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Full-Text Articles in Paleontology
Modeling Stromatolite Formation With Diffusion-Limited Aggregation, Laura E. Stevens
Modeling Stromatolite Formation With Diffusion-Limited Aggregation, Laura E. Stevens
Graduate Student Theses, Dissertations, & Professional Papers
Stromatolites, microbialites, and other microbially induced sedimentary structures exist in the rock record as far back as 3.6 billion years ago and continue to form in the present day. Better characterizing these structures and better understanding how they form is crucial in distinguishing these biosignatures from similar, abiotic structures, which can help us to understand the conditions of early Earth and early Mars. To that end, I have modified DLA 3D EXT, an open-source stromatolite modeling program, to more closely reflect the process of microbial trapping-and-binding by filamentous microbes in a calcite-precipitating hot spring system. This modified program includes a …
A Record Of The Precambrian-Cambrian Transition In Sw Montana: A Late Neoproterozoic To Early Cambrian Stratigraphic Window, Fortunian Biostratigraphic Assemblage And Treptichnus Pedum, R. Reid Trippe
Graduate Student Theses, Dissertations, & Professional Papers
This study documents a Late Neoproterozoic through Early Cambrian stratigraphic record in the Humbolt anticline of southwestern Montana. The Precambrian-Cambrian transition includes a Fortunian-aged biostratigraphic trace-fossil assemblage with the ichnofossil Treptichnus pedum. The Humbolt anticline represents an inverted paleo-graben that exposes a stratigraphic window interpreted to be a record of rifting along the Cordilleran miogeoclinal margin, linked with the breakup of the Rodinia supercontinent. The graben subsided and captured sediment during late-stage rifting and final-stage dissociation along the rift margin. Its structural axis paralleled the rift margin. Sevier/Laramide orogenic thrusting inverted the graben into the Humbolt anticline. The Late …
The Neocene Lake Beds Of Western Montana And Descriptions Of Some New Vertebrates From The Loup Fork, Earl Douglass
The Neocene Lake Beds Of Western Montana And Descriptions Of Some New Vertebrates From The Loup Fork, Earl Douglass
Graduate Student Theses, Dissertations, & Professional Papers
Since coming to Montana in the spring of 1894 I have spent rnuoh of ay time in studying the lake bed deposits in the western part of the state, and in collecting and studying the vertebrate fossils found in them. These deposits occur in nearly every large valley in the westem part of the state. I have myself observed them in the valleys of the upper Missouri (above the re-rrion of Helena), Gallatin, Madison, Jefferson, Beaverhead, Ruby, Big Hole, Hell Gate, and Bitter Boot rivers, and their tributaries.