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Articles 1 - 30 of 59
Full-Text Articles in Physical Sciences and Mathematics
The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman
The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman
Jonathan R. Hendricks
No abstract provided.
Preliminary Geophysical Characterization Of The Karst Within A Transverse Glade In The Atlantic Coastal Ridge, Miami-Dade County Florida, Usa, Lee J. Florea, Jeff Ransom, Dallas Hazelton
Preliminary Geophysical Characterization Of The Karst Within A Transverse Glade In The Atlantic Coastal Ridge, Miami-Dade County Florida, Usa, Lee J. Florea, Jeff Ransom, Dallas Hazelton
Lee J Florea, PhD, P.G.
In this paper we present results of two DC Electrical Resistivity Tomography surveys at Deering Estate at Cutler in the Atlantic Coastal Ridge of Miami-Dade County, Florida. This County Natural Area encompasses Deering Glade and hosts one of the largest remaining tropical hardwood-hammock ecosystems in the USA. A canal extension, wetland restoration, and pump station recently constructed at Deering Estate by the South Florida Water Management District is designed to re-hydrate Deering Glade to pre-development conditions thus helping to sustain the hammock ecosystem and reverse trends in salt-water intrusion in this portion of the Biscayne aquifer. For these transects, we …
Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks
Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks
Jonathan R. Hendricks
The biology of modern Conidae (cone snails)—which includes the hyperdiverse genus Conus—has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to …
Changes In Beach Gravel Lithology Caused By Anthropogenic Activities Along The Southern Coast Of Lake Michigan, Usa, Zoran Kilibarda, Nolan Graves, Melissa Dorton, Richard Dorton
Changes In Beach Gravel Lithology Caused By Anthropogenic Activities Along The Southern Coast Of Lake Michigan, Usa, Zoran Kilibarda, Nolan Graves, Melissa Dorton, Richard Dorton
Zoran Kilibarda
The southern coast of Lake Michigan is the most urbanized and most densely populated area in the Great Lakes region. Development of steel mills, harbors, and municipalities in NW Indiana and in NE Illinois in the last century and a half altered the nearshore environment so much that native beach gravel (>8 mm) now exist only in the exhumed paleo-beach remnants from the Nipissing Phase (~4,500 years ago) of Lake Michigan. Native gravel, collected from paleo-beach remnants at Mount Baldy Dune and Beach House Blowout, contain predominantly beach shingle, very platy siltstones (71–78 %), with secondary crystalline pebbles (18 …
Isotopes Of Carbon In A Karst Aquifer Of The Cumberland Platea Of Kentucky , Usa, Lee J. Florea
Isotopes Of Carbon In A Karst Aquifer Of The Cumberland Platea Of Kentucky , Usa, Lee J. Florea
Lee J Florea, PhD, P.G.
In this study, the concentration and isotopic composition of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are measured in the karst groundwater of the Otter Creek watershed of the Cumberland Plateau of Kentucky, USA. Comparisons among these data and with the geochemistry of carbonate and gypsum equilibrium reactions reveal that DOC concentration is inversely related to discharge, multiple reaction pathways provide DIC with isotopic enrichment that may be directly related to mineral saturation, and oxidation of reduced sulfur is possible for dissolution. DOC is derived from C3 vegetation with an average δ13CDOC of ‒27‰. DIC in groundwater is …
Preliminary Lineament Analysis Within The Vicinity Of Kainji Dam, Nigeria Using Ers-1 Sar Image, M S. Kolawole, E G. Ameh, A Daniel
Preliminary Lineament Analysis Within The Vicinity Of Kainji Dam, Nigeria Using Ers-1 Sar Image, M S. Kolawole, E G. Ameh, A Daniel
Confluence Journal Environmental Studies (CJES), Kogi State University, Nigeria
Various affordable, operational technologies such as remote sensing, Geographic Information Systems (GIS) can significantly contribute to improved efficiency. The main focus of the project has been directed to the use of remote sensing to gain geological and geohazard information. This study examines the use of Remote Sensing (RS) technology in geological studies of Kainji area. Radar SAR images were used to classify the various geological fractures found in the area located in the Northern part of Nigeria. A wide variety of digital image processing techniques were applied such as the Principal Components (PC) analysis and ratioing. ERS-1 SAR image that …
