Fort:Ton of the Eastern.Most Ventura Basin Eu Gene M. Shoemaker

Total Page:16

File Type:pdf, Size:1020Kb

Fort:Ton of the Eastern.Most Ventura Basin Eu Gene M. Shoemaker Geomorphology o f a :F o r t:ton of the East e rn.most Ventura Basin by Eu gene M. Shoemaker 1 948 Relief model of the HtUJi.phreys ( uadr&.ngl e, view lool\:ing northe <~ st (model and photograph by John Lnnce}. Abstract The hl..UYiphreys ;{uadrangl e is a p o rtion of the eastern­ ; most Ventura Basin underlain by a thic k series of Tertiary sedime ntary rocks . On t~eso rocks a gr eat variety of geomorphic forms have bee n molded by t he p rocess es of r unninc water t y:o ical of· a semi-arid climate ancl. b y several ty:qe s of :rw.ss movement . Among t he dii'ferent c a t ar;o:r> i e s of n1s.ss mo v ement -o:i:' e sent, t:t n evr t ype, the sil t f'l..£:2: ,,._ras obs r-i rvc d . 'T'b.e r::eomor::;hj_c f orm.s o:f s:oecia1 int er•e s t :ore ,s-":'nt i .n thG c:~ ·n ·'.' C\ r !.1.:r~ :) .0 :;. r e rock .;ones, open can:y-onh e ads, as~!rmne tri c cs.nyons , e.nd s tre8In terraces and stra.ths . 'l'he author urges t h e a doption of the definition of strath as thRt :p ai~t o f a n old dissectec~. v alley floor, i ncluding the floors of tributary valleys, which was not part of t h e floodp l a i n of t he main v.all ey strearn. An old erosion surface, the Puc k et·~ Kesa Surface:: , is '?.-,, -.'< p re s e nt in t he Hu..m.nh rey. s I '.~ua dran p:... l e ,:1h.ic-:rr· is corre lHti ve vd,th c 0rtain of the o lde1'"' streain t e rraces . By c o rrc:Jla ting the varis.t i on of .rrad ient a nd of f ill of the stream t e 1'"'r nc e s J-/ with post- 1.ii s consin cliJn2..tic f l uctuati ons ~ the a .~·e of t he :f ucl:e t t i.·~e sa Su rface is s e t a t approximately 600 0 B . c. This correla tion s ets t he p rob&ble ace of the older Ranch o Le. Bl'"' e a deposits 8.t 6 000 to 8000 B. C. and the p :C'obable age of the Car~)8nteria brea deposits at 1 000 to 1 B . C . Contents Introduction. • • • • • • • • 1 • 1 Top o g r aphy • . • o • • • • • • • Geolog ic ~etting . • • • 2 Influenc~ of t he Jrcs ent f 1imate on t h e iro sional /roce sse s • • • 3 Geomorphic Y, rocesse s. • • • • • • 6 General / s pects o f trosion • • • • • 6 '.'J ea t he ring . • • .. • • • • .. • • • • 6 Th e l elati v e 1f ase of l rosi on in t he Te rtiary Y'orma tions 7 ,-~ - ~ I • • • • • • • • • • L>;;1i?.!-? ,I'. i ' 8 Degr8.da tion a l f r ocesses. • • • • • • • • • .. • _\ ,~}' ,/•>I ,; {)1i''. c#'14·- '.I'he Net ion o f Al.mnj_ng '/!at e r 8 ,,.,/"~ : • • • • • • • Llass ]foveme nt • • • • • • • • • • • • • • • 9 Aggradation - The Fact ors Controlling A5gradation by ~~ unni ng 'ii a.t e r • • • • • • • • • • • • • • . 1 7 Cl imatic Flu c t uation. • • • • • • • • ..17 Eeander i n g [>..nd Shi fting o f Eajor St r eo.ms ••1 9 L ass Eovement • • • • • • • • • . 22 •1';. ggr 2. d o.tion Du e t o Reduction of b ast er Strec:rn1 Drain a ge b y Capture o f t h e Catcbrnent B8.sin • • • • • • • • . 22 Stream Cap ture • • • • • • • • • • • • • • • .23 Capture Cau sed by Diffnr ence in Strc8.m 0'7. Load. • • • • • • • • • • • • • • Jo.-J c..) ·.6 9r-::· :.-::2.p ture .Lrom Diff'erenc e in Base Level • • .~ o r.:: apture from Di fference in St rea.rn Leng th. 24 Captur e b y Landsliding . • • • • • • • • " . 