Carnets de Geologie is an academic journal focused on the field of geology, dedicated to publishing high-quality research papers and review articles covering various aspects of geology, including geological history, petrology, and mineralogy. The journal aims to provide a platform for researchers to communicate and share the latest research findings.

《Carnets de Geologie》是一本专注于地质学领域的学术期刊，致力于发表高质量的研究论文和综述文章，涵盖地质学的各个方面，包括地质历史、岩石学、矿物学等。期刊旨在为研究人员提供一个交流和分享最新研究成果的平台。

Carnets de Geologie

Since the 1970's, aragonite neomorphism (conversion of aragonite to calcite with partial retention of original internal structure) has been attributed to thin diagenetic films, often in meteoric water. Pleistocene material from Enewetak, the Bahamas and eastern Yucatan show the transition from aragonite to calcite "in progress". Original aragonitic material includes coral, Halimeda, molluscs (especially gastropods) and ooids. In all three areas, aragonite commonly shows partial intrafabric dissolution. In many cases, calcite crystals grew over that highly microporous aragonite to create calcite with partial retention of the original depositional fabric, creating neomorphosed (calcitized) aragonite. Geochemical data support this scenario. Carbon and oxygen isotopic compositions of the neomorphic calcites are similar to sparry meteoric calcite cements indicating crystals precipitated from similar waters as the cements. Stable carbon isotopes and Mg concentrations in neomorphic calcites are different from their aragonitic precursors and are not consistent with the thin-film model, which assumes a semi-closed system. Approximately 40 of the 95 Pleistocene Enewetak samples have aragonite with intrafabric dissolution adjacent to calcitized (neomorphic) aragonite. Neomorphosed (calcitized) aragonite was not observed immediately adjacent to unaltered aragonite (i.e., separated by what would have been a thin film) in any Enewetak samples. This supports aragonite neomorphism by a two-stage process (intrafabric dissolution followed by calcite precipitation) rather than by thin films. Variations in concentration of inclusions in neomorphosed aragonite are similar to variations of relict material in aragonite with partial intrafabric dissolution and span a continuum from abundant aragonitic inclusions in neomorphic spar to inclusion-free calcite cement.

Arthur Saller

Carnets de géologie (Notebooks on geology)

Aragonite neomorphism via intrafabric dissolution and calcite precipitation, not thin films

文石通过内部结构溶解和方解石沉淀的再结晶作用，而非薄膜作用

Earlier misidentifications of ammonites from Busot (SE Spain) led to two incorrect hypotheses regarding calpionellids, which are today attributed to the Calpionellopsis Zone (D) of the upper Berriasian. The first hypothesis suggested that some calpionellid species survived into Hauterivian times, while the second hypothesis proposed that these calpionellids were reworked into Hauterivian strata. However, the revision of the ammonitic material collected in 1993-1994, along with the study of new material collected in 2024, suggests a late Berriasian age, as the ammonite assemblages likely correspond to the Fauriella boissieri and Tirnovella alpillensis Standard Ammonites zones. Nannofossil assemblages and the presence of Octahedronoides tethysianus further support this dating. This reassessment calls for a reexamination of claims regarding the occurrence of calpionellids in strata younger than the Valanginian in the literature.

Bruno R.C. Granier

José Miguel Andreu Rodes

Mohamed Benzaggagh

Joachim Blau

Éric Böker

Antonio Estévez Rubio

Bruno Ferré

Bernard C. Lambert

Agostino Marini

Eric Monteil

Stéphane Reboulet

Aurélien Virgone

Rectifying a substantial biostratigraphic error: There are no Hauterivian calpionellids in Busot (Alicante, Spain)