Using Marine Snails To Teach Biogeography And Macroevolution: The Role Of Larvae And Dispersal Ability In The Evolution And Persistence Of Species, Jonathan R. Hendricks
Using Marine Snails To Teach Biogeography And Macroevolution: The Role Of Larvae And Dispersal Ability In The Evolution And Persistence Of Species, Jonathan R. Hendricks
Jonathan R. Hendricks
While some marine animals are capable of traveling great distances, many have limited mobility as adults and spend the majority of their lifetimes in a small geographical area or may even be cemented to a single place. While it might be expected that species with limited mobility would have small geographic distributions, some nevertheless occur over very large areas. This is the case for some marine snails (gastropods). A key factor that impacts the geographic distribution of marine snails is the type of larvae they have during the phase of their life history that follows hatching from an egg. Because …
Mapping Lava Flows From Nyamuragira Volcano (1967-2011) With Satellite Data And Automated Classification Methods, Elisabet Head, Ann L. Maclean, Simon A. Carn
Mapping Lava Flows From Nyamuragira Volcano (1967-2011) With Satellite Data And Automated Classification Methods, Elisabet Head, Ann L. Maclean, Simon A. Carn
Elisabet Head
The volume, location and extent of historical lava flows are important when assessing volcanic hazards, as well as the productivity or longevity of a volcanic system. We use a Landsat/Hyperion/ALI dataset and automated classification methods to map lava flows at Nyamuragira volcano (1967-2011) in the Democratic Republic of the Congo. The humid tropical climate ofNyamuragira is advantageous because its lava flows are emplaced onto heavily forested flanks, resulting in strong contrast between lava and vegetation, which contributes to efficient flow mapping. With increasing age, there is an increase in Landsat band-4 reflectance, suggesting lava flow revegetation with time. This results …
A Comparison Of Three Terrain Parameters That May Be Used To Identify Denudation Surfaces Within A Gis: A Case Study From Wales, United Kingdom., Matt D. Rowberry
A Comparison Of Three Terrain Parameters That May Be Used To Identify Denudation Surfaces Within A Gis: A Case Study From Wales, United Kingdom., Matt D. Rowberry
Matt D Rowberry
The study of denudation surfaces has long formed a major theme within geomorphic and tectonic research. This paper describes the computational methods used to identify these surfaces through three terrain parameters within a GIS. The investigated parameters are slope angle, relative relief, and the elevation-relief ratio. The study area under consideration is that of Wales, United Kingdom. The SRTM DEM forms the basis of this investigation, with all data interrogation undertaken in ArcMap 9.3. The computational methods are described in detail and then the results relating to each terrain parameter are compared. The denudation surface maps based on slope angle …
The Monitoring Of Slow Moving Landslides And Assessment Of Stabilisation Measures Using An Optical-Mechanical Crack Gauge, Jan Klimeš, Matt D. Rowberry, Jan Blahůt, Miloš Briestenský, Filip Hartvich, Blahoslav Košťák, Jan Rybář, Josef Stemberk, Petra Štěpančíková
The Monitoring Of Slow Moving Landslides And Assessment Of Stabilisation Measures Using An Optical-Mechanical Crack Gauge, Jan Klimeš, Matt D. Rowberry, Jan Blahůt, Miloš Briestenský, Filip Hartvich, Blahoslav Košťák, Jan Rybář, Josef Stemberk, Petra Štěpančíková
Matt D Rowberry
It is possible to monitor slow moving landslides and assess landslide stabilisation measures over protracted periods using an optical-mechanical crack gauge, called a TM-71. This technical note outlines the theoretical background to the gauge and illustrates its practical application through a number of case studies. These studies are drawn from a range of landslide types and stabilisation measures. In terms of monitoring slow moving landslides, three studies of deep-seated deformations are presented. The Taukliman coastal landslide on the Black Sea Coast is characterised by vertical and horizontal displacements of up to 0.2 mm.yr-1 and sudden earthquake-induced dilations of up to …
