Mono Lake (CA) is a hydrologically closed lacustrine basin well-known for its paleo-shorelines, which record fluctuations in water level for the last deglacial and late Holocene. Mono Lake is a sentinel of California’s water supply, situated in the rain shadow of the Sierra Nevada, a mountain range whose snowpack is a vital source of freshwater for urban and agricultural districts to the west and south. Recent droughts, floods, and wildfires show that California is threatened by climate change, but how these changes impact and get recorded by Mono Lake sediments remains poorly known. Here, we use a new radiocarbon-dated deepwater sediment core from Mono Lake to test the hypothesis that organic facies development is controlled by climate and limnological change. An integrated stratigraphic analysis of the core reveals seven lithostratigraphic units that track environmental changes from ~16-4 ka. When compared to available paleo-shoreline and shallow water core data, our results show that high amplitude lakelevel fluctuations of the late Pleistocene produce different patterns of sedimentation and organic enrichment than lower-amplitude water level changes of the early and middle Holocene. The results have implications for understanding patterns of paleo-production and hydroclimate change at Mono Lake.

Nearly 550 samples of fine grained carbonates, collected every 0.5 to 1.0 m from the Bloom Member of the Snaky Canyon Formation at Gallagher Peak, Idaho, were analyzed to determine the high-resolution carbon isotope stratigraphy. To constrain for diagenesis, thin sections were petrographically analyzed and viewed using cathodoluminescence microscopy. Chemical analyses were performed using an electron microprobe. Average delta18O and delta13C values from the Bloom Member are -4.5% +/- 1.6% (1 sigma) and 2.1% +/- 1.1%, respectively. Maximum delta13C values are about 1% higher for the Desmoinesian and Missourian than the Morrowan and Atokan, similar to results from the Yukon Territory. delta18O and delta13C values are lowest for crystalline mosaic limestones and siltstones, moderate for packstones, wackestones, and mudstones, and highest for boundstones and grainstones. The delta13C profile from Gallagher Peak consists of high frequency 1% oscillations with several larger excursions. No large delta13C increase at the base of the section suggests the Mid-Carboniferous boundary is in the underlying Bluebird Mountain formation. delta13C of Gallagher Peak and Arrow Canyon, NV, correlate well from 318 to 310 Ma, but correlation becomes more difficult around 310 Ma. This may result from increased restriction of the Snaky Canyon platform beginning in the Desmoinesian. Most of the short term (<1 Ma) isotopic excursions are the result of diagenesis. Two of the largest negative excursions at Gallagher Peak correlate with two large negative excursions at Big Hatchet Peak, NM, possibly due to sea level lowstands of the Desmoinesian. Phylloid algal mounds at Gallagher Peak are associated with positive excursions because of original aragonite composition and increased open marine influence. Positive excursions related to other facies characteristics also result from increased marine influence. The delta13C curve for the upper half of Gallagher Peak contains three repeated cycles of increasing delta13C over 1-1.5 Ma, which are possibly related to long-term sea level fluctuations. Given the complexity of each local environment, without detailed biostratigraphy, detailed rock descriptions, and analysis of the various rock components, delta13C stratigraphy of whole rocks can be misinterpreted.

The Oligocene Te Kuiti Group in Waitomo County, North Island, New Zealand, is divided into two subgroups, six formations and seven limestone members; six of the members are new. The stratigraphic definition, distribution, thickness, lithology and contacts of major rock units, and the three dimensional relationships between them, are described and figured in detail. Rapid lateral and vertical lithologic variation in strata is accomodated by recognition of 31 lithofacies. Te Kuiti sediments, which include mainly bioclastic lutites, bioclastic arenites and biocalcarenites, were deposited in sublittoral waters, from a few to about 100 metres depth, as seas transgressed south over a topoqraphically subdued, but locally varied landscape cut in Mesozoic lutites and arenites. Distribution of major paleotectonic elements indicates the gross sedimentary environment was one of a north-facing, partly enclosed basin with a prominent north-trending median basement ridge (Piopio High) in the south. Deposition continued until this ridge was almost completely buried, at which time the Te Kuiti embayment expanded rapidly and linked with more southerly basins. The contact with the overlying Mahoenui Group is generally conformable in Waitomo County. Formations and members are commonly bounded by unconformities, mainly disconformities, some of which preserve features consistent with their interpretation as submarine hardgrounds. The unconformities record periods of erosion or non-deposition during major downward shifts in base level controlled partly by eustatic sea level changes. Comprehensive paleontological charts are prepared for each formation and age relationships established. Macrofossils are generally scarce, and dominated by thick-shelled, epifaunal bivalves. Foraminifera are more abundant and are mainly benthonic forms. Formations may straddle New Zealand stage boundaries and, within Waitomo County, are not strongly diachronous. Primary sedimentary structures in arenites and calcarenites include mainly thinly bedded wavy-, lenticular-, and cross-stratification formed by the spreading and interfering of sand sheets, sand ribbons and sand waves across extensive areas of flat shallow sea floor, possibly under the influence of tidal currents. Lutites and muddy arenites are massive and bioturbated. A new classification for mixed terrigenous-allochemical rocks is proposed and an X-ray technique developed for modal analyses of lutites. The petrography of individual lithofacies is described and illustrated in detail and summarised on pie diagrams. Variations in the kind, quantity, size, sorting and abrasion of bioclasts, in the king and quantity of matrix add/or cement, and in the content of glauconite and terrigenous sand and mud serve to distinguish the various lithofacies. Bioclasts are derived principally from bryozoans, echinoids and benthonic foraminifers and, to a lesser extent, from coralline algae, planktonic foraminifers, molluscs and brachiopods. Siliciclasts include mainly quartz, oligoclase – andesine plagioclase, potash feldspar, montmorillonitic clays and glauconite. Quartz and feldspar were detritally inherited from Mesozoic basement rocks; montmorillonite formed from the marine diagenetic transformation of vermiculite and degraded chlorite and illite derived from Oligocene soils; glauconite developed from mont-morillonitic clays under specific environmental conditions. Complete chemical analyses of seven glauconite concentrates are presented and compared with published analyses. The principal non-opaque heavy minerals