纠正一个重大的生物地层学错误：西班牙阿利坎特布索特地区不存在豪特里维阶钙球虫

The Ankara region (central Türkiye) comprises a part of the Sakarya Terrane and the accretionary remnants inherited from the Izmir-Ankara-Erzincan (IAE) branch of the Northern Neotethys. The Sakarya Terrane is characterized by a pre-Jurassic basement overlain by Jurassic-Cretaceous sedimentary assemblages, collectively known as the Sakarya Continent Cover. In this study, we aim to elucidate the Jurassic-Cretaceous evolution of the Sakarya Terrane through detailed geological mapping in the regions of Haymana, Yakacık, north of Alagöz and west of Memlik, located to the west and southwest of Ankara city, central Türkiye. By analyzing radiolarian and planktonic foraminiferal assemblages, we provide precise dating for three key lithological units: the Soğukçam Limestone Group (part of the Sakarya Continent Cover), the Elmadağ Olistostrome, and the Unaz Formation (from the overlying units). The oldest rock unit exposed in the Haymana region, south of Ankara city, is the Bilecik Limestone Group, consisting of Tithonian to lower Berriasian platform carbonates. A drowning unconformity separates the Bilecik Limestone Group from the overlying middle Berriasian-uppermost Albian Soğukçam Limestone Group, which has been elevated to "group" status in this study. The Soğukçam Limestone Group is subdivided into two formations -the Seyran Formation and the Akkaya Formation- separated by a disconformity surface. The Seyran Formation, at the base, consists of middle Berriasian limestone breccia in a micritic pelagic matrix, and upper Berriasian-lower Aptian micritic clayey, cherty pelagic limestones with abundant and diverse radiolarians in its upper part. The disconformity between the Seyran and Akkaya formations represents a small depositional gap corresponding to the middle to late Aptian. The lower part of the Akkaya Formation contains lower to middle Albian debris flow deposits while the upper part is composed of clayey pelagic limestones rich in glauconite and planktonic foraminifers, dating to the latest Albian. Overall, the Akkaya Formation is roughly assigned to the Albian stage. The Akkaya Formation within the Soğukçam Limestone Group is unconformably overlain by the Coniacian Elmadağ Olistostrome, which also covers the ophiolitic mélange of the IAE Ocean (containing Turonian radiolarian blocks) to the west of the Memlik region. The basal part of the Elmadağ Olistostrome is characterized by an unstratified, loosely-packed, gray- to beige-colored carbonate matrix, while its upper part features stratified, highly-sheared gray- to beige-colored clayey carbonate/marl matrix with embedded carbonate blocks. These blocks, dated through radiolarians and planktonic foraminifers, range from the early Callovian to Coniacian. These blocks, observed in the Haymana, north of Alagöz, and Yakacık regions, primarily originated from the underlying Soğukçam Limestone Group. The Elmadağ Olistostrome was likely deposited in a peripheral foreland flysch basin, resembling trench-like settings, in front of the southward-moving nappes derived from the Neotethys Intra-Pontide Ocean. This olistostrome is unconformably overlain by the Unaz Formation, which represents the lowermost unit of the fore-arc basin within the Galatean Arc and is present in all four studied regions. The Unaz Formation mainly consists of thin-bedded, gray- to red-colored clayey limestones with abundant planktonic foraminifers, along with red- to pink-colored marls. In the northern part (west of Memlik), the Unaz Formation also includes basal clastics. Based on its characteristic planktonic foraminiferal assemblages, the formation is dated to the late Santonian and correlates well with the type locality in the Pontides, northwestern Türkiye. Following this sequence, a brief period of continental arc magmatism occurred in the Santonian-Campanian, accompanied by the deposition of fore-arc sediments (the Haymana Formation, consisting of clastics) during the Campanian-Maastrichtian interval. In this study, an abundant, well-preserved, and diverse radiolarian microfauna (146 taxa, including fourteen new species and four new subspecies from the early Hauterivian to early Aptian, Early Cretaceous) were recovered from the clayey micritic limestones of the Seyran Formation in the Soğukçam Limestone Group. The vertical distributions of these radiolarians and their age correlations with previous studies are also documented.

U. Kağan Tekin

Bilal Sarı

Alaettin Tuncer

Kaan Sayit

Cengiz Okuyucu

Çağrı Güzgün

Radiolarian and planktonic foraminiferal biochronology of the Soğukçam Limestone Group, Elmadağ Olistostrome, and Unaz Formation (Ankara region, central Türkiye): Insights into the Cretaceous evolution of the Sakarya Continent and overlying units

