Pedogenic and lacustrine features of the Brushy Basin Member of the Upper Jurassic Morrison Formation in western Colorado: Reassessing the paleoclimatic interpretations
Keywords:
Aridisol, Inceptisol, calcrete, palustrine, lacustrine, pedogenesisAbstract
Study of the pedogenic features of the Upper Jurassic Morrison Formation in western Colorado, USA, shows a clear difference in the types of paleosols between the strata of the lower and upper Brushy Basin Member. Lower Brushy Basin paleosols are mostly calcareous Aridisols with Stage I through Stage III calcrete Bk horizons, abundant root traces, occasional vertic features, but only rarely with ochric epipedons. Upper Brushy Basin paleosols are mainly thicker and commonly display ochric epipedons and well-developed Bt and Bw horizons. We assign these paleosols to the order Inceptisol. Limestones occur in the Brushy Basin Member and include both uniformly micritic limestones and limestones with strongly brecciated textures. The former contain sparse body fossils and charophyte debris, while the latter are characterized by clotted-peloidal fabrics with circumgranular cracking and silica replacement. We interpret these limestones as the deposits of carbonate in small water bodies on a low-gradient flood plain, with the textures resulting from pedogenic reworking of the carbonate sediment. We find no evidence for the presence of extensive lacustrine or wetlands (Lake T’oo’dichi’) deposits in the study area. The paleoclimate suggested by all of these features is strongly seasonal, but subject to variations on orbital (precessional and higher) timescales causing intervals of semi-aridity during weaker monsoons, to alternate with sub-humid periods during stronger monsoons. The apparent long-term change in climate during Brushy Basin deposition potentially resulted from northward drift of North America.Downloads
Issue
Section
License
Submission of a manuscript implies that the work described has not been published before (except in the form of an abstract or a part of a lecture, review or thesis) and that is not under consideration for publication elsewhere. If and when the manuscript is accepted for publication, the authors agree to transfer the copyright of their work to the publisher. The copyright covers the exclusive rights to reproduce and distribute the work, all translation rights as well as the rights to publish the work in any electronic form.
Copyright allows you to protect your original material and stop others from using your work without your permission. It means others will generally need to credit you and your work properly, increasing its impact. If you choose to assign copyright to us, as part of the publication process, you will be asked to sign a publishing agreement. This will be after your manuscript has been through the peer-review process, been accepted, and moves into production.
Authors and authors responsibilities: Authorship should be limited to those who have made a significant contribution to the manuscript content. All those who have made significant contribution should be listed as co-authors. It is declared by the author(s) that manuscripts in all categories submitted to the journal and subjects to peer-review have not been published or submitted to any other journal or book. If the manuscript is written by several authors, the corresponding author should be indicated. It is declared that the corresponding author represents all the co-authors in certifying that all of them contributed meaningfully in preparation of the study, and that the final submitted version of the text is approved by all the co-authors. The author(s) should not publish in their study any copied part of the text and or figures from other sources without proper citation or permission (if necessary) – which is plagiarism – and stay in conflict with basal requirements of the authorship. All the authors are obliged to participate in peer review process, providing retractions or corrections of mistakes. The author(s) should indicate (the best in acknowledgements) the financial support and/or program within which the study has been prepared. Affiliation (all authors/co-authors) and corresponding address (main author) must be clearly stated.
Publication ethics and malpractice requirements: the Volumina Jurassica seeks to publish original work in the best possible form and to the highest possible standards. It is necessary to agree upon standards of expected ethical behavior for all parties involved in the act of publishing (authors, editors, peer reviewers, publisher). The Volumina Jurassica ethic statements are based on the guidelines and standards developed and published by the Committee on Publication Ethics (COPE- http://publicationethics.org/).
Anti-plagiarism Policy: Plagiarism is understood in the sense of the “use another person’s ideas or work and pretend that it is own’ (Cambridge Dictionary) or “the practice of taking someone else’s work or ideas and passing them off as one’s own” (Oxford Dictionaries), self-plagiarism (re-use of significant parts of one’s own copyrighted work without citing the original sources).
All articles in the Volumina Jurassica are supposed to be original. Authors submitting manuscript declare that submitted manuscript is original and has not been prepared from other published material. A paper should contain sufficient detail and references to permit others to replicate the work; any used information resources (phrases, data, images) must be appropriately cited or quoted.
Editors: the Volumina Jurassica editor is responsible for deciding which of the articles submitted to the journal should be published. The Volumina Jurassica editor will accept and evaluate manuscripts for their intellectual content only. Editors must not disclose any information about a submitted manuscript to anyone than stakeholders. The excluded from publication procedure are manuscripts which are beyond the scope of the interest of the journal (i.e. presenting the themes not related with the Jurassic System), and those evidently showing research misconduct (published elsewhere before, plagiarisms or bearing fundamental research mistakes). Unpublished manuscripts or materials must not be used in an editor’s own research. All submitted manuscripts will be considered for publication free of charge. When an author discovers a significant error or inaccuracy in own published work, it is the author’s obligation to promptly notify the Publisher and cooperate with the editor to retract or correct the paper.