in the group are zircon, epidote and apatite. Sediment pores are infilled with granular and rim ortho-sparite cement, or by a variety of matrix materials, including micrite, calcilutite and lutite. Petrologs display the vertical variation in petrographic properties through the group and, in conjunction with grain size analyses of insoluble residues, are used to interpret the energy level of the environment of deposition of individual rock units. Te Kuiti sediments accumulated under a spectrum of environmental energy conditions, ranging from quiet to strongly agitated waters. The primary Te Kuiti sediment was dominated by metastable magnesium calcite and, less abundant, aragonite skeletons. These skeletons underwent syndiagenetic stablisation reactions at, or close below, the sea floor. Large quantities of skeletal aragonite were dissolved from the sediment before lithification. Aragonite was preserved only where anaerobic conditions were maintained in the sediment. Stabilisation of magnesium calcite grains involved the texturally non-destructive process of incongruent dissolution, which yielded a replacement product of calcite. Sources of CaCO3 for cement included (a) solution of aragonite grains, (b) intergranular solution of bioclasts and, most important, (c) pervasive solution of bioclasts, under shallow burial loads, at those levels in the sediment relatively enrichment in siliciclastic, and especially muddy, material. Dissolved CaCO3 was precipitated as calcite cement in adjacent or nearby sediment layers. A paragenetic sequence of diagenetic events is established for the group. Finally, Oligocene paleogeography and paleoclimate are outlined and a synthesis of the environment of formation and depositional history of sediments of the Te Kuiti Group in Waitomo Country is established.

The Oligocene Te Kuiti Group in Waitomo County, North Island, New Zealand, is divided into two subgroups, six formations and seven limestone members; six of the members are new. The stratigraphic definition, distribution, thickness, lithology and contacts of major rock units, and the three dimensional relationships between them, are described and figured in detail. Rapid lateral and vertical lithologic variation in strata is accomodated by recognition of 31 lithofacies. Te Kuiti sediments, which include mainly bioclastic lutites, bioclastic arenites and biocalcarenites, were deposited in sublittoral waters, from a few to about 100 metres depth, as seas transgressed south over a topoqraphically subdued, but locally varied landscape cut in Mesozoic lutites and arenites. Distribution of major paleotectonic elements indicates the gross sedimentary environment was one of a north-facing, partly enclosed basin with a prominent north-trending median basement ridge (Piopio High) in the south. Deposition continued until this ridge was almost completely buried, at which time the Te Kuiti embayment expanded rapidly and linked with more southerly basins. The contact with the overlying Mahoenui Group is generally conformable in Waitomo County. Formations and members are commonly bounded by unconformities, mainly disconformities, some of which preserve features consistent with their interpretation as submarine hardgrounds. The unconformities record periods of erosion or non-deposition during major downward shifts in base level controlled partly by eustatic sea level changes. Comprehensive paleontological charts are prepared for each formation and age relationships established. Macrofossils are generally scarce, and dominated by thick-shelled, epifaunal bivalves. Foraminifera are more abundant and are mainly benthonic forms. Formations may straddle New Zealand stage boundaries and, within Waitomo County, are not strongly diachronous. Primary sedimentary structures in arenites and calcarenites include mainly thinly bedded wavy-, lenticular-, and cross-stratification formed by the spreading and interfering of sand sheets, sand ribbons and sand waves across extensive areas of flat shallow sea floor, possibly under the influence of tidal currents. Lutites and muddy arenites are massive and bioturbated. A new classification for mixed terrigenous-allochemical rocks is proposed and an X-ray technique developed for modal analyses of lutites. The petrography of individual lithofacies is described and illustrated in detail and summarised on pie diagrams. Variations in the kind, quantity, size, sorting and abrasion of bioclasts, in the king and quantity of matrix add/or cement, and in the content of glauconite and terrigenous sand and mud serve to distinguish the various lithofacies. Bioclasts are derived principally from bryozoans, echinoids and benthonic foraminifers and, to a lesser extent, from coralline algae, planktonic foraminifers, molluscs and brachiopods. Siliciclasts include mainly quartz, oligoclase – andesine plagioclase, potash feldspar, montmorillonitic clays and glauconite. Quartz and feldspar were detritally inherited from Mesozoic basement rocks; montmorillonite formed from the marine diagenetic transformation of vermiculite and degraded chlorite and illite derived from Oligocene soils; glauconite developed from mont-morillonitic clays under specific environmental conditions. Complete chemical analyses of seven glauconite concentrates are presented and compared with published analyses. The principal non-opaque heavy minerals in the group are zircon, epidote and apatite. Sediment pores are infilled with granular and rim ortho-sparite cement, or by a variety of matrix materials, including micrite, calcilutite and lutite. Petrologs display the vertical variation in petrographic properties through the group and, in conjunction with grain size analyses of insoluble residues, are used to interpret the energy level of the environment of deposition of individual rock units. Te Kuiti sediments accumulated under a spectrum of environmental energy conditions, ranging from quiet to strongly agitated waters. The primary Te Kuiti sediment was dominated by metastable magnesium calcite and, less abundant, aragonite skeletons. These skeletons underwent syndiagenetic stablisation reactions at, or close below, the sea floor. Large quantities of skeletal aragonite were dissolved from the sediment before lithification. Aragonite was preserved only where anaerobic conditions were maintained in the sediment. Stabilisation of magnesium calcite grains involved the texturally non-destructive process of incongruent dissolution, which yielded a replacement product of calcite. Sources of CaCO3 for cement included (a) solution of aragonite grains, (b) intergranular solution of bioclasts and, most important, (c) pervasive solution of bioclasts, under shallow burial loads, at those levels in the sediment relatively enrichment in siliciclastic, and especially muddy, material. Dissolved CaCO3 was precipitated as calcite cement in adjacent or nearby sediment layers. A paragenetic sequence of diagenetic events is established for the group. Finally, Oligocene paleogeography and paleoclimate are outlined and a synthesis of the environment of formation and depositional history of sediments of the Te Kuiti Group in Waitomo Country is established.