Determination Of Paleoearthquake Timing And Magnitudes On The Southern Segment Of The East Cache Fault, Utah, James P. Mccalpin
Determination Of Paleoearthquake Timing And Magnitudes On The Southern Segment Of The East Cache Fault, Utah, James P. Mccalpin
James P. McCalpin
We investigated the late Quaternary rupture history of the southern East Cache Fault zone [ECFZ], northern Utah with geologic mapping, paleoseismic logging of fault trenches, ground-penetrating radar, and optically stimulated luminescence dating. McCalpin (1989) indicated that the southern segment of the ECFZ consisted of three strands. We excavated four trenches across these strands, and evaluate the stratigraphy and structure of the sites. We conclude that the western fault strand of the ECFZ has had no late Quaternary displacement or does not exist; the central strand has not had any late Quaternary movement and may be a drape fold; and the …
Insight Into Volatile Behavior At Nyamuragira Volcano (D.R. Congo, Africa) Through Olivine-Hosted Melt Inclusions, Elisabet M. Head, Alison M. Shaw, Paul J. Wallace, Kenneth W. W. Sims, Simon A. Carn
Insight Into Volatile Behavior At Nyamuragira Volcano (D.R. Congo, Africa) Through Olivine-Hosted Melt Inclusions, Elisabet M. Head, Alison M. Shaw, Paul J. Wallace, Kenneth W. W. Sims, Simon A. Carn
Elisabet Head
[1] We present new olivine-hosted melt inclusion volatile (H20, C02, S, Cl, F) and major element data from five historic eruptions ofNyamuragira volcano (1912, 1938, 1948, 1986, 2006). Host-olivine Mg#'s range from 71 to 84, with the exception of the 1912 sample (Mg# = 90}.lnclusion compositions extend from alkali basalts to basanite-tephritcs. Our results indicate inclusion entrapment over depths ranging from 3 to 5 km, which agree with independent estimates of magma storage depths (3-7 km) based on geophysical methods. Melt compositions derived from the 1986 and 2006 Nyamuragira tephra samples best represent pre-eruptive volatile compositions because these samples contain …
The Use Of A Karstic Cave System In A Study Of Active Tectonics: Fault Movements Recorded At Driny Cave, Malé Karpaty Mts (Slovakia), Miloš Briestenský, Josef Stemberk, Jozef Michalík, Pavel Bella, Matt D. Rowberry
The Use Of A Karstic Cave System In A Study Of Active Tectonics: Fault Movements Recorded At Driny Cave, Malé Karpaty Mts (Slovakia), Miloš Briestenský, Josef Stemberk, Jozef Michalík, Pavel Bella, Matt D. Rowberry
Matt D Rowberry
This paper reports on a study of active tectonics undertaken in the intracratonic setting of central Europe in the junction zone between Eastern Alps and Western Carpathians. The study site is focused on the karstic system of Driny Cave in the Malé Karpaty Mts, Slovakia. A range of geological, geomorphological, and in situ displacement data are presented. From previous geological mapping and our slickenside analyses, it is clear that the cave system has developed along significant fault structures. Further geomorphological investigations pointed towards ongoing faulting and block movements. For example, a number of slope failures can be seen on the …
Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman
Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman
Michelle Hoffman
Background levels of four fluorescent compounds were monitored biweekly at thirteen sampling sites on Guam, consisting of subtidal and intertidal springs, dissolution fractures, and internal upland contact spring discharge, over a 13-month period from 2006 to 2007. Samples were compared to local precipitation and to seawater samples from four nearby reef flats. The data revealed that the concentrations of optical brighteners were consistently two orders of magnitude greater than either sodium fluorescein or rhodamine WT, while Eosine Y was rarely detected. Background levels in seawater, by comparison, accounted for 25% or more of the fluorescent compounds detected at the thirteen …
Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker
Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker
Thomas Bradley Walker
