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HomeMy WebLinkAboutPaleontological Resources Review Memorandum MEMORANDUM To: Mr. Thomas Edmunds, Silvergate Development From: Sarah Siren, M.S., GISP, Senior Paleontologist Subject: Paleontological Resources Review – Bonita Glen Drive Project Date: January 8, 2018 cc: Callie Amoaku, Dudek Attachment(s): Paleontological Records Search Results Letter Dudek is providing this memorandum after completing a review of the potential for impacts to paleontological resources during construction of the Bonita Glen Drive Project located in the City of Chula Vista, San Diego County, California. The project site is relatively undeveloped with the majority of the project site mapped as Quaternary very old paralic deposits, undivided which are roughly correlative with the Lindavista Formation (early to middle Pleistocene, approximately 1.5 to 0.5 million years old ) (Kennedy and Tan, 2008; McComas, 2018). The San Diego Formation (Pliocene and Pleistocene in age, approximately 3 to 1.5 million years old) is mapped at the eastern most extent of the project area, and presumably underlies the Lindavista Formation at depth within the project area. Surface mapped young alluvial flood-plain deposits (less than 11,000 years old) occur at the northern most extent of the project area (Kennedy and Tan, 2008). According to the San Diego County guidelines for paleontology (County of San Diego, 2009; Deméré and Walsh, 1993), and the records search results received from the San Diego Natural History Museum (SDNHM) on January 5, 2018, the San Diego Formation has a high potential to yield paleontological resources, the Lindavista Formation has a moderate potential to yield paleontological resources (i.e. moderate resource importance), whereas younger alluvial flood-plain deposits have a low potential to yield paleontological resources. The museum records search results letter indicates that 24 paleontological localities are documented within a one-mile radius of the project boundaries (McComas, 2018; see attached Paleontological Records Search Results Letter). A large number of these localities (23) are documented nearby from the same geological units that occur beneath portions of the project site, specifically, the San Diego Formation. These sedimentary deposits have the potential to yield scientifically significant vertebrate fossils. Memorandum Subject: Paleontological Resources Review – Bonita Glen Drive Project 10271 2 January 2018 The Lindavista Formation consists of strandline deposits which have been known to produce marine invertebrate and vertebrate fossils elsewhere in San Diego County (Kennedy, 1973; Kennedy and Tan, 2008; McComas, 2018). These Pleistocene age deposits have the potential to yield scientifically significant fossils. As such, the Lindavista Formation would require part-time paleontological monitoring during any excavations into native. The older, marine San Diego Formation is likely to produce at least some fossils if impacted during construction excavation. This formation is known to produce well preserved marine invertebrates and vertebrates, as well as terrestrial vertebrates (Deméré, 1982, 1983) and would require full time paleontological monitoring. A paleontological resources mitigation program is recommended for excavation within moderate to high sensitivity geological units (e.g., Lindavista Formation and San Diego Formation, respectively) and should be implemented in accordance with the mitigation measures included at the end of this report. Excavation within lower sensitivity units (e.g, Holocene age alluvial flood- plain deposits) does not require mitigation. If you have any questions regarding this memo, please feel free to contact me (760.846.9326 or ssiren@dudek.com). Sincerely, ______________________ Sarah A. Siren, M.S., GISP Senior Paleontologist, Dudek Enc. Paleontological Records Search Results Letter Memorandum Subject: Paleontological Resources Review – Bonita Glen Drive Project 10271 3 January 2018 Mitigation Measures: Prior to the issuance of grading permits, the Applicant shall provide written confirmation to the City that a qualified paleontologist has been retained to carry out an appropriate mitigation program. (A qualified paleontologist is defined as an individual with an M.S. or Ph.D. in paleontology or geology who is familiar with paleontological procedures and techniques). A pre grade meeting shall be held among the paleontologist and the grading and excavation contractors. A paleontological monitor shall be onsite at all times during the original cutting of previously undisturbed sediments of highly sensitive geologic formations (i.e., San Diego Formation) to inspect cuts for contained fossils. (A paleontological monitor is defined as an individual who has experience in the collection and salvage of fossil materials.) The paleontological monitor shall work under the direction of a qualified paleontologist. The monitor shall be onsite on at least a half-time basis during the original cutting of previously undisturbed sediments of moderately sensitive geologic formations (e.g. Lindavista Formation) to inspect cuts for contained fossils. • The monitor shall be onsite during the original cutting of previously undisturbed sediments of moderate and high sensitivity geologic formations (e.g., Lindavista Formation and San Diego Formation, respectively) to inspect cuts for contained fossils. Monitoring is not required during excavation into low resource sensitivity geologic formations (e.g., young alluvial flood-plain deposits). • In the event that fossils are discovered in unknown, low, or moderately sensitive formations, the Applicant shall increase the per-day field monitoring time. Conversely, if fossils are not discovered, the monitoring, at the discretion of the City's Deputy City