The Oligocene Te Kuiti Group in Waitomo County, North Island, New Zealand, is divided into two subgroups, six formations and seven limestone members; six of the members are new. The stratigraphic definition, distribution, thickness, lithology and contacts of major rock units, and the three dimensional relationships between them, are described and figured in detail. Rapid lateral and vertical lithologic variation in strata is accomodated by recognition of 31 lithofacies. Te Kuiti sediments, which include mainly bioclastic lutites, bioclastic arenites and biocalcarenites, were deposited in sublittoral waters, from a few to about 100 metres depth, as seas transgressed south over a topoqraphically subdued, but locally varied landscape cut in Mesozoic lutites and arenites. Distribution of major paleotectonic elements indicates the gross sedimentary environment was one of a north-facing, partly enclosed basin with a prominent north-trending median basement ridge (Piopio High) in the south. Deposition continued until this ridge was almost completely buried, at which time the Te Kuiti embayment expanded rapidly and linked with more southerly basins. The contact with the overlying Mahoenui Group is generally conformable in Waitomo County. Formations and members are commonly bounded by unconformities, mainly disconformities, some of which preserve features consistent with their interpretation as submarine hardgrounds. The unconformities record periods of erosion or non-deposition during major downward shifts in base level controlled partly by eustatic sea level changes. Comprehensive paleontological charts are prepared for each formation and age relationships established. Macrofossils are generally scarce, and dominated by thick-shelled, epifaunal bivalves. Foraminifera are more abundant and are mainly benthonic forms. Formations may straddle New Zealand stage boundaries and, within Waitomo County, are not strongly diachronous. Primary sedimentary structures in arenites and calcarenites include mainly thinly bedded wavy-, lenticular-, and cross-stratification formed by the spreading and interfering of sand sheets, sand ribbons and sand waves across extensive areas of flat shallow sea floor, possibly under the influence of tidal currents. Lutites and muddy arenites are massive and bioturbated. A new classification for mixed terrigenous-allochemical rocks is proposed and an X-ray technique developed for modal analyses of lutites. The petrography of individual lithofacies is described and illustrated in detail and summarised on pie diagrams. Variations in the kind, quantity, size, sorting and abrasion of bioclasts, in the king and quantity of matrix add/or cement, and in the content of glauconite and terrigenous sand and mud serve to distinguish the various lithofacies. Bioclasts are derived principally from bryozoans, echinoids and benthonic foraminifers and, to a lesser extent, from coralline algae, planktonic foraminifers, molluscs and brachiopods. Siliciclasts include mainly quartz, oligoclase – andesine plagioclase, potash feldspar, montmorillonitic clays and glauconite. Quartz and feldspar were detritally inherited from Mesozoic basement rocks; montmorillonite formed from the marine diagenetic transformation of vermiculite and degraded chlorite and illite derived from Oligocene soils; glauconite developed from mont-morillonitic clays under specific environmental conditions. Complete chemical analyses of seven glauconite concentrates are presented and compared with published analyses. The principal non-opaque heavy minerals in the group are zircon, epidote and apatite. Sediment pores are infilled with granular and rim ortho-sparite cement, or by a variety of matrix materials, including micrite, calcilutite and lutite. Petrologs display the vertical variation in petrographic properties through the group and, in conjunction with grain size analyses of insoluble residues, are used to interpret the energy level of the environment of deposition of individual rock units. Te Kuiti sediments accumulated under a spectrum of environmental energy conditions, ranging from quiet to strongly agitated waters. The primary Te Kuiti sediment was dominated by metastable magnesium calcite and, less abundant, aragonite skeletons. These skeletons underwent syndiagenetic stablisation reactions at, or close below, the sea floor. Large quantities of skeletal aragonite were dissolved from the sediment before lithification. Aragonite was preserved only where anaerobic conditions were maintained in the sediment. Stabilisation of magnesium calcite grains involved the texturally non-destructive process of incongruent dissolution, which yielded a replacement product of calcite. Sources of CaCO3 for cement included (a) solution of aragonite grains, (b) intergranular solution of bioclasts and, most important, (c) pervasive solution of bioclasts, under shallow burial loads, at those levels in the sediment relatively enrichment in siliciclastic, and especially muddy, material. Dissolved CaCO3 was precipitated as calcite cement in adjacent or nearby sediment layers. A paragenetic sequence of diagenetic events is established for the group. Finally, Oligocene paleogeography and paleoclimate are outlined and a synthesis of the environment of formation and depositional history of sediments of the Te Kuiti Group in Waitomo Country is established.

