Previous work._____________________________________ 3 Pimple Hills syncline___________________________ 29 Rocks of metasedimentary origin _____________________ 5 Beaver Lake anticline.___-_________-_-__--_-_-_- 29 Marble or metalimestone________________________ 5 Edison syncline._._____-______-___-_-_-----_-_- 29 Quartz-potassium feldspar and associated gneiss____ 5 Ryker Lake syncline____________________________ 29 Pyroxenic gneiss._______________________________ 6 Mount Paul anticline.__________________________ 29 Garnetiferoxis gneiss and amphibolite____________ 7 Weldon Brook anticline.____-_--------_-------_- 30 Hypersthene-quartz-oligoclase gneiss______________ 7 Lineation ______________________------_--__---_- 30 Biotite-quartz-feldspar and associated gneiss_---__- 8 Emplacement of igneous rocks.________-_-------_- 30 Epidote-scapolite-quartz gneiss and associated rocks. 9 East fault and Morris Lake fault zone. _ __-___---_- 31 Miscellaneous gneiss.___________________________ 10 Sand Hills fault zone.____-_-___-----_-_-_------- 31 Stratigraphy of metasedimentary gneiss.______________ 10 Vernon fault._________---_-._-----------_------ 31 Orthogneiss._______________________________________ 10 Reservoir and Longwood Valley faults..___________ 32 Metagabbro gneiss._____________________________ 10 Transverse faults___________-__---------------_- 33 Syenite gneiss._________________________________ 11 Magnetite deposits._______________---_---_--------- 33 Igneous rocks._____________________________________ 12 Economic possibilities._____________-___--__---_- 34 Pyroxene syenite, pyroxene granite, and pyroxene Magnetite in quartz-potassium feldspar gneiss.____ 34 alaskite series._______________________________ 12 Sherman-Bunker deposits.______-.__--------_- 34 Petrology.._-------______--__________._____ 12 Other occurrences._________-_------------- 34 Sparta Lake belt__________________________ 15 Magnetite in amphibolite and pyroxenic gneiss. ____ 34 Ford belt.__.-_-.-______.____.___________ 16 Ford-Schofield-Dodge mines-_______-.------- 36 Holland belt.______________________________ 17 Origin of magnetite deposits in amphibolite-__. 37 Hyper«thene granite, _______________________ 17 Magnetite in marble____________----_-.--------- 37 Hornblende granite and alaskite__________________ 17 Titaniferous magnetite in granite pegmatite-.------ 37 Rocks of uncertain origin-___________________________ 18 Edison deposits.__-____---_--__----------------- 37 Amphibolite_ ___________________________________ 18 Quartz-potassium feldspar and associated gneiss Quartz-oligoclase gneiss._________________________ 19 (mixed gneiss compiex)___________--------- 39 Biotite-quartz-oligoclase gneiss._______________,..._ 20 Quartz-microcline gneiss. -------------------- 41 Albite alaskite________________________________ 20 Biotite-quartz-feldspar gneiss _____________ 43 Quartz-microcline gneiss.________________________ 20 Epidote-scapolite-quartz gneiss and related Dikes.____________________________________________ 21 facies_ --------------------------------- 44 Petrogenesis ______________________________________ 22 Metamorphism and metasomatism._______---_ 46 Pyroxenic gneiss._______________________________ 22 Quartz-potassium feldspar and associated Quartz-potassium feldspar gneiss and associated gneiss. ------------------------------ 46 epidotic gneiss._______________________________ 22 Epidote-scapolite-quartz gneiss and re­ Quartz-oligoclase rocks._________________________ 22 lated facies. ___________.___-___--_- 47 Hypersthene-quartz-oligoclase gneiss__________ 22 Biotite-quartz feldspar gneiss _____--__ 48 Quartz-oligoclase gneiss (Losee Gneiss)________ 23 Quartz-microcline gneiss --------------- 49 Amphibolite_ _ ________________________________ 23 Structure of the Edison area.____-_---.-_---- 49 Quartz-microcline gneiss.________________________ 24 Foliation.. __ _ ___________-____-_-------- 49 Hornblende and pyroxene syenite orthogneiss_____ 24 Lineation. ----------------------------- 50 Granitic and syenitic rocks_______________________ 24 Folds___ ----------------------------- 50 Metamorphic facies_____________________________ 25 Faults and joints ________--------- 50 Franklin block.