Work done to build a chronology of deglaciation using varves has been the focus of a number of researchers in New England for many years. The locations employed to build their timeline have been quite useful to date. However, New England is not the only place in the Northeast conducive to studying the last deglaciation of North America. The discovery of a set of ice proximal varves in an ancient glacial lake, now a swamp, in Oswego County, central New York, has shown that some locations outside of New England would be suitable for similar studies. The land having been …
Assessing The Impact Of Geosciences Laboratories On Student Learning: Who Benefits From Introductory Labs, Karl Nelson, Kristin Huysken, Zoran Kilibarda
Assessing The Impact Of Geosciences Laboratories On Student Learning: Who Benefits From Introductory Labs, Karl Nelson, Kristin Huysken, Zoran Kilibarda
Zoran Kilibarda
Laboratories serve as an integral part of geoscience education at most colleges and universities. While anecdotal evidence supports the beneficial impact of laboratories on science class learning, little quantitative research backs this statement. This study compared classroom data from students who completed a geoscience laboratory in conjunction with an introductory-level lecture-based course to those who completed the lecture course only. Laboratory-enrolled students performed better in the lecture class, resulting in an increase of 5.5% in their final class score. Even after controlling for GPA, laboratory enrollment accounted for a statistically significant proportion of the variance. Nontraditional students (age 25 and …
Diurnal Patterns Of Blowing Sand, John E. Stout
Diurnal Patterns Of Blowing Sand, John E. Stout
John E. Stout
The diurnal pattern of blowing sand results from a complex process that involves an interaction between solar heating, thermal instability, atmospheric turbulence, wind strength, and surface threshold conditions. During the day, solar heating produces thermal instability, which enhances the convective mixing of high momentum winds from the upper levels of the atmosphere to the surface layer. The sun also dries the sand surface so that the critical threshold is as low as possible. Thus, in the afternoon, the combination of strong turbulent winds and a low surface threshold increases the likelihood that winds may intermittently exceed the critical threshold of …
Quaternary Geology And Geochronology Of The Uppermost Arkansas Valley, Colorado- Glaciers, Ice Dams, Landslides, And Floods, James P. Mccalpin
Quaternary Geology And Geochronology Of The Uppermost Arkansas Valley, Colorado- Glaciers, Ice Dams, Landslides, And Floods, James P. Mccalpin
James P. McCalpin
This field trip to the uppermost Arkansas Valley of central Colorado is based mainly on work performed since 2008, in an area with a long history of bedrock mapping by renowned geologists of the U.S. Geological Survey beginning in the 1880s (e.g. Emmons, 1886). The Quaternary features of the region were first described by Capps in 1909. Despite over 100 years of intermittent geologic studies here, there were still new discoveries to be made in the past few years. Day 1 of the trip emphasizes landslides (in the morning) and glacial deposits (in the afternoon). The “take-home messages” of the …
The Southeastern Coastal Plain: An Overview, Lee J. Florea, H L. Vacher
The Southeastern Coastal Plain: An Overview, Lee J. Florea, H L. Vacher
Lee J Florea, PhD, P.G.
Florida enjoys the highest density of large springs in North America (Scott et al., 2004); Silver Springs is just one of the 33 first-magnitude springs (mean flow greater than 100 cfs (2.8 m3/s), and there are hundreds of smaller springs (Fig. 6.2; see Meinzer, 1927, and Scott et al., 2004). They are supplied by spectacular underwater caves that are internationally recognized in the cave-diving community. Less well known are the many air-filled caves of the region (see Florea, 2006; Moore, 2006; Lane 1986). Though generally smaller than their aquatic counterparts, their beauty can rival the world’s best show caves. This …
The Cumberland Plateau Of Eastern Kentucky, Larry C. Simpson, Lee J. Florea
The Cumberland Plateau Of Eastern Kentucky, Larry C. Simpson, Lee J. Florea
Lee J Florea, PhD, P.G.