24: Capture by Monoclinal Shifting. • • • • .25 Ot her F actors Gove ring the Sha.pe of t be Land Porms. .. • • • • • • • .26 Structure • • • • • • • • • • • .. • • .26 ~ ejuvenation. • • • • • • • • • • • • . 27 Ge omorphic F orms. • • • • • • • • • • • • • • • • . 28 Hock Cones • • • • • • • • • • • • • • .28 Open Ca nyon Heads. • • • • • • • • • • • • • .30 Puckett Mesa - An Op en Canyon Head. • .30 I·1~ iniatur e Op en Ca nyon Heads • • • • • • 33 As-ywmetri c Canyons and Shifting Stre 1.=m1s. • • . 34 Stream Terraces a n d Rel a.ted Erosion Surfa c es .35 Types of Surfaces and Terraces. • • • • .35 Nature and Distribution, Sources, and Economic Value of the Strath and Terr2ce Deposits. • • • • • • • • • • . 42 Correl ation of the Terra ces and Rel a t ed Surfa c e s. • • • • • • • • • • .46 Causes of Rejuvenation and Terrace Formation • • • • • • • • • • • • • • . 57 Geomorph ic Ei s tory o f the Humphreys Ciuadrangl e and t he Surrounding Re s ion • • • • • • • 61 Illustra tions Helie f m.ocle l of t h e Hump hrey s Sluadr a n gle. .Fr ontispiece I P i gurc 1. F1... e sh l a ndslid e • • • • • • • • • • • • • .11 ? igure 2. Deta il of Landslide • • • • • • • • .11 F i gure 3 . Concomita nt slide • • • • • • • • .. • • • .11 ?'i g,ure 4. Si l tflow . • • • • • • • • • • • • • • • . 15 Fi gur e 5. Alluvial cone in Plum Canyon. • • • • .21 F'igure 6. Flum Ca ny on • • • • • • • • • • • • • • . 21 Figure 7 . Alluvia l cone i n I'!iint Canyon. • • • • • • .29 li' i gure 8. Rock cone • • • • • • • • • • • ~ . 29 ? i gure 9. Puck ett Mesa, looking south • • • • • • • .31 i.<' i p;ure 1 0 . Puckett r!ie sa as s e en f'rom the air. • • • .31 F i gu re 11. P anorarnic view of the Sa nta Cla r o. :R i ve1" v alle y • • .. • • • • • • • • • • • • • . 36 li' i cur e 1 2 . 'i'an l-~ Le v e l Surfa c e b e nch • • • • • • • • . 52 / .i:''i r-:ure 1 3 . Terra c e s, strath s, a nd l a ndsl:tde s in t h e • • • • • • • • • • • • . 52 1 L onp:i. t u cl~ ina. 1 t_ r o1~ 1. -.Le on_v er l o .i.,,.,....,,ne '.1. ... S t-.'L""'"' am of .1.v u_cl.<.. e tt hiesa. • • • • • • • • • • • • • • • • • • • Plate I I / Comp ositi on of' the San ta Cla r e.<. Terra c e Gravels .Pl a t e II / I 'l'he Que.t e rna r y JJe ~) O S i ts of the v/e ste rnmo s t Tvvo Thirds of the Eu.mp hr e~• s ;hu a dr ~m gl e , Cal iforni a • • Fl a t e III 're rra c e cSorre l a tion ,£'lap • • • • • • • • • • • . Plate IV • • • • • • • • • • • Pl a t e V Reconstructed Contou r bo.p of the Puckett Ii·! e s a .'.3urfa ce • • • • • • • • • • . l'l a te VI 1 Introduction The area discusse d in this r eport occupies t h e we stern.most two thirds of t he Humphreys ;6u adr a ngle, a s:tx and one- lrnlf minute quadrangl e of' t he Los .Angeles County s eri e s l y ing just nort h of the 34°24 1 parallel 7 ,• 0 ./ and east of t he 118 30 1 me ridian. It covers 25 square miles a n d is readily a cce ssible b y t wo highways from Los Angel e s, one in Bouquet Can yon, and t he other in h int Canyon. Since the top o graphic surveying n as done wit h considerable accura c y , and in fine de tail, it p roved p r actical to do the field mapping on an o z alid cop y of' the published. to:)o gr aphic map enl arged from t h e scale of 1 /2400 to t he s cal e of 1/1200 . Topography Although the n1aximum relief of the area is onl y 1100 feet; t h e s l opes are , in many p l a c e s, exces sive~y steep, especially in the well devel oped