Manager/Development Services Director or its designee, shall be reduced. A paleontological monitor is not needed during grading of rocks with no resource sensitivity. When fossils are discovered, the paleontologist (or paleontological monitor) shall recover them. In most cases, this fossil salvage can be completed in a short period of time. However, some fossil specimens (such as a complete whale skeleton) may require an extended salvage time. In these instances, the paleontologist (or paleontological monitor) shall be allowed to temporarily direct, divert, or halt grading to allow recovery of fossil remains in a timely manner. Because of the potential for the recovery of small fossil remains such as isolated mammal teeth, it may be necessary in certain instances and at the discretion of the paleontological monitor to set up a screen-washing operation on the site. Memorandum Subject: Paleontological Resources Review – Bonita Glen Drive Project 10271 4 January 2018 Prepared fossils along with copies of all pertinent field notes, photos, and maps shall be deposited in a scientific institution with paleontological collections such as the San Diego Natural History Museum. A final summary report shall be completed. This report shall include discussions of the methods used, stratigraphy exposed, fossils collected, and significance of recovered fossils. References Cited: County of San Diego, 2009. Guidelines for Determining Significance, Paleontological Resources. Department of Planning and Land Use, Department of Public Works. March 19, Modified January 15, 2009. Deméré, T.A., 1982. Review of the lithostratigraphy, biostratigraphy and age of the San Diego Formation. In, Abbott, P.L., ed. Geologic studies in San Diego. San Diego Association of Geologists, Field Trip Guidebook, pp. 127-134. Deméré, T.A., 1983. The Neogene San Diego Basin: a review of the marine Pliocene San Diego Formation, p. 187-195. In, D.K. Larue and R.J. Steel (eds.), Cenozoic Marine Sedimentation Pacific Margin, U.S.A. Society of Economic Paleontologists and Mineralogists, Pacific Section, Book 28: 187-195, figs. 1-6. Deméré, T.A. and S.L. Walsh, 1993. Paleontological Resources, County of San Diego. Prepared for the San Diego Planning Commission, pp. 1-68. Kennedy, G.L. 1973. A marine invertebrate faunule from the Lindavista Formation, San Diego, California. Transactions of the San Diego Society of Natural History, 17(10): 119 – 128, figs 1-3. Kennedy, M.P., and Tan, S.S., 2008, Geologic map of the San Diego 30' x 60' quadrangle, California: California Geological Survey, Regional Geologic Map No. 3, scale 1:100,000. McComas, K. 2018. Paleontological Record Search – Bonita Glen Project (Project No. 10271). Unpublished letter report by the San Diego Natural History Museum. January 5, 2018. 5 January 2018 Ms. Sarah Siren Dudek 605 Third Street Encinitas, CA 92024 RE: Paleontological Records Search – Bonita Glen Project (Project No. 10271) Dear Ms. Siren: This letter presents the results of a paleontological records search conducted for the Bonita Glen project, located in the northwestern portion of the City of Chula Vista, San Diego County, CA. The project site is bounded to the west and south by Bonita Glen Drive, to the east and northeast by Vista Drive, and to the north and northwest by commercial development. A review of published geological maps covering the project site and surrounding area was conducted to determine the specific geologic units underlying the project. Each geologic unit was subsequently assigned a paleontological resource sensitivity following County of San Diego guidelines (Deméré and Walsh, 1993; Stephenson et al., 2009). Published geological reports (e.g., Kennedy and Tan, 2008) covering the project area indicate that the proposed project has the potential to impact the early to middle Pleistocene-age Lindavista Formation and the late Pliocene- to early Pleistocene-age San Diego Formation. These geologic units and their paleontological sensitivity are summarized in detail in the following section. In addition, a search of the paleontological collection records housed at the San Diego Natural History Museum (SDNHM) was conducted in order to determine if any documented fossil collection localities occur at the project site or within the immediate surrounding area (Figure 1). The SDNHM has 24 recorded fossil localities within one mile of the project site. One of these localities is from the Pleistocene-age Bay Point Formation, which is not anticipated to be impacted by construction. The remaining 23 localities are from the San Diego Formation, and are described in greater detail below. Geologic Rock Units Underlying the Project Area Lindavista Formation – The majority of the project site is underlain by the marine and/or non- marine terrace deposits of the early to middle Pleistocene-age (approximately 1.5 to 0.5 million years old) Lindavista Formation. The SDNHM does not have any fossil collection localities from these deposits within a 1-mile radius of the project site, but the Lindavista Formation has produced remains of nearshore marine invertebrates (e.g., clams, scallops, snails, barnacles, and sand dollars), as well as sparse remains of marine vertebrates (e.g., sharks and baleen whales). Fossils have primarily been recovered from localities in Tierrasanta and Mira Mesa where the Lindavista Formation is assigned a high paleontological sensitivity; elsewhere in San Diego County, including in the vicinity of the project site, the Lindavista Formation is assigned a moderate paleontological sensitivity. San Diego Formation – Marine sedimentary deposits of the late Pliocene to early Pleistocene- age (approximately 3 to 1.5 million years old) San Diego Formation underlie the eastern margin of the Bonita Glen Project - Paleontological Records Search 2 project site, and likely underlie the