Eastern Kentucky contains almost the same Mississippian limestones that appear at Mammoth Cave in south-central Kentucky (Chapter 3). To the east these strata dip below the Appalachian Basin and reappear as the Greenbrier Group in the Virginias. The limestone outcrop in eastern Kentucky follows the western margin of the Cumberland Plateau and forms a ragged ribbon of karst that is continuous from southeastern Ohio through Kentucky and Tennessee and into northern Alabama. There are more than 2,000 documented caves comprising over 470 km of surveyed passage in the Kentucky segment of the Cumberland Plateau (Fig. 2.115). At least 14 are …
Caves And Karst Of West-Central Florida, Lee J. Florea, David Budd, Robert Brinkmann
Caves And Karst Of West-Central Florida, Lee J. Florea, David Budd, Robert Brinkmann
Lee J Florea, PhD, P.G.
The real west-central Florida is far from the “Sunshine State” image of white sand beaches and palm trees. Gently rolling hills, dense jungle-like forests, pine and palmetto scrublands, impenetrable cypress swamps, and alligator-laden rivers are more common. Numerous crystal-clear springs offer a glimpse of the hidden world below – a world that could challenge the most imaginative Disney artists (Fig. 6.17).
Geology And Hydrology Of Karst In West-Central And North-Central Florida, Lee J. Florea
Geology And Hydrology Of Karst In West-Central And North-Central Florida, Lee J. Florea
Lee J Florea, PhD, P.G.
The state of Florida is blessed with the highest density of large springs in North America and hundreds of smaller springs where the water from limestone aquifers returns to the surface (Scott et al., 2004). Spectacular underwater caves supply water to these springs. Lesser known are the equally fantastic air-filled caves of Florida and South Georgia (Florea, 2006; Lane, 1986). This paper features these underwater and airfilled caves, explores the impact of changes in sea level on karst in this near-coastal environment, and establishes several geologic and hydrologic characteristics that distinguish karst in the limestones of the southeast from karst …
W(H)Ither Fossils? Studying Morphological Character Evolution In The Age Of Molecular Sequences, Elizabeth J. Hermsen, Jonathan R. Hendricks
W(H)Ither Fossils? Studying Morphological Character Evolution In The Age Of Molecular Sequences, Elizabeth J. Hermsen, Jonathan R. Hendricks
Jonathan R. Hendricks
A major challenge in the post-genomics era will be to integrate molecular sequence data from extant organisms with morphological data from fossil and extant taxa into a single, coherent picture of phylogenetic relationships; only then will these phylogenetic hypotheses be effectively applied to the study of morphological character evolution. At least two analytical approaches to solving this problem have been utilized: (1) simultaneous analysis of molecular sequence and morphological data with fossil taxa included as terminals in the analysis, and (2) the molecular scaffold approach, in which morphological data are analyzed over a molecular backbone (with constraints that force extant …
Visualization Of Groundwater Flow Within Touching-Vug And Matrix Porosity In An Eogenetic Karst Aquifer, Lee J. Florea, Kevin J. Cunningham, Stephen Altobelli
Visualization Of Groundwater Flow Within Touching-Vug And Matrix Porosity In An Eogenetic Karst Aquifer, Lee J. Florea, Kevin J. Cunningham, Stephen Altobelli
Lee J Florea, PhD, P.G.
In this study, we use an innovative, non-invasive technology, nuclear magnetic resonance imaging (NMRI), to visualize the direction and magnitude of groundwater flow in field samples of late Pleistocene limestone of the Biscayne aquifer. Specific goals of the first set of NMRI experiments are to map the advective velocity of water flowing at two rates of specific discharge (0.00025 and 0.00013 m/s) through a 10-cm-diameter cylindrical, epoxy-resin model. The model interior accurately reproduces a well-connected maze of ichnologically influenced, centimeter-scale, touching-vug macroporosity common within preferred flow zones in parts of the Biscayne aquifer. A second set of NMRI experiments investigates …
Focus Group On Karst Hydrology - Conceptual Models, Aquifer Characterization, And Numerical Modeling, Martin Sauter, Lee J. Florea, Others
Focus Group On Karst Hydrology - Conceptual Models, Aquifer Characterization, And Numerical Modeling, Martin Sauter, Lee J. Florea, Others
Lee J Florea, PhD, P.G.
No abstract provided.