badlana.s po:etj_ ons~/ The elevation, i n senRra l decreases from north t o south, t he h i ghest hills, unde:elain b y shists, b e ing [ioca te;g on t he extreme nor•tbern edge o f t he quadrangle. The region i s a portion of' tbe e a.sternmost Ventura b a sin and i s drained 8 by the we stwaPd flowi ng .S anta Cl8.ra Hi ver and its tr-i b u - tar ie s, the southwe st1'ra1"'d f'lowing strea.rn.s in Has kell, Bouquet, and l'Eint Cany ons. Three minor ca.nyons branch of':L /Vl..,a_,._,,..,,_.,J.Af I ., to the east from Bouquet Canyon, <Which are j. from north to 2 I s out h , Texas, Vasqu ez, and Plum fan yons. Ge ologic Setting / 9 An amaz inc; thickne s s of dominantly nonmarine 'J~er ti ary i/ s e d i ments underlies t he entire q_u adrane;l e v1i t h the ezc eption / 0 of t he ex treme northern edge. The formations ~-ecrease in a geJ/1.rom nortb) t~ !\~out h, the general d irection of dip , . /" lt!!,,.() and are usually separated by la~ angula r u n conformity·. Overl y ing t he pre-Cretaceous Felona sch ists are the mode r- ) "!,/"'' a tel y indurated , c ourse , angular beds of the Vasquez s e r ies - \1/ 3 of Oligocene ( ?) ~ge. Above t h is are t h e p oorly consolidated 1 silts, sands, and grav els of t he 'fick Canyon and IHnt Can- yon f ormations , of Lower and Upper Miocene age, respective l y , a p ortior( of t h e Ei n t Canyon for mation bein g l acust1..
Recommended publications
  • Abandonment of Unaweep Canyon (1.4–0.8 Ma), Western Colorado: Effects of Stream Capture and Anomalously Rapid Pleistocene River Incision
    CRevolution 2: Origin and Evolution of the Colorado River System II themed issue Abandonment of Unaweep Canyon (1.4–0.8 Ma), western Colorado: Effects of stream capture and anomalously rapid Pleistocene river incision Andres Aslan1,*, William C. Hood2,*, Karl E. Karlstrom3,*, Eric Kirby4, Darryl E. Granger5,*, Shari Kelley6, Ryan Crow3,*, Magdalena S. Donahue3,*, Victor Polyak3,*, and Yemane Asmerom3,* 1Department of Physical and Environmental Sciences, Colorado Mesa University, Grand Junction, Colorado 81501, USA 2Grand Junction Geological Society, 515 Dove Court, Grand Junction, Colorado 81501, USA 3Department of Earth and Planetary Sciences, University of New Mexico, Northrop Hall 141, Albuquerque, New Mexico 87131, USA 4College of Earth, Ocean and Atmospheric Sciences, Oregon State University, 202D Wilkinson Hall, Corvallis, Oregon 97330, USA 5Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, Indiana 47907, USA 6New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, New Mexico 87801, USA ABSTRACT opment of signifi cant relief between adjacent through resistant Precambrian bedrock (Fig. 2). stream segments, which led to stream piracy. It has no major river at its base, and is currently Cosmogenic-burial and U-series dating, The response of rivers to the abandonment drained by two underfi t streams, East and West identifi cation of fl uvial terraces and lacus- of Unaweep Canyon illustrates how the Creeks, which drain the northeast and southwest trine deposits, and river profi le reconstruc- mode and tempo of long-term fl uvial incision ends of the canyon, respectively. Starting with tions show that capture of the Gunnison are punctuated by short-term geomorphic the Hayden Survey (Peale, 1877), geologists River by the Colorado River and abandon- events such as stream piracy.