Soğukçam石灰岩群、Elmadağ滑塌岩和Unaz组（土耳其安卡拉地区中部）的放射虫和浮游有孔虫生物年代学：揭示萨卡里亚大陆及其上覆地层的白垩纪演化

The Coskinolinidae are a family of Middle Jurassic to Paleogene, typically orbitoliniform, Larger Benthic Foraminifera (LBF) characterized by a pseudokeriothecal wall structure. The type genus, Coskinolina Stache, 1875, lacks an exoskeleton (i.e., beams, rafters), resulting in an undivided marginal chamber zone. However, other taxa within the family, such as the Upper Cretaceous Lepinoconus Cruz-Abad et al., 2017, or the Paleogene Coleiconus Hottinger &amp; Drobne, 1980, are genera with vertical partitions (beams) that subdivide the marginal chamber zone. In the currently accepted classification of agglutinated benthic foraminifera, the nature of the exoskeleton is a criterion for distinction at subfamily level, e.g., Cyclamminidae Marie, 1941. Thus, here, the presence or absence of an exoskeleton in the marginal chamber lumen is treated as a criterion at the subfamily level within the classification of the Coskinolinidae, leading to a division into two subfamilies: the Coskinolininae Moullade, 1965 (lacking an exoskeleton), and the newly proposed Coleiconinae subfam. nov. (with an exoskeleton of vertical partitions), as exemplified by Coleiconus Hottinger &amp; Drobne, 1980.

Felix Schlagintweit

A new subfamily classification of the Coskinolinidae Moullade, 1965, Middle Jurassic-Paleogene Larger Benthic Foraminifera

中新世-古近纪大型底栖有孔虫Coskinolinidae Moullade, 1965新亚科分类

A new paracomatulid crinoid, Tiburtocrinus toarcensis gen. et sp. nov., is described from the Lower Jurassic of Tivoli (central Apennines, Italy). This type of stemless crinoids has never previously been recorded in Italy, and this report bridges a significant gap. Morphofunctional analysis of the radial facets suggests that Tiburtocrinus toarcensis gen. et sp. nov. may have been a crawling paracomatulid, very different from other paracomatulids that probably swam.

Riccardo Manni

Rolando Di Nardo

A possible crawling paracomatulid crinoid from the Lower Jurassic of central Italy

意大利中部下侏罗纪可能的爬行类副花鳞海百合

In the literature, numerous accounts exist of microspheres scattered in the pelagic environments of the Tethys realm at the Jurassic-Cretaceous transition. These microspheres are commonly associated with genera such as Cadosina, Colomisphaera, or Stomiosphaera, and attributed to calcareous dinocysts. On the other hand, there are few records of the microsphere, initially described as Cadosina minuta BORZA, 1980, which are arranged in small clusters, likely comprising six cells. This distinctive grouping and its architecture preclude attribution to the calcareous dinocysts. A new genus and a new species (as Octahedronoides tethysianus n.gen., n.sp.) are introduced to define these clusters of leiospheres, which are here reascribed to the acritarchs.

Octahedronoides tethysianus n.gen., n.sp., enigmatic clusters of microspheres at the Jurassic-Cretaceous transition

新属新种泰提斯八面体球群（Octahedronoides tethysianus n.gen., n.sp.）：侏罗纪-白垩纪过渡期的神秘微球团簇

Abbreviation
Journal Impact	1.35
Quartiles(Global)	PALEONTOLOGY(Q2)

ISSN	1634-0744, 1765-2553, 2108-5196
h-index	20

Publication Information	Publisher: Carnets de Geologie，Publishing cycle: Irregular，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2007，Proportion of original research papers: 100.00%，Self Citation Rate:6.70%， Gold OA Rate: 0.00%
Average review cycle	网友分享经验：>12周，或约稿
Average recruitment ratio	网友分享经验：容易

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Aragonite neomorphism via intrafabric dissolution and calcite precipitation, not thin films

Rectifying a substantial biostratigraphic error: There are no Hauterivian calpionellids in Busot (Alicante, Spain)

Radiolarian and planktonic foraminiferal biochronology of the Soğukçam Limestone Group, Elmadağ Olistostrome, and Unaz Formation (Ankara region, central Türkiye): Insights into the Cretaceous evolution of the Sakarya Continent and overlying units

A new subfamily classification of the Coskinolinidae Moullade, 1965, Middle Jurassic-Paleogene Larger Benthic Foraminifera

A possible crawling paracomatulid crinoid from the Lower Jurassic of central Italy

Rectifying a substantial biostratigraphic error: There are no Hauterivian calpionellids in Busot (Alicante, Spain)

Aragonite neomorphism via intrafabric dissolution and calcite precipitation, not thin films

Radiolarian and planktonic foraminiferal biochronology of the Soğukçam Limestone Group, Elmadağ Olistostrome, and Unaz Formation (Ankara region, central Türkiye): Insights into the Cretaceous evolution of the Sakarya Continent and overlying units

A new subfamily classification of the Coskinolinidae Moullade, 1965, Middle Jurassic-Paleogene Larger Benthic Foraminifera

Octahedronoides tethysianus n.gen., n.sp., enigmatic clusters of microspheres at the Jurassic-Cretaceous transition