4 Eoi,O(; Ical Survey Wasfiington
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Professional Paper No. 2 Series {A, Economic Geology, 19 \B, Descriptive Geology, 21 DEPARTA1P:NT OF TI11 INTERIOR UNITED S'l'A'l'ES (4 EOI,O(; ICAL SURVEY CHARLEb I). WALCOTT, 1)IILRCTOK OF THE WASFIINGTON GOVERNJIENT PRINTING OFFICE 19' 0 2 CONTENTS. Page . Introduction ............................................................................. 7 Geography ............................................................................... 11 General outline ............................................................... 11 Shore line .................................................................... 11 Harbors ...................................................................... 12 Drainage ..................................................................... 13 Relief ........................................................................ 13 General geology ........................................................................... 14 Outline ............................................................................... 14 Stratigraphic succession ............................................................... 16 Kigluaik series ................................................................... 16 . Kuzitrin series .................................................................... 16 Nome series ...................................................................... 17 Introduction .................................................................. 17 Port Clarence limestone ...................................................... 18 Kugruk group ............................................................... 21 Surficial deposits ..................................................................... 24 General description ............................................................... 24 Coastal plain deposits ............................................................. 25 Arctic coastal plain ........................................................... 25 Port Clarence coastal plain .................................................... 25 Inland basins ..................................................................... 26 Agiapuk lowland ............................................................. 26 Imuruk lowland .............................................................. 26 Kuzitrin lowland ............................................................. 26 Mammoth remains ................................................................ 27 Alluvial sands and gravels ........................................................ 28 Elevated surficial deposits ......................................................... 28 Glaciation ........................................................................ 28 Igneous rocks ........................................................................ 29 Introduction ...................................................................... 29 Greenstones ...................................................................... 29 Granitic and rhyolitic intrusive8 ................................................... 29 Basalts ........................................................................... 30 Dynamic history ...................................................................... 31 3 4 CONTENTS. General geology--Continued . ' Page . Physiography ........................................................................ 34 Introduction ..................................................................... 34 NulukPlateau .................................................................... 35 Kugrok Plateau ........................................... :-..................... 35 York Plateau ..................................................................... 36 Lowland plains ................................................................... 40 Valley lowlands .................................................................. 40 Drainage ......................................................................... 42 Summary ........................................................................ 42 Econonlic geology ........................................................................ 43 lnt,reduction ........................................................................ 43 Distribution and source of placer gold .................................................. 43 Description of localities ............................................................... 44 Introduction ...................................................................... 44 Grantley Harbor region ............................................................ 44 Port Clarence and York Mountain region ........................................... 46 Y ork region ...................................................................... 47 Gold ......................................................................... 48 Till .......................................................................... Arctic region ..................................................................... Pinguk River ................................................................. NulnkRiver .................................................................. KugrukRiver Other streams ................................................................ Quartz veins ................................................................. Shishmaref region ................................................................ Arctic River ................................................................... Serpentine River ............................................................. Bgiapukregion ................................................................... American River .............................................................. Kuzitrin Basin ................................................................... Southern tributaries of the Kuzitrin .................................? .......... Index .................................................................................... ILLUSTRATTONS. Page. PLATEI. Outline map of Seward Peninsula and adjacent region, Alaska, showing area of larger- scale map.. .... .. .. .. ...... ... ... ..............................------ -----.- - 8 11. A, Teller, from the point of sand spit; C,Valley of Quartz Creek cut in high gravel bench .........................................................................10 111. Geologic recon~~aissancemap and section of the northwestern portion of Seward Peninsula, Alaska ..............................................................14 IV. A, Crumpled limestone, Brooks Mountain; B, Port Clarence limestone, Nuluk River.. 18 V. A, Schistose limestone, Kugruk group, head of Portage Creek; B, Schistose limestone, Kuigruk group, Budd Creek.. .-. -. .. - - - - - - 20 VI. A, Bedding and cleavage in Kugruk limestone south of Igloo Creek; B, Frozen silts containing spruce logs on Quartz Creek.. .. .-. .- .. -. .. .-. ....--- . ... .. ... ... 22 VII. A, Ear Mountain, from bench at 1,000 feet elevation; B, The Ears, granite pim~lacles on Ear Mountain ......-...--------------------.- - ---- -- 28 VIII. A, Platy structure in granite near hot springs; B, Platy structure in granite, Ear Mountain -.--..--...........-----------------------------------------------30 IX. Granite outcrops near hot springs .. -. -. .-.. - -.. 32 X. A, South side of York Mountain and beach; B, Cape ATountain from York.. .. .. --. 38 XI. Economic map of northwestern portion of Seward Peninsula, Alaska ..--.... -. 44 XII. Topographic map of northern portion of Seward Peninsula --.---...-. ----. ..-. In pocket. 6 A RECONNAISSANCE OF THE NORTHWESTERN PORTION OF SEWARD PENINSULA. ALASKA. INTRODUCTION. In response to an urgent denland by the public, the Geological Survey, in 1900, undertook a topographic and geologic reconnaissance of the southern half of the Seward Penins~la.~The area mapped embraced the more important gold fields of the peninsula. The topographic map made in 1900 included the drainage of Bering Sea from Cape Darby to Port Clarence, the southern drainage of Grantley Harbor and Imuruk Basin, and the northern drainage of Norton Sound. A geologic reconnaissance was also made of the York nlining district and of part of the Kuzitrin drainage. In view of the northern extension of these gold fields it was deemed desirable that the northern part of the peninsula should be investigated, and a party wag organized for this purpose in 1901. This party, to which the writer was detailed as geologist, was placed under the 'leadership of Mr. T. G. Gerdine, topographer; Mr. D. C. TVitherspoon acted ah assistant topographer, and Ed. Brown, Robert Baskins, Samuel Conrad, J. G. De Forest, and E:. Goodall were engaged as camp hands. Twelve horses were provided for the transportation of the camp outfit in the field. It was thought that a party thus organized and equipped would be able to cover a larger area than any one party of the previous season, when canoes and men were used for transportation. This expectation was realized, although a backward and unusually stormy season made the work difficult and prevented the accomplishment of the entire planYbwhich contemplated the comple- tion of the survey of the peninsula. Gee Preliminary Report on the Cape Nome Gold Region. Alaska, by F. C. Schrader and Alfred H. Brooks; U. S. Geol. Survey, 1900. Also Reconnaissances in the Cape Nome and Norton Bay Regions, Alaska, in 1900, by Alfred H. Brooks, George B. Richardson, Arthur J. Collier, and Walter C. Mendenhall; U. S. Geol. Survey,