    [Show full text]
  • Topographic Controls on Divide Migration, Stream Capture, and Diversification in Riverine Life
    Earth Surf. Dynam., 8, 893–912, 2020 https://doi.org/10.5194/esurf-8-893-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Topographic controls on divide migration, stream capture, and diversification in riverine life Nathan J. Lyons1, Pedro Val2, James S. Albert3, Jane K. Willenbring4, and Nicole M. Gasparini1 1Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA, USA 2Department of Geology, Federal University of Ouro Preto, Ouro Preto, Brazil 3Department of Biology, University of Louisiana at Lafayette, Lafayette, CA, USA 4Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA Correspondence: Nathan J. Lyons ([email protected]) Received: 16 October 2019 – Discussion started: 24 October 2019 Revised: 9 August 2020 – Accepted: 2 September 2020 – Published: 26 October 2020 Abstract. Drainages reorganise in landscapes under diverse conditions and process dynamics that impact biotic distributions and evolution. We first investigated the relative control that Earth surface process parameters have on divide migration and stream capture in scenarios of base-level fall and heterogeneous uplift. A model built with the Landlab toolkit was run 51 200 times in sensitivity analyses that used globally observed values. Large- scale drainage reorganisation occurred only in the model runs within a limited combination of parameters and conditions. Uplift rate, rock erodibility, and the magnitude of perturbation (base-level fall or fault displacement) had the greatest influence on drainage reorganisation. The relative magnitudes of perturbation and topographic relief limited landscape susceptibility to reorganisation. Stream captures occurred more often when the channel head distance to divide was low.
    [Show full text]
  • A Groundwater Sapping in Stream Piracy
    Darryll T. Pederson, Department of energy to the system as increased logic settings, such as in a delta, stream Geosciences, University of Nebraska, recharge causes groundwater levels to piracy is a cyclic event. The final act of Lincoln, NE 68588-0340, USA rise, accelerating stream piracy. stream piracy is likely a rapid event that should be reflected as such in the geo- INTRODUCTION logic record. Understanding the mecha- The term stream piracy brings to mind nisms for stream piracy can lead to bet- ABSTRACT an action of forcible taking, leaving the ter understanding of the geologic record. Stream piracy describes a water-diver- helpless and plundered river poorer for Recognition that stream piracy has sion event during which water from one the experience—a takeoff on stories of occurred in the past is commonly based stream is captured by another stream the pirates of old. In an ironic sense, on observations such as barbed tribu- with a lower base level. Its past occur- two schools of thought are claiming vil- taries, dry valleys, beheaded streams, rence is recognized by unusual patterns lain status. Lane (1899) thought the term and elbows of capture. A marked of drainage, changes in accumulating too violent and sudden, and he used change of composition of accumulating sediment, and cyclic patterns of sediment “stream capture” to describe a ground- sediment in deltas, sedimentary basins, deposition. Stream piracy has been re- water-sapping–driven event, which he terraces, and/or biotic distributions also ported on all time and size scales, but its envisioned to be less dramatic and to be may signify upstream piracy (Bishop, mechanisms are controversial.
    [Show full text]
  • Formation Mechanism for Upland Low-Relief Surface Landscapes in the Three Gorges Region, China
    remote sensing Article Formation Mechanism for Upland Low-Relief Surface Landscapes in the Three Gorges Region, China Lingyun Lv 1,2, Lunche Wang 1,2,* , Chang’an Li 1,2, Hui Li 1,2 , Xinsheng Wang 3 and Shaoqiang Wang 1,2,4 1 Key Laboratory of Regional Ecology and Environmental Change, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China; [email protected] (L.L.); [email protected] (C.L.); [email protected] (H.L.); [email protected] (S.W.) 2 Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China 3 Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, Wuhan 430062, China; [email protected] 4 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China * Correspondence: [email protected] Received: 9 November 2020; Accepted: 26 November 2020; Published: 27 November 2020 Abstract: Extensive areas with low-relief surfaces that are almost flat surfaces high in the mountain ranges constitute the dominant geomorphic feature of the Three Gorges area. However, their origin remains a matter of debate, and has been interpreted previously as the result of fluvial erosion after peneplain uplift. Here, a new formation mechanism for these low-relief surface landscapes has been proposed, based on the analyses of low-relief surface distribution, swath profiles, χ mapping, river capture landform characteristics, and a numerical analytical model. The results showed that the low-relief surfaces in the Three Gorges area could be divided into higher elevation and lower elevation surfaces, distributed mainly in the highlands between the Yangtze River and Qingjiang River.