____________________________ 25 Deposits. ____________________-_------------ 61 Beaver Lake block__________________________ 26 History and production _________-__-_- 51 Ryker Lake block_________________________ 26 Distribution...- _ ----------------------- 51 Comparison with nearby areas._______________ 26 Sources of data-______-_--_------------- 51 xn. IV CONTENTS Magnetite deposits Continued Page Magnetite deposits Continued Page Edison deposits Continued Edison deposits Continued Deposits Continued Deposits Continued Structure. ______________________________ 52 M agnetite-hetnatite-ilmenite-rutile para- Petrology and mineralogy._______________ 52 genesis Continued Sulfide zone____________________________ 53 Metailmenite_ _____________________ 63 Potassium feldspar______________________ 54 Iron-titanium oxides of the other rocks. 63 Garnet._______________________________ 54 Partial chemical analyses________________ 64 Magnetite-hematite-ilmenite-rutile parage- Origin and classification.________________ 64 nesis_ _______________________________ 55 Sources of iron.____________________ 66 Magnetite-ilmenite and magnetite-he­ Mode of transportation of iron, ______ 67 matite. _________________________ 56 Mode and time of emplacement of iron- 67 Hematite-ilmenite-rutile _____________ 58 Conclusion.________________________ 68 Intergrowths of magnetite with non­ References cited-__-__-__--_________-_-____--____-__ 68 magnetic iron and titanium oxides __ 61 Index_____________________________________________ 71 ILLUSTRATIONS PLATE 1. Geologic map of the Franklin quadrangle and part of the Hamburg quadrangle, New Jersey.______________________________________________________________ In pocket 2. Geologic map of the Edison magnetite deposits____________-_-_-___-__________ In pocket Pare FIGURE 1. Index map_______________________________________________________-__________ 2 2. Aerial photograph of Beaver Lake and Lake Girard______________________________ 3 3. Aerial photograph of Bowling Green and Green Pond Mountains. _________________ 32 4. Geologic map of the Sherman-Bunker magnetite deposits.________________________ 35 5. Aerial photograph of the Edison magnetite deposits area._________________________ 38 6-10. Photomicrographs of rocks from the Edison area: 6. Magnetite-quartz-potassium feldspar gneiss._____________________________ 39 7. Magnetite-potassium feldspar-quartz gneiss._____________________________ 39 8, 9. Sillimanitic gneiss____________--___________-__--__--_---_---_------_-_- 40 10. Microcline gneiss._____________________________________________________ 42 11, 12. Photographs of interlayered rocks from the Edison area._-_-_---------_----_---_- 42 13. Photomicrograph of gneiss from the Edison area.________________________________ 43 14. Photograph of contact relations..-__-_-__________-_____-___-__--_---_---____-__ 53 15-22. Photomicrographs of mineral intergrowths: 15. Ilmenomagnetite and martite-______-_________--_---__------_---_-----_ 56 16. Ilmenohematite and magneto-ilmenohematite____________________________ 59 17. Ilmenohematite-_____________________________________________________ 59 18. Magneto-hemoilmenite.______________-__________-_------_--_-_-_---___ 60 19. Ilmeno-rutilohematite_________________________________________________ 61 20. Hemorutile._________________________________----___-______ 61 21. Magneto-rutilohematite-_________-_______-____-----_---_-_----__----_- 61 22. Magnetorutile.-.--___________________-----__--__--__ 62 TABLES Pa *« TABLE 1. Modes of quartz-potassium feldspar gneiss________________-_--_-_-___-___------_- 6 2. Modes of pyroxenic gneiss-________________-__-_-_-__----_-------_------------- 7 3. Modes of hypersthene-quartz-plagioclase gneiss.__________-_____--_------__------ 8 4. Chemical analysis, norm, and approximate mode of hypersthene-quartz-oligoclase gneiss._____________________________________________-_------------.----- 8 5. Modes of biotite-quartz-feldspar gneiss________--__-__--_---_------------------- 9 6. Modes of graphitic biotite-quartz-plagioclase gneiss______-____---_----_--------- 9 7. Modes of garnetiferous biotitic quartz-feldspar gneiss.____________-__--_-------_-- 9 8. Modes of metagabbro gneiss__________--________-_____-__--_--_----_---------