The Oligocene Te Kuiti Group in Waitomo County, North Island, New Zealand, is divided into two subgroups, six formations and seven limestone members; six of the members are new. The stratigraphic definition, distribution, thickness, lithology and contacts of major rock units, and the three dimensional relationships between them, are described and figured in detail. Rapid lateral and vertical lithologic variation in strata is accomodated by recognition of 31 lithofacies. Te Kuiti sediments, which include mainly bioclastic lutites, bioclastic arenites and biocalcarenites, were deposited in sublittoral waters, from a few to about 100 metres depth, as seas transgressed south over a topoqraphically subdued, but locally varied landscape cut in Mesozoic lutites and arenites. Distribution of major paleotectonic elements indicates the gross sedimentary environment was one of a north-facing, partly enclosed basin with a prominent north-trending median basement ridge (Piopio High) in the south. Deposition continued until this ridge was almost completely buried, at which time the Te Kuiti embayment expanded rapidly and linked with more southerly basins. The contact with the overlying Mahoenui Group is generally conformable in Waitomo County. Formations and members are commonly bounded by unconformities, mainly disconformities, some of which preserve features consistent with their interpretation as submarine hardgrounds. The unconformities record periods of erosion or non-deposition during major downward shifts in base level controlled partly by eustatic sea level changes. Comprehensive paleontological charts are prepared for each formation and age relationships established. Macrofossils are generally scarce, and dominated by thick-shelled, epifaunal bivalves. Foraminifera are more abundant and are mainly benthonic forms. Formations may straddle New Zealand stage boundaries and, within Waitomo County, are not strongly diachronous. Primary sedimentary structures in arenites and calcarenites include mainly thinly bedded wavy-, lenticular-, and cross-stratification formed by the spreading and interfering of sand sheets, sand ribbons and sand waves across extensive areas of flat shallow sea floor, possibly under the influence of tidal currents. Lutites and muddy arenites are massive and bioturbated. A new classification for mixed terrigenous-allochemical rocks is proposed and an X-ray technique developed for modal analyses of lutites. The petrography of individual lithofacies is described and illustrated in detail and summarised on pie diagrams. Variations in the kind, quantity, size, sorting and abrasion of bioclasts, in the king and quantity of matrix add/or cement, and in the content of glauconite and terrigenous sand and mud serve to distinguish the various lithofacies. Bioclasts are derived principally from bryozoans, echinoids and benthonic foraminifers and, to a lesser extent, from coralline algae, planktonic foraminifers, molluscs and brachiopods. Siliciclasts include mainly quartz, oligoclase – andesine plagioclase, potash feldspar, montmorillonitic clays and glauconite. Quartz and feldspar were detritally inherited from Mesozoic basement rocks; montmorillonite formed from the marine diagenetic transformation of vermiculite and degraded chlorite and illite derived from Oligocene soils; glauconite developed from mont-morillonitic clays under specific environmental conditions. Complete chemical analyses of seven glauconite concentrates are presented and compared with published analyses. The principal non-opaque heavy minerals in the group are zircon, epidote and apatite. Sediment pores are infilled with granular and rim ortho-sparite cement, or by a variety of matrix materials, including micrite, calcilutite and lutite. Petrologs display the vertical variation in petrographic properties through the group and, in conjunction with grain size analyses of insoluble residues, are used to interpret the energy level of the environment of deposition of individual rock units. Te Kuiti sediments accumulated under a spectrum of environmental energy conditions, ranging from quiet to strongly agitated waters. The primary Te Kuiti sediment was dominated by metastable magnesium calcite and, less abundant, aragonite skeletons. These skeletons underwent syndiagenetic stablisation reactions at, or close below, the sea floor. Large quantities of skeletal aragonite were dissolved from the sediment before lithification. Aragonite was preserved only where anaerobic conditions were maintained in the sediment. Stabilisation of magnesium calcite grains involved the texturally non-destructive process of incongruent dissolution, which yielded a replacement product of calcite. Sources of CaCO3 for cement included (a) solution of aragonite grains, (b) intergranular solution of bioclasts and, most important, (c) pervasive solution of bioclasts, under shallow burial loads, at those levels in the sediment relatively enrichment in siliciclastic, and especially muddy, material. Dissolved CaCO3 was precipitated as calcite cement in adjacent or nearby sediment layers. A paragenetic sequence of diagenetic events is established for the group. Finally, Oligocene paleogeography and paleoclimate are outlined and a synthesis of the environment of formation and depositional history of sediments of the Te Kuiti Group in Waitomo Country is established.