    [Show full text]
  • Guided Notes on Stream Development, Section 9.2
    Guided Notes on Stream Development, Section 9.2 1. As a stream develops, it changes in shape, width, and size, as well as the landscapes over which it flows. 2. The first and foremost condition necessary for stream formation is an adequate supply of water. 3. The region where water first accumulates to supply a stream is called the headwaters. 4. Moving water carves a narrow pathway into the sediment or rock called a stream channel. 5. Stream banks are the ground bordering the stream on each side. 6. The process by which small streams erode away the rock or soil at the head of a stream is known as headward erosion. 7. Sometimes, a stream erodes its way through the high area separating two drainage basins, joins another stream, and then draws away its water. This process is called stream capture or stream piracy. 8. As a stream actively erodes its path through the sediment or rock, a V-shaped channel develops. V-shaped channels have steep sides and sometimes form canyons or gorges. 9. The lowest base level possible for any stream is sea level, the point at which the stream enters the ocean. 10. As stream channels develop into U-shaped valleys, the volume of water and sediment that they are able to carry increases. 11. A bend or curve in a stream channel caused by moving water is called a meander. 12. The blocked-off meander becomes an oxbow lake, which eventually dries up. 13. The differences in the rate of water flow within meanders cause the meanders to become more accentuated over time.
    [Show full text]
  • Deficiencies in Our Understanding of the Hydro-Ecology of Several Native Australian Fish: a Rapid Evidence Synthesis
    Marine and Freshwater Research, 2018, 69, 1208–1221 © CSIRO 2018 https://doi.org/10.1071/MF17241 Supplementary material Deficiencies in our understanding of the hydro-ecology of several native Australian fish: a rapid evidence synthesis Kimberly A. MillerA,D, Roser Casas-MuletB,A, Siobhan C. de LittleA, Michael J. StewardsonA, Wayne M. KosterC and J. Angus WebbA,E ADepartment of Infrastructure Engineering, The University of Melbourne, Parkville, Vic. 3010, Australia. BWater Research Institute, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK. CArthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, Heidelberg, Vic. 3084, Australia. DPresent address: Healesville Sanctuary, Badger Creek Road, Healesville, Vic. 3777, Australia. ECorresponding author. Email address: [email protected] Page 1 of 30 Marine and Freshwater Research © CSIRO 2018 https://doi.org/10.1071/MF17241 Table S1. All papers located by standardised searches and following citation trails for the two rapid evidence assessments All papers are marked as Relevant or Irrelevant based on a reading of the title and abstract. Those deemed relevant on the first screen are marked as Relevant or Irrelevant based on a full assessment of the reference.The table contains incomplete citation details for a number of irrelevant papers. The information provided is as returned from the different evidence databases. Given that these references were not relevant to our review, we have not sought out the full citation details. Source Reference Relevance Relevance (based on title (after reading and abstract) full text) Pygmy perch & carp gudgeons Search hit Anon (1998) Soy protein-based formulas: recommendations for use in infant feeding.
    [Show full text]
  • Geomorphologyi
    Bear River Geomorphologyi Two historical effects set the Bear River apart from other Sierra watersheds. The first is the “capture” of the Bear’s upper watershed during a recent glacial period, discussed herein. The second, discussed in bear mining legacy, is the extensive impact of hydraulic mining, perhaps more intense here than in any other watershed in the range, and its legacy of mercury contamination. Stream capture The Bear River is a classic example of an “underfit” stream—a stream whose channel was formed by a larger flow than presently exists. The deep V-shaped canyon of the Bear reflects the work of a much larger river at some point in the past. Lake Spaulding stream capture point South Fork Yuba River Bear River North Fork American River Steephollow Creek Topographic view looking northeast up the Bear River canyon, with the South Fork Yuba River to the left. The arrow indicates the point of stream capture. Graphic by Russel Towle, http://personal.neworld.net/~rtowle/Topography/topography.html 1 “Stream capture” is an event in fluvial geomorphology that occurs when stream channels from adjacent watersheds meet after eroding headward over time. The headwaters from both streams then flow down one of the channels, “capturing” the water from the upper watershed of the other stream channel. Researchers have studied glacial stratigraphy of the Bear River using the present-day evidence of lateral moraines, glacial erratics, and striae on rocks. These features indicate that at least two and probably three glacial advances occupied both the South Yuba and Bear valleys. These advances are believed to have ground through a narrow ridge separating the South Fork of the Yuba from the Bear River, just downstream of what is now Lake Spaulding (see graphic).