Lindavista Formation at unknown depths throughout the rest of the project site. The SDNHM has 23 fossil collection localities from the San Diego Formation within a 1-mile radius of the project area. These localities produced trace fossils (e.g., sponge borings) and fossilized impressions or remains of marine invertebrates (e.g., bryozoans, brachiopods, snails, mussels, oysters, scallops, clams, tusk shells, barnacles, crabs, starfish, sand dollars, and sea urchins), marine vertebrates (e.g., sharks, skates, rays, bony fish, sea birds, walruses, eared seals, dolphins, and whales), and terrestrial vertebrates (e.g., snakes). Based on the important fossil remains of marine mammals, sea birds, and mollusks recovered from this geologic unit, the San Diego Formation has been assigned a high paleontological sensitivity. Summary and Recommendations The moderate paleontological sensitivity of the Lindavista Formation and high paleontological sensitivity of the San Diego Formation in San Diego County (Deméré and Walsh, 1993; Stephenson et al., 2009), as well as the presence of fossil localities nearby, suggest the potential for construction of the proposed project to result in impacts to paleontological resources. Any proposed excavation activities that extend deep enough to encounter previously undisturbed deposits of these geologic units have the potential to impact the paleontological resources preserved therein. For these reasons, implementation of a complete paleontological resource mitigation program during ground-disturbing activities is recommended. The fossil collection locality information contained within this paleontological record search should be considered private and is the sole property of the San Diego Natural History Museum. Any use or reprocessing of information contained within this document beyond the scope of the Bonita Glen project is prohibited. If you have any questions concerning these findings please feel free to contact me at 619-255- 0321 or kmccomas@sdnhm.org. Sincerely, Katie McComas Paleontology Collections Assistant San Diego Natural History Museum Enc: Figure 1: Project map Appendix: Localities in the vicinity of the project Bonita Glen Project - Paleontological Records Search 3 Literature Cited Deméré, T.A., and Walsh, S.L. 1993. Paleontological Resources, County of San Diego. Prepared for the San Diego Planning Commission: 1–68. Kennedy, M.P. and Tan, S.S. 2008. Geologic Map of the San Diego 30’ X 60’ Quadrangle, California. California Geological Survey. Scale 1:100,000. Stephenson, B., and seven others. 2009. County of San Diego Guidelines for determining significance, paleontological resources. Land Use and Environment Group, Department of Planning and Land Use, Department of Public Works, 46 p. FIGURE1 Bonita Glen ProjectCity of Chula Vista, San Diego County, California 0 0.4 scale in miles Project Map San D iegoCo. Imperial Co. map extent Sources: Bing Maps Hybrid Imagery, Microsoft et al., 2017 Project site 1 mile radius buffer SDSNH localities Project Site Riverside Co. Appendix: Locality List San Diego Natural History Museum Department of Paleontology Locality Number Locality Name Location Elevation (feet)Geologic Unit Era Period Epoch 4839 Villa San Miguel City of Chula Vista, San Diego County, CA 120 Bay Point Formation, unnamed nonmarine deposit Cenozoic Quaternary Pleistocene 3153 Hidden Vista Development City of Chula Vista, San Diego County, CA 200 San Diego Formation Cenozoic Neogene Pliocene 3182 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 176 San Diego Formation Cenozoic Neogene Pliocene 5053 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5054 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5055 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5056 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5057 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5058 Rice Canyon City of San Diego, San Diego County, CA 270 San Diego Formation Cenozoic Neogene Pliocene 5472 Bonita Creek Housing Development City of National City, San Diego County, CA 42 San Diego Formation Cenozoic Neogene Pliocene 3159 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 280 San Diego Formation, lower member Cenozoic Neogene Pliocene 3164 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 240 San Diego Formation, lower member Cenozoic Neogene Pliocene 3165 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 276 San Diego Formation, lower member Cenozoic Neogene Pliocene 3166 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 230 San Diego Formation, lower member Cenozoic Neogene Pliocene 3168 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 200 San Diego Formation, lower member Cenozoic Neogene Pliocene 3183 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 230 San Diego Formation, lower member Cenozoic Neogene Pliocene 3184 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 236 San Diego Formation, lower member Cenozoic Neogene Pliocene 3185 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 248 San Diego Formation, lower member Cenozoic Neogene Pliocene 3186 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 222 San Diego Formation, lower member Cenozoic Neogene Pliocene 3187 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 220 San Diego Formation, lower member Cenozoic Neogene Pliocene 3188 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 230 San Diego Formation, lower member Cenozoic Neogene Pliocene 3189 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 266 San Diego Formation, lower member Cenozoic Neogene Pliocene 3190 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 200 San Diego Formation, lower member Cenozoic Neogene Pliocene 4044 Hidden Vista Village Project City of Chula Vista, San Diego County, CA 180 San Diego Formation, member 2 Cenozoic Neogene late Pliocene 1 of 1