The Oligocene Te Kuiti Group in Waitomo County, North Island, New Zealand, is divided into two subgroups, six formations and seven limestone members; six of the members are new. The stratigraphic definition, distribution, thickness, lithology and contacts of major rock units, and the three dimensional relationships between them, are described and figured in detail. Rapid lateral and vertical lithologic variation in strata is accomodated by recognition of 31 lithofacies. Te Kuiti sediments, which include mainly bioclastic lutites, bioclastic arenites and biocalcarenites, were deposited in sublittoral waters, from a few to about 100 metres depth, as seas transgressed south over a topoqraphically subdued, but locally varied landscape cut in Mesozoic lutites and arenites. Distribution of major paleotectonic elements indicates the gross sedimentary environment was one of a north-facing, partly enclosed basin with a prominent north-trending median basement ridge (Piopio High) in the south. Deposition continued until this ridge was almost completely buried, at which time the Te Kuiti embayment expanded rapidly and linked with more southerly basins. The contact with the overlying Mahoenui Group is generally conformable in Waitomo County. Formations and members are commonly bounded by unconformities, mainly disconformities, some of which preserve features consistent with their interpretation as submarine hardgrounds. The unconformities record periods of erosion or non-deposition during major downward shifts in base level controlled partly by eustatic sea level changes. Comprehensive paleontological charts are prepared for each formation and age relationships established. Macrofossils are generally scarce, and dominated by thick-shelled, epifaunal bivalves. Foraminifera are more abundant and are mainly benthonic forms. Formations may straddle New Zealand stage boundaries and, within Waitomo County, are not strongly diachronous. Primary sedimentary structures in arenites and calcarenites include mainly thinly bedded wavy-, lenticular-, and cross-stratification formed by the spreading and interfering of sand sheets, sand ribbons and sand waves across extensive areas of flat shallow sea floor, possibly under the influence of tidal currents. Lutites and muddy arenites are massive and bioturbated. A new classification for mixed terrigenous-allochemical rocks is proposed and an X-ray technique developed for modal analyses of lutites. The petrography of individual lithofacies is described and illustrated in detail and summarised on pie diagrams. Variations in the kind, quantity, size, sorting and abrasion of bioclasts, in the king and quantity of matrix add/or cement, and in the content of glauconite and terrigenous sand and mud serve to distinguish the various lithofacies. Bioclasts are derived principally from bryozoans, echinoids and benthonic foraminifers and, to a lesser extent, from coralline algae, planktonic foraminifers, molluscs and brachiopods. Siliciclasts include mainly quartz, oligoclase – andesine plagioclase, potash feldspar, montmorillonitic clays and glauconite. Quartz and feldspar were detritally inherited from Mesozoic basement rocks; montmorillonite formed from the marine diagenetic transformation of vermiculite and degraded chlorite and illite derived from Oligocene soils; glauconite developed from mont-morillonitic clays under specific environmental conditions. Complete chemical analyses of seven glauconite concentrates are presented and compared with published analyses. The principal non-opaque heavy minerals in the group are zircon, epidote and apatite. Sediment pores are infilled with granular and rim ortho-sparite cement, or by a variety of matrix materials, including micrite, calcilutite and lutite. Petrologs display the vertical variation in petrographic properties through the group and, in conjunction with grain size analyses of insoluble residues, are used to interpret the energy level of the environment of deposition of individual rock units. Te Kuiti sediments accumulated under a spectrum of environmental energy conditions, ranging from quiet to strongly agitated waters. The primary Te Kuiti sediment was dominated by metastable magnesium calcite and, less abundant, aragonite skeletons. These skeletons underwent syndiagenetic stablisation reactions at, or close below, the sea floor. Large quantities of skeletal aragonite were dissolved from the sediment before lithification. Aragonite was preserved only where anaerobic conditions were maintained in the sediment. Stabilisation of magnesium calcite grains involved the texturally non-destructive process of incongruent dissolution, which yielded a replacement product of calcite. Sources of CaCO3 for cement included (a) solution of aragonite grains, (b) intergranular solution of bioclasts and, most important, (c) pervasive solution of bioclasts, under shallow burial loads, at those levels in the sediment relatively enrichment in siliciclastic, and especially muddy, material. Dissolved CaCO3 was precipitated as calcite cement in adjacent or nearby sediment layers. A paragenetic sequence of diagenetic events is established for the group. Finally, Oligocene paleogeography and paleoclimate are outlined and a synthesis of the environment of formation and depositional history of sediments of the Te Kuiti Group in Waitomo Country is established.