    [Show full text]
  • Grade 12 Geography Geomorphology Revised Learner Notes
    GRADE 12 SECONDARY SCHOOL IMPROVEMENT PROGRAMME (SSIP) 2019 GEOGRAPHY REVISED LEARNER NOTES SESSIONS 6 –9 GEOMORPHOLOGY 1 TABLE OF CONTENTS SESSION TOPIC PAGE 6 Drainage Basins in South Africa 7 Fluvial processes River Capture and drainage basin and river 8 management 9 Geomorphology consolidation ACTION VERBS IN ASSESSMENTS VERB MEANING SUGGESTED RESPONSE Account to answer for - explain the cause of - so as to Full sentences explain why Analyse to separate, examine and interpret critically Full sentences Full sentences Annotate to add explanatory notes to a sketch, map or Add labels to drawing drawings Appraise to form an opinion how successful/effective Full sentences something is Argue to put forward reasons in support of or against Full sentences a proposition Assess to carefully consider before making a judgment Full sentences Categorise to place things into groups based on their One-word characteristics answers/phrases Classify to divide into groups or types so that things One-word answers with similar characteristics are in the same /phrases group - to arrange according to type or sort Comment to write generally about Full sentences Compare to point out or show both similarities and Full sentences differences Construct to draw a shape A diagram is required Contrast to stress the differences, dissimilarities, or Full sentences unlikeness of things, qualities, events or problems Create to develop a new or original idea Full sentences Criticise to make comments showing that something is Full sentences bad or wrong Decide to consider
    [Show full text]
  • Maccullochella Ikei, an Endangered Species of Freshwater Cod (Pisces: Percichthyidae) from the Clarence River System, NSW and M
    Records of the Australian Museum (1993) Vo1.45: 121-145. ISSN 0067-1975 121 Maccullochella ikei, an Endangered Species of Freshwater Cod (Pisces: Percichthyidae) from the Clarence River System, NSW and M. peelii mariensis, a New Subspecies from the Mary River System, Qld STUART J. ROWLAND NSW Fisheries, Eastern Freshwater Fish Research Hatchery, Grafton, NSW 2460, Australia ABSTRACT. The eastern freshwater cod, Maccullochella ikei, from the Clarence River system, NSW, is described and M. peelii mariensis is described as a new subspecies from the Mary River system, Qld. The Murray cod, M. p. peelii and the trout cod, M. macquariensis, are indigenous to the Murray-Darling River system. Using electrophoretic data for 19 presumed loci, the coefficient of genetic identity between M. p. peelii and M. ikei was 0.72 and the banding-patterns of the muscle general protein, liver esterases and five other enzymes, were species-specific. A high proportion of abnormal and inviable hybrid larvae in a cross-breeding experiment indicate that post-zygotic isolating mechanisms have evolved between M. p. peelii and M. ikei. The coefficient of genetic identity between M. p. peelii and M. p. mariensis was 0.85 and banding patterns of muscle general protein were diagnostic. Canonical variates analysis using 18 morphological and nine meristic characters, clearly separated both spccies and the subspecies. Maccullochella ikei is distinguished from M. p. peelii by having longer pelvic fins, larger orbit length, and larger and morphologically distinct sagittalotoliths. Maccullochella p. mariensis differs from M. p. pee/ii by the combination of a deeper and shorter caudal peduncle, longer pelvic fins, larger sagittal otoliths and lesser extension of the first anal pterygiophore towards the first caudal vertebra, and from M.
    [Show full text]
  • Biogeography of Freshwater Fishes of Northwestern
    * BIOGEOGRAPHY OF FRESHWATER FISHES OF NORTHWESTERN MEXICO by Heidi Blue Blasius A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science ARIZONA STATE UNIVERSITY December 1996 ABSTRACT Northwestern Mexico provides the connecting link in a broad geographic transition between continental ichthyofaunas of the Western Hemisphere. A. biotic assemblage with diversified relationships results from a varied biogeographic history involving two much larger regions, Nearctic in the north and Neotropical to the south. This thesis delineates and analyzes relationships of the regional ichthyofauna within this broader pattern of transition. Three levels of specimen records were used (Level I, those in museums; II, peer-reviewed literature; and HI, "gray" literature) to address two questions: 1) are within-region distributions more a function of ecologic or geologic history, or 2) are ecologic and geologic histories so inexorably intertwined they cannot be separated one from the other? The fauna proved strongly northern in affinity, comprised of three Nearctic (salmonids, catostomids, cyprinids), one transitional Nearctic (ictalurids), two transitional Neotropical (poeciliids, cichlids), and two shared (cyprindontids, clupeids) families that occur across diverse geologic structure and through temperate and tropical habitats to form a distributional mosaic most closely attuned to latitudinal and altitudinal ecology of the region. 111 DEDICATION For my Mom, Sondra Katherine Blasius and Dad, Gary Lee Blasius who loved and supported me throughout graduate school, and my beautiful daughter Nashashibi Tahara Blasius whom I love dearly. I love you all. iv ACKNOWLEDGEMENTS I wish to thank my committee members, Dr. M. J. Fouquette, Jr., and Dr. D. J. Pinkava for their critical review and comments on this manuscript, and Dr.