Biogenic Porosity And Its Lattice Boltzmann Method Permeability In The Karst Biscayne Aquifer, Kevin Cunningham, Mike Sukop, Haibo Huang, Pedro Alvarez, Allen Curran, Michael Waker, Lee J. Florea, Robert Renken, Joann F. Dixon
Biogenic Porosity And Its Lattice Boltzmann Method Permeability In The Karst Biscayne Aquifer, Kevin Cunningham, Mike Sukop, Haibo Huang, Pedro Alvarez, Allen Curran, Michael Waker, Lee J. Florea, Robert Renken, Joann F. Dixon
Lee J Florea, PhD, P.G.
No abstract provided.
Exceptionally Preserved Jellyfishes From The Middle Cambrian, Paulyn Cartwright, Susan L. Halgedahl, Jonathan R. Hendricks, Richard D. Jarrard, Antonio C. Marques, Allen G. Collins, Bruce S. Lieberman
Exceptionally Preserved Jellyfishes From The Middle Cambrian, Paulyn Cartwright, Susan L. Halgedahl, Jonathan R. Hendricks, Richard D. Jarrard, Antonio C. Marques, Allen G. Collins, Bruce S. Lieberman
Jonathan R. Hendricks
Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (~505 million years old) Marjum Formation of Utah. These are the first described Cambrian jellyfish fossils to display exquisite preservation of soft part anatomy including detailed features of structures interpreted as trailing tentacles and subumbrellar and exumbrellar surfaces. If the interpretation of these preserved characters is correct, their presence is diagnostic of modern jellyfish …
International, Cooperative Research In The Apuseni Mountains Of Western Romania, Lee J. Florea, Bogdan P. Onac
International, Cooperative Research In The Apuseni Mountains Of Western Romania, Lee J. Florea, Bogdan P. Onac
Lee J Florea, PhD, P.G.
In May of 2006, nine American scientists and cavers from the Karst Research Group at the University of South Florida traveled to western Romania to attend and present at an international conference on records of climate change in caves in the historic Roman town of Baile Hurculane. The conference, co-sponsored by the “Emil Racoviţă” Speleological Institute of Romania and the Karst Waters Institute, drew more than 100 experts in the field of climate change and karst, and was a wonderful time spent alongside the thermal springs and Austro-Hungarian bathhouses nestled within the massive limestone canyon of the Cerna River. Following …
I Sinkholes Nella Letteratura Scientifica Internazionale: Una Breve Rassegna, Con Particulare Riferimento Agli Stati Uniti D'America, Lee J. Florea, Mario Parise
I Sinkholes Nella Letteratura Scientifica Internazionale: Una Breve Rassegna, Con Particulare Riferimento Agli Stati Uniti D'America, Lee J. Florea, Mario Parise
Lee J Florea, PhD, P.G.
Fenomeni di sinkholes sono diffusi in moltissimi paesi del mondo, in ambiti geologici e morfologici alquanto differenziati, e coinvolgono svariate litologie, sia nelle successioni di copertura che in quelle direttamente affioranti alla superficie. Il presente contributo intende fornire una breve rassegna, certamente non esaustiva, sullo stato dell’arte delle ricerche relative ai sinkholes in ambito internazionale. Esso consiste in una descrizione della più aggiornata e diffusa classificazione dei sinkholes e, a seguire, in descrizioni delle più tipiche casistiche di sinkholes nei vari paesi. Tra questi, viene dato particolare risalto agli Stati Uniti d’America (e, più in particolare, alla Florida), dove le …
Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman
Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman
Jonathan R. Hendricks
Biogeographic patterns in primarily Cambrian arachnomorph taxa are investigated using a recently constructed phylogenetic hypothesis in order to explore the biogeographic context of the Cambrian radiation. A modified version of Brooks Parsimony Analysis is employed to elucidate patterns of vicariance and geodispersal in taxa from six regions (Laurentia, Baltica, Siberia, Australia, Africa and China). Well resolved vicariance and geodispersal trees are very similar and reconstruct Laurentia and China as sister areas. This close area relationship between Laurentia and China provides extensive evidence for congruent vicariance and range expansion in Cambrian arachnomorphs, while data from trilobites do not show this pattern. …