A Formação Candeias (PACK & ALMEIDA, 1945) pertencente ao Grupo Santo Amaro, consiste em arenitos e folhelhos do período Cretáceo e corresponde aos primeiros depósitos da abertura plena do rifte da Bacia do Recôncavo. A idade destes sedimentos varia do Berriasiano médio ao Valanginiano inferior (~143M. a.), com uma amplitude temporal de 4,5 M.a. e uma espessura média de 1000 m. Localiza-se no andar Rio da Serra, e os sedimentos são interpretados como lacustres e depósitos de corrente de turbidez, da fase de clímax do Rifte (PROSSER, 1993), possuindo um papel muito importante na historia do desenvolvimento da extração de petróleo e gás na Bacia do Recôncavo, pois os folhelhos desta formação são as rochas geradoras desta bacia, e os arenitos são importantes reservatórios de hidrocarbonetos. Entender os processos sedimentológicos desta formação, bem como sua evolução estratigráfica, ainda é um desafio, pois a maioria das informações provém de dados indiretos (sísmica, perfis elétricos e dados de produção de petróleo), já que os afloramentos são escassos. Assim, os estudos das rochas de testemunhos seriam os dados diretos principais e aqui explorados. A área de estudo está localizada no compartimento estrutural denominado Borda Nordeste da Bacia do Recôncavo, e abrange os campos de Rio Itariri, Fazenda Bálsamo e Riacho da Barra, que estão alinhados ao longo da Falha de Salvador (borda falhada do rifte) no Patamar de Patioba. O sistema deposicional é interpretado como lacustre com depósitos arenosos provenientes de corrente de turbidez, é composto principalmente por pelitos, heterolitos, arenitos arcoseanos (FOLK, 1968) e arenitos híbridos (ZUFFA, 1980). Os fluxos turbiditicos são interpretados como resultado da desestabilização do talude lacustre em período de atividade tectônica intensa. Durante o período de quiescência tectônica, a maior parte da sedimentação é atribuída a rochas pelíticas. Estes depósitos podem ser correlacionados em toda a borda nordeste e os pelitos possuem uma boa resposta em perfis elétricos e sísmica. A estratigrafia de sequências (ES) em bacias tipo rifte pode utilizar os mesmos critérios dos utilizados em bacias intracratônicas ou de margem passiva, porém deve-se levar em conta a intensa atividade tectônica atuante, como propõem Prosser, (1993) e Martins - Neto & Catuneanu (2010). A metodologia utilizada baseia-se identificar tendências Transgressiva – Regressiva (T-R) segundo Embry & Johannenessen (1992), de 3ª e 4ª ordens e, a partir destas, identificar as principais superfícies estratigráficas. Foram assim, identificadas cinco superfícies estratigráficas (duas superfícies de inundação máxima (SIM) e três limites de sequência (LS)) para as três sequências deposicionais, denominadas como Sequencia I, Sequencia II e Sequencia III. Estas superfícies permitiram correlacionar os depósitos arenosos, utilizando os perfis elétricos (Raios Gama, Resistividade e densidade-neutrão). Para isso, foram descritos 1430m de testemunhos, 54 lâminas petrográficas, feita a interpretação sísmica dos horizontes estratigráficos de duas sísmicas 3D, análises geoquímica de minerais pesados, análise de palinofácies e geoquímica orgânica, de seis poços dos três campos em estudo. A análise estratigráfica e sedimentológica baseou-se na correlação rocha x perfil destes poços, descrição granulométrica e interpretação das fácies, suas associações e petrofácies. As fácies arenosas são descritas como arenitos finos a grossos, com estratificação plana paralela a cruzada de baixo ângulo, muitas vezes com fluidização e carga e maciços. Estas fácies estão relacionadas à fácies de canais turbidíticos ou a lobos turbidíticos proximais. Heterolitos e arenitos muito finos com ripples de corrente e intensa fluidização e pelitos cinza laminados e maciços estão relacionados a lobos turbidíticos distais ou a depósitos de fundo de bacia. A análise petrográfica dos arenitos revelou que estes são essencialmente arcoseanos, e com presença abundante de bioclastos de ostracodes, oncolitos, além de pelóides e alguns aloquímicos indiferenciados, para sequencia I, e fragmentos de rocha metamórfica, ígnea e sedimentar, além de cristais de carbonato, fosfatos e intraclasto lamoso, para a sequência II. Calcita, calcita ferrosa, dolomita, dolomita ferrosa e são os principais cimentos encontrados provavelmente devido à dissolução dos aloquímicos carbonáticos. Porém os processos diagenéticos mais frequentes são a autigênese de sílica gerando crescimento de quartzo e albita. Muitos destes processos diagenéticos podem contribuir para redução substancial da porosidade primária e permeabilidade, porém quando a principal porosidade (primária intergranular) está combinada com a secundária (dissolução de feldspatos ou bioclastos gerando porosidade móldica ou intragranular), pode melhorar consideravelmente a porosidade destes arenitos. As características permoporosas melhores estão localizadas na sequência II, porém os reservatórios mais extensos, e de boa correlação lateral estão na sequência I, isso de dá pelo fato da sequencia I ter sido depositada em um ambiente desconfinado, e a sequencia II estar numa região mais confinada. Além da sequencia I ter sofrido maior processo de diagênese que a sequencia II, resultado provavelmente da cimentação de carbonato abundante neste intervalo estratigráfico e autigênese de sílica nos grãos de quartzo. Porém a porosidade secundária gerada pela dissolução dos constituintes carbonáticos e feldspato, proporcionou um aumento desta porosidade. A análise de palinofácies e geoquímica orgânica revelaram um aumento de fitoclastos para o topo da formação, o que indica que estes ficam cada vez mais continentais e com influencia fluvial mais acentuada. A intensa concentração de matéria orgânica resultando em um COT alto corresponde as SIM, reconhecidas em perfil e sísmica, sendo estes os intervalos Geradores da Bacia. Os dados de geoquímica dos minerais pesados permitiu reconhecer a existência de duas proveniências diferentes para os arenitos da sequencia I e sequência II, com base na assembleia de minerais pesados e principalmente pelos índices de Ar e Titanio+Zr. Revela ainda que a sequência I corresponde a sedimentos de segundo ciclo, ou seja, a retrabalhamento de rochas sedimentares preexistentes, e a grande quantidade de granada em todo o poço revela que estas rochas sofreram pouco processo de intemperismo, com rápida erosão e deposição. A importância dos estudos sedimentológicos e estratigráficos em escala de campo é principalmente para a previsão das fácies e sistema deposicional e consequentemente do reservatório encontrado. Sob o ponto de vista da ocorrência de reservatórios, estas correlações são muito importantes, pois permitem realizar previsões destes depósitos, e das suas fácies. / Candeias Formation (PACK & ALMEIDA, 1945) is belonging to the Santo Amaro Group, and consisting in sandstones and shales of the Cretaceous period and corresponds to the first deposit of the Rift phase from Recôncavo Basin. The age of these sediments varies from Medium Berriasian to lower Valanginian (~ 143M.a.). With a time range from of 4.5 M.a. and an average thickness of 1000 m. Located in Rio da Serra stage and this sediments are interpreted as lacustrine shales and deposits of turbidity current. The Rift climax (PROSSER, 1993), or Candeias Formation had a very important role in the history of development of oil and gas extraction in the Recôncavo Basin, because the shales are the source rocks from this basin, and the sandstones are important hydrocarbon reservoirs. Understanding the sedimentological processes of this formation and their stratigraphic evolution, is still a challenge, because most of the information comes from indirect data (seismic, logs and oil production data), because the outcrops are scarce. Thus, studies of the cores are the main and direct data explored here. The study area is located in the structural compartment from Recôncavo Basin, called Borda Nordeste, and covers the Rio Itariri field, Fazenda Bálsamo field and Riacho da Barra field, which are aligned along the Salvador Fault in Patioba plateau. The depositional system is interpreted as lake with sandy deposits from turbidity current, and is mainly composed of shales, intercalation of shale and very fine sandstones, arkosean sandstones (FOLK, 1968) and sandstones hybrids (ZUFFA, 1980). The turbidite flows are interpreted as a result of destabilization of the lake platform in intense tectonic activity period. During the tectonic quiescence, most of shale sedimentation is assigned. These deposits can be correlated throughout the study area and the shale has a good response in electrical and seismic profiles. The sequence stratigraphy (SE) in rift basins could be used with the same criteria from those used in intracratonic basins or passive margin basins, but always thinking that this kind of basin are constantly affected by tectonics, as proposed by Prosser (1993) and Martins - Neto & Catuneanu (2010). The methodology is based on identify tendencies Transgressive - Regressive (TR) as proposed for Embry & Johannenessen (1992), from 3rd and 4th orders of sequence and, identify key stratigraphic surfaces then. Have been interpreted five stratigraphic surfaces (two of maximum flood surfaces (MFS) and three sequence limit (SL)) for the three depositional sequences, referred to as Sequence I Sequence II and Sequence III. These surfaces allowed correlating the sandy deposits, using the electric logs (Gamma, Resistivity and neutron-density). Have been described 1430m core, 54 thin sections, seismic interpretation of the stratigraphic surfaces of two 3D seismic, geochemical analysis of heavy minerals, palynofacies analysis and organic geochemistry, of six wells from the three fields in study. The stratigraphic and sedimentological analysis was based on the rock x core correlation, size description and interpretation from facies, and their associations. The sandstones facies are described as fine and coarse sandstones, parallel stratification and cross low angle stratification, often fluidization and massive sandstones happens. These facies are related to facies of turbidite channels or proximal turbidite lobes. Very fine sandstones with intercalation of shales and sandstones with current ripples and intense fluidization and gray shales laminated and massive are related to distal turbidite lobes or the basin bottom deposits. The petrographic analysis of sandstones showed that they are essentially arkosean, and had presence abundant of ostracod bioclasts, oncolites, and peloids to sequence I, and metamorphic rock fragments, and plutonic, and carbonate crystals, phosphates to the sequence II. Calcite, ferrous calcite, dolomite, ferrous dolomite are the main cements probably found due to the dissolution of carbonate components. But the most common diagenetical processes are silica authentic growth of quartz and albite. Many of these diagenetic processes can contribute to substantial reduction of primary porosity and permeability, but when the main porosity (primary intergranular) is combined with secondary porosity (dissolution of feldspars or bioclasts) can greatly improve the porosity of these sandstones. Best permoporosity features are located in the sequence II, but the most extensive reservoirs and good lateral correlation are in sequence I. It happens because the sequence I was placed in a large environment and the sequence II is a region more confined. Sequence I have suffered larger process of diagenesis that the sequence II, probably as result of the carbonate cementation in this stratigraphic interval and authigenic silica in quartz grains. But the secondary porosity generated by dissolution of carbonate constituents and feldspar, provided an increase of this porosity. The palynofacies and geochemical organic analysis showed an increase of phytoclasts to the top of the Candeias Formation, showing increasingly more severe continental and river influences. The intense concentration of organic matter is resulting in a high organic total carbon matches the MFS recognized in profile and seismic, which are the generators of the Recôncavo Basin. The geochemical data of heavy minerals allowed to recognize the existence of two different sources for the sandstones of sequence I and II, based on the assembly of heavy minerals and especially the rates of ARi and Titanium + Zr. It also reveals that the sequence I is formed by the second cycle sediments, like an erosion of pre-existing sedimentary rocks, and the large amount of garnet around the well shows that the rocks have no significant intemperism process, with quickly erosion and deposition. The importance of sedimentological and stratigraphic studies in field scale is mainly for the prediction of facies and depositional system of the reservoir. From the point of view of the occurrence of reservoirs, these correlations are very important, since these allow to forecast deposits and their facies.

O Alogrupo Guaritas, inserido na fase final de preenchimento da Bacia do Camaquã, é composto por arenitos castanho avermelhados de origem aluvial, lacustre, fluvial e eólica e é subdividido em duas sequências deposicionais nomeadas Pedra Pintada e Varzinha. Este estudo envolveu a realização de análises químicas em rocha total de vinte e seis amostras selecionadas do Alogrupo Guaritas e a consequente aplicação desses dados geoquímicos para fins de caracterização geoquímica, quimioestratigráfica e isotópica desta unidade, além da tentativa de restringir sua proveniência e intemperismo das suas rochas fontes. Os arenitos são composicionalmente uniformes e apresentam similaridade com a Crosta Continental Superior, indicando derivação de fontes mais diferenciadas. Entretanto, enquanto que os arenitos da Aloformação Pedra Pintada mostram-se depletados em praticamente todos os elementos terras raras, os arenitos da Aloformação Varzinha são depletados apenas em Sc, V, Sr, Y, Zr, Ni e enriquecidos em Ba e Rb em relação à Crosta Continental Superior. Os padrões de Elementos Terras Raras mostram enriquecimento em Elementos Terras Raras Leves, com razões La(N)/Sm(N) entre 3,7 e 6,1 e padrões mais suaves para Elementos Terras Raras Pesados, com razões Gd(N)/Yb(N) entre 1,0 e 2,7; acoplados a presença de anomalias de Eu moderadas. O Índice Químico de Alteração (CIA: 55-64) revelam protólitos pouco a moderadamente intemperizados para os arenitos estudados indicando predomínio de intemperismo físico de desagregação das rochas fonte. Considerações geoquímicas apresentadas pelas razões SiO2/Al2O3 e K2O/Na2O indicam a possibilidade de áreas fontes mais diferenciadas ou com maior retrabalhamento sedimentar na Aloformação Pedra Pintada, com aporte de fontes menos diferenciadas na Aloformação Varzinha. Uma indicação de proveniência compatível com áreas fonte dominadas predominantemente por rochas ígneas graníticas é sugerida para o Alogrupo Guaritas através das elevadas razões Th/Sc e Zr/Sc apresentadas pelas amostras e pela composição isotópica Nd-Sr utilizada como traçadora de proveniência. / The final phase of the Camaquã Basin sedimentary filling is represented by the Guaritas Alogroup. Reddish and brownish sandstones of alluvial, lacustrine, fluvial and eolic origin are the main litology, subdivided into two units named Pedra Pintada and Varzinha. This research presents twenty six chemical analyses of selected whole rock samples of the Guaritas Alogroup and the application of these data concerning the chemical characterization, chemical and isotopic stratigraphy and also indications of provenance and weathering of their source rocks. Guaritas sandstones are homogeneous in relation to the composition and very similar to the SCC (Superior Continental Crust) thus indicating derivation of more differentiated sources. Although the sandstones of the Pedra Pintada Aloformation are depleted in relation to the rare earth elements, the sandstones of the Varzinha Aloformation are only depleted in Sc, V, Sr, Y, Zr Ni and enriched in Ba and Rb (related to the SCC). The patterns of the Rare Earth Elements (REE) indicate enrichment in the Light Rare Earth Elements (LREE) with ratios La(N)/Sm(N) between 3,7 e 6,1 and slightly patterns to the Heavy Rare Earth Elements (HREE), with ratios Gd(N)/Yb(N) between 1,0 e 2,7; and a visible Eu anomaly. The index CIA calculated to the studied sandstones is around 55 to 64 and can be correlated with protolites slightly to moderately weathered, associated with a predominance of physical processes. Ratios SiO2/Al2O3 and K2O/Na2O are indicative of source areas more differentiated or with better reworking in the Pedra Pintada and arriving of detritus associated with source slightly enriched in the Varzinha Aloformation. High ratios Th/Sc and Zr/Sc and Nd-Sr isotopic compositions indicates a provenance of source areas dominated by granitic igneous rocks to the Guaritas Alogroup.

A Bacia de Campos está limitada pelo Alto de Vitória ao Norte e pelo Alto de Florianópolis ao sul, possuindo uma área de aproximadamente 100.000 km2. Sua seção rifte é composta pela porção basal a mediana do Grupo Lagoa Feia, e inclui a principal rocha geradora da bacia, reconhecidamente rica em matéria orgânica, sendo a maior produtora de hidrocarbonetos do Brasil, e rochas reservatório carbonáticas. O presente estudo foca sua análise no intervalo rifte, onde foi realizada uma interpretação e mapeamento sistemático de linhas sísmicas 2D em uma área chave da bacia. Esta análise é baseada em adaptações de modelos já existentes de evolução de bacias rifte, e nos conceitos de estratigrafia de sequências aplicados à sismoestratigrafia. Através da interpretação e mapeamento das seções sísmicas, foi possível elaborar um modelo evolutivo para a fase inicial da Bacia de Campos, com a elaboração de uma carta cronoestratigráfica e estabelecimento dos tratos de sistemas que distinguem as diferentes fases de evolução dos meio-grábens reconhecidos. O resultado foi a delimitação de três tratos de sistemas tectônicos, que permitiram uma compreensão detalhada da complexa evolução e desenvolvimento das calhas da Bacia de Campos durante a fase rifte. / The Campos Basin is limited northward by the Vitória High and southward by the Florianópolis High, with an area of approximately 100,000 km2. The rift section in the Campos Basin comprises the basal and median portions of the Lagoa Feia Group, and includes the main source rocks in the basin, which is known to be rich in organic matter and is the best hydrocarbon producer in Brazil, as well as carbonate reservoir rocks. The present study focuses its analysis on the rift section, where a systematic mapping and interpretation of 2D seismic lines in a key area of the basin was carried out. This analysis is based on adaptations of existing evolution models for rift basins, and the concepts of sequence stratigraphy applied to seismic stratigraphy. Through the interpretation and mapping of seismic sections, it was possible to propose an evolution model for the initial phase of the Campos Basin, with the construction of a chronostratigraphic chart and the establishment of systems tracts that distinguish different stages on the evolution of the recognized half-grabens. The result was the delimitation of three tectonic systems tracts that allowed the detailed understanding of the complex evolution and trough development of the Campos Basin during the rift phase.