    [Show full text]
  • IN the SOUTHERN ROCKY MOUNTAINS By
    EVOLUTION & CONSERVATION OF CUTTHROAT TROUT (ONCORHYNCHUS CLARKII SSP.) IN THE SOUTHERN ROCKY MOUNTAINS by SIERRA MAGENTA LOVE STOWELL B.A., University of Colorado 2007 A thesis submitted Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Master of Arts Department of Ecology and Evolutionary Biology 2011 This thesis entitled Evolution & Conservation of Cutthroat Trout (Oncorhynchus clarkii spp.) in the Southern Rocky Mountains written by Sierra Magenta Love Stowell has been approved for the Department of Ecology & Evolutionary Biology Andrew Martin Sharon Collinge Christy McCain Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. Love Stowell, Sierra Magenta (M.A., Ecology & Evolutionary Biology) Evolution & Conservation of Cutthroat Trout (Oncorhynchus clarkii ssp.) in the Southern Rocky Mountains Thesis directed by Dr. Andrew P. Martin ABSTRACT Cutthroat trout are endemic to the cold waters of the American West. The subspecies probably evolved in isolated drainages during the Quaternary. I developed nuclear DNA markers to distinguish between closely related subspecies and estimate divergence times between populations in the southern Rocky Mountains. The subspecies native to Colorado are much older than previous estimates: using a molecular clock, I estimated that greenback and Colorado River cutthroat trout split 0.79 MYA. Human movement of fish has obscured the evolutionary legacy of cutthroats. I used assessments of purity and stocking records for Rocky Mountain National Park, combined with Geographic Information Systems, to assess the utility of geographic measures to serve as proxies for propagule pressure.
    [Show full text]
  • Principles of Underfit Streams
    Principles of Underfit Streams GEOLOGICAL SURVEY PROFESSIONAL PAPER 452-A Principles of Underfit Streams By G. H. DURY GENERAL THEORY OF MEANDERING VALLEYS GEOLOGICAL SURVEY PROFESSIONAL PAPER 452-A UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1964 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director First printing 1964 Second printing 1967 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $1 (paper cover) CONTENTS Page Page Abstract.--_----_-__---_-_-_._____._.._______._____ Al Principles of underfit streams Continued Introduction --.--_.__.________,______._._____.__._. 1 Regional distribution and a regional hypothesis.___ A26 Acknowledgments__ _ _ _____________________________ 3 Climatic hypothesis and underfitness other than Perspective on terminology.-._-_---_______-__-_____- 4 manifest. ____________-_----_--_--__------ 29 Principles of underfit streams_______________________ 9 Meandering tendency of a drainage ditch __ 32 Diversion unnecessary__-_______________,________ 9 Creeks in Iowa------------------------- 33 Diversions other than capture the question of spill­ Humboldt River, Nev___________________ 35 ways --_--__-_____________--________________- 16 Shenandoah River, Va-__-----_-_-------- 36 Ozarks and Salt and Cuivre River basins, Wabash River, Ind., and glacial Lake Whittle- Missouri- _-_______-_---_--__---_----- 39 sey ---__..______-________..___.__-_._- 17 Rivers in New England________________ 47 Souris River at Minot, N. Dak...____________ 18 Canyons in Arizona.____________________ 55 Sheyenne River, N. Dak., and glacial Lake Problems of the influence of bedrock. _________ 59 Agassiz._________________________________ 18 Canyons as flumes._____________________ 63 Stratford Avon, England, and glacial Lake Summary __________________________________________ 65 Harrison __ _____________________________ 22 References cited---_-_-----__-----____-------------- 66 ILLUSTRATIONS Page PLATE 